Investigators at University of California, San Francisco, and other centers, report a case of leptospirosis in a 14-year-old boy with severe combined immunodeficiency. He presented with headache and fever that lasted 6 days. In the previous 8 months he swam in a river in Puerto Rico and in a pool frequented by feral cats. A previous episode of fever and headache was complicated by conjunctivitis and followed by uveitis and thrombocytopenia. A recurrence of headache and fever was associated with increased CSF white cells (125/cmm) and protein (97 mg/dL), lowered glucose (24 mg/dL) and negative cultures, compatible with meningoencephalitis. He was readmitted with fever, headache, weakness, myalgias, nausea and vomiting. MRI showed T2-weighted hyperintensities in the basal ganglia and granulomatous leptomeningitis. A worsening hydrocephalus was treated with an extraventricular drain, and new-onset status epilepticus was controlled by a medically induced coma. CSF and serum samples sent for unbiased next-generation sequencing was positive for leptospira infection in the CSF but not in serum. Clinical assays for leptospirosis were negative. Treatment with high-dose intravenous penicillin G was followed by a gradual recovery over 7 days, resolution of status epilepticus, normal CSF, and resolution of leptomeningitis on serial MRI scans. PCR and serological testing at the CDC subsequently confirmed evidence of Leptospira santarosai infection. [1]

COMMENTARY. Leptospirosis is caused by spirochetes contracted from the urine of infected wild or domestic animals, usually while swimming in contaminated water. The incubation period is 5 to 14 days (range, 2 to 30 days). The most characteristic clinical findings are conjunctival suffusion, uveitis, and myalgias of the calf and lumbar regions [2]. An initial septicemic phase is followed by an immune-mediated phase, complicated by purpuric rash. Duration varies from less than 1 week to several months, with occasional episodes of apparent recovery. Severity ranges from self-limited systemic illness (90% patients) to life-threatening illness with jaundice, renal failure, and hemorrhagic pneumonitis (Weil syndrome).