Subacute measles encephalitis: The neurological sequelae of the measles outbreak in South Africa

Master Thesis


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University of Cape Town

A measles outbreak occurred in South Africa between 2009 and 2011 with 18 699 confirmed cases. This highly contagious virus can affect the central nervous system in many ways. Early in the disease course there may be direct viral involvement as a primary measles encephalitis or indirectly as an inflammatory immune mediated demyelinating meningoencephalitis. Latent infections are rare and may manifest in two ways: years later as subacute sclerosing panencephalitis (SSPE) caused by viral persistence in a seemingly immunocompetent host or months later as subacute measles encephalitis (SME) in an immunocompromised host. SME is characterised by seizures, typically epilepsia partialis continua, and altered mental status and carries a high mortality. It is an elusive diagnosis and usually confirmed on brain biopsy. Patients and results: Eight patients were diagnosed with SME between July and October 2010 at our tertiary referral hospital. All patients were HIV positive, with a median CD4 lymphocyte count of 37 cells/µl (range 1 to 268). All patients had epilepsia partialis continua during the course of the illness and other common features included encephalopathy, visual loss, hearing loss, and generalised seizures. Strikingly, cerebrospinal fluid (CSF) examination was normal in all patients and computed 4 tomography (CT) Brain imaging was normal in all but one patient. Magnetic resonance imaging (MRI) Brain demonstrated superficial and deep grey matter abnormalities in the majority of patients with contiguous cortical spread over weeks documented in one patient. Electroencephalograms (EEGs) showed periodic epileptiform discharges in seven patients. Diagnosis was confirmed by brain biopsy in one patient, by post-mortem examination in three patients and by supportive laboratory findings (positive measles PCR and/or measles antibodies in urine or CSF) in the remainder. The outcome was fatal in seven of the cases with a median time to death of 3 weeks. Conclusion: South Africa has the greatest number of people living with HIV: 12.6% of the population (6·4 million people) are infected. This is the largest SME case series to date and is seen in the aftermath of a measles outbreak in South Africa. Immunocompromised patients are clearly susceptible and typically present with epilepsia partialis continua and rapid decline in neurological functioning and death ensuing within a month in the majority of cases. MRI T2-weighted signal changes in the cortical grey matter, are typical. In the absence of a brain biopsy, we propose the use of measles virus PCR in urine and CSF. The importance of herd immunity, by enforcing the national vaccination programme, is reiterated.

Includes bibliographical references.