A 53-year-old man with HIV/AIDS on HAART was admitted with nausea, vomiting, diarrhea, and a right facial droop of three days duration. Six months prior to admission he had an absolute CD4 cell count of 287 cells/mm3, an absolute lymphocyte count of 1402 cells/mm3, CD4:CD8 ratio of 0.4, and undetectable viral load. At admission, physical examination was notable for orthostatic hypotension, dry mucous membranes, and right-sided facial droop without other focal neurologic deficits. Laboratory studies were significant for white blood cell differential of 70% neutrophils and 19% lymphocytes, blood urea nitrogen of 12 mg/dL and creatinine of 2.0 mg/dL. Computed tomography and magnetic resonance imaging of the head were unremarkable.
The patient was diagnosed with Bell’s palsy and gastroenteritis and treated with prednisone (60 mg daily), valacyclovir (1 g three times daily), and intravenous volume repletion. Repeat studies obtained four hours after the first dose of steroids showed a reduced absolute CD4 count of 103 cells/mm3 and absolute lymphocyte count of 596 cells/mm3, but an unchanged CD4:CD8 ratio of 0.38 and HIV viral load of <20 copies/mL. Repeat CBC showed a shift in differential to 87% neutrophils and 9% lymphocytes. The patient was not started on prophylaxis for opportunistic infections. He was discharged with a 7-day course of valacyclovir and prednisone.
Discussion:
Absolute CD4 cell count is a cornerstone used to guide opportunistic infection prophylaxis in patients with HIV. However, a number of factors can influence CD4 counts, including acute infections and certain medications. Corticosteroids induce neutrophil demargination, leading to neutrophilia and a relative lymphopenia that can cause a transient but significant reduction in the absolute CD4 count that may not reflect an individual’s true immune status. In these cases, the CD4:CD8 ratio and viral load are helpful surrogates. The CD4:CD8 ratio ranges from 1-4 in healthy individuals, while it is typically <1 in HIV and <0.15 in AIDS. Discordance between a low absolute CD4 count and a stable CD4:CD8 ratio with an undetectable viral load should raise suspicion for an alternative explanation besides worsening immunodeficiency.
While isolated mononeuropathies are uncommon in HIV, idiopathic Bell’s palsy tends to occur early in the disease and secondary causes such as infection or malignancy are more likely in advanced HIV. Current guidelines support the use of early glucocorticoids in the treatment of Bell’s palsy. Antiviral therapy may be offered in addition to steroids, although an added benefit has not been established despite suspicion for an underlying viral etiology.
Conclusions:
Although absolute CD4 cell count is used to guide opportunistic infection prophylaxis in HIV, it can transiently vary in the setting of infections and medications such as corticosteroids. In these cases, the CD4:CD8 ratio and viral load should be used to guide appropriate therapy.