Board Review: Infectious Disease
A 60-year-old male presents with fever, dry cough, headache, nausea, vomiting and diarrhea. He saw his primary care physician who prescribed him Amoxicillin for which he has been taking for 4 days but feeling worse. Labs show a Sodium of 130 and mild transaminitis, other labs are within normal limits. What is the most likely diagnosis?
A. Tularemia
B. Hantavirus
C. Legionella
D. Q-fever
E. PCP pneumonia
Answer: C - Legionella
-Micro: Gram negative bacillus found in water systems.
-Clinical: pneumonia type symptoms + GI symptoms +/- neuro symptoms (confusion, ataxia); can have associated fever-pulse dissociation (relative bradycardia in setting of fever).
-Hyponatremia and transaminitis are common lab findings in Legionella.
-Diagnosis is via urinary antigen test.