June 2019 Pulmonary Case of the Month: Try, Try Again

Lewis J. Wesselius, MD

Department of Pulmonary Medicine

Mayo Clinic Arizona

Scottsdale, AZ USA

History of Present Illness

A 53-year-old woman from presented with a 3-year history of shortness of breath. She was diagnosed with pneumonia in 2016, but even after treatment with antibiotics, continued to require supplemental oxygen. A CT-guided biopsy of a lung nodule was performed but there were no diagnostic findings. A surgical lung biopsy at another hospital was done but the report is unavailable. She had been diagnosed with possible scleroderma and treated with mycophenolate for 3 months and then azathioprine. 

Past Medical History, Social History and Family History

Aside from her history as in the HPI she has a remarkably negative past medical history. She does not smoke. Family history is noncontributory.

Physical Examination

• HEENT:  negative
• Chest:  Fine crackles at both lung bases
• Cardiovascular: regular rhythm, no murmur
• Skin:  skin thickening on fingers and distal forearms, but not elsewhere.  No pitting, ulcerations or calcinosis

Radiology

A chest x-ray was performed (Figure 1).

Figure 1. PA chest radiography done on presentation.

Which of the following should be done? (Click on the correct answer to be directed to the second of six pages)

1. Obtain previous radiography and biopsy reports
2. Pulmonary function testing
3. Thoracic CT scan
4. 1 and 3
5. All of the above

Cite as: Wesselius LJ. June 2019 pulmonary case of the month: Try, try again. Southwest J Pulm Crit Care. 2019;18(6):144-51. doi: https://doi.org/10.13175/swjpcc026-19 PDF

Update and Arizona Thoracic Society Position Statement on Stem Cell Therapy for Lung Disease

Summary

Infusions of stem cells are increasingly being offered for a variety of diseases, including chronic lung diseases such as chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF) and cystic fibrosis. However, the potential for harm, the lack of any proven benefit, and the high fees that many of these programs charge make recommending stem cell therapy untenable. At the time of this writing (April 2019) it appears that stem cell therapy can be safely performed, although the long-term side effects remain unknown. However, the little data available show no benefit in meaningful outcomes, such as mortality, morbidity or patient well-being, for stem cell treatment of chronic lung disorders. Patients with severe, incurable diseases may be motivated to seek innovative therapies. We encourage such patients to contact their primary care physician or pulmonologist. Clinical trials in the United States and Canada investigating stem cell therapy for lung diseases can be found on the website of the National Institutes of Health at Clinicaltrials.gov. The Arizona Thoracic Society encourages regulatory agencies to protect the public health and take appropriate action against non-investigational, for-profit stem cell clinics when appropriate.

Introduction

A central component of the mission of medical societies is to translate new scientific information into patient education. There appears to be increasing direct-to-consumer advertising of untested, unapproved, and potentially ineffective “stem-cell” treatments for a variety of diseases, including lung disorders (1). One may come across information regarding stem cell therapy for chronic obstructive pulmonary disorders and fibrotic lung disease, in the United States and worldwide, on the internet, patient support groups, or other sources. Recently, a direct mailing to the home of one of the members of the Arizona Thoracic Society was received (Figure 1).

Figure 1. Direct mailing for stem cell therapy for several diseases including COPD received by one of the members of the Arizona Thoracic Society.

These programs are often characterized by:

• Exorbitant fees
• Misrepresentation of risks and benefits
• Overreliance on, and advertisement of, patient testimony
• Poor patient follow-up
• Absence of regulatory oversight and objective clinical evidence for claimed benefits

Therefore, they differ substantially from therapies approved by legitimate regulatory agencies, from well-designed, controlled, and appropriately regulated clinical trials, and from regulated compassionate use of innovative cell therapies.

Chronic Obstructive Pulmonary Disease (COPD)

Stem cells can differentiate into several different lung cell types, including the alveolar epithelial cells. Since COPD is a disease associated with destruction of alveoli induced by cigarette smoke, the concept of rebuilding the alveoli through stem cell therapy is attractive. Pre-clinical trials in animal models have suggested regeneration of alveolar-like structures, repair of emphysematous lungs, and reduction of inflammatory responses, with the greatest success being in acute lung injury models.

Currently, regenerative therapies are divided into extrinsic therapeutic strategies and intrinsic cell therapy methods. Extrinsic cell therapy refers to the vascular infusion of (or endotracheal installation) of stem cells, including embryonic stem cells (ESCs), induced pluripotent stem cells (iPSs), mesenchymal stem cells (MSCs), and human lung stem cells (hLSCs). Intrinsic therapy refers to the delivery of small molecules (retinoid compounds have been the most studied) that can stimulate the endogenous lung stem/progenitor cells to regenerate and replace damaged structures.

