Medical Image of the Week: Nocardiosis

Figure 1. Panel A: Thoracic CT scan showing enlarged left upper lobe mass. Panel B: CT scan from one month earlier showing a smaller lesion.

Figure 2. Panel A: GMS Silver stain showing Nocardia (200X magnification). Panel B: GMS silver stain showing Nocardia (400X magnification).

Figure 3. MRI Brain with arrows pointing to the lesion.

A 67 year-old man with advanced adenocarcinoma of the lung on chemotherapy and severe steroid dependent chronic obstructive pulmonary disease (COPD) was admitted for treatment of acute on chronic respiratory failure. He was admitted to the intensive care unit and required non-invasive positive pressure ventilation. He had a chest computed tomography scan (Figure 1A), with a left upper lobe mass, which was significantly larger than noted on a previous PET/CT scan (Figure 1B) from one month ago. He was placed on empiric broad-spectrum antibiotics and clinically improved. He underwent a transthoracic lung biopsy (Figure 2), which revealed the presence of organisms consistent with Nocardia on silver stain.  A brain MRI (Figure 3) showed the presence of a 4 mm enhancing lesion likely consistent with Nocardia.

Nocardiosis is a gram-positive bacterial infection caused by aerobic actinomycetes and is an important opportunistic pulmonary infection. It should be considered in the differential diagnosis of pulmonary infiltrates in immunosuppressed patients, including those with neoplasms, after organ transplantation, advanced HIV disease and those receiving chronic corticosteroid therapy or chemotherapy (1). Of importance to pulmonologists, in two reviews, COPD was a common underlying condition, representing over 20% of patients with Nocardiosis in these reports (2,3). Nocardia species are found in soil and infection is generally acquired through inhalation. The most common symptoms are fever, cough, pleuritic chest pain and headache. Common chest radiographic findings include consolidation, nodules, cavities and pleural effusions. Nocardia infections can disseminate to any organ but it has a predilection for spread to the central nervous system and patients with pulmonary Nocardia infections should have brain imaging to evaluate for cerebral dissemination. Antibiotics that are typically effective in Nocardia infections include trimethoprim-sulfamethoxazole (TMP-SMX), imipenim, amikacin, ceftriaxone and cefotaxime. However, antibiotic susceptibilities should be obtained and treatment tailored accordingly. It is recommended to treat severe systemic infections with two or three intravenous agents while awaiting susceptibility results. Treatment is usually prolonged because of the tendency of Nocardia infections to relapse or progress.  For patients with serious pulmonary infections and immunocompromised patients, duration of therapy is often at least 6 to 12 months or longer. Our patient was treated with TMP-SMX and meropenem and clinically improved. His steroids were rapidly tapered. Sputum cultures grew Nocardia farcinica.

Aarthi Ganesh MD, Muna Omar MD, James Knepler MD, and Linda Snyder MD

Department of Pulmonary and Critical Care

Banner University Medical Center

Tucson, AZ

References

1. Grigor LM, Hoover SE. Nocardiosis at a university medical center in the American southwest. Infect Dis Clin Pract 2014:22:279-82. [CrossRef]
2. Minero MV, Marín M, Cercenado E, Rabadán PM, Bouza E, Mu-oz P. Nocardiosis at the turn of the century. Medicine (Baltimore). 2009;88(4):250-61. [CrossRef] [PubMed]
3. Martínez Tomás R, Menéndez Villanueva R, Reyes Calzada S, Santos Durantez M, Vallés Tarazona JM, Modesto Alapont M, Gobernado Serrano M. Pulmonary nocardio-sis: risk factors and outcomes. Respirology. 2007;12(3):394-400. [CrossRef] [PubMed]

Reference as: Ganesh A, Omar M, Knepler J, Snyder L. Medical image of the week: nocardiosis. Southwest J Pulm Crit Care. 2015;10(5):220-2. doi: http://dx.doi.org/10.13175/swjpcc046-15 PDF

Medical Image of the Week: Esophageal Perforation

Figure 1. Axial, non-contrast CT of chest demonstrates wall thickening of the mid-thoracic esophagus with an extra-luminal focus of gas (blue arrow) in the mediastinum in addition to a small amount of right peri-esophageal fluid (red arrow).

Figure 2. Sagittal, non-contrast CT of chest demonstrates extra-luminal air posterior to the mid-thoracic esophagus (blue arrows).

A 74 year old man with a past medical history of esophageal strictures status post dilatation, coronary artery disease status post CABG, and atrial fibrillation presented to hospital with complaints of severe chest pain that began after the consumption of tortilla chips one hour prior to presentation. Electrocardiogram and cardiac enzymes were not consistent with acute coronary syndrome. Chest X-ray was consistent with a widened mediastinal silhouette. Contrast esophogram was negative for extra luminal extravasation. CT scan of the chest with oral contrast demonstrated thickening of the mid-thoracic esophagus with an extra-luminal focus of gas in the mediastinum along with fluid along the inferior aspect of the esophagus (Figures 1 and 2). These findings were concerning for esophageal perforation. The patient was taken to the operating room for endoscopy which showed micro perforation in mid-esophagus.

Esophageal perforation remains a highly morbid condition. Mortality rates are based predominantly on time of presentation and the etiology of perforation. Symptoms of esophageal perforation are non-specific and include neck or chest pain, dysphagia, odynophagia, difficulty breathing, vomiting, drooling, hematemesis, and abdominal rigidity (1) Initial diagnostic assessment includes conventional radiography, which can be normal in up to 10% of patients. Follow-up contrast esophograms are used to determine the presence and precise location of an esophageal perforation. However, false negative rates of 10% have been reported (2). CT scan of the chest or abdomen is indicated when contrast esophogram cannot be performed or all other diagnostic modalities have not been helpful in diagnosing esophageal perforation despite high clinical suspicion. Extra-luminal air in the mediastinum or surrounding the esophagus is the most reliable sign and when taken in conjunction with the clinical presentation, has 92% accuracy. Other common findings include obliteration of fat planes in the mediastinum resulting from inflammation, peri-esophageal or mediastinal fluid (92% accuracy), esophageal thickening, pleural effusions, extravasation of oral contrast material into the peri-esophageal tissues, and a tract at the site of the tear (3).

Jawad Bilal MD, David Testa MD, Irbaz bin Riaz MD and Ryan Nahapetian MD MPH

University of Arizona

Tucson, AZ

References

1. Aronberg RM, Punekar SR, Adam SI, Judson BL, Mehra S, Yarbrough WG. Esophageal perforation caused by edible foreign bodies: A systematic review of the literature. Laryngoscope. 2015;125(2):371-8. [CrossRef] [PubMed]
2. Bladergroen MR, Lowe JE, Postlethwait RW. Diagnosis and recommended management of esophageal perforation and rupture. Ann Thorac Surg. 1986;42(3):235-9. [CrossRef] [PubMed]
3. Lee S, Mergo PJ, Ros PR. The leaking esophagus: CT patterns of esophageal rupture, perforation, and fistulization. Crit Rev Diagn Imaging. 1996;37(6):461-90. [PubMed] 

Reference as: Bilal J, Testa D, Riaz I, Nahapetian R. Medical image of the week: eosphageal perforation. Southwest J Pulm Crit Care. 2015;10(4):201-2. doi: http://dx.doi.org/10.13175/swjpcc033-15 PDF