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Pulmonary

Last 50 Pulmonary Postings

(Click on title to be directed to posting, most recent listed first, CME offerings in Bold)

July 2018 Pulmonary Case of the Month
Phrenic Nerve Injury Post Catheter Ablation for Atrial Fibrillation
Evaluating a Scoring System for Predicting Thirty-Day Hospital 
   Readmissions for Chronic Obstructive Pulmonary Disease Exacerbation
Intralobar Bronchopulmonary Sequestration: A Case and Brief Review
Sharpening Occam’s Razor – A Diagnostic Dilemma
June 2018 Pulmonary Case of the Month
May 2018 Pulmonary Case of the Month
Tobacco Company Campaign Contributions and Congressional Support of
   Tobacco Legislation
Social Media: A Novel Engagement Tool for Miners in Rural New Mexico
April 2018 Pulmonary Case of the Month
First-Line Therapy for Non-Small Cell Lung Cancer Including Targeted
   Therapy: A Brief Review
March 2018 Pulmonary Case of the Month
February 2018 Pulmonary Case of the Month
January 2018 Pulmonary Case of the Month
Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia in a Patient
   with Multiple Pulmonary Nodules: Case Report and Literature Review
Necrotizing Pneumonia: Diagnosis and Treatment Options
December 2017 Pulmonary Case of the Month
First Report of Splenic Abscesses Due to Coccidioidomycosis
November 2017 Pulmonary Case of the Month
Treatment of Lymphoma and Cardiac Monitoring during Pregnancy
October 2017 Pulmonary Case of the Month
September 2017 Pulmonary Case of the Month
August 2017 Pulmonary Case of the Month
Tip of the Iceberg: 18F-FDG PET/CT Diagnoses Extensively Disseminated 
   Coccidioidomycosis with Cutaneous Lesions
July 2017 Pulmonary Case of the Month
Correlation between the Severity of Chronic Inflammatory Respiratory
   Disorders and the Frequency of Venous Thromboembolism: Meta-Analysis
June 2017 Pulmonary Case of the Month
May 2017 Pulmonary Case of the Month
April 2017 Pulmonary Case of the Month
March 2017 Pulmonary Case of the Month
February 2017 Pulmonary Case of the Month
January 2017 Pulmonary Case of the Month
December 2016 Pulmonary Case of the Month
Inhaler Device Preferences in Older Adults with Chronic Lung Disease
November 2016 Pulmonary Case of the Month
Tobacco Company Campaign Contributions and Congressional Support
   of the Cigar Bill
October 2016 Pulmonary Case of the Month
September 2016 Pulmonary Case of the Month
August 2016 Pulmonary Case of the Month
July 2016 Pulmonary Case of the Month
June 2016 Pulmonary Case of the Month
May 2016 Pulmonary Case of the Month
April 2016 Pulmonary Case of the Month
Pulmonary Embolism and Pulmonary Hypertension in the Setting of
   Negative Computed Tomography
March 2016 Pulmonary Case of the Month
February 2016 Pulmonary Case of the Month
January 2016 Pulmonary Case of the Month

 

For complete pulmonary listings click here.

The Southwest Journal of Pulmonary and Critical Care publishes articles broadly related to pulmonary medicine including thoracic surgery, transplantation, airways disease, pediatric pulmonology, anesthesiolgy, pharmacology, nursing  and more. Manuscripts may be either basic or clinical original investigations or review articles. Potential authors of review articles are encouraged to contact the editors before submission, however, unsolicited review articles will be considered.

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Sunday
Jul012018

July 2018 Pulmonary Case of the Month

Anjuli M. Brighton, MB, BCh, BAO

Mayo Clinic Arizona

Scottsdale, AZ USA

 

Pulmonary Case of the Month CME Information

Completion of an evaluation form is required to receive credit and a link is provided on the last page of the activity. 

0.25 AMA PRA Category 1 Credit(s)™

Estimated time to complete this activity: 0.25 hours

Lead Author(s): Anjuli M. Brighton, MB. All Faculty, CME Planning Committee Members, and the CME Office Reviewers have disclosed that they do not have any relevant financial relationships with commercial interests that would constitute a conflict of interest concerning this CME activity.

Learning Objectives: As a result of completing this activity, participants will be better able to:

  1. Interpret and identify clinical practices supported by the highest quality available evidence.
  2. Establish the optimal evaluation leading to a correct diagnosis for patients with pulmonary, critical care and sleep disorders.
  3. Translate the most current clinical information into the delivery of high quality care for patients.
  4. Integrate new treatment options for patients with pulmonary, critical care and sleep related disorders.

Learning Format: Case-based, interactive online course, including mandatory assessment questions (number of questions varies by case). Please also read the Technical Requirements.

CME Sponsor: University of Arizona College of Medicine at Banner University Medical Center Tucson

Current Approval Period: January 1, 2017-December 31, 2018

Financial Support Received: None

 

History of Present Illness

An 81-year-old gentleman was admitted for syncope. He had felt unwell for one month. His recent illness started with the “flu”. He had lingering productive cough, low volume hemoptysis and felt very fatigued. After a coughing episode he apparently lost consciousness and was taken to the emergency department.

Past Medical History, Social History and Family History

He has a past medical history of hypertension, glaucoma, diverticulosis and COPD. He was taking only antihypertensives including a diuretic. He has a 30 pack-year history of smoking but quit 10 years ago.

Physical Examination

  • Normotensive
  • Tachypneic
  • SpO2 96% on 2L NC
  • Afebrile
  • Diffuse wheezing, diminished at L base
  • Irregularly irregular heart rate

Which of the following are indicated at this time? (Click on the correct answer to be directed to the second of six pages)

  1. Chest x-ray
  2. Complete blood count (CBC)
  3. Electrocardiogram (EKG)
  4. 1 and 3
  5. All of the above

Cite as: Brighton AM. July 2018 pulmonary case of the month. Southwest J Pulm Crit Care. 2018;17(1):1-6. doi: https://doi.org/10.13175/swjpcc073-18 PDF 

Thursday
Jun282018

Phrenic Nerve Injury Post Catheter Ablation for Atrial Fibrillation

Payal Sen, MD1 

Uddalak Majumdar, MD2 

Ali Imran Saeed, MD1

1University of New Mexico

Albuquerque, NM USA

2Cleveland Clinic Foundation

Cleveland, Ohio USA

 

Abstract

Objective: Phrenic nerve injury (PNI) is a complication of catheter ablation treatment of atrial fibrillation (AF). This condition can mimic that of comorbid conditions like congestive heart failure (CHF) and chronic obstructive pulmonary disease (COPD).

Case details: A 77-year-old woman with past medical history of heart failure with preserved ejection fraction and mild COPD, presented with dyspnea for 8 days. One week ago, she had undergone radiofrequency catheter ablation for persistent symptomatic AF. After the ablation, she reported dyspnea during PCP and pulmonary office visits and was given increasing doses of diuretics and inhalers since her symptoms were attributed to acute exacerbation of heart failure in the setting of COPD. However, a chest x-ray showed elevation of the right hemidiaphragm, and she had a positive sniff test. She was thus diagnosed with right sided phrenic nerve palsy and was treated with oxygen therapy.

Discussion: Phrenic nerve injury can be diagnosed via clinical exam, chest x-ray and sniff test. A sniff Test which shows paradoxical elevation of the paralyzed hemidiaphragm with inspiration, compared with the rapid descent of the normal hemidiaphragm.

Conclusion: Phrenic nerve palsy is a complication which occurs in 6.6 percent of cases, post catheter ablation procedure for atrial fibrillation. This condition can mimic pulmonary conditions like acute exacerbation of COPD. Not keeping this complication in mind can lead to biased diagnostic reasoning and missed or delayed diagnosis.