A number of recent review articles have summarized the current state of research in the use of stem cells in COPD (2-4). These review articles all contain summaries of trials conducted to date using both extrinsic and intrinsic therapies. There have been several phase I clinical trials, primarily assessing safety, and a handful of small phase II clinical trials that have been negative for meaningful clinical outcomes. Sun et al. (3) point out that the available trials have all been conducted on patients with advanced COPD. The authors suggest that further research is required on how to enhance the engraftment of exogenous mesenchymal stem cells in damaged lungs. Further, considering the anti-inflammatory and immunomodulatory effects of exogenous mesenchymal stem cells, they may be most effective potentially in treating acute lung disease, as opposed to chronic progressive disease with severe structural damage.

Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive debilitating lung disease of unknown etiology characterized by a combination of histological changes, including extracellular matrix (ECM) deposition, phenotypic changes of fibroblasts, and alveolar epithelial cells, the formation of fibroblastic foci, and scattered areas of aberrant wound healing interspersed with normal lung parenchyma (5).

There are two approved compounds for the treatment of IPF: pirfenidone and nintedanib. Pirfenidone is an antifibrotic compound with an unclear mechanism of action, targeting several molecules, including transforming growth factor-β (TGF-β), tumor necrosis factor-α (TNF-α), and interleukin 6 (6). Nintedanib is a tyrosine-kinase inhibitor, targeting vascular endothelial growth factor receptor (VEGFR), fibroblast growth factor receptor (FGFR), and platelet derived growth factor receptor (PDGFR) (7). While the use of pirfenidone and nintedanib has been shown to slow the progression of IPF, neither is curative and morbidity and mortality from IPF remains high (8,9).

Because of the inadequacy of therapy in IPF, the use of mesenchymal stem cells (MSCs) has attracted interest as a potential option. Early clinical studies have shown that the MSCs can be safely administered (5,10-12). A phase Ib study of endobronchially administered autologous adipose-derived MSCs showed not only acceptable safety outcomes, but also improvements in quality of life parameters (12). However, there were no significant differences in any of the studied functional parameters (FVC, FVC%pred. and DLCO% pred.) at baseline and 6 and 12 months following 3 endobronchial infusions of MSCs.

Cystic Fibrosis

Cystic fibrosis (CF) is a genetic syndrome usually resulting in a high mortality rate due to progressive lung disease. Several drugs targeting specific mutated cystic fibrosis transmembrane regulator (CFTR) proteins are already in clinical trials. However, new therapies, based on stem cells, are also emerging. Interest has focused on induced pluripotent stem (iPS) cells. It is possible to make iPS cells using cells from people with CF, and then use gene editing to correct CFTR mutations in those cells (13). This suggests the possibility of re-implanting the corrected iPS cells into the lungs of people with CF to generate healthy lung cells. Currently, three trials examining the safety of stem cells in cystic fibrosis are ongoing according to Clinicaltrials.gov. 

Adult Respiratory Distress Syndrome (ARDS)

Four clinical trials are listed on Clinicaltrials.gov for ARDS and stem cells; one, which involved 3 patients, has been completed (14). No outcome information is available.

Other Lung Diseases

We are unaware of any human trials at this time with outcomes in other lung diseases.

Regulatory and Legal Actions

The Food and Drug Administration (FDA) and the Attorney General of New York have both expressed concern over stem cell therapy. The concerns follow reports of three patients becoming blind after receiving injections of stem cells into the eye and twelve patients who became seriously ill after receiving injections that purportedly contained stem cells from umbilical cord blood (15,16). The FDA has issued warning letters to stem cell clinics, including one letter claiming violation of Federal law, and another 20 warnings to clinics of that their claims and actions were subject to FDA approval. The NY Attorney has filed a lawsuit against a for-profit stem cell clinic, Park Avenue Stem Cell, claiming it performed unproven procedures on patients with a wide range of medical conditions, from erectile dysfunction to heart disease (17).

The Arizona Thoracic Society encourages further investigation into stem cell transplantation in lung disease. However, we do not at this time encourage non-investigational use of stem cells since the therapy has not been shown to have meaningful patient benefits. We also encourage state and local regulatory agencies in the Southwest to protect the public health and take appropriate action against non-investigational, for-profit stem cell clinics when appropriate.

