From the Research
The Jarisch-Herxheimer reaction in leptospirosis manifests as a temporary worsening of symptoms that occurs shortly after starting antibiotic treatment, with a reported incidence of 21% in some studies 1. This reaction is characterized by fever, chills, headache, myalgia, tachycardia, hypotension, and occasionally rash or exacerbation of skin lesions. The reaction usually begins within 1-2 hours of the first antibiotic dose and resolves within 24 hours. Management is primarily supportive, including antipyretics like acetaminophen (500-1000mg every 6 hours) for fever and pain, adequate hydration, and close monitoring of vital signs. In severe cases with significant hypotension, IV fluids may be necessary. Despite this reaction, antibiotic therapy should not be discontinued as it remains essential for treating the underlying leptospirosis infection. The reaction occurs because rapid killing of spirochetes by antibiotics releases endotoxins and inflammatory mediators, triggering a robust immune response, with tumor necrosis factor, interleukin-6, and interleukin-8 proposed as mediators of the reaction 2. Some studies suggest that the incidence of Jarisch-Herxheimer reaction may be higher in certain populations, such as those infected with Leptospira interrogans serogroup Australis, and in patients who receive antibiotic treatment early in the course of the disease 1. Patients should be informed about this potential reaction before starting antibiotics to reduce anxiety if symptoms worsen initially. The reaction is generally self-limiting and does not indicate treatment failure or allergic reaction to the medication. It is essential to note that the true prevalence of JHR in leptospirosis is unknown, and awareness of this event is insufficient, highlighting the need for systematic monitoring for clinical status early after antibiotic administration 3. In addition, large well-designed studies are required to precise the incidence and the impact of JHR as well as the severity and rates between various antibiotics 3. Overall, the Jarisch-Herxheimer reaction is a significant consideration in the management of leptospirosis, and clinicians should be aware of its potential to cause morbidity and mortality, particularly in severe cases 4, 5.