Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 34-10: Leptospirosis + Key Features Download Section PDF Listen +++ +++ Essentials of Diagnosis ++ Clinical illness can vary from asymptomatic to fatal liver and kidney failure Anicteric leptospirosis is the more common and milder form of the disease Icteric leptospirosis (Weil syndrome) is more severe form of the disease +++ General Considerations ++ Leptospirosis is an acute and sometimes severe infection caused by 21 species within the genus Leptospira Leptospirosis Occurs worldwide Transmitted to humans by the ingestion of food and drink contaminated by the urine of the infected animal The organism may also enter through minor skin lesions and probably via the conjunctiva Cases have occurred in international travelers after swimming or rafting in contaminated water Occupational cases occur among sewer workers, rice planters, abattoir workers, and farmers Sporadic urban cases have been seen in homeless persons exposed to rat urine The incubation period is 2–20 days + Clinical Findings Download Section PDF Listen +++ +++ Symptoms and Signs ++ Anicteric leptospirosis is often biphasic Initial or "septicemic" phase characterized by Abrupt fever to 39–40°C Chills Abdominal pain Severe headache Myalgias Marked conjunctival suffusion The second or "immune" phase begins after a 1- to 3-day period of improvement and is characterized by Appearance of specific antibodies Recurrence of symptoms with the onset of meningitis Uveitis—unilateral or bilateral Rash Nausea, vomiting, diarrhea Adenopathy However, in severe disease the phases may appear indistinct Icteric leptospirosis (Weil syndrome) is often continuous and is characterized by Impaired kidney and liver function Abnormal mental status Hemorrhagic pneumonia Hypotension +++ Differential Diagnosis ++ Bacterial meningitis Influenza Viral hepatitis Yellow fever Dengue Rickettsial disease Hemorrhagic fever, eg, hantavirus Relapsing fever + Diagnosis Download Section PDF Listen +++ +++ Laboratory Tests ++ Early in the disease, the organism may be identified by Darkfield examination of the patient's blood (a test requiring expertise since false-positives are frequent in inexperienced hands) Culture on a semisolid medium (eg, Fletcher medium); cultures may take 1–6 weeks to become positive but may remain negative if antibiotics were started prior Leptospires are excreted in the urine, and urine cultures may be positive from 10 days to 6 weeks Leukocyte count may be normal or as high as 50,000/mcL (0.05/L) Urine bile, protein, casts, and red cells Oliguria is common; uremia may occur in severe cases Elevated bilirubin and aminotransferases in 75% Elevated creatinine (> 1.5 mg/dL [> 132.6 mcmol/L]) in 50% Serum creatine kinase is usually elevated Diagnosis is usually made by serologic tests Agglutination tests show a fourfold or greater rise in titer Indirect hemagglutination, enzyme immunosorbent assay (EIA), and ELISA tests are also available. The IgM EIA is particularly useful (positive as early as 2 days into illness, extremely sensitive and specific [93%]) Polymerase chain reaction methods Appear to be sensitive, specific, positive early in disease Able to detect leptospiral DNA in blood, urine, CSF, and aqueous humor However, still investigational + Treatment Download Section PDF Listen +++ +++ Medications ++ Many cases are self-limited without specific treatment Mild to moderate leptospirosis Doxycycline, 100 mg orally twice daily for 7 days, is effective if started early Amoxicillin, 50 mg/kg orally divided into three doses daily Azithromycin is also active, but clinical experience is limited Severe leptospirosis Drugs of choice: doxycycline (100 mg every 12 hours orally or intravenously), penicillin (1.5 million units intravenously every 6 hours intravenously) or ceftriaxone (1 g/day intravenously) Especially effective if started within the first 4 days of illness Jarisch–Herxheimer reactions may occur + Outcome Download Section PDF Listen +++ +++ Complications ++ Myocarditis, aseptic meningitis, acute kidney injury, and pulmonary infiltrates with hemorrhage Iridocyclitis +++ Prognosis ++ Anicteric leptospirosis Usually self-limited Lasts 4–30 days Almost never fatal Complete recovery is the rule Icteric leptospirosis: mortality rate for those under age 30 is 5%; for those over age 60, it is 40% +++ Prevention ++ Avoidance of potentially contaminated food and water Prophylaxis with doxycycline (200 mg orally once a week) has been effective in trials and may be useful if a person is a high risk due to being in an area or season when exposure would be more likely Human vaccine is used in some limited settings but is not widely available +++ When to Admit ++ Patients with jaundice or other evidence of severe disease + References Download Section PDF Listen +++ + +Bourque DL et al. Illnesses associated with freshwater recreation during international travel. Curr Infect Dis Rep. 2018 May 22;20(7):19. [PubMed: 29789961] + +Grennan D. JAMA patient page. Leptospirosis. JAMA. 2019 Feb 26;321(8):812. [PubMed: 30806697] + +Jiménez JIS et al. Leptospirosis: report from the task force on tropical diseases by the World Federation of Societies of Intensive and Critical Care Medicine. J Crit Care. 2018 Feb;43:361–5. [PubMed: 29129539]