Primary amoebic meningoencephalitis

Primary amoebic meningoencephalitis (PAM) is a rare, usually fatal brain infection caused by Naegleria fowleri. The amoeba typically enters through the nose during exposure to contaminated warm freshwater and travels along olfactory nerves to the brain.

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Naegleria fowleri: A free-living amoeba that can cause primary amoebic meningoencephalitis when it enters the human nose. This species causes nearly all PAM cases and initiates infection after nasal exposure.
Naegleria fowleri infection prevention: Measures that reduce the chance of Naegleria fowleri entering the nose during freshwater or water-system exposure. Avoiding nasal exposure is the main practical way to reduce PAM risk.
Bacterial meningitis: Meningeal inflammation caused by bacteria, often requiring prompt antimicrobial treatment. Its early symptoms can resemble PAM, but its cause and treatment differ.
Lake exposure and Naegleria fowleri: Nasal exposure to warm freshwater lakes and similar environments where Naegleria fowleri may be present. Many reported infections follow swimming or other activities that force freshwater into the nose.
Olfactory nerve: The cranial nerve that carries smell signals from the nasal cavity to the brain. Naegleria can migrate from the nose toward the brain along this nerve.
Naegleria fowleri diagnosis: Laboratory identification of Naegleria fowleri in cerebrospinal fluid or brain tissue from a suspected infection. PAM progresses quickly, so distinguishing it from other meningoencephalitis can guide urgent care.
Viral encephalitis: Inflammation of brain tissue caused by a virus. It can produce a similar acute neurological illness without Naegleria exposure.
Neti pot: A device that rinses the nasal passages with liquid, usually saline solution. Rare PAM cases have been associated with nasal rinsing using contaminated tap water.
Meningoencephalitis: Inflammation involving both the meninges, which surround the brain, and the brain tissue itself. PAM is a specific, amoeba-caused form of this broader disease pattern.
Primary amoebic meningoencephalitis treatment: Emergency treatment of PAM using combinations of anti-amoebic drugs and intensive supportive care. Treatment must begin urgently because the infection can worsen over days.