References

1. American Lung Association. Statement on Unproven Stem Cell Interventions for Lung Diseases (July 2016). Available at: https://www.thoracic.org/members/assemblies/assemblies/rcmb/working-groups/stem-cell/resources/statement-on-unproven-stem-cell-interventions-for-lung-diseases.pdf (accessed 4/5/19).
2. Balkissoon R. Stem Cell Therapy for COPD: Where are we? Chronic Obstr Pulm Dis. 2018;5(2):148-53. [CrossRef] [PubMed]
3. Sun Z, Li F, Zhou X, Chung KF, Wang W, Wang J. Stem cell therapies for chronic obstructive pulmonary disease: current status of pre-clinical studies and clinical trials. J Thorac Dis. 2018 Feb;10(2):1084-98. [CrossRef] [PubMed]
4. Cheng SL, Lin CH, Yao CL. Mesenchymal Stem Cell Administration in Patients with Chronic Obstructive Pulmonary Disease: State of the Science. Stem Cells Int. 2017;2017:8916570. [CrossRef] [PubMed]
5. Tzouvelekis A, Toonkel R, Karampitsakos T, Medapalli K, Ninou I, Aidinis V, Bouros D, Glassberg MK. Mesenchymal stem cells for the treatment of idiopathic pulmonary fibrosis. Front Med (Lausanne). 2018 May 15;5:142. [CrossRef] [PubMed]
6. Kolb M, Bonella F, Wollin L. Therapeutic targets in idiopathic pulmonary fibrosis. Respir Med. 2017;131:49–57. [CrossRef] [PubMed]
7. Fletcher S, Jones MG, Spinks K, et al. The safety of new drug treatments for idiopathic pulmonary fibrosis. Expert Opin Drug Saf. 2016;15:1483–9. [CrossRef] [PubMed]
8. King TE, Bradford WZ, Castro-Bernardini S, et al. Phase 3 trial of pirfenidone in patients with idiopathic pulmonary fibrosis. N Engl J Med. 2014;370:2083–92. [CrossRef] [PubMed]
9. Richeldi L, du Bois RM, Raghu G, et al. Efficacy and safety of nintedanib in idiopathic pulmonary fibrosis. N Engl J Med. 2014;370:2071–82. [CrossRef] [PubMed]
10. Tzouvelekis A, Ntolios P, Karampitsakos T, et al. Safety and efficacy of pirfenidone in severe idiopathic pulmonary fibrosis: a real-world observational study. Pulm Pharmacol Ther. 2017;46:48-53. [CrossRef] [PubMed]
11. Tzouvelekis A, Koliakos G, Ntolios P, et al. Stem cell therapy for idiopathic pulmonary fibrosis: a protocol proposal. J Transl Med. 2011;9:182. [CrossRef] [PubMed]
12. Tzouvelekis A, Paspaliaris V, Koliakos G, et al. A prospective, non-randomized, no placebo-controlled, phase Ib clinical trial to study the safety of the adipose derived stromal cells-stromal vascular fraction in idiopathic pulmonary fibrosis. J Transl Med. 2013;11:171. [CrossRef] [PubMed]
13. The Cystic Fibrosis Foundation. Stem cells for cystic fibrosis therapy. Available at: https://www.cff.org/Research/Research-Into-the-Disease/Restore-CFTR-Function/Stem-Cells-for-Cystic-Fibrosis-Therapy/ (accessed 4/5/19).
14. Clinicaltrials.gov. Human Mesenchymal Stem Cells For Acute Respiratory Distress Syndrome (START). Available at: https://www.clinicaltrials.gov/ct2/show/results/NCT01775774?term=Stem+cells&cond=ARDS&rank=4 (accessed 4/5/19).
15. Kuriyan AE, Albini TA, Townsend JH, et al. Vision loss after intravitreal injection of autologous "stem cells" for AMD. N Engl J Med. 2017 Mar 16;376(11):1047-53. [CrossRef] [PubMed]
16. Grady D. 12 People hospitalized with infections from stem cell shots. NY Times. Dec. 20, 2018. Available at: https://www.nytimes.com/2018/12/20/health/stem-cell-shots-bacteria-fda.html?action=click&module=RelatedCoverage&pgtype=Article&region=Footer (accessed 4/9/19).
17. Abelson R. N.Y. attorney general sues Manhattan stem cell clinic, citing rogue therapies. NY Times. April 4, 2019. Available at: https://www.nytimes.com/2019/04/04/health/stem-cells-lawsuit-new-york.html (accessed 4/9/19).

