The first documented case of Alzheimer’s disease (AD) in an HIV-positive patient was recently diagnosed after a PET scan found deposition of amyloid in the brain of a 71-year-old male.

Before this finding, presented at the Alzheimer’s Association International Conference 2016, clinicians believed that individuals with HIV might not develop AD because of HIV-related brain inflammation that may prevent the formation of amyloid clumps. However, the results suggest that some of the older HIV patients with dementia may be misdiagnosed with HIV-associated neurocognitive disorders (HAND) when they, in fact, might be developing AD.

“This patient may be a sentinel case that disputes what we thought we knew about dementia in HIV-positive individuals,” said Scott Turner, MD, PhD, neurologist who diagnosed the patient.

Researchers stated that some patients might potential experience a new type of mixed dementia: HAND and AD.

“Chronic HIV infection and amyloid deposition with aging may represent a ‘double-hit’ to the brain that results in progressive dementia,” Turner said.

It is estimated that 30% to 50% of individuals with long-term HIV will develop HAND. However, the symptoms of hand are identical to AD, which may result in misdiagnoses.

“The medical community assumes that dementia with HIV is caused by HAND,” Turner said. “Physicians haven’t considered Alzheimer’s, so it’s possible that a number of older HIV-positive individuals may be misdiagnosed. While it may be challenging to diagnose the cause of dementia in an HIV-positive patient, the diagnosis matters because HAND and AD are treated differently. For Alzheimer’s disease, we now have 4 FDA approved drugs and more effective treatments are on the way. For HAND, we prescribe antiretroviral drugs that have a better chance of penetrating the brain. So getting a correct diagnosis is important, and a critical first step in advancing the field.”

In published studies to date, only 5 individuals with HAND who had undergone amyloid PET imaging were all negative, but the oldest patient was 67-years-old. The diagnosis of dementia in older HIV patients is on the rise, with HIV individuals over 55-years-old that comprise the fastest growing age group in the HIV population.

Currently, there are 37 million people with HIV worldwide, and 53,000 in the United States age 65 and older, the age when Alzheimer’s disease risk begins to increase, according to the most recent CDC HIV Surveillance Report.

“This case report reveals important new insights into the specific issue of HIV-related neurological impairment,” said Jeffrey Crowley, MPH, program director of the National HIV/AIDS Initiative. “This finding must lead to additional population-based studies, as well as timely clinical and programmatic interventions to better support individuals with HIV who are facing neurological decline.” 

The case was first published in the Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring.

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