Clinical Features of Naegleria fowleri infection

What to know

  • Naegleria fowleri can cause a rare brain infection called primary amebic meningoencephalitis (PAM).
  • PAM destroys brain tissue and is nearly always fatal.
  • PAM progresses rapidly so it's important to recognize signs of the disease.
Man holds his head while talking with a healthcare provider

Disease presentation


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Naegleria fowleri infections destroy brain tissue and cause cerebral edema, which is often the cause of a patient's death. Most people with PAM die within 1 to 18 days after symptoms begin. PAM usually leads to coma and death after 5 days.

The most common early symptoms of PAM are headache, fever, nausea, and vomiting. Later symptoms include stiff neck, lethargy, confusion, disorientation, photophobia, seizures, and cranial nerve abnormalities.

Findings on an exam may include meningeal signs and focal neurologic deficits. Signs and symptoms mimic those of bacterial meningitis, especially in the early stages. Rarely, abnormalities in taste or smell, nasal obstruction, and nasal discharge have been observed.

Autopsy findings have included hemorrhagic necrosis of the olfactory bulbs and cerebral cortex.