Cite as: Arizona Thoracic Society*. Update and Arizona Thoracic Society position statement on stem cell therapy for lung disease. Southwest J Pulm Crit Care. 2019;18(4):82-6. doi: https://doi.org/10.13175/swjpcc020-19 PDF

*The below contributed to the update and position statement on stem cell therapy

• Bhargavi Gali, MD
• Michael B. Gotway, MD
• Kenneth S. Knox, MD
• Timothy T. Kuberski, MD
• Stuart F. Quan, MD
• George Parides, DO
• Richard A. Robbins, MD
• Gerald F. Schwartzberg, MD
• Allen R. Thomas, MD
• Lewis J. Wesselius, MD

March 2019 Pulmonary Case of the Month: A 59-Year-Old Woman with Fatigue

Lewis J. Wesselius, MD¹

Michael B. Gotway, MD²

¹Department of Pulmonary Medicine and ²Department of Radiology

Mayo Clinic Arizona

Scottsdale, AZ USA

History of Present Illness

A 59-year-old woman from Kingman, Arizona had a one-year history of fatigue with some shortness of breath. For this reason, she saw her primary care physician.

Past Medical History, Social History and Family History

She has no significant past medical history. She does not smoke. Family history is noncontributory.

Physical Examination

Physical examination was unremarkable.

Which of the following should be done? (Click on the correct answer to be directed to the second of seven pages)

1. Chest x-ray
2. Complete blood count
3. Electrolytes, blood urea nitrogen and creatinine
4. Liver panel
5. All of the above

Cite as: Wesselius LJ, Gotway MB. March 2019 pulmonary case of the month: A 59-year-old woman with fatigue. Southwest J Pulm Crit Care. 2019;18(3):52-7. doi: https://doi.org/10.13175/swjpcc008-19 PDF 

Co-Infection with Nocardia and Mycobacterium Avium Complex (MAC) in a Patient with Acquired Immunodeficiency Syndrome

Zahira Babwani DO

Kenneth Wojnowski Jr DO

Sunil Kumar MD

Broward Health Medical Center

Fort Lauderdale, FL USA

Abstract

We present a case in which a patient with acquired immunodeficiency syndrome (AIDS) and nocardiosis was found to have co-infection with Mycobacterium avium complex (MAC). Despite the fact that MAC is a known colonizer of the pulmonary system, ​ it is possible to have co-infection and a high degree of suspicion is necessary to ensure prompt treatment of both organisms. We wish to describe how radiologic findings were instrumental in guiding our differential diagnosis.

Case Report

History of Present Illness​: A 64-year-old man with history of alcohol and tobacco abuse presented with a chronic, productive cough for 5-6 months. Associated symptoms included shortness of breath and 30-pound weight loss. He denied all other symptoms.

Physical Exam​: Pertinent positives revealed temporal wasting, poor dental hygiene, oral thrush and diffuse rhonchi bilaterally. Initial vital signs were within normal limits.

Laboratory and Radiology​: Pertinent laboratory findings revealed leukocytosis with a left shift. Viral respiratory polymerase chain reaction (PCR) testing was negative. Human immunodeficiency virus (HIV) testing was positive with a CD4 count of 46 cells/mm³. QuantiFERON gold testing was negative. Sputum cultures, acid-fast bacilli (AFB) and blood cultures were obtained. Bronchoalveolar lavage (BAL) was performed with no evidence of Pneumocystis jirovecii (PJP). Chest X-ray (CXR) and computed tomography (CT) of the chest (Figure 1) revealed a multifocal right lung abscess with complex pleural fluid, empyema, nodular cavitary lesion in the left lower lobe and hilar lymphadenopathy.

Figure 1. Panel A: initial chest X-ray shows a complex infiltrate and effusion in the right lung. There is a cavitary lesion with air-fluid level vs lung abscess on the right. A nodule or consolidation is present in the left lung base. Panel B: A representative image from the initial CT of the chest showing a multifocal right lung abscess and complex pleural fluid.

Hospital Course: ​After admission, the patient was started on broad spectrum antimicrobials with vancomycin and piperacillin-tazobactam. A thoracentesis was performed due to right sided pleural effusion which yielded 65 cc of thick, purulent, green fluid. Thoracotomy with complete decortication of the right lung was performed with biopsies of the abscesses. Two 32-French chest tubes were placed due to the presence of multiple intraparenchymal lung abscesses, loculations, and empyema. Biopsy and pleural fluid cultures grew gram positive, beaded organisms which were later identified as nocardia, with no evidence of MAC or Mycobacterium tuberculosis (MTB). The patient was started on amikacin, meropenem and trimethoprim-sulfamethoxazole for newly diagnosed pulmonary nocardiosis. MAC prophylaxis was initiated due to his low CD4 count. After initiation of therapy for nocardiosis, three sputum AFB cultures began to stain positive. Since nocardiosis stains weakly positive for AFB, we initially did not suspect non-tuberculous Mycobacteria (NTM). Repeat CT scan of the chest (Figure 2) revealed ground glass opacities, nodular densities and both mediastinal and hilar lymphadenopathy.