Introduction

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia (1). In the past decade, catheter ablation of AF has evolved from an investigational procedure to a frequent therapeutic one (2). Phrenic nerve injury (PNI) is a complication of ablation that pulmonologists should be familiar with, due to its increasing incidence (3). This condition can mimic that of comorbid conditions like congestive heart failure (CHF) and chronic obstructive pulmonary disease (COPD). Hence it is important to develop clinical suspicion of phrenic nerve injury, and correlate onset of symptoms to the ablation, to prevent missed or delayed diagnosis, and to avoid falling prey to availability bias.

Case Report

History of Present Illness: A 77-year-old Caucasian woman with past medical history of heart failure with preserved ejection fraction and mild COPD (GOLD Stage 1), presented with dyspnea and right sided chest discomfort for 7 days. One week ago, she had undergone radiofrequency catheter ablation at the University of New Mexico, for persistent symptomatic AF. After the ablation, she reported dyspnea during PCP and pulmonary office visits, which was attributed to acute exacerbation of heart failure in the setting of COPD. She had been given increasing doses of diuretics which did not relieve her symptoms. A short course of azithromycin and prednisone had also been prescribed for possible acute exacerbation of COPD, but her symptoms had remained unchanged. Review of systems were negative for fever, chills, cough, leg swelling and hemoptysis. She led an active lifestyle, did not require oxygen, and had quit smoking 10 years ago. There was no history of cardio- respiratory diseases in the family.

Physical Examination:

Vitals: Temperature: 97.1°F, Pulse – 88/minute, RR 22/minute, BP –

140/70 mm Hg., Spo2 – 90% in Room air (baseline >95 percent).

She appeared to be in mild distress. Baseline dry weight had not increased. She had no clinical signs of heart failure- no peripheral edema, no JVD, no S3, no bibasilar crackles. There were decreased breath sounds in the base of the right lung but no rales or rhonchi. No significant wheezing was heard in any of the lobes of the lungs.

No clubbing or cyanosis was noted. The rest of the exam was unremarkable with a normal abdominal, and skin exam. There was no lymphadenopathy.

Laboratory: White blood cell count 10,000/mm3, hemoglobin 11 g/dL, with normal electrolytes, liver function tests and negative troponins. Arterial blood gases on room air showed a pH 7.38, paO2 of 62 mm Hg, pCO2 41 mm Hg and HCO3- 25.

EKG: negative for signs of ischemia.

Radiography: Chest radiography showed an elevated right diaphragm (Figure 1).

Figure 1. A: PA chest radiograph and B: 3 weeks earlier for comparison.

Sniff test performed under fluoroscopy showed paradoxical elevation of the right hemidiaphragm with inspiration, compared with rapid descent of the left hemidiaphragm, confirming right hemidiaphragm paralysis (Figure 2).

Figure 2. Static images from sniff test under fluoroscopy: A: pre-sniff. B: post-sniff. When the patient sniffs in, the left hemidiaphragm moves downwards but right hemidiaphragm does not (actually moves upwards very slightly).

After obtaining proper imaging, the patient was finally diagnosed with right-sided diaphragmatic paralysis due to phrenic nerve injury from the catheter ablation procedure done to treat AF. She was discharged with home oxygen and her symptoms have resolved. Follow up clinic visits revealed complete resolution of symptoms.

Discussion

Ectopic discharges from pulmonary veins are an important cause of atrial fibrillation, the most common sustained cardiac arrhythmia (1). Calkins et al. (4) carried out a study in 2009, where they showed statistically significant improvement in symptoms and quality of life in patients receiving ablation therapy versus those patients who received anti arrhythmic drugs (4). Traditionally, isolating the pulmonary vein by point-by-point radiofrequency catheter ablation was the cornerstone of catheter ablation strategies for the treatment of atrial fibrillation (2). However, this procedure had various complications such as thromboembolism, cardiac perforation, injury to adjacent structures and pulmonary vein stenosis (5). Hence, with the hope of finding an effective alternative approach with less complications, cryothermal ablation was started. This particular procedure involves electrically isolating pulmonary veins, by creating circumferential lesions by means of a cryoballoon catheter (6). Nonetheless, in both techniques, the most common complication is hemi‐diaphragmatic paralysis, due to phrenic nerve injury. This especially occurs whilst trying to isolate the right superior pulmonary vein (3). The approximate incidence of this complication is close to 3–11% (7). It is thought that the phrenic nerve gets injured due to the close anatomic relationship of the phrenic nerve to the heart (Figure 3).

Figure 3. Thoracic CT scan showing anatomical relationships (yellow star is the right phrenic nerve).

Both the right and the left phrenic nerves can get damaged - the right phrenic nerve is specifically at risk when ablations are carried out in the superior caval vein and the right superior pulmonary vein, and the left phrenic nerve is liable to damage during lead implantation into the great cardiac and left obtuse marginal veins (8). In our patient, the right phrenic nerve, which runs along the lateral surfaces of the superior vena cava and right atrium, was injured by energy delivered to the adjacent area during ablation.

In 2005 Bunch et al. (9) investigated the specific mechanism of phrenic nerve injury. Their study revealed that the phrenic nerve tended to retain heat after ablation. This phenomenon resulted in higher local temperatures with subsequent energy deliveries, causing early transient injury. Andrade et al. (3) in 2014, were the first to define this phrenic nerve injury histopathologically. According to them, phrenic nerve injury consisted of Wallerian degeneration characterized by loss of large myelinated axons with variable degrees of endoneural edema, vacuolated macrophages, myelin ovoids, and myelin digestion chambers (6).

Phrenic nerve injury can be diagnosed on clinical exam, and via a chest X-ray. Thereafter one can confirm the diagnosis with the sniff test or phrenic nerve stimulation/diaphragm electromyography. An upright chest x-ray will reveal an elevated diaphragm on the affected side. This test is sensitive, but not specific for the diagnosis of unilateral diaphragmatic paralysis (10). Another frequently done test is the sniff test which shows paradoxical elevation of the paralyzed hemidiaphragm with inspiration, compared with the rapid descent of the normal hemidiaphragm (11). The sniff test has more than 90 percent sensitivity (11). In 2014, Linhart et al. (12) performed studies to show that fluoroscopic assessment of diaphragm movement during spontaneous breathing was more sensitive for the diagnosis of phrenic nerve injury as compared to SVC pacing (12). It has also been seen that EMG‐guided approach results in less damage to the phrenic nerve and a significant reduction in hemi‐diaphragmatic paralysis as compared to current methods of abdominal palpation and fluoroscopy (13).

In unilateral diaphragmatic paralysis, patients are usually asymptomatic, have good prognosis and do not always need treatment. This is specifically true in the absence of underlying lung disease (14). Another procedure often done is the surgical plication of the affected hemidiaphragm (15). In bilateral diaphragm paralysis, ventilatory failure often occurs and these patients may require continuous positive airway pressure or mechanical ventilation and tracheostomy (16). According to Kauffman (17) in 2014, functional restoration of the paralyzed diaphragm should also be part of the standard treatment algorithm in managing symptomatic patients.

Conclusion

Phrenic nerve palsy is a complication which occurs in about 6 percent of cases post catheter ablation procedure for atrial fibrillation. This condition can mimic pulmonary conditions like acute exacerbation of COPD. It is important to develop clinical suspicion and correlate onset of symptoms to the ablation. Not keeping this complication in mind can lead to biased diagnostic reasoning and missed or delayed diagnosis.

