The great masquerader: Acanthamoeba myelopathy mimicking tropical spastic paraparesis–a case series

Acanthamoeba spp. typically causes granulomatous amoebic encephalitis in immunocompromised hosts. ¹ We describe three apparently immunocompetent patients who presented with progressive spastic quadriparesis to our hospital in Kerala, India. Neuroimaging showed parenchymal changes in the spinal cord in two patients. After extensive evaluation for common causes of noncompressive myelopathy proved unrevealing, Free-Living Amoeba-associated Parainfectious Neuroinflammation (FLA-PIN) was considered. Amoeba-specific PCR of cerebrospinal fluid (CSF) confirmed Acanthamoeba species in all cases. Patients responded to anti-acanthamoeba therapy with significant clinical and CSF improvement. Probable exposure routes included skin breach and nasal ablution. This series demonstrates that Acanthamoeba infection warrants inclusion in the differential diagnosis of noncompressive myelopathy. CSF wet mount and molecular testing should be performed in inflammatory myelopathies to prevent misdiagnosis as incurable neurodegenerative diseases.