Figure 2. Panel A: after initiation of treatment for nocardiosis, improvement of right empyema and cavitary lesion with bilateral patchy airspace disease right greater than left. Panel B: CT of the chest after initiation of treatment for nocardiosis, prominent lymph nodes in the hilar regions and mediastinum. less cavitation than the previous study. There are innumerable ground glass and nodular densities throughout both lungs, right greater than left.

Suspicion for active MAC co-infection was raised, the prophylactic dose of azithromycin was increased to the treatment dose, and ethambutol was initiated. After three weeks of intravenous amikacin, meropenem and trimethoprim-sulfamethoxazole the patient showed considerable improvement in his respiratory symptoms and was transitioned to oral trimethoprim-sulfamethoxazole for outpatient treatment of nocardiosis with continuation of ethambutol and clarithromycin for MAC.

Discussion

The Mycobacterium Avium Complex ​(MAC) is a Non-tuberculous mycobacterium (NTM) that is commonly found in patients with HIV and a CD4 count of less than 50. The diagnosis of NTM is challenging due to the fact that the organism is a known colonizer of the pulmonary system (1) ​. Supportive radiologic evidence is needed to distinguish colonization from active infection (2).

Common CT findings of nocardiosis include ground glass opacities, lung nodules, cavitation, pleural effusion and masses (3)​. The presence of mediastinal and hilar lymphadenopathy is the most common finding in immunosuppressed patients with MAC infection but is not​ a usual feature of pulmonary nocardiosis (3,4) ​. Our​ patient’s repeat CT scan showed mediastinal and hilar lymphadenopathy with improvement of cavitary lesions which suggests improvement of CT findings related to nocardiosis, but persistent findings related to NTM (5). This led us to believe that the patient was appropriately treated for nocardiosis, but with an underlying presence of active MAC infection that presented with atypical radiographic findings. As per the American Thoracic Society (ATS) guidelines for NTM pulmonary infection (6)​ ​, this patient’s pulmonary symptoms, radiological evidence on the chest CT, and positive AFB cultures from at least two separate expectorated sputum samples lends credibility to MAC as a true active infection in the setting of nocardiosis and AIDS. The patient was appropriately placed on clarithromycin and ethambutol as an outpatient, and our suspicions were confirmed for MAC with no evidence of MTB by PCR testing 5 weeks after initial AFB smears were collected.

Co-infection with Nocardiosis and MAC may be underestimated since they both often develop in immunocompromised hosts. MAC, along with other NTM species account for 20% of mycobacterium pulmonary infections in HIV infected patients (5)​. Nocardia accounts for less than 3% of pulmonary infections in HIV infected patients (5)​. A high degree of clinical suspicion is imperative to promptly treat infection with both organisms.

References

1. Young J, Balagopal A, Reddy NS, Schlesinger LS. Differentiating colonization from infection can be difficult Nontuberculous mycobacterial infections: Diagnosis and treatment. Patient Care. 2007. Available at: http://www.patientcareonline.com/infection/differentiating-colonization-infection-can-be-difficult-nontuberculous-mycobacterial-infections (accessed 10/3/18).
2. Trinidad JM, Teira R, Zubero S, Santamaría JM.Coinfection by Nocardia asteroides and Mycobacterium avium- intracellulare in a patient with AIDS. Enferm Infecc Microbiol Clin. 1992 Dec;10(10):630-1. [PubMed]
3. Kanne JP, Yandow DR, Mohammed TL, Meyer CA. CT findings of pulmonary nocardiosis. AJR Am J Roentgenol. 2011 Aug;197(2):W266-72. [CrossRef] [PubMed]
4. Erasmus JJ, McAdams HP, Farrell MA, Patz EF Jr. Pulmonary nontuberculous mycobacterial infection: radiologic manifestations. Radiographics. 1999 Nov-Dec;19(6):1487-505. [PubMed]
5. Benito N, Moreno A, Miro JM, Torres A. Pulmonary infections in HIV-infected patients: an update in the 21st century. Eur Respir J. 2012 Mar;39(3):730-45. [CrossRef] [PubMed]
6. Griffith DE, Aksamit T, Brown-Elliott BA, et al. An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases. Am J Respir Crit Care Med. 2007 Feb 15;175(4):367-416. [CrossRef] [PubMed]

Cite as: Babwani Z, Wojnowski K Jr, Kumar S. Co-Infection with Nocardia and Mycobacterium avium complex (MAC) in a patient with acquired immunodeficiency syndrome. Southwest J Pulm Crit Care. 2019;18(1):22-5. doi: https://doi.org/10.13175/swjpcc123-18 PDF