References

  1. Yamazaki M, Filgueiras-Rama D, Berenfeld O, Kalifa J. Ectopic and reentrant activation patterns in the posterior left atrium during stretch-related atrial fibrillation. Prog Biophys Mol Biol. 2012 Oct-Nov;110(2-3):269-77. [CrossRef] [PubMed]
  2. Pedrote A, Acosta J, Jauregui-Garrido B, Frutos-Lopez M, Arana-Rueda E. Paroxysmal atrial fibrillation ablation: Achieving permanent pulmonary vein isolation by point-by-point radiofrequency lesions. World J Cardiol. 2017 Mar 26;9(3):230-40. [CrossRef] [PubMed]
  3. Andrade JG, Dubuc M, Ferreira J, Guerra PG, Landry E, Coulombe N, et al. Histopathology of cryoballoon ablation-induced phrenic nerve injury. J Cardiovasc Electrophysiol. 2014 Feb;25(2):187-94. [CrossRef] [PubMed]
  4. Calkins H, Reynolds MR, Spector P, et al.  Treatment of atrial fibrillation with antiarrhythmic drugs or radiofrequency ablation: two systematic literature reviews and metaanalyses. Circ Arrhythm Electrophysiol. 2009 Aug;2(4):349-61. [CrossRef] [PubMed]
  5. Sarabanda AV, Bunch TJ, Johnson SB, et al. Efficacy and safety of circumferential pulmonary vein isolation using a novel cryothermal balloon ablation system. J Am Coll Cardiol. 2005 Nov 15;46(10):1902-12. [CrossRef] [PubMed]
  6. Andrade JG, Khairy P, Guerra PG, et al. Efficacy and safety of cryoballoon ablation for atrial fibrillation: a systematic review of published studies. Heart Rhythm. 2011 Sep;8(9):1444-51. [CrossRef] [PubMed]
  7. Omran H, Gutleben KJ, Molatta S, et al. Second generation cryoballoon ablation for persistent atrial fibrillation: an updated meta-analysis. Clin Res Cardiol. 2018 Feb;107(2):182-92. [CrossRef] [PubMed]
  8. Sanchez-Quintana D, Cabrera JA, Climent V, Farre J, Weiglein A, Ho SY. How close are the phrenic nerves to cardiac structures? Implications for cardiac interventionalists. J Cardiovasc Electrophysiol. 2005 Mar;16(3):309-13. [CrossRef] [PubMed]
  9. Bunch TJ, Bruce GK, Mahapatra S, et al. Mechanisms of phrenic nerve injury during radiofrequency ablation at the pulmonary vein orifice. J Cardiovasc Electrophysiol. 2005 Dec;16(12):1318-25. [CrossRef] [PubMed]
  10. Chetta A, Rehman AK, Moxham J, Carr DH, Polkey MI. Chest radiography cannot predict diaphragm function. Respir Med. 2005 Jan;99(1):39-44. [CrossRef] [PubMed]
  11. Alexander C. Diaphragm movements and the diagnosis of diaphragmatic paralysis. Clin Radiol. 1966 Jan;17(1):79-83. [CrossRef] [PubMed]
  12. Linhart M, Nielson A, Andrie RP, et al. Fluoroscopy of spontaneous breathing is more sensitive than phrenic nerve stimulation for detection of right phrenic nerve injury during cryoballoon ablation of atrial fibrillation. J Cardiovasc Electrophysiol. 2014 Aug;25(8):859-65. [CrossRef] [PubMed]
  13. Miyazaki S, Ichihara N, Nakamura H, et al. Prospective evaluation of electromyography-guided phrenic nerve monitoring during superior vena cava isolation to anticipate phrenic nerve injury. J Cardiovasc Electrophysiol. 2016 Apr;27(4):390-5. [CrossRef] [PubMed]
  14. Piehler JM, Pairolero PC, Gracey DR, Bernatz PE. Unexplained diaphragmatic paralysis: a harbinger of malignant disease? J Thorac Cardiovasc Surg. 1982 Dec;84(6):861-4. [PubMed]
  15. Kuniyoshi Y, Yamashiro S, Miyagi K, Uezu T, Arakaki K, Koja K. Diaphragmatic plication in adult patients with diaphragm paralysis after cardiac surgery. Ann Thorac Cardiovasc Surg. 2004 Jun;10(3):160-6. [PubMed]
  16. Davis J, Goldman M, Loh L, Casson M. Diaphragm function and alveolar hypoventilation. Q J Med. 1976 Jan;45(177):87-100. [PubMed]
  17. Kaufman MR, Elkwood AI, Colicchio AR, et al. Functional restoration of diaphragmatic paralysis: an evaluation of phrenic nerve reconstruction. Ann Thorac Surg. 2014 Jan;97(1):260-6. [CrossRef]

Cite as: Sen P, Majumdar U, Saeed AI. Phrenic nerve injury post catheter ablation for atrial fibrillation. Southwest J Pulm Crit Care. 2018;16(6):362-7. doi: https://doi.org/10.13175/swjpcc070-18 PDF 

Tuesday
Jun262018

Evaluating a Scoring System for Predicting Thirty-Day Hospital Readmissions for Chronic Obstructive Pulmonary Disease Exacerbation

Vanessa Yap, MD1

Diahann Wilcox, APRN, DNP1

Richard ZuWallack, MD2

Debapriya Datta, MD1

 

1Division of Pulmonary & Critical Care Medicine

University of CT Health Center

Farmington, CT USA

2Division of Pulmonary & Critical Care Medicine

St Francis Hospital & Medical Center

Hartford, CT USA

 

Abstract

Introduction: Chronic obstructive pulmonary disease (COPD) results in 700,000 hospitalizations annually in the United States and 12-25% of patients are readmitted within 30 days of hospital discharge. A simple scoring system to risk-stratify these patients would be useful in allocating scarce resources.

Objective: The objectives of this study were to identify possible predictor variables to develop a clinically-useful instrument that can predict 30-day hospital readmissions in COPD patients.

Methods: Fifty patients hospitalized for a COPD exacerbation at two hospitals over a one-month period were studied prospectively. Demographics, disease severity, symptoms, functional status, psychological, and co-morbidity variables were assessed during the hospitalization. Patients were contacted telephonically thirty days post-discharge to determine readmission. Baseline variables were tested as predictors of 30-day readmissions.

Results: Mean age was 71 ± 11 years; 77% were female, 60% had Medical Research Council dyspnea 3 or 4; mean FEV1 was 41 ± 13% of predicted. Mean length of stay was 4.3 ± 3.2 days. Sixty percent had ≥ 1 clinical exacerbations in the preceding year, 52% had been hospitalized at least once for a respiratory exacerbation; 61% had been hospitalized at least once; 26% were on chronic prednisone. Thirty-day readmission rate was 24%. Three variables were found to be predictive of hospitalization: Clinical exacerbations in the previous year, chronic prednisone use, and functional limitation from dyspnea predictive of hospitalization.

Conclusions: Exacerbations in the previous year, chronic prednisone use, and functional limitation from dyspnea hold promise in a scoring system used to predict 30-day re-hospitalization and could be quickly assessed from a review of hospital record or a brief interview.

Introduction

Chronic obstructive pulmonary disease (COPD) is a common disease and is a leading cause of mortality in the United States (1). Much of the cost of care in COPD involves expenses related to exacerbations of this disease (2). Hospital readmissions within 30 days in COPD are frequent – with approximately 9-20% being readmitted (3-6). Hospitals will soon be financially penalized for 30-day readmissions for COPD. Risk stratification would be useful in directing scarce medical resources toward those patients most likely to be readmitted. The objectives of our study were: 1. To evaluate predictors of 30-day hospital readmission in patients hospitalized for an exacerbation of COPD and 2. To develop a simple, clinically-useful instrument that can predict any-cause 30-day hospital readmissions in COPD patients. To this end, the final tool would have to be brief (taking < 10 minutes to complete), convenient to use and have sufficient predictive power to predict hospital readmission.

