Medical Image of the Month: Viral Pneumonias

Figure 1. Pulmonary viral infection spectrum on thoracic CT scan in lung windows: A= Coronavirus NL63; B= Adenovirus; C= Influenza AH1 2009; D= COVID-19; E= Coronavirus HKU1; F= Influenza AH1 2009.

Numerous viruses, including the corona, influenza and adenoviruses can cause lower respiratory tract infection in adults (1). Viral pneumonia in adults can be classified into two clinical groups: so-called atypical pneumonia in otherwise healthy hosts and viral pneumonia in immunocompromised hosts. Until the COVID-19 pandemic, influenza virus types A and B caused most cases of viral pneumonia in immunocompetent adults. Immunocompromised hosts are susceptible to pneumonias caused by a wide variety of viruses including cytomegalovirus, herpesviruses, measles virus, and adenovirus. The CT imaging findings consist mainly of patchy or diffuse ground-glass opacity, with or without consolidation, and reticular areas of increased opacity, are variable and overlapping. The imaging findings in COVID-19 pneumonia are generally not distinctive compared to other viral pneumonias, including other coronaviruses such as SARS and MERS (2). A recent study systematically reviewed the longitudinal changes of CT findings in COVID-19 pneumonia. The results suggested that the lung abnormalities increase quickly after the onset of symptoms, peak around 6-11 days, and are followed by persistence of the findings.

Bacterial pneumonias may also take multiple forms and are sometimes difficult to radiographically separate from viral pneumonia (3). However, the presence of ground-glass opacities alone is unusual for a bacterial pulmonary infection. Rather, bacterial infections commonly present as areas of consolidation with air bronchogram formation, centrilobular nodules (often with branching configurations) and airway thickening.

Michael B. Gotway MD

Department of Radiology

Mayo Clinic Arizona

Scottsdale, AZ USA

References

1. Kim EA, Lee KS, Primack SL, et al. Viral pneumonias in adults: radiologic and pathologic findings. Radiographics. 2002 Oct;22 Spec No:S137-49. [CrossRef] [PubMed]
2. Wang Y, Dong C, Hu Y, Li C, Ren Q, Zhang X, Shi H, Zhou M. Temporal Changes of CT Findings in 90 Patients with COVID-19 Pneumonia: A Longitudinal Study. Radiology. 2020 Mar 19:200843. [CrossRef] [PubMed]
3. Panse PM, Jokerst CE, Gotway MB. May 2020 Imaging Case of the Month: Still Another Emerging Cause for Infiltrative Lung Abnormalities. Southwest J Pulm Crit Care. 2020. May 1. (in press). [CrossRef]

Cite as: Gotway MB. Medical image of the month: viral pnuemonias. Southwest J Pulm Crit Care. 2022;20(5):163-4. doi:  https://doi.org/10.13175/swjpcc028-20 PDF 

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: Pneumothorax with Air Bronchograms

Figure 1. Panel (A) shows mild congestion with prominent bronchovascular markings. Panel (B) shows a large left pneumothorax with total collapse of the left lung marked by extensive airspace opacities and distinct air bronchograms. Panel (C) shows interval placement of a left-sided pigtail catheter with partial resolution of the left pneumothorax. There is persistent collapse of the medial aspect of the left upper lobe. Panel (D) shows complete resolution of the left pneumothorax and left lung atelectasis with continued bilateral airspace disease.

Development of pneumothoraces in critically ill patients is commonly encountered in the critical care unit (ICU). Incidence has been reported between 4-15% of patients. In most instances, pneumothorax in the ICU is considered a medical emergency especially when the patient is mechanically ventilated (1).  Here, we present a 61-year-old man with a past medical history of insulin dependent diabetes and paraplegia from prior spine injury who presented with acute respiratory distress after a pulseless electrical activity cardiac arrest. Cardiopulmonary resuscitation (CPR) was initiated by emergency medical services at home, and continued and the emergency department (ED) for a total of 30 minutes. The patient presented previously to the ED, one week prior, for a mild respiratory illness and tested positive for influenza B. He was sent home on oseltamivir. His family is unsure of compliance with medication but reported he was clinically stable up to the morning of presentation. The patient, as shown in the images, developed a left pneumothorax complicating an "adult respiratory distress syndrome (ARDS)- like" picture probably due to positive pressure ventilation with high positive end expiratory pressure, CPR, or both. The patient underwent immediate chest tube placement and with successful lung re-expansion. Unfortunately, his hemodynamic status/septic shock/multi-organ system failure continued to deteriorate within hours and he expired despite maximal support. Pneumothorax in patients with ARDS has higher morbidity and mortality compared to other critically ill patients due to the high-pressure needed during mechanical ventilation. This places patients at a high risk for the rapid progression to tension pneumothorax and even death. Therefore, in this high-risk population, a pneumothorax requires a high index of suspicion, prompt recognition, and immediate intervention (2).

