Is there HIV in my brain? Neurologist Dr. Joanna Hellmuth fills us in
Twice a month, the San Francisco AIDS Foundation program Positive Force hosts free The Dr. Is In events for people living with HIV in our community. Dr. Neal Sheran, the special populations clinical chief at the Mission Neighborhood Health Center HIV clinic, selects speakers for the event that share information about HIV health and wellness and other topics of concern for people living with HIV.
This month, Dr. Sheran invited Joanna Hellmuth, MD, MHS, a neurologist at the University of California, San Francisco, to share information about age- and HIV-related changes to thinking, memory and other cognitive processes. Here’s what we learned.
Does HIV travel to the brain?
The brain is in a special compartment in our bodies, said Dr. Hellmuth. It is protected by something called the blood-brain barrier. Substances (like chemicals, drugs, bacteria and viruses) have a more difficult time getting to our brains even if they’re in our bloodstream because of this barrier in our body.
HIV does find a way to enter the brain compartment, very soon after infection (usually within the first two weeks). Scientists think that HIV is able to cross the blood-brain barrier by infecting monocytes (which are a type of immune system cell). Once HIV reaches the brain, it doesn’t affect brain nerve cells (called neurons), but it does infect and use other types of cells in the brain (astrocytes and other immune system cells) to replicate.
Once HIV establishes an infection in the brain compartment, the virus replicates and mutates separately from the virus in the bloodstream.
“People actually develop a different form of the virus in their brain than in the rest of their body as time goes on. If we genotype the virus in the brain and the virus in the blood, it’s often very different,” said Hellmuth.
People who are cognitively active, physically active and socially active do better cognitively.
—Joanna Hellmuth, MD, MHS
Is there virus in my brain even if I’m on HIV medications?
When Hellmuth sees people living with HIV who are experiencing new cognitive problems, one thing she tries to determine is if the virus is replicating in the brain.
“This may seem weird, because most everyone I see is on antiretrovirals. And if you’re on antiretrovirals, you get suppressed really quickly. But there’s this phenomenon called ‘CNS [central nervous system] escape’ where you can have replicating virus in your brain, but not in your blood.”
People living with HIV have their blood viral load tested on a regular basis. Rarely, though, do people have their cerebrospinal fluid (which surrounds the spinal cord and brain) checked for replicating virus. To check for CNS escape, Hellmuth performs a procedure called a spinal tap, which is a way to extract a sample of cerebrospinal fluid.
“Spinal taps are not that bad,” said Hellmuth. “Most people don’t have any pain. They’ll say, it feels a little weird, but it doesn’t hurt.”
Hellmuth finds that of the people she tests, about 10% of people who have the virus controlled in their blood have a low level of virus replicating in the brain.
“This can cause a lot of problems, but all we have to do is change your antiretroviral regimen [to stop this].”
Does HIV in the brain cause problems?
About half of people with acute (very early) HIV infection show signs of some neurological problems, explained Hellmuth. About one-third report cognitive problems, such as feeling like their concentration has been “off” for the past few days or taking longer to remember things. About one-fourth of people have slowed movements, and about one-fifth have neuropathy (nerve pain or tingling).
Most of these early neurocognitive problems resolve after a person starts antiretroviral therapy (and has continued taking them for at least six months). Although antiretroviral therapy does not completely prevent neurocognitive issues caused by HIV, said Hellmuth.
“I see a lot of patients at my clinic who have [had their viral loads] suppressed for 10, some of them 20 years—and then they start getting cognitive problems.”
HIV-associated neurocognitive problems are different than the neurocognitive changes seen in normal aging. In normal aging, people may notice that they have more difficulty retrieving information (for example, remembering someone’s name) or multitasking.
“With HIV, there’s a different pattern,” said Hellmuth. “Part of the change might be in cognition—how your brain works in terms of thinking and memory. We see changes in how well people are able to concentrate. We also notice more cognitive slowing than we see in normal aging—they’re not as fast at tasks than they used to be. People also experience behavioral changes. They may notice they’re more irritable than they used to be, or they may get more agitated. We also notice motor symptoms, like slowed movements. People can have HIV and have none of these symptoms. But you can also have any and all of these things, which we think are related to HIV.”
One thing to keep in mind, said Hellmuth, is that everybody has memory lapses once in a while. To figure out if HIV truly might be causing cognitive problems, she asks her clients to think about if they notice a pattern to any issues they’re experiencing. Have their symptoms gotten worse recently? Are they having more memory lapses than they used to? Are their memory or cognitive issues impairing their ability to do things?
“Have an honest conversation with yourself. I talk to some people who will say things like, ‘If I don’t make a list, I’ll come out of the grocery store and miss five things that I should have gotten.’ Or, ‘I’ll leave my house without my glasses and without my wallet.’ These are things that can impair your life on a day-to-day basis.”
How many people experience HIV-related cognitive changes?
Studies have shown that about 50% of people living with HIV have asymptomatic impairment, mild neurocognitive impairment or HIV-associated dementia. (People with asymptomatic impairment demonstrate some degree of impairment during neurocognitive testing but do not describe any impairment during everyday life.)
This percentage is about the same as the percentage of people affected before combination antiretroviral therapies were available. Although, fewer people experience the more severe forms of neurocognitive impairment now than before combination antiretroviral therapy was available (and more people experience asymptomatic or mild forms of cognitive impairment).
What can you do to prevent or reverse cognitive changes?
There is still a lot that researchers and clinicians have to learn about what people living with HIV can do to reduce the risk that they will develop neurocognitive impairments, said Hellmuth. But, there are a few things that people can do to try to reduce their risk.
“In 2017, half of people living with HIV in the U.S. will be age 50 or older. That’s one reason I’m really interested in how people age with HIV, and how we can help people do better.”
—Joanna Hellmuth, MD, MHS
Protect the blood vessels in your brain, by doing things like making sure your blood pressure isn’t too high, lowering your cholesterol and not smoking.
Regular, vigorous cardiovascular exercise is also protective.
“If you have cognitive problems, and you start exercising a lot, you’ll do better,” said Hellmuth. She advises people to follow the American Heart Association recommendation, which is to engage in 150 minutes of vigorous exercising per week.
“That’s five days per week for 30 minutes at a time. And it’s not a leisurely stroll, it’s something that really gets your heart moving. Some people tell me, ‘I don’t walk so well,’ or, ‘I have balance problems.’ I’ll say, ‘let’s get you on the couch, and we’ll get you a foot pedal so you can pedal to get your heart rate up. There’s always a way to get moving to get your heart rate up.”
Social and cognitive stimulation is also important to maintain brain health. You don’t have to enroll in an online educational program to stimulate your brain.
“Just do something interesting,” said Hellmuth. “Do something active that keeps you around people and socializing. Engage with other people. People who are cognitively active, physically active and socially active do better cognitively.”
Positive Force is a program of San Francisco AIDS Foundation offering free social and educational events. For more information or to get involved, email email@example.com.