Methods

This was a prospective study, performed by means of review of medical records and patient interview. Approval for the study was obtained from the IRBs of both participating institutions. There was no extramural funding for the study.

Fifty patients admitted with acute exacerbation of COPD over a 3-month period were studied. The primary inclusion criterion was a clinical diagnosis of a COPD exacerbation resulting in hospitalization. Patients with primary diagnosis of acute exacerbation of COPD exacerbation but with concomitant diagnosis of heart failure or pneumonia were included in the analysis. Inability to effectively communicate with the investigator, including language barrier or cognitive defect was the exclusion criterion.

The hospitalist physician, after receiving verbal approval from the hospitalized COPD patient of his/her potential willingness to see an investigator for a clinical research study, was then seen by an investigator, and informed consent was obtained. Following this, an interview and review of medical records were performed to obtain demographic and disease variables. Variables (from interview or record review) included: demographics (age, gender), disease severity, all-cause and respiratory-related hospitalizations over the preceding year, outpatient treated respiratory exacerbations over the preceding year, functional status, co-morbidities, psychological status, treatment upon admission. COPD assessment test (CAT) (7), Charlson Comorbidity Index (CCI) (8) and LACE Index (9) were determined for all patients. We also measured the treating physician’s “gut feeling” of the likelihood of a 30-day readmission. The treating physician was blinded as to the specific variables we measured. (All variables tested are detailed in Appendix. Post-bronchodilator forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and FEV1/FVC ratio were obtained from previous spirometry (within 3 years), if available. The patients without a historical spirometric diagnosis of COPD had spirometry before hospital discharge. Consented patients were then contacted at 30-days to determine whether they had readmissions and if so, for what cause.

General statistics are reported as means ± standard deviations (SD). Univariate logistic regression analyses were used to determine which of our tested variables predicted 30-day admission for exacerbation of COPD. Following this, multivariate forward logistic regression, incorporating variables that were predictive in univariate analyses, was utilized to determine which variables were predictive of 30-day hospitalization for COPD exacerbations.

Hospitalizations were analyzed as binary variables (yes-no). Based on the univariate analysis, two scoring systems were developed to predict readmission. The 2 scoring systems, each including three variables, significantly predicted 30-day readmissions.

The first scoring system (scoring system I) was as follows:

  1. MRC dyspnea. This score ranges from 0 (least) to 4 (greatest) dyspnea. Our scoring was dichotomized to 0 (MRC 0, 1, 3, or 3) or 1 (MRC 4: “too short of breath to leave the house or short of breath dressing/undressing.”
  2. Exacerbation history: Those with 1 or more hospitalizations for exacerbations in the preceding year were given a score of 1; those below this threshold had a score of 0.
  3. Chronic prednisone use prior to admission: Chronic prednisone use was defined as prednisone used on all or most days for at least three months prior to admission. Those meeting this criterion were given a score of 1, those without chronic prednisone use had a score of 0.

The second scoring system (scoring system II) was as follows:

  1. MRC dyspnea. This was identical to # 1 in the first scoring system.
  2. Exacerbation history: Those with 2 or more outpatient -treated exacerbations (some of these could result in hospitalization) in the preceding year were given a score of 1; those below this threshold had a score of 0.
  3. Chronic prednisone use prior to admission: This was identical to # 3 in the first scoring system.

Scores for each of the above scoring systems could, therefore, range from 0-3. The relationship between the above scores and 30-day hospital readmissions were evaluated using receiver operating characteristic (ROC) curves, which plot the true-positive rate (sensitivity) versus the false-positive rate (1-specificity).

A receiver operating characteristic (ROC) curve, plotting the true-positive rate (sensitivity) versus the false-positive rate (1-specificity) was used to characterize the relation. The ROC model was used to predict the likelihood of readmission for scoring system I and scoring system II.

Results

Of the 50 studied patients, 77% were female; mean age was 71 ± 11 years. The body mass index (BMI) was 29.65 + 9 kg/m2. Clinical characteristics of subjects are shown in Table 1.

Table 1. Clinical characteristics of studied subjects.

Sixty percent had Medical Research Council (MRC) dyspnea 3 or 4 (moderate to severe). Mean length of stay was 4.3 ± 3.2 days. Thirty-four percent lived alone at home.  

In our study, all patients readmitted within thirty days had respiratory exacerbations of COPD as principal diagnoses (i.e., the frequency of respiratory-related and all-cause 30-day readmissions was identical). Thirty-day readmission rate for exacerbation of COPD was 24%. Of the studied parameters, the ones that did not predict rehospitalization in univariate logistic regression analyses are shown in Table 2.

Table 2. Variables that did not predict 30-day readmission.

Variables that significantly predicted or tended to predict readmission included: 1) two or more clinical exacerbations (not necessarily resulting in hospitalization) in the previous year (OR 4.6, p= 0.04); 2) prednisone use (chronic or prior to admission) (OR 4.4, p< 0.04); 3) MRC = 4 (OR 2.7, p = 0.16); 4) one or more respiratory hospitalizations in the preceding year (OR 3.1, p = 0.08).

Using scoring system I, 16 patients had a score of 0; 16 had a score of 1, 14 patients had a score of 2, and 4 had a score of 3. Readmission rates for each of these categories were as follows: 13%, 19%, 29%, and 75%, respectively. Using the ROC model (Figure 1), odds ratios for readmission for- Score 0 versus 3 was 18; (2) odds ratios for readmission for score 1 versus 3 was 16 and (3) odds ratios for readmission for score 2 versus 3 was 6.7.

Figure 1. Receiver operating characteristic (ROC) curve for scoring system I, showing odds ratio for readmission for Score 0 versus 3, Score 1 versus 3 and Score 2 versus 3.

In scoring system II, 19 had a score of 0, 16 had a score of 1, 11 had a score of 2, and 4 had a score of 3. Readmission rates for each of these categories were as follows: 11%, 19%, 36%, and 75%, respectively.  Using the ROC model (Figure 2), odds ratios for readmission for- Score 0 versus 3 was 24; (2) Score 1 versus 3 was 15 and (3) Score 2 versus 3 was 4.5.

Figure 2. Receiver operating characteristic (ROC) curve for scoring system II, showing odds ratio for readmission for score 0 versus 3, score 1 versus 3 and score 2 versus 3.

In both scoring systems, the combined score of 3, with all 3 variables present, was associated with a high rate of readmission. The odds ratio was calculated for the clinical scores as it provides a valid effect measure and allows comparison of the clinical scores with regards to outcome, i.e. the readmission for COPD exacerbation, in a small study such as this.

The closer AUC is to 1, the better the predictive performance of the test, with the practical lower limit for the AUC of a predictive test being 0.5. In this study, scoring system I with an AUC of 0.69 (Figure 1) and scoring system II, with an AUC of 0.73 (Figure 2), indicate fair strength as predictors for COPD readmission.

Discussion

The purpose of our study was to create a simple scoring system that might predict 30-day readmissions in patients hospitalized with COPD exacerbations. Data regarding factors which predisposes to hospital readmissions within 30 days of discharge after hospitalization for acute exacerbations of COPD is variable and remains limited (4-6, 10,11). Our study aimed at identifying potential risk factors and evaluating probable predictors of hospital re-admission in COPD patients within a month of discharge.

In our study, three variables held promise in a scoring system used to predict re-hospitalization within 30 days: exacerbations (either clinically-treated or hospitalized), chronic prednisone use, and functional limitation from dyspnea. These three variables could be assessed within a few minutes from a review of the inpatient hospital record or from a brief interview.

