1. Presented by Harsimar Kaur, MD
Reviewed by Karen Carroll, MD

A young adult with no significant past medical history presented to the Emergency Department with complaints of sore throat, fever, chills, and shortness of breath that started about 5 days ago and right flank pain that started 2 days ago. They also had tonsillar enlargement with cervical lymph node enlargement. They were diagnosed with infectious mononucleosis by a primary care physician. Their flank pain was 9/10 in severity, throbbing in nature, radiating to the left flank, with no aggravating or relieving factors. Of note, they had developed rhinorrhea and loss of smell 6 weeks ago and was diagnosed with COVID-19. The patient isolated at home and was recovered now in terms of COVID-19. On physical examination, they were ill appearing, tachycardic, tachypneic, hypotensive and had bilateral tonsillar enlargement and right costovertebral angle tenderness.

Laboratory studies showed the patient had mild leukocytosis, bandemia, thrombocytopenia, elevated lactate, and hyponatremia. Chest CT showed numerous nodular densities scattered peripherally within both lungs measuring up to 2.2 cm in size, compatible with multifocal pneumonia (Figure 1). The patient was admitted for bilateral pneumonia and urinary tract infection, and was started on azithromycin and ceftriaxone. They tested positive for COVID-19 again, but it was believed to be due to prolonged shedding. Urine culture grew mixed skin and urogenital flora. Urine Legionella antigen test was negative, as was urine Streptococcus pneumoniae antigen and rapid Streptococcus group A nucleic acid test. Epstein-Barr virus IgM and IgG antibodies were detected. Blood culture was positive for gram negative bacilli in the anaerobic bottle (Figure 2). An ultrasound of the neck veins revealed a partial thrombus in the left internal jugular vein (Figure 3), confirming the clinical team's suspicion.

Figure 1. Chest CT showing peripheral cavitary nodular density.

Figure 2. Gram stain showing pleomorphic gram-negative bacilli.

Figure 3. Doppler ultrasound showing partial thrombus involving the left internal jugular vein.

The clinical team consults you for your expert opinion. What do you think is the diagnosis?