Progressive Massive Fibrosis in Workers Outside the Coal Industry: A Case Series from New Mexico

Landon Casaus, MD¹

Sapna Bhatia, MD¹

Akshay Sood, MD, MPH^{1, 2}

¹Department of Internal Medicine

University of New Mexico School of Medicine

Albuquerque, NM, USA

²Miners’ Colfax Medical Center

Raton, NM USA

Abstract

Four clinical patterns of diffuse lung disease may be seen with silicosis: acute silicosis or silicoproteinosis (the latter resembling pulmonary alveolar proteinosis), simple nodular sclerosis, accelerated silicosis, and progressive massive fibrosis (PMF). The intensity and duration of exposure as well as host susceptibility dictates the presentation and progression of PMF. Although most cases of PMF in the literature are reported among coal miners in whom this disease has shown a recent increase in prevalence, this disease can also be seen in exposed workers outside the coal industry. In this article, we will review the clinical, physiological, and pathological manifestations of the disease, illustrated by three case examples of PMF among non-coal miners from New Mexico. Diagnosis and management of patients with PMF can be difficult, and carries medicolegal implications for the patient. Physicians and policymakers need to be aware of PMF in workers exposed to silica within and outside the coal industry.

Introduction

The worldwide prevalence of silicosis peaked by the beginning of the 20^th century during the development of mechanized industry (1). Outbreaks of silicosis are still noted in the developed world, particularly where workers are consistently exposed to silica particles that are small enough to be inhaled (≤10 µm in diameter) and at levels above a “safe” concentration (action level of 25 µm/m³ as a time-weighted average over an 8-hour work day, as recommended by the U.S. Occupational Safety and Health Administration or OSHA) (2,3). The four Appalachian coal mining states of Pennsylvania, West Virginia, Virginia, and Kentucky accounted for more than 75 percent of all silicosis-related deaths in the United States (U.S.) in 2007 (4).  A recent study however indicates that the age-standardized mortality rate from silicosis in the U.S. in 2014 was amongst the highest in the mining intense regions of the Southwest, particularly in the Four Corners area where the borders of New Mexico, Arizona, Utah, and Colorado meet (5). The number of diagnosed silicosis cases has increased in New Mexico between 2000 and 2011, and residents of New Mexico are twice as likely to die from or with silicosis when compared to the rest of the country for reasons that are unexplained (6).

Four clinical patterns of diffuse lung disease may be seen with silicosis: acute silicosis or silicoproteinosis (the latter resembling pulmonary alveolar proteinosis), simple nodular sclerosis, accelerated silicosis, and progressive massive fibrosis (PMF). PMF represents the coalescence of multiple small pneumoconiotic opacities to form larger opacities or conglomerate masses measuring over 10 millimeters in size on a chest radiograph, with smaller rounded opacities usually seen in simple silicosis. Silicotic opacities are classified on their shape, size, and profusion using the International Labour Organization’s (ILO) International Classification of Radiographs for Pneumoconiosis system (commonly referred to as B reads) (7-9). The 1970-2017 radiographic data from the National Institute for Occupational Safety and Health (NIOSH) surveillance program concluded that the national prevalence of coal workers’ pneumoconiosis in coal miners with 25 years or more of tenure now exceeds 10% (10). This is an increase from the previous estimate of 7% in 2012 (11,12). A resurgence of progressive massive fibrosis in coal miners has also been described, particularly those working in smaller mines (13). The rate of PMF in silica exposed workers outside of the coal mine industry, similar to those illustrated in this paper, is unknown. We herein describe three New Mexico non-coal miners with PMF that were followed at the University of New Mexico Occupational Pulmonary Medicine Clinic. Each of the three cases had already received compensation under the United States Energy Employees Occupational Illness Compensation Program, based upon prior abnormal B reads of chest radiographs. The epidemiology, pathogenesis, and management of PMF is also reviewed.

Case reports

Case 1

An 83-year-old man presented in 2017 with worsening dyspnea over the prior 10 years. He worked at a federal national laboratory in northern New Mexico, from 1962-1992 as a construction worker. His work included digging ditches, removing insulation, demolishing buildings, breaking up concrete with jackhammers, and working around sandblasters in enclosed areas, without any respiratory protection. He had a 5-pack year smoking history, and quit 50 years prior.

A 2017 chest radiograph showed small, upper lobe predominant, nodular opacities. A high-resolution computed tomography (CT) scan in 2009 showed innumerable micronodules in the upper lobes of the lung with a centrilobular distribution.  A repeat CT scan obtained in 2017 (Figure 1) showed new-onset coalescence of several upper lobe nodules, as large as 1.5 cm x 2 cm.

