MRI Scans Help Spot Persistent HIV in Brain

A new study suggests that diffuse white matter signal abnormalities (DWMSAs) in HIV-infected individuals with neurological problems should raise suspicion of possible cerebrospinal fluid (CSF) discordance.

Researchers at University College London and Central and North West London NHS Foundation Trust conducted a retrospective study involving 46 HIV patients (median age 45 years) who were investigated for cognitive problems between 2011 and 2015, and who underwent a concomitant diagnostic lumbar puncture (LP). Clinical and neuroimaging variables – associated with CSF discordance and/or escape – were identified using multivariate logistic regression.

The results showed that 24 (14.7%) LPs in 22 patients showed CSF discordance, of which 10 LPs in nine patients represented CSF escape, with both CSF discordance and escape associated with DWMSAs on cranial MRI. Patients with definite signs of DWMSAs were also 10 times more likely to have HIV in the brain than those with normal white matter appearances. All seven patients with CSF escape had been diagnosed with HIV over seven years prior to the LP. The study was published on March 13, 2017, in Clinical Infectious Diseases.

“Before we had effective treatments for HIV, AIDS often led to dementia and other problems in the brain. Thankfully this is less common now that we can treat HIV, but up to half of HIV patients still report cognitive problems,” said senior author Professor Ravi Gupta, MD, of UCL, and colleagues. “At the moment we have to perform a lumbar puncture to confirm this; this is quite an invasive procedure that requires patients to stay in hospital for several hours.”

“HIV treatments have come a long way, but patients whose HIV is suppressed by drugs can still have cognitive problems due to HIV-related inflammation,” concluded Professor Gupta. “MRI scans can help to diagnose these patients, whether showing an elevated risk of HIV-related problems or finding a different cause that can then be treated. Where HIV has spread to the brain, we can change the treatment regime to add drugs that cross the blood-brain barrier more effectively to control the infection.”

Human immunodeficiency virus (HIV) can continue to replicate in disparate compartments during suppressive antiretroviral therapy, with up to 10% of individuals who are peripherally suppressed showing detectable HIV RNA in CSF, which can cause neurological problems. Reasons for this include intermittent adherence and treatment interruption leading to viral rebound. There are also data on inadequate control in CSF due to regimens of suboptimal potency, for example, protease inhibitor (PI) monotherapy, or triple therapy with drug resistance, but in many cases the cause is unclear.