Medical Image of the Week: Staphylococcal Pneumonia in a Patient with Influenza

Figure 1. Thoracic CT scan axial view demonstrating bilateral cavitary infiltrates.

A 63-year-old, obese diabetic man presented to his primary care physician with complaints of fever, headache, myalgias, and cough. A nasal swab specimen was positive for influenza A by fluorescent immunoassay. Therapy with oseltamivir was initiated. The patient’s symptoms progressed and he was transported to the emergency department , where he was found to have a room air oxygen saturation of 74%, bilateral basilar infiltrates on chest radiograph, a white blood count of 24.2 K/uL and a procalcitonin level of 12.66 ng/ml. He was placed on BIPAP with high flow supplemental oxygen,  started on empiric intravenous antibiotic therapy with vancomycin and piperacillin/tazobactam, and admitted to the intensive care unit.  Blood and sputum cultures were eventually positive for methicillin-sensitive Staphylococcus aureus, and the patient’s antibiotic therapy was de-escalated to nafcillin. On hospital day 5, a CT of the chest obtained to evaluate pleuritic pain revealed extensive bilateral cavitary infiltrates (Figure 1). The patient’s discomfort resolved without further intervention, he continued to improve, and was uneventfully transitioned to oral therapy. 

S. aureus pneumonia is characterized by high fever, productive cough, and a radiographic pattern of patchy, often multilobar, infiltrates which may exhibit cavitary change.  In the USA, approximately 2% of patients admitted to the hospital for treatment of community-acquired pneumonia demonstrate microbiologic evidence of S. aureus infection (1). There is a slight predominance of methicillin sensitive species (MSSA) compared to methicillin resistant species (MRSA).  Morbidity and mortality are both high, with over 80% of patients requiring care in the ICU, and a fatality rate of 13% (2).

Among patients admitted to the intensive care unit with a primary diagnosis of influenza, there is a 15% incidence of S. aureus pneumonia. Risk factors for co-infection in this setting  include obesity, HIV infection, and immunosuppressive medication. There is a robust association between bacteremia and mortality (3).  Early empiric antibiotic therapy with an agent active against S. aureus should be strongly considered for patients admitted to the ICU with influenza complicated by pneumonia, pending the return of blood and respiratory cultures.

¹Charles VanHook, ²Kristin Dahlem, and ¹Angela Taylor

¹Longmont United Hospital, Longmont, Colorado USA

²Massachusetts College of Pharmacy and Health Sciences, Boston, Massachusetts USA

References

1. Jain S, Self WH, Wunderink R, et al. Community-acquired pneumonia requiring hospitalization among U.S. adults. N Engl J Med. 2015 Jul 30;373(5):415-27. [CrossRef] [PubMed]
2. Self WH, Wunderink RG, Williams DJ, et al. Staphylococcus aureus community-acquired pneumonia: prevalence, clinical characteristics, and outcomes. Clin Infect Dis. 2016 Aug 1;63(3):300-9. [CrossRef] [PubMed]
3. Martin-Loeches I, J Schultz M, et al. Increased incidence of co-infection in critically ill patients with influenza. Intensive Care Med. 2017 Jan;43(1):48-58. [CrossRef] [PubMed]

Cite as: VanHook C, Dahlem K, Taylor A. Medical image of the week: staphylococcal pneumonia in a patient with influenza. Southwest J Pulm Crit Care 2017:14(4):170-1. doi: https://doi.org/10.13175/swjpcc045-17 PDF

Medical Image of the Week: Bronchopulmonary Sequestration

Figure 1. A) Chest x-ray PA view demonstrating an oblong soft tissue density in the retrocardiac region overlying the medical aspect of the left hemidiaphragm. B) Chest x-ray lateral view demonstrating the same opacity anterior to a lower thoracic vertebral body, suspicious for a lung mass.

Figure 2. Chest computed tomography A) axial and B) coronal sections demonstrating a lobulated, cystic structure within the left lower lobe with a feeding artery off the aorta, consistent with a pulmonary sequestration.

A 49-year-old woman was incidentally found to have a lung mass on a pre-operative chest x-ray done prior to an elective cholecystectomy (Figure 1). Chest computed tomography, ordered to further characterize this mass revealed a left lower lobe lobulated, cystic opacity with a feeding artery from the aorta, consistent with bronchopulmonary sequestration (BPS) (Figure 2). Given that she has not had any complications of BPS we elected to manage her conservatively with observation.

BPS is a rare congenital malformation of the lower airways characterized by abnormal lung tissue that does not communicate with the tracheobronchial tree and receives its blood supply from the systemic circulation (1). Our patient’s BPS was intralobar in location, occurring within a normal lobe but lacking its own visceral pleura. The posterior basal left lower lobe is the most common intralobar location. Among cases that escape clinical detection in infancy, BPS comes to light in childhood or adulthood as either an incidental radiographic finding or as a symptomatic presentation of a lung infection. While surgical resection is generally considered to be the treatment of choice given the risk of developing infection, hemorrhage or malignancy (2), some asymptomatic adults with BPS may be managed conservatively with observation with serial imaging (3).

Udit Chaddha MD¹, Niusha Damaghi MD¹, Ashley Prosper MD², and Ching-Fei Chang MD¹

¹Division of Pulmonary, Critical Care and Sleep Medicine and ²Department of Radiology

Keck School of Medicine

University of Southern California

Los Angeles, CA USA

References

1. Biyyam DR, Chapman T, Ferguson MR, Deutsch G, Dighe MK. Congenital lung abnormalities: embryologic features, prenatal diagnosis, and postnatal radiologic-pathologic correlation. Radiographics. 2010 Oct;30(6):1721-38. [CrossRef] [PubMed]
2. Azizkhan RG, Crombleholme TM. Congenital cystic lung disease: contemporary antenatal and postnatal management. Pediatr Surg Int. 2008 Jun;24(6):643-57. [CrossRef] [PubMed]
3. Stanton M, Njere I, Ade-Ajayi N, Patel S, Davenport M. Systematic review and meta-analysis of the postnatal management of congenital cystic lung lesions. J Pediatr Surg. 2009 May;44(5):1027-33. [CrossRef] [PubMed]

Cite as: Chaddha U, Damaghi N, Prosper A, Cha C-F. Medical image of the week: bronchopulmonary sequestration. Southwest J Pulm Crit Care. 2017;14(4):168-9. doi: https://doi.org/10.13175/swjpcc036-17 PDF