Figure 1. Computed tomography scan of the chest showing several silicotic opacities in both lung apices and coalescence to progressive massive fibrosis in right apex.

His pulmonary function tests (PFT) showed mild obstruction with evidence of air trapping. A diagnostic bronchoscopy showed no evidence of infection or neoplasm.

Case 2

A 78-year-old man presented in 2014 with several-years history of progressive New York Heart Association Class III dyspnea. The patient worked as an underground uranium miner from 1960 to 1989 where he was exposed to hauling, “mucking” (a term referring to the loading of fragmented ore), and blasting. He wore a respirator intermittently. He had a five-pack year smoking history, quitting in 1981.

Chest x-ray showed innumerable micronodules, predominately in the upper lobes.  A CT scan of the chest with 3 mm cuts in 2012 showed innumerable upper lobe predominant micronodules in a perilymphatic and centrilobular distribution, with coalescence in the upper lobes. Repeat CT scans in 2014 and 2015 demonstrated no disease progression (Figure 2).

Figure 2. Computed tomography scan of the chest demonstrating progressive massive fibrosis in the right upper lung and several silicotic opacities in bilateral upper lungs.

PFTs showed a mild restrictive defect. An infectious etiology was ruled out by negative sputum acid fast bacilli (AFB), and bacterial smears and cultures.

Case 3

A 79-year-old man presented with dyspnea at rest and upon exertion, and chronic bronchitis symptoms, with occasional hemoptysis. The patient worked as an underground uranium miner from 1959-1980 performing drilling, blasting and “mucking”, with significant self-reported exposure to dust and without use of respiratory protection. The patient reported a 15-pack year smoking history, but quit in 1976.

A chest x-ray showed hilar and mediastinal nodal calcifications with small scattered lung nodules. A HRCT scan of the chest in 2016 (Figure 3) showed multiple calcified nodules as well as calcified hilar and mediastinal lymph nodes.

Figure 3. Computed tomography scan of the chest demonstrating progressive massive fibrosis with evidence of traction in both lobes.

Conglomerate masses in the upper lobes measuring up to 3.3 cm were noted and moderate background emphysematous changes were also noted.  The PFTs on initial evaluation were within normal limits. He was noted to be hypoxic on room air, necessitating 2 L/min oxygen supplementation. Sputum AFB smears and cultures were negative.

Discussion

PMF is seen in workers employed in industries that cut, grind, or drill silica-containing materials such as concrete, masonry, tile and/or rock (3). Most cases of PMF in the literature have been reported among coal miners, likely a reflection of the fact that coal miners undergo active surveillance due to governmental regulations (12). Although more commonly believed to occur in underground coal miners, PMF can be seen in surface coal miners as well (14). PMF outside the coal industry has been described in limited studies of barium miners, sandblasters, blacksmiths, welders, metal polishers, and quartz surface fabricators (15-17). More recently, PMF has been reported in ‘distressed’ denim jean industry workers (18). In this case series, we report PMF in New Mexico construction and uranium workers.

The latency for PMF is usually 10-30 years. Latency is greatly impacted by the exposure concentration and duration, as well as type of silica exposure. Additionally, it is influenced by underlying diseases, genetics, and smoking. Although PMF typically occurs in a setting of high cumulative dust exposures (14), some studies indicate that the host patterns of deposition and clearance of dust may be more relevant (19).

The pathogenesis of PMF is not completely understood; however, it is known that alveolar macrophages initiate a complex cascade results in inflammation and fibrosis (20). Histopathological findings include nodules, usually located near the respiratory bronchioles, composed of silica particles surrounded by whorled collagen in concentric layers. Larger masses of collagen define the lesion of PMF, which may be associated with avascular necrosis in the center and endarteritis in the periphery (21). The extensive fibrotic reaction in PMF is associated with high serum levels of interleukin (IL)-8 and intercellular adhesion molecule (ICAM)-1, which are important as neutrophil attractants and adhesion molecules (22).

