Case Presentation: A 68-year-old woman with an unknown past medical history presented to the emergency department after a bystander who had previously seen her sleeping in a park noticed her looking unwell. Her vital signs were normal. She endorsed moderate, bilateral leg pain. Exam was notable for scleral icterus. While alert and oriented, she was unable to provide additional history about her symptoms. Notable laboratory results included thrombocytopenia (platelets 20 K/uL), anemia (hemoglobin 10.6 g/dL), hypokalemia (K 2.5 mEq/L), abnormal renal function (creatinine 1.5 mg/dL), and abnormal liver function tests (total bilirubin 2.1mg/dL, ALT 56 U/L, AST 86 U/L). She had no known baseline labs. On hospital day two, piperacillin/tazobactam was started after one of two blood cultures grew gram-positive rods, which was later determined to be a contaminant. Urinalysis was consistent with a urinary tract infection, and cultures grew Klebsiella pneumoniae. Due to her constellation of abnormal laboratory findings, bilateral leg pain, and history of homelessness, urine and serum Leptospirosis polymerase chain reaction (PCR) assays were ordered. Piperacillin/tazobactam was continued both for her drug resistant Klebsiella pneumonia in the urine and empiric treatment of possible leptospirosis. She remained clinically stable and completed a seven day course of piperacillin/tazobactam. Her urine leptospirosis PCR resulted positive near the end of this antibiotic course. Two weeks later, her platelets, liver tests and creatinine had all improved.
Discussion: Leptospirosis is a zoonotic bacterial infection caused by Leptospira, a mobile, aerobic spirochete found in amphibians, reptiles, and mammals in temperate and tropical areas of the world. Infections occur after exposure to water or soil contaminated by animal urine. There are 100-200 cases reported annually in the United States, with more than half in Hawaii. The last case of leptospirosis reported to the San Francisco Department of Public Health was in 2020 in a patient experiencing homelessness, although this patient had also traveled outside of the city. Other locations in the United States, including both in Florida and New York City have identified homelessness as a risk for infection, with dogs and rodents the likely bacterial reservoirs [1,2].The patient’s non-oliguric renal failure, hypokalemia, and jaundice are consistent with Weil’s disease, a serious complication of leptospirosis. Other notable clinical and laboratory findings that are consistent with leptospirosis include lower extremity muscle tenderness, fever, thrombocytopenia, proteinuria, microscopic hematuria, muddy brown and WBC casts in the urine, elevations in ALT/AST, and hyperbilirubinemia. Notably, about half of patients with leptospirosis have conjunctival suffusion, which our patient did not have.
Conclusions: While leptospirosis is rare in most of the United States outside Hawaii, our patient’s homelessness increased her risk for exposure to infected animals and their urine. Leptospirosis should be considered in all patients from temperate and tropical areas of the world with the characteristic constellation of clinical findings and laboratory results, particularly in individuals experiencing homelessness.