A 42-year-old woman with chronic HIV infection presented with sudden onset of progressive limb weakness, leading to immobility within 4 days. This was preceded by severe abdominal pain, nausea, and vomiting for 2 days and episodes of confusion and agitation. Six weeks prior, she had commenced highly active antiretroviral therapy (HAART), consisting of efavirenz/emtricitabine/tenofovir and cotrimoxazole for opportunistic infection prophylaxis. Additional history included constipation for 4 weeks and an admission for psychiatric symptoms 1 week before starting HAART. She had declined HAART when HIV infection was diagnosed 6 years earlier, but was successfully treated for multidrug-resistant tuberculosis.