The clinical diagnosis of PMF has three requirements: the patient must have a history of inhalational silica exposure significant enough to cause disease; chest imaging must be consistent with PMF; and other illnesses that mimic PMF must be reasonably ruled out (1). The disease presentation of PMF is highly variable. Patients may have debilitating symptoms of dyspnea on exertion and exercise intolerance, obstructive and/or restrictive patterns on PFTs, as well as experience complications such as cor pulmonale, spontaneous pneumothorax, and hypoxic respiratory failure (23). On the other hand, a normal spirogram is described in up to 11% of subjects with PMF, as also noted in Case 3 above (23).  The level of pulmonary impairment in patients with PMF generally increases with increasing radiologic size of large opacities (23). Spirometry is repeated upon follow-up visits to assess for functional deterioration (24). Invasive tests such as arterial blood gas or cardiopulmonary exercise test are usually not indicated. Surveillance chest radiographs are classified for small and large opacities using the International Labour Organization’s (ILO) International Classification of Radiographs for Pneumoconiosis system (7-9). CT scan of the chest is more sensitive in diagnosing PMF than chest radiographs, and may be considered if the radiograph fails to show large opacities but demonstrates small opacities of relatively larger diameter or a tendency for opacities to coalesce (25,26). Lung tissue for histology or mineral analysis is rarely needed. The presence of atypical features in a patient with simple silicosis such as fever, hemoptysis, worsening dyspnea, weight loss, disproportionate fatigue, and the presence of a new infiltrate or cavitation of a pre-existing lesion on chest imaging should prompt the clinician to look for PMF, tuberculosis, or lung cancer. Patients with PMF are at elevated risk for concomitant tuberculosis. This risk is directly proportional to the level of profusion of silicotic small opacities (27), and the risk in patients with the highest level of profusion is comparable to that in patients with HIV infection (3). Autopsy studies from Welsh coal workers during the period 1952–1954 demonstrated tubercle bacilli in as many as 35% of cases with PMF (21). A recently published study from Brazil reported coexisting microbiologically confirmed tuberculosis in about half of patients with PMF, raising concerns about tuberculosis infection as a risk factor for the development of PMF ¹⁵. Patients with silicosis are also at high risk for lung cancer (28), with a greater risk for lung cancer described in patients with PMF as compared to patients with simple coal workers pneumoconiosis in one study (29). Positron emission tomography with F-18 fluorodeoxyglucose is of limited utility in differentiating malignancy from PMF lesions (30).

The prevention of PMF remains a focus at the exposed workplace. This includes primary prevention such as worker education; control of airborne dust exposure via engineering and work practice interventions such as improving ventilation, providing a means of exhaust, adding water to the cutting surface, and using enclosed cabs or booths; and use of respiratory protective devices (3). In June 2018, OSHA mandated personal breathing zone air sampling to monitor exposure and medical surveillance of workers with exposure above the permissible exposure limits (31). Medical surveillance constitutes secondary prevention, facilitating early diagnosis and treatment. Surveillance should be done periodically and should include a medical examination and occupational questionnaire, chest radiograph with B read interpretation, tuberculosis screening, and spirometry, with referral of affected workers to a pulmonologist or occupational medicine physician for further evaluation (32).

Once PMF has been diagnosed, it is important to immunize the patient against influenza and pneumococcal infection, assess the need for oxygen supplementation, and encourage pulmonary rehabilitation. Exclusion of active tuberculosis is recommended and screening for latent tuberculosis infection by either skin testing or interferon gamma release assay should be considered (33). Systemic corticosteroids, inhaled aluminum citrate, poly(vinlypyridine-N-oxide) and whole lung lavage are unlikely to benefit patients with PMF and lung transplantation may be considered (4). 

Patients with PMF are considered ‘totally disabled’ from coal mine employment under the Black Lung Benefits Act in the United States. Outside the coal industry, they may be eligible for benefits under the Social Security Impairment system or the state workers’ compensation systems.

Conclusion

PMF represents the coalescence of smaller radiographic pneumoconiotic opacities to those over 10 millimeters in size. The rate of PMF in American coal miners has recently increased. Although most cases of PMF are reported among coal miners, this is likely a reflection of the fact that coal miners undergo active surveillance due to governmental regulations ¹². In this case series, we report PMF in workers outside the coal industry. Physicians and policymakers need to be aware of this condition in workers exposed to silica within and outside the coal industry.

Acknowledgments

Guarantor: Landon Casaus, M.D., takes responsibility for the content of the manuscript, including the data and analysis.

Author contributions: All authors had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. All authors contributed substantially to the data analysis and interpretation and the writing of the manuscript.

Financial/non-financial disclosures: All authors report no conflict of interest.

Abbreviations List

• AFB: Acid fast bacilli
• CT: computed tomography
• HIV: Human immunodeficiency virus
• HRCT: High resolution computed tomography
• IL: interleukin
• ICAM: Intercellular adhesion molecule
• NIOSH: National Institute for Occupational Safety and Health
• OSHA: Occupational Safety and Health Administration
• PMF: Progressive massive fibrosis
• PFT: Pulmonary function test
• US: United States

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Cite as: Casaus L, Bhatia S, Sood A. Progressive massive fibrosis in workers outside the coal industry: A case series from New Mexico. Southwest J Pulm Crit Care. 2019;18(1):10-9. doi: https://doi.org/10.13175/swjpcc110-18 PDF