Background: Progressive multifocal leukoencephalopathy (PML) is a demyelinating disorder of the central nervous system found in immunodeficient patients, most frequently now in those infected with HIV. It may represent the initial manifestation of HIV infection. Since the central visual pathways may be affected, a variety of neuro-ophthalmic signs and symptoms can manifest. We studied the clinical, radiographic and histopathological characteristics of patients with PML.
Methods: The charts of 13 patients in whom PML was diagnosed in the Neuro-AIDS clinic at the Montreal Neurological Institute between November 1987 and March 1995 were reviewed. The diagnosis of PML was established by characteristic clinical features together with typical computed tomographic or magnetic resonance imaging findings, such as nonenhancing low-density (on computed tomography) or hyperintense (on T2-weighted magnetic resonance imaging) white-matter lesions, without mass effect. Neuro-ophthalmic findings were based on clinical examination by an ophthalmologist, neuro-ophthalmologist or neurologist. Tissue for pathological examination was obtained by biopsy in one case and at postmortem study in a second case.
Results: The most common finding was homonymous hemianopia, in five patients (38%). Other features included nystagmus (in two patients), diplopia with cranial nerve palsy (in one) and cortical blindness (in one). One of the patients exhibited involvement of the brain stem, a site not usually affected by this demyelinating process.
Interpretation: The diagnosis of PML should be considered in immunocompromised patients with neuro-ophthalmic findings, particularly those with homonymous hemianopia.