Previous studies evaluating readmission risk factors in COPD up to one year have identified several variables. These include: a lower FEV1 (12- 16), reduced physical activity, functional limitation and poor health-related quality of life (2,4,17-19), need for self-care assistance, active/ passive smoking, long term supplemental O2-requirement (12,16-18), and presence of selected co-morbid conditions (20, 21).

More recent studies found low physical activity to be a significant factor (5,18). Minutes of physical activity per day in the first week following discharge was lower in those readmitted (42 + 14 minutes vs. 114 + 19 minutes, p = 0.02) (5). Ngyuen et al. (19) reported an 18% readmission rate in 4000 patients, with independent predictors of increased readmission including reduced activity, anemia, prior hospitalizations, longer lengths of stay, more comorbidities, receipt of a new oxygen prescription at discharge, use of the emergency department or observational stay before the readmission. In another retrospective study, multivariate analysis showed the following risk factors to be associated with early readmission within 30 days of discharge- male gender, history of heart failure, lung cancer, osteoporosis, and depression; no prior prescription of statin within 12 months of the index hospitalization and no prescription of short-acting bronchodilator, oral steroid and antibiotic on discharge; length of stay, <2 or >5 days and lack of follow-up visit after discharge (10). Another study found these variables to have a significant association with 30-day readmissions: age, diastolic blood pressure, COPD severity score, length of stay, pH, paCO2, FEV1< 50%, number of previous days until exacerbation (6). This study also found an increased mortality at 6 months and one year in patients readmitted within 30 days of discharge (6).

In our study, the most influential variable 30-day readmission was the history of two or more exacerbations in the preceding year (OR: 2.47, CI= 1.51-4.05, p< 0.001). This variable was also found in our study to be significantly associated with 30-day readmission, following discharge for a COPD exacerbation hospitalization.

Our study found steroid use (chronic or prior to admission) to be a significant predictor of COPD readmissions. Steroid use has been associated with a significantly increased risk of readmission in a few other studies (12,13,16,22). We hypothesize chronic prednisone use reflects instability and variability in the chronic respiratory disease or a recent exacerbation prior to the index hospitalization- hence its relatively strong relationship to re-hospitalization.

The second significant predictor in our study, exacerbations resulting in hospital admission in the preceding year, has been found to be a risk factor readmission in prior studies (6,12,13,23). Three admissions in the year preceding recruitment was found to increase risk for readmission for COPD exacerbation (12,13,23). Frequent exacerbations in the preceding year likely reflect the severity of disease in these patients. A retrospective study found no association between the number of previous hospital COPD admissions and readmission (24).

Our third significant predictor, the severity of dyspnea has also been reported in some studies to be an independent risk factor for hospital admission for an acute exacerbation of COPD. Kessler et al. (14) reported that COPD patients with a dyspnea of grade 3, 4 or 5 (defined as breathlessness with mild, minimal or limited exertion respectively), had a significant risk of hospitalization at one year but those with dyspnea of grade 2 did not. Patients with “severe dyspnea” have been found to be more likely to be readmitted to hospital in studies (15,18). Our study using the MRC rating for dyspnea and found patients with an MRC rating of 4, which is equal to the most severe grading of dyspnea in this scale. The severity of dyspnea by MRC dyspnea being a predictor for readmission in COPD indicates that the severity of the disease predisposes to exacerbations of COPD and consequent readmissions.

A systematic review of studies on risk factors for readmission for patients with COPD exacerbation found 3 predictive factors similar to our study, namely- previous hospital admission, dyspnea and oral corticosteroids (25). This review also identified other variables including use of LTOT, having low health status or poor health related quality of life and reduced routine physical activity as risk factors for admission and readmission for COPD exacerbation (25).

A scoring system similar to ours, using 3 the significant predictors of COPD readmission (chronic prednisone use, MRC dyspnea rating and prior exacerbations, either clinical or requiring hospitalizations) has not been studied in predicting the 30 day- readmission for COPD exacerbation. This scoring system was a fairly strong predictor of readmission for COPD and may serve as a useful tool in risk-stratifying patients and directing medical resources toward those patients most at risk for readmission. This is especially of relevance at the present time when hospitals will face financial penalties for 30-day readmissions for COPD.

The risk factors identified for COPD readmission in this study are not modifiable. However, if patients more at risk for readmissions can be identified based on these risk factors, more resources can be directed to these group of patients- such as closer outpatient follow-up, VNA services, inpatient and outpatient pulmonary rehabilitation, more gradual steroid taper and institution of anti-inflammatory therapy such as azithromycin.

One limiting factor of this study is the small number of patients. The scoring system generated by the study using the 3 identified predictors, though fairly predictive of readmissions for COPD exacerbations, cannot be used without corroboration. The validity of the scoring system using needs to be established in a larger group of patients. Based on the results of this study, we intend to assess these variables as part of a quality assurance study on a larger number of hospitalized COPD patients. We plan to attempt to refine the scoring system, if possible, with an emphasis on simplicity in assessing data, brevity in data collection and predictive power for 30-day and subsequent hospitalization.

Conclusions

A simple 3-point scoring system, incorporating three variables: 1) chronic prednisone use; 2) MRC dyspnea rating; and 3) prior exacerbations (either clinical or requiring hospitalizations) has a fairly high predictive value for 30 -day readmission due to COPD exacerbation. This can be easily assessed within a few minutes from a review of the inpatient hospital record or from a brief patient interview. It can serve as a useful tool in risk-stratifying patients and directing medical resources toward those patients most at risk for readmission. This scoring system using these three variables holds promise for future validation studies.

References

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Cite as: Yap V, Wilcox D, ZuWallack R, Datta D. Evaluating a scoring system for predicting thirty-day hospital readmissions for chronic obstructive pulmonary disease exacerbation. Southwest J Pulm Crit Care. 2018;16(6):350-9. doi: https://doi.org/10.13175/swjpcc054-18 PDF

Friday
Jun222018

Intralobar Bronchopulmonary Sequestration: A Case and Brief Review

Uddalak Majumdar, MD1 

Payal Sen, MD2

Akshay Sood, MD2

1Cleveland Clinic Foundation, Cleveland, OH USA

2Univeristy of New Mexico, Albuquerque, NM USA

 

Abstract

Objective: Bronchopulmonary sequestration is a rare congenital abnormality of the lower respiratory tract, seen mostly in children but often in adults. The term implies a mass of lung tissue that has no function and lacks normal communication with the rest of the tracheobronchial tree.

Case: A 40-year-old man presented with acute onset of left flank pain for 4 hours. He was born in Yemen and emigrated to the US in 1998; at that time, he had been tested for tuberculosis which was negative. In this admission, he met systemic inflammatory response (SIRS) criteria and had basilar crackles in the left lower lobe of the lung. CT scan revealed a cavitary lesion with air-fluid level in the left lower lobe airspace. There was systemic arterial blood supply to this region arising off the celiac axis. He was diagnosed with an infected intralobar bronchopulmonary sequestration and underwent video-assisted thoracoscopic wedge resection. On follow up 3 months later, he was doing well.

Discussion: Pulmonary sequestration is a rare congenital anomaly of a mass of lung tissue, which can have cystic changes and is a very important differential diagnosis of cavities in the lung. Confirmation of diagnosis is by visualization of a systemic vessel supplying sequestrated pulmonary, and this is accomplished by contrast-enhanced CT scan, MRI or invasive angiography. 

Conclusion: The delay in diagnosis in our patient was due to falling prey to anchoring and availability biases and chasing the diagnosis of tuberculosis in a patient from Yemen with a lower lobe cavitation.