Huthayfa Ateeli, MBBS and Steve Knoper, MD.

Department of Medicine, Division of Pulmonary, Critical Care, Sleep and Allergy Medicine. University of Arizona, Tucson, AZ USA

References

1. Yarmus L, Feller-Kopman D. Pneumothorax in the critically ill patient. Chest. 2012 Apr;141(4):1098-105. [CrossRef] [PubMed] 
2. Gattinoni L, Bombino M, Pelosi P, Lissoni A, Pesenti A, Fumagalli R, Tagliabue M. Lung structure and function in different stages of severe adult respiratory distress syndrome. JAMA. 1994 Jun 8;271(22):1772-9. [CrossRef] [PubMed] 

Cite as: Ateeli H, Knoper S. Medical image of the week: pneumothorax with air bronchograms. Southwest J Pulm Crit Care. 2016:13(3):129-30. doi: http://dx.doi.org/10.13175/swjpcc066-16 PDF

Medical Image Of The Week: Secondary Pneumonia Presenting as Hemoptysis

Figure 1. A-C: Axial images of the chest demonstrating bilateral consolidation of the lung with air bronchograms. D: Chest radiograph on presentation. E: BAL findings. F: Bronchoscopic images of diffuse airway sloughing; this is the main carina.

A 44 year-old man with a history of asthma presented to the hospital with encephalopathy, severe hypoxia and what was reported to be hematemesis. The patient was intubated in the Emergency Department and mechanical ventilation was instituted. Upper endoscopy was performed but source of bleeding could not be identified. Imaging of the chest showed pulmonary consolidation on both plain radiograph (D) and computed tomography (A-C). Bronchoscopy revealed a very friable mucosa with sloughing of the respiratory epithelium from the main carina (F) to at least the subsegmental level. Bronchoalveolar lavage (BAL) returned bloody fluid (E) but without any increase in blood with subsequent aliquots of fluid. The patient had progressively worsening hypoxia consistent with the acute respiratory distress syndrome (ARDS) requiring rescue maneuvers including paralysis, airway pressure release ventilation, and inhaled nitric oxide but we were unable to implement proning or transfer for extracorporeal life support due to profound cardiovascular collapse refractory to treatment. Ultimately, he succumbed from multiorgan failure. On laboratory evaluation of the BAL both Staphylococcus aureus and Influenza B virus were detected.

Bacterial pneumonia is a common complication of influenza infection. Historically, patients at the extremes of age have been most susceptible to secondary pneumonia. However, during the recent 2009 influenza pandemic an unusually high rate of secondary pneumonia among young adults was observed (1). The most common bacterial pathogens isolated following influenza infection include Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus mitis, Streptococcus pyogenes and Haemophilus influenzae (2). A number of pathogenic mechanisms for synergies between influenza and bacteria have been proposed including disruption of the respiratory epithelium leading to enhanced bacterial adhesion (3).

Cameron Hypes MD MPH^1,2, Christian Bime MD MSc¹, Kevin Sun MD³, and Elizabeth Ulliman MD³

¹ Department of Medicine, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, University of Arizona Medical Center; Tucson, AZ

² Department of Emergency Medicine, University of Arizona Medical Center; Tucson, AZ

³ Department of Medicine, University of Arizona Medical Center; Tucson, AZ

References

1. Chowell G, Bertozzi SM, Colchero MA, Lopez-Gatell H, Alpuche-Aranda C, Hernandez M, et al. Severe respiratory disease concurrent with the circulation of H1N1 influenza. New Engl J Med. 2009;361(7):674-9. [CrossRef] [PubMed]
2. Centers for Disease Control and Prevention (CDC). Bacterial coinfections in lung tissue specimens from fatal cases of 2009 pandemic influenza A (H1N1) - United States, May-August 2009. MMWR Morb Mortal Wkly Rep. 2009;58(38):1071-4. [PubMed]
3. Metersky ML, Masterton RG, Lode H, File Jr TM, Babinchak T. Epidemiology, microbiology, and treatment considerations for bacterial pneumonia complicating influenza. Int J Infect Dis. 2012;16(5):e321-e31. [CrossRef] [PubMed]

Reference as: Hypes C, Bime C, Sun K, Ulliman E. Medical image of the week: secondary pneumonia presenting as hemoptysis. Southwest J Pulm Crit Care. 2014;9(3):177-8. doi: http://dx.doi.org/10.13175/swjpcc116-14 PDF