Infectious Disease

Leptospirosis — Clinical Reference

Last reviewed 2026-06-19 · TruelyserMD Clinical Reference
For Patients & General Readers

Leptospirosis is an illness caused by bacteria found in the urine of infected animals like rodents and dogs. People can get it by touching contaminated water or soil, or through cuts in their skin. It can cause flu-like symptoms but sometimes leads to serious problems with the liver, kidneys, and brain.

Clinical Overview

Leptospirosis is a zoonotic spirochetal infection caused by pathogenic Leptospira species. It presents with a wide spectrum of illness, from asymptomatic infection to severe multiorgan failure (Weil's disease), characterized by jaundice, renal impairment, and hemorrhage.

Clinical Presentation

Signs & Symptoms

Symptoms (Patient-Reported)

  • Sudden onset of fever
  • Severe headache
  • Muscle aches (especially in the calves and lower back)
  • Chills
  • Nausea and vomiting
  • Diarrhea
  • Red eyes (conjunctival suffusion)
  • Jaundice (yellowing of skin and eyes)

Signs (Clinician-Observed)

  • Fever
  • Conjunctival suffusion
  • Jaundice
  • Tenderness on palpation of calf muscles
  • Meningeal signs (nuchal rigidity, Kernig's sign, Brudzinski's sign)

Differential Diagnoses

ConditionDistinguishing Feature
InfluenzaLeptospirosis often presents with more prominent conjunctival suffusion, myalgias, and potential for jaundice and renal involvement.
Dengue FeverDengue typically has a petechial rash and retro-orbital pain; leptospirosis may have jaundice and more severe myalgias.
MalariaMalaria has cyclical fevers and often a history of travel to endemic areas; leptospirosis can be acquired in non-endemic regions and lacks cyclical fever patterns.
Hepatitis A/EHepatitis primarily affects the liver and may present with jaundice, but typically lacks the prominent myalgias and renal involvement seen in leptospirosis.
Viral MeningitisWhile leptospirosis can cause aseptic meningitis, the presence of fever, myalgias, conjunctival suffusion, and potential for systemic organ involvement helps differentiate.
Hantavirus Pulmonary SyndromeHantavirus causes respiratory distress and often a history of rodent exposure, but typically lacks the jaundice and prominent muscle aches of leptospirosis.

Red Flags — Seek Immediate Care

Key Investigations

Management Overview

Treatment of leptospirosis involves supportive care and antibiotic therapy, typically with doxycycline or penicillin, initiated as early as possible. Severe cases require hospitalization for management of organ dysfunction, including fluid resuscitation, electrolyte correction, and renal replacement therapy if indicated.

Disclaimer: This article is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment. TruelyserMD does not replace clinical judgement.