Case

History of Present Illness: A 40-year-old man with a past medical history of atrial fibrillation presented to the hospital with acute onset of left flank pain for 4 hours, fevers and chills. The pain was sharp and stabbing, pleuritic, non-radiating, and was severe with an intensity of 10/10. He denied extraneous activity or trauma earlier in the day, denied substernal pain, cough, night sweats, weight loss or change in urinary habits. He was born in Yemen and emigrated to the US in 1998; at that time, he was tested for tuberculosis (TB) which was negative. He was known to have a cavitary lesion in left lower lobe since 2005, and had undergone extensive evaluation (imaging, sputum and PPD) which showed no form of tuberculosis. He denied taking prophylactic TB treatment. Annual PPD testing had always been negative.

The patient worked on a ship, which travelled in the Great Lakes on the US-Canada border. He was a current smoker with a 20-pack-year smoking history. He lived at home with his wife and children. There was no history of IV drug use, prior imprisonment or homelessness. He denied being in contact with anyone with TB while in Yemen. He was sexually active with his wife and had no other sexual partners. He denied history of sexually transmitted infections.

Physical Examination:

Vital Signs: Temp – 38.3 degrees Fahrenheit, Pulse- 111/minute, RR- 18/min, BP- 151/66 mm Hg. Spo2- 90 % on Room Air.

Basilar crackles and rhonchi in the left lower lobe of the lung. No cervical or inguinal lymphadenopathy. Rest of the physical exam was normal.

Significant Laboratory Findings:

WBC elevated at 15,500/mm3 with 65 percent Neutrophils.

Lactate - 1.1 mmol/dL

Radiography:

Chest x-ray was done while in the emergency department, which revealed left basilar sub-segmental atelectasis (Figure 1).

Fig.1. Chest x-ray showing left basilar sub-segmental atelectasis without focal consolidation, large pleural effusion or pneumothorax.

Initial CT scan of abdomen and pelvis was done to rule out renal/ureteral stone. It showed a left lower lobe airspace consolidation with bronchiectasis and bronchiolectasis and a cavitary lesion with air-fluid level (Figure 2). 

Figure 2. Representative images from the CT scan in lung windows showing left lower lobe airspace consolidation concerning for an acute on chronic process.

C-reactive protein and erythrocyte sedimentation rate were normal, CRP and ESR- normal; blood cultures revealed no growth; procalcitonin 0.4 ng/mL (normal <0.15); anti-nuclear antibody – negative; Aspergillus antigen – negative; urine Legionella antigen – negative; Streptococcus pneumoniae antigen – positive.

Sputum Gram stain and acid-fast bacilli culture/stain could not be obtained because the patient did not produce any sputum.

Subsequently CT chest with IV contrast was done which showed findings compatible with a pneumonia within a left lower lobe intrapulmonary sequestration. (Figure 3).

Figure 3. Representative images from the thoracic CT chest with IV contrast. The left lower lobe demonstrates a 69 x 83 mm heterogeneous fluid collection with multiple locules of air. There was systemic arterial blood supply to this region arising off the celiac axis (arrows).

The patient was diagnosed with an infected intralobar bronchopulmonary sequestration. He was treated initially with intravenous fluids and piperacillin-tazobactam. He underwent video-assisted thoracoscopic wedge resection of infected bronchopulmonary sequestration in left lower lobe and ligation of the systemic feeding vessels from the celiac artery. Pathologic examination revealed a fibrotic lung with areas of centrilobular emphysema, bronchiolectasis, mucus pooling and microscopic honeycomb changes. Findings also showed an elastic artery, with features most suggestive of intralobar sequestration. His symptoms completely resolved after his operation.

Discussion

Bronchopulmonary sequestration is a rare congenital abnormality of the lower respiratory tract, seen mostly in children but often in adults, like in our patient (1). In 1946, Pryce coined the term "pulmonary sequestration" to describe a disconnected bronchopulmonary mass or cyst with an anomalous arterial supply (2). The term implies a mass of lung tissue that has no function and lacks normal communication with the rest of the tracheobronchial tree. This mass of non-functional lung tissue receives blood supply from the systemic circulation (3). The exact etiology is unknown and is thought to be an embryologic process error in foregut budding (4), although some have indicated a non-congenital acquired process in intralobar sequestration.

Sequestration may be intra- or extralobar based on its relation with the normal lung lobes. An intralobar sequestration (ILS), like the name suggests, is located within a normal lobe, lacks its own visceral pleura (5) and also has aberrant connections to bronchi, and lung parenchyma, or even the gastrointestinal tract, and often presents with recurrent infections (6,7). Compared to ILS, an extralobar sequestration (ELS) is located outside the normal lung and has its own visceral pleura (8), with the rare occurrence of infectious complications (9). About 75% of BPS is intralobar while 25% is extralobar (10). Bronchopulmonary sequestration is often associated with other congenital abnormalities like congenital diaphragmatic hernia, vertebral anomalies, congenital heart disease, pulmonary hypoplasia, colonic duplication, and congenital pulmonary airway malformation (11). 

Clinically, pulmonary sequestration is latent until infection leads to symptoms (12). Symptoms, like that of any pathological lung condition depend on the type, size, and location of the lesion. Sepsis and extracardiac shunting are common complications of untreated sequestration. Hemoptysis can also be a presentation. The mechanism of pneumonia is post-obstructive and usually recurrence of pneumonia leads to diagnosis. Recurrent pneumonia especially in the lower lobes should always include intralobar sequestration in the differential diagnoses. But the pathophysiology of infection and/or hemoptysis when ILS is not connected to airway is a mystery. Sometimes there is a partial or anatomically abnormal connection to the tracheobronchial tree, which can lead to poor mucus clearance, plugging and recurrent infection.

The mainstay of diagnosis is pre-operative imaging and post-operative histopathology of the resected specimen. The pathognomonic imaging characteristic is systemic vascular supply of the affected area of the lung (intra or extra-lobar), which is seen in about 80% of CT scans. Recurrent infection can lead to cystic areas within the mass (clusters of “ring shadows” on X-ray) (13). The surrounding normal lung may have air trapping and show emphysematous changes. Radiologic signs of BPS are a spectrum and represent the chronic and recurrent inflammation of the sequestrated lung: recurrent focal airspace disease, a parenchymal mass, a cavitary consolidation or mass, cystic lesions, localized bronchiectasis or adjacent emphysema. Bronchoscopy has little role in the management of BPS, which needs to be kept in mind by clinicians investigating cystic lung lesions. Identifying the systemic feeding vessel also helps with surgical planning.  

Symptomatic patients are treated with surgical excision; surgery is curative and is associated with minimal morbidity (14). Surgery is urgent in patients with significant respiratory distress but may be an elective procedure in adults or older children with less symptoms (15, 16). 

For asymptomatic patients of any age, management depends on how ‘high risk’ they are considered for developing complications. High risk patients are those with large lesions occupying >20 percent of the hemithorax, bilateral or multifocal cysts, or those with pneumothorax. In these patients, surgical resection is preferred to observation (17). On the other hand, in asymptomatic patients without these high-risk characteristics, either elective surgical resection or conservative management with observation are reasonable options (18). 

Apart from surgery, even embolization of the anomalous arterial supply has been reported to result in a complete resolution of symptoms and imaging changes to a certain in some cases (19). Since identification of vascular supply during surgery may be difficult during surgery, presurgical embolization may reduce risk of vascular complications (19). Embolization also has a more important role in hemoptysis and heart failure from shunting.

