Progressive multifocal leukoencephalopathy: a challenging diagnosis established at autopsy

Area of Science:

• Neurology
• Immunology
• Infectious Diseases

Background:

• Progressive multifocal leukoencephalopathy (PML) is a rare, opportunistic infection of the central nervous system.
• It primarily affects individuals with severe immunodeficiency, particularly those with advanced HIV/AIDS.
• Despite advances like HAART, PML remains a significant neurological complication in HIV patients, especially in regions like Brazil.

Observation:

• A middle-aged man presented with acute neurological symptoms including facial and body hyposensitivity and limb weakness, shortly after testing HIV positive.
• Initial diagnostic workup, including negative cerebrospinal fluid JCV PCR, suggested PML, but clinical deterioration was rapid.
• Despite initiating HAART, the patient's condition worsened, leading to death within seven weeks of hospitalization.

Findings:

• Autopsy revealed extensive demyelination in the brain white matter, characteristic of PML.
• Microscopic examination showed hallmark features: demyelination, oligodendrocyte abnormalities, atypical astrocytes, and perivascular lymphocytic infiltration.
• Immunohistochemistry confirmed SV40 positivity, and PCR on brain tissue confirmed John Cunningham virus (JCV) presence, despite initial negative CSF results.

Implications:

• This case underscores the diagnostic difficulties in PML, particularly when initial tests are inconclusive.
• It emphasizes the critical need for early and accurate diagnosis and timely intervention for better patient outcomes.
• The study highlights the persistent threat of PML in HIV patients and the importance of considering it in differential diagnoses of neurological disorders in immunocompromised individuals.