Discordance of the Urinary and Pleural Fluid Antigen Test and False Positive for Streptococcus pneumoniae in Empyema Secondary to Necrotizing Bacterial Pneumonia.

Empyema is a severe complication of pneumonia with high morbidity and mortality rates. Rapid diagnosis and tailoring of antibiotic therapy are crucial to treatment success for these severe bacterial lung infections. A Streptococcus pneumoniae (S. pneumonia) antigen test drawn from the pleural fluid rather than a urine sample has been found to have equivalent diagnostic utility to the urinary antigen test. Discordance between these tests is rare. We report a case of a 69-year-old female with CT imaging findings consistent with empyema and a bronchopulmonary fistula. A rapid S. pneumonia antigen test was negative from the urinary sample but positive when drawn from a patient's pleural fluid sample. Final pleural fluid cultures resulted in Streptococcus constellatus (S. constellatus). This case demonstrates discordance between the results of urinary and pleural fluid S. pneumoniae antigen tests, representing a potential pitfall in using rapid antigen testing on pleural fluid samples. False positives for the S. pneumoniae antigen in patients with viridans streptococci infections have been documented due to the cross-reactivity of cell wall proteins in different streptococcal species. Physicians encountering bacterial pneumonia of unknown etiology complicated by empyema should understand the potential for discordance and false positives using this diagnostic method.

The Curious Case of Elevated Tryptase: Workup and Differential in Family of Four.

Elevated basal serum tryptase (BST) levels are markers of both mast cell activation and overall mast cell burden. We present a family of four individuals with elevated tryptase levels greater than or equal to 20 mcg/L, all of whom exhibited signs and symptoms suggestive of mast cell activation. Differential diagnoses included hereditary alpha tryptasemia (HaT), systemic mastocytosis (SM), and mast cell activation syndrome (MCAS). In three individuals, SM was ruled out with normal morphology on bone marrow biopsy combined with negative genetic markers. Further workup would be required for the diagnosis of MCAS since serum tryptase levels were not obtained in our emergency department during acute episodes. Although genetic testing for HaT was not available upon initial workup, HaT remains the most likely explanation for this family's elevated BST.

A Case of Lyme Carditis With Variable Heart Block Successfully Treated With Oral Doxycycline.

A 39-year-old male without significant past medical history presented with three weeks of worsening fatigue, migratory arthralgia, rash, and unilateral facial weakness after spending three months in Vermont. Serology showed positive Lyme titers 1:64 for both IgM and IgG. EKG on presentation showed a P-R interval of 384 ms, and the patient was admitted for concern of Lyme carditis. Serial EKGs obtained throughout his stay demonstrated variability between first- and second-degree heart blocks. After consultation with Infectious Disease, he was transitioned to oral doxycycline to complete a 21-day course. The patient's heart block and other symptoms had resolved on follow-up after the treatment course had been completed.