Conclusions

  • Pulmonary sequestration is a rare congenital anomaly of a mass of lung tissue without a normal connection to the tracheobronchial tree and a systemic vascular supply.
  • Presentation in adults is due to complication of the mass, undiagnosed in childhood. 
  • Sequestrated lung can have cystic changes and is a very important differential diagnosis of the cavitation. 
  • Confirmation of diagnosis is by visualization of a systemic vessel supplying sequestrated pulmonary, and this is usually accomplished by contrast-enhanced CT scan, MRI or invasive angiography.

Teaching points

This is a case of adult presentation of congenital pulmonary malformation and represents a delay in diagnosis, even though the patient’s symptoms started 10 years ago. The delay was due to falling prey to anchoring and availability biases and chasing the diagnosis of TB ten years ago in a patient from Yemen with a lower lobe cavitation. 

The feeding vessel from the celiac axis can only be demonstrated via a contrast enhanced CT, and thus, when in doubt, we should always get angiography by contrast-enhanced-CT or MRI or by invasive angiography. Had it been thought of and done 10 years ago, the patient would’ve been diagnosed and treated earlier.

Disclosure Statement

Drs. Majumdar, Sen and Sood have no conflicts of interest or financial ties to disclose.

References

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Cite as: Majumdar U, Sen P, Sood A. Intralobar bronchopulmonary sequestration: A case and brief review. Southwest J Pulm Crit Care. 2018;16(6):343-9. doi: https://doi.org/10.13175/swjpcc075-18 PDF

Monday
Jun042018

Sharpening Occam’s Razor – A Diagnostic Dilemma

Payal Sen, MD1

Uddalak Majumdar, MD2

Patrick Rendon, MD1

Ali Imran Saeed, MD1

Akshay Sood, MD1

 

1University of New Mexico

Albuquerque, NM US

2Cleveland Clinic Foundation

Cleveland, OH USA

 

Abstract

Objective: Physicians often search for Occam’s Razor, that is, to have a single diagnosis explain all clinical manifestations in an individual patient. Herein, we describe a case which was significant for a dual clinical diagnosis, thus proving that Occam’s razor may not always hold true. 

Case Summary: A 22-year-old Caucasian man presented with 4 days history of fever, and dry cough. Chest x-ray revealed a right middle lobe pneumonia. Mycoplasma IgM antibody titer was significantly elevated (>1:320), using the rapid diagnosis enzyme-immunoassay (EIA) test, and clinical course was complicated by rhabdomyolysis. He was treated with oral azithromycin for 5 days. The patient however returned to the ER in 2 weeks with similar symptoms and repeat chest x-ray revealed a persistent right middle lobe infiltrate. Endobronchial biopsy revealed necrotizing granulomatous inflammation which stained positive for Histoplasma capsulatum. Serum complement fixation antibody test for Histoplasma demonstrated an elevated titer of 1:64. The patient was diagnosed to have an ‘atypical pneumonia due to sub-acute Histoplasma capsulatum and acute Mycoplasma Pneumoniae infections, complicated by rhabdomyolysis.’

Discussion: This case is unusual because the patient had an acute community-acquired atypical pneumonia from Mycoplasma pneumoniae, complicated by rhabdomyolysis, and also had subacute Histoplasma pneumonia. Physicians often search for Occam’s Razor. However, following Hickam’s dictum, we made the unusual diagnosis of concomitant lung infection in an immunocompetent host with Mycoplasma pneumoniae and Histoplasma capsulatum

Conclusion: This was an immunocompetent patient who ran a complex, protracted, and unusual course of community acquired pneumonia. Often, the pursuit of additional or alternative diagnoses may require repeated and multiple invasive diagnostic sampling. Occam’s razor may not always hold true.

Introduction

Occam's razor proposes that the simplest explanation is usually the correct one. However, in the science of medicine, simple solutions may be elusive. Often there is an incredibly complex constellation of symptoms co-occurring with one another, thereby confounding the scientific community. We described the diagnostic conundrums in managing our patient who ran a complex protracted course of community acquired pneumonia.

Case

A 22-year-old Caucasian male college student with no significant past medical history, initially presented to the University hospital in New Mexico, United States, with 4 days’ history of fever, dry cough, and dyspnea. He had recently returned from a family vacation in Illinois and had spent several weeks fishing on the Mississippi river. Review of systems was negative for chest pain, headache, fever, chills, or night sweats. He denied any sick contacts. He did not smoke and did not use recreational drugs. His grandfather, who had been a heavy cigar smoker, had died of lung cancer.

His vital signs were significant for a body temperature of 100.6° Fahrenheit, respiratory rate of 32 breaths per minute, pulse rate of 94 bpm, blood pressure of 130/82 millimeters of mercury, and pulse oximetry of 90 percent on room air. Physical examination demonstrated that he was in mild respiratory distress. Chest auscultation revealed decreased breath sounds over the right mid to lower lung field. The rest of his physical examination was otherwise unremarkable. 

His laboratory tests revealed a normal complete blood count with a hematocrit of 40.5%, white blood cell count of 8,200 cells per microliter, and platelet count of 263,000 per microliter.  His electrolyte levels showed a serum sodium of 136 mEq per liter, potassium of 3.4 mEq per liter, chloride of 100 mEq per liter, bicarbonate of 21 mEq per liter, blood urea nitrogen of 15 mg/dL and creatinine of 0.9 mg/dL. His blood glucose was normal at 98 mg/dL. His urine analysis revealed 3+ blood without red blood cells. His liver function tests demonstrated an elevated aspartate aminotransferase at 244 units per liter, elevated alanine aminotransferase at 72 units per liter, with normal total bilirubin, albumin, and alkaline phosphatase levels. His serum creatinine kinase (CK) was highly elevated at 26,000 units per liter (normal reference range 39-308 units per liter). His arterial blood gas at rest on room air at an elevation of 5500 feet above sea level showed acute respiratory alkalosis with a normal alveolar arterial gradient with a pH of 7.57, PaCO2 of 28 mmHg, PaO2 of 77 mmHg, and bicarbonate of 22 mEq per liter.  His mycoplasma IgM antibody titer was significantly elevated (> 1:320) using the rapid diagnosis enzyme-immunoassay (EIA) test. Anti-mycoplasma pneumoniae IgA was also elevated. The urinary legionella and pneumococcal antigen levels, sputum culture, blood cultures, and urine toxicology screen were negative. Chest radiograph revealed a right middle and lower lobe pneumonia (Figure 1). 

Figure 1. CXR revealed right mid and lower lobe pneumonia.

The patient was diagnosed with sepsis secondary to Mycoplasma pneumoniae infection of the lungs, with the added complication of rhabdomyolysis. He was treated with intravenous followed by oral azithromycin 500 mg daily for 5 days and given intense hydration therapy. Within 48 hours, his low-grade fever subsided, CK decreased to 1000 units per liter, and the patient felt better. He was then discharged on Day 3 of hospitalization.

The patient however returned to the emergency department 2 weeks after discharge with persistent cough, chest discomfort, and loss of wellbeing. Repeat chest radiograph revealed a persistent right lower lobe infiltrate. Computed tomography (CT) scan of the chest revealed a right lower lobe consolidation with surrounding nodular opacities with a possible endobronchial lesion in the right lower lobe (Figure 2).

Figure 2. Panel A: Coronal view of thoracic CT scan showing right lateral basilar segment consolidation. Panel B: Axial view showing consolidation in the right lower lobe with surrounding nodular opacities.

He underwent bronchoscopy which revealed a mass-like endobronchial lesion in the lateral basilar segmental bronchus of the right lower lobe (Figure 3).

Figure 3. Bronchoscopy revealing a mass-like endobronchial lesion in a lateral segmental bronchus of the right lower lobe.

