An unusual cause of sciatica in an immunocompromised patient

A woman in her 40s presented at the antiretroviral centre with 12 hours of severe lower back pain radiating to the anterior aspect of her right leg and down to the dorsum of her right foot. She was positive for HIV antibody and had been taking antiretroviral drugs (tenofovir, lamivudine, and efavirenz) for one year. Examination showed she had no motor or sensory deficit in the lower legs, a straight leg raise test was negative, and she did not have any cutaneous signs. Radiography of the lumbosacral spine (anteroposterior view and lateral view) showed no vertebral or intervertebral disc abnormalities. Table 1 shows her blood test results at presentation.

Intramuscular diclofenac twice daily did not relieve the pain.

On day 3, she developed clusters of painful vesicular eruptions on the right lower leg in the distribution of dermatomes L3_, L4_{, …}