A healthy 16-year-old boy develops abrupt-onset high fever, severe headache, and neck stiffness three days after swimming in a warm stagnant pond. Lumbar puncture shows purulent CSF with high neutrophil count, low glucose, and motile amoeboid organisms that transform into biflagellate forms when the CSF is cooled. The most effective drug used in the treatment of this condition is:

• A Metronidazole
• B Nitazoxanide
• C Amphotericin B ✓
• D Ivermectin

Explanation

The history of swimming in warm freshwater followed by rapid-onset purulent meningitis with flagellating amoebae is diagnostic of primary amoebic meningoencephalitis caused by Naegleria fowleri. Amphotericin C, given intravenously with intrathecal administration, is the mainstay of therapy, occasionally combined with miltefosine, rifampin, and fluconazole. Metronidazole is active against Entamoeba histolytica but has poor activity against Naegleria, which explains why the common amoebic drug fails here.

Reference: Paniker's Textbook of Medical Parasitology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.