Acanthamoeba spp. and Balamuthia mandrillaris leading to fatal granulomatous amebic encephalitis

Area of Science:

• Neurology
• Infectious Diseases
• Parasitology

Background:

• Free-living amebae, including Acanthamoeba spp. and Balamuthia mandrillaris, can cause rare but fatal granulomatous amebic encephalitis (GAE).
• These infections primarily affect the central nervous system, leading to severe neurological dysfunction.

Observation:

• This report presents two distinct lethal cases: an acute Acanthamoeba spp. infection in an immunocompromised female with thalamic lesions and a subacute Balamuthia mandrillaris infection in a Hispanic male with multifocal frontal lobe lesions.
• Clinical presentations varied, with rapid deterioration in the Acanthamoeba case and a prolonged course in the Balamuthia case.
• Cerebrospinal fluid analysis was non-specific in both instances.

Findings:

• Post-mortem histology revealed trophozoites in a perivascular distribution, associated with necrosis and neutrophil infiltration in both cases.
• Histopathological findings confirmed the presence of amebae despite non-specific CSF results.

Implications:

• Accurate and timely diagnosis of these infrequent amebic infections is crucial for patient management.
• Understanding the clinical nuances and diagnostic pitfalls is essential for clinicians encountering GAE.
• This case series underscores the importance of considering rare pathogens in central nervous system infections.