Case Presentation: A 58 year-old undomiciled man with no known medical history presented with three days of anorexia, malaise, abdominal pain, nausea and decreased urine output. His exam was notable for scleral icterus. Initial lab work was remarkable for sodium 133 mEq/L, BUN 132mg/dL, creatinine 8.82 mg/dL, platelet 64 K/uL, total bilirubin 6.4 mg/dL, and direct bilirubin 5 mg/dL. Lab work two years prior was within normal limits. An HCV antibody was reactive, a urinalysis revealed microscopic hematuria, and cocaine was detected on urine toxicology. An abdominopelvic CT and renal sonogram were non-pathologic. On the 5th hospital day, the creatinine began to downtrend. Despite resolution of his somatic complaints, the total bilirubin continued to rise to a peak of 11.2 mg/dL and a leukocytosis without fever developed, with a peak of 21.2 K/uL. Ceftriaxone was empirically started and an extensive work up with blood cultures, acute viral hepatitis serologies, ANA, alpha-1 antitrypsin, complement, cryoglobulin and ceruloplasmin levels, microsomal, smooth muscle and antimitochondrial antibodies were normal. An MRCP was normal. Review of the pre-admission history revealed potential exposure to rodents as he slept in close proximity to a dumpster. Leptospirosis serology was sent and antibiotics were adjusted to doxycycline. At the time of discharge, the WBC and platelet counts had normalized, and the total bilirubin and creatinine down-trended. After discharge, the IgM serology for leptospira resulted as positive.

Discussion: Leptospirosis is a worldwide zoonotic disease commonly associated with moist environments, poor housing and inadequate sanitation. Rodents are important reservoirs, shedding spirochetes through their urine. Human infection results from exposure to animal urine, contaminated soil or water, or infected animal tissue. Portals of entry include cuts, mucous membranes or conjunctivae. Person-to-person transmission is rare. The incubation period is usually 5–14 days and illness severity can range from subclinical to life-threatening. Disease manifestations include jaundice with acute kidney failure (Weil’s disease), rash, conjunctival suffusion, hyponatremia, thrombocytopenia, microscopic hematuria, myocarditis, pulmonary hemorrhage, and meningitis. A biphasic illness, the acute febrile bacteremic phase can last 2-9 days followed by a period of apparent improvement. An “immune” phase then follows, characterized by development of complications (as in our patient). During this phase, leptospires are absent from blood but may appear in the urine. While human cases of leptospirosis are rarely reported in the US outside of Puerto Rico and Hawaii (in the absence of travel), there was a significant rise reported to the NYC Department of Health in 2021 than in any prior year. A potential explanation is an increase in housing insecurity and disruptions to waste management as a consequence of the Covid-19 pandemic.

Conclusions: Leptospirosis is an important consideration in at-risk populations who may unknowingly be exposed as a result of their living conditions. Our case of unexpected Weil’s disease in an urban setting underscores the importance of a thorough social history and highlights the importance of timely recognition of uncommon infections as possible reversible causes of multi-organ failure in the context of a changing world climate.