Endobronchial biopsy revealed necrotizing granulomatous inflammation and stained positive for the yeast form of Histoplasma capsulatum.  Serum complement fixation antibody test for Histoplasma demonstrated an elevated titer of 1:64. Acid fast bacilli were not seen on smear or culture and cytology and histopathology tests did not reveal malignancy.

The patient was diagnosed with an atypical pneumonia due to sub-acute Histoplasma capsulatum and acute Mycoplasma Pneumoniae infections, complicated by rhabdomyolysis. The mycoplasma infection and rhabdomyolysis had already been treated and resolved. For the subacute pulmonary histoplasmosis, the patient was treated with 10 weeks of oral itraconazole. Post treatment clinic follow-up revealed resolution of symptoms and radiological abnormalities.

Discussion

Mycoplasma pneumoniae is a common causative pathogen for community-acquired pneumonia in both children and adults (1).  Apart from respiratory tract symptoms, it is associated with a variety of extra-pulmonary manifestations (2). Recognizing this association can lead to timely diagnosis and treatment of both the mycoplasma infection and its complications. In this case report, we also want to highlight the fact that infection with endemic mycoses can often be mistaken for community acquired pneumonias, and thus having a high index of suspicion for fungal infection is very important, even in immunocompetent patients (3), to prevent a delay in treatment. Physicians often search for Occam’s Razor, i.e., to have a single diagnosis explain all clinical manifestations in an individual patient. This case is significant because of a dual clinical diagnosis, thus proving that Occam’s razor may not always hold true in an individual patient.

Mycoplasma infection can cause several unusual extra-pulmonary manifestations such as hemolytic anemia, immune thrombocytopenic purpura, transverse myelitis, Guillain-Barre syndrome, acute hepatitis and arthritis (4). Another lesser known complication of mycoplasma infection is rhabdomyolysis (5). Rhabdomyolysis is a syndrome caused by injury to the skeletal muscles, thereby resulting in leakage of myoglobin into blood (6). The classic triad of mycoplasma infection consists of myalgias, pigmenturia, and generalized muscle weakness, but this classic triad is seen in less than 10 percent of infected patients (7). Acute renal failure due to acute tubular necrosis as a result of mechanical obstruction by myoglobin is the most common complication, in particular if the serum CK level is >16,000 IU/l, which may be as high as 100,000 IU/l (8). In addition to mycoplasma infection, more common causes of rhabdomyolysis are trauma, immobilization, and recreational drug and alcohol use (9). 

Other organisms known to cause rhabdomyolysis are Influenza A and B virus, Coxsackie virus, Epstein-Barr virus, Primary Human Immunodeficiency virus, Legionella species, Staphylococcus aureus, and Streptococcus pyogenes (9). With respect to Mycoplasma pneumoniae infection, a possible mechanism for rhabdomyolysis is the induction of inflammatory cytokines, such as tumor necrosis factor-alfa (TNF-α) and interleukin-1 (IL-1), which may cause proteolysis of skeletal muscles (10). 

The rapid and reliable diagnosis of Mycoplasma pneumoniae (Mp) enables the correct and prompt use of antibiotics. Methods for identifying Mp infection include culture, molecular detection of pathogen specific antigen or nucleic acid, and serological analysis (11). Each of these methods has its pros and cons. Culture is the definitive method for diagnosis and is critical for monitoring trends in epidemiology but is slow and requires specialized media and trained personnel (11). Although molecular methods for nucleic acid or antigen detection have emerged as the primary techniques for identification of MP pneumoniae in surveillance programs, adoption of these methods is still lagging behind in USA.

Serologic analysis can prove to be problematic due to poor sensitivity and specificity, and the inability to characterize the specific Mp strain. Having said that, most physicians in the United States continue to rely on serological testing in concordance with the IDSA guidelines (11). It is well known that a single serologic test is of limited value in the early diagnosis of mycoplasma pneumoniae since there are often no IgM antibodies in the early stage of infection, and these IgM antibodies may persist long after the infection (12). However, if these IgM antibodies are present along with anti-Mycoplasma pneumoniae IgA, it is usually indicative of recent primary mycoplasma pneumoniae infection (13). A single high Mp-specific antibody titer (> 1:320) has been regarded as a diagnostic marker of mycoplasma pneumoniae, although it is present in only about 30 percent of the patients (12). Since our hospital relies on serological testing, we tested for the specific Mycoplasma pneumoniae IgM and IgA, both of which were positive. The MP-specific antibody titer was also greater than 1:320, thus signifying it indeed was early MP infection.

Symptoms of Mp infection generally resolve within 3–4 weeks after disease onset but can be shortened with antibiotic therapy; macrolides and doxycycline are the mainstay of this treatment (14). The mainstay for the prevention of pigment-induced acute kidney injury is the correction of volume depletion, prevention of intratubular cast formation, and the treatment of the underlying cause of rhabdomyolysis (4). This is done by aggressive fluid resuscitation resulting in increased renal blood flow and thus increasing the urinary flow with consequential wash out of partially obstructing tubular casts (4). Physicians will be served well to watch out for mycoplasma associated rhabdomyolysis in patients with atypical pneumonia and manifestations like myalgia, elevated aminotransferase levels, and myoglobinuria. 

Moving on to the second teaching point, endemic mycoses like coccidioidomycosis, histoplasmosis, and blastomycosis are often overlooked causes for community acquired pneumonia, particularly when immunocompetent patients travel out of the endemic zones (15). Often, testing is not even performed until the patient has failed to improve on antibacterial therapy. Delays in recognition, diagnosis and proper treatment may lead to disastrous outcomes (3). Performance of fungal antigen testing on bronchial washings or lavage fluid may improve the sensitivity for diagnosis over microscopic examination and the speed of diagnosis over culture even though isolation of the fungus by culture remains the gold standard method for definitive diagnosis (16). In this case, our patient was previously treated as mycoplasma pneumonia, thus leading to prolonged symptom course from histoplasmosis.

This case is unusual because the patient had an acute community-acquired atypical pneumonia from Mycoplasma pneumoniae, complicated by rhabdomyolysis, and also had subacute Histoplasma pneumonia. Physicians often search for Occam’s Razor, a principle from philosophy that when presented with competing hypothetical answers to a problem, one should select the one that makes the fewest assumptions.  Countering

Occam’s Razor, Dr. John Hickam said “Patients can have as many diseases as they damn well please!” (17). Following Hickam’s dictum, we made the unusual diagnosis of concomitant lung infection in an immunocompetent host with Mycoplasma pneumoniae and Histoplasma capsulatum.

Conclusion

With this case report, the authors wish to highlight two important teaching points. The first being that rhabdomyolysis is a serious but treatable extrapulmonary complication of Mycoplasma pneumoniae infection of the lungs. Having a high index of suspicion can limit treatment delay for rhabdomyolysis caused by mycoplasma infection and will therefore limit consequential morbidity like renal insufficiency. The second point that the authors wish to emphasize is that endemic fungal infection can often be mistaken for bacterial and viral community-acquired pneumonia in an immunocompetent host, particularly when they present with symptoms outside the endemic zone, thus delaying timely management. Hence one should have a high suspicion for fungal infection in immunocompetent hosts with unusual presentations such as history of travel to endemic zone, chronicity of symptoms, lack of response to therapy for community-acquired pneumonia, nodular lung lesions, and endobronchial abnormalities.

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Cite as: Sen P, Majumdar U, Rendon P, Saeed AI, Sood A. Sharpening Occam's razor-a diagnostic dilemma. Southwest J Pulm Crit Care. 2018;16(6):324-31. doi: https://doi.org/10.13175/swjpcc061-18 PDF