Question
How does HIV and HIV meds affect the brain?
17 April 2012. Related: All topics, Living with HIV long-term, Opportunistic infections.
Answer
The best way to answer this complicated question is to look at HIV and HIV drugs separately in terms of the brain.
HIV and the brain
HIV gets into the brain within the first few weeks of infection. However, most people luckily do not seem to experience any direct symptoms from this. Most people are able to continue with day to day life so long as their CD4 count stays high.
If your CD4 count drops below 200, the risk increases for infections that can affect how you feel and think. If the CD4 count drops to below 100 and especially below 50, this includes HIV-related dementia.
If ARV treatment is when the CD4 count is above 350, these problems are very unlikely. Even if started late, HIV drugs can often reverse problems related to brain function.
So for people on effective and stable treatment, HIV does not seem to progress to damage the brain or cause symptoms. Most people continue to be able to lead a normal life.
Ongoing research is now looking at long term complications of HIV. Some researchers think that there may be small changes that we haven;t know about before. Just as getting older increases the risk of symptoms like memory loss, this risk may be higher if you are HIV positive, or it might occur at an earlier age.
The medical name for changes in brain function is neuro-cognitive impairment (NCI for short).
HIV meds and the brain
How HIV drugs affect the brain is difficult to study but it is the focus of a lot of research.
The brain is physically difficult to research because it is encased in the skull and surrounded by a fluid that is also difficult to test. This fluid is called cerebral spinal fluid – or CSF for short. There is a filter between the blood and the CSF called the blood-brain barrier (BBB).
In practice, the BBB only lets the smallest HIV drug molecules get in to the CSF and the larger compounds are blocked. One group of researchers has summarised which drugs are likely to cross the BBB using CSF penetrating effectiveness (CPE) score.
Table 1: Estimated CSF penetration of individual HIV meds (CPE score)
| Drug class | 4 | 3 | 2 | 1 |
| Nukes | AZT | abacavir, FTC | ddI, 3TC, d4T | tenofovir, ddC |
| NNRTIs | nevirapine | efavirenz,
delavirdine |
etravirine | |
| PIs | indinavir/r | darunavir/r,
fosamprenavir/r, indinavir, lopinavir/r (Kaletra) |
atazanaivr/r,
atazanavir, fosamprenavir |
nelfinavir,
ritonavir, saquinavir, saquinavir/r, tipranavir/r |
| Entry inhibitors | maraviroc | T-20 (enfuvirtde) | ||
| Integrase inhibitors | raltegravir |
4=good CSF penetration; 1=little or no CSF penetration
This table is based on limited data though and sometimes the position of individual drugs changes as new research develops.
Some drugs can find another route into the brain and CSF that gets around the BBB, so this may not be the full story.
How important is it to use drugs that get into the CSF?
The answer to this question is not known. People using drugs that have low CSF penetration do not seem to be at higher risk of HIV brain-related illnesses compared to people using drigs that we think do get to the brain. However, in someone with NCI symptoms, guidelines recommended adding or switching to drugs that are more likely to get into the CSF.
Two other aspects of this research are important.
One is that drug levels in the CSF are only an indirect measure of whether drugs reach brain tissue. Measuring CSF is difficult enough. It involves a lumbar puncture (spinal tap) but is used because we cannot biopsy brain tissue directly. Really we need to know about whether drugs get into brain tissue (cells).
Another is that a few studies have suggested that drugs getting into the CSF also has the potential to cause side effects. There is even less data on whether this might be a long term concern. So far, again luckily, the balance of risk vs benefit seems to support getting in mat be better than not getting in, especially in someone with NCI symptoms.
Assessment and monitoring
Part of the difficulties about anything related to the brain is that changes in brian function can be difficult to measure and monitor. Extensive tests that take several hours or use difficult and expensive scanning techniques that are not practical for testing everyone in a clinic.
How you think and feel, including memory, can be affected by other things in your life. Brain function also changes over time in most people as we age.
The following three areas are used in the European EACS guidelines for assessing whether further testing might be needed.
- If you have changes in memory loss (e.g. do you forget the occurrence of special events even the more recent ones, appointments, etc. ?)
- If you feel that you are slower when reasoning, planning activities, or solving problems?
- If you have difficulties paying attention (e.g. to a conversation, a book, or a movie)?
Your doctor should also ask about these aspects of your health as part of routine monitoring, especially in older patients or in people with a low CD4 count.
Further reading
CHARTER study for details of 2010 CPE penetration score. 17th CROI, abstract 430.
http://www.retroconference.org/2010/Abstracts/39373.htm
PDF link
http://www.retroconference.org/2010/PDFs/430.pdf
EACS guidelines includes a section for assessing neurocognitive impairment (NCI) – see page 48.
http://www.europeanaidsclinicalsociety.org/images/stories/EACS-Pdf/eacsguidelines-v6_english.pdf
IADL (daily Living Score – used in EACS guidelines)
http://www.europeanaidsclinicalsociety.org/guid/index.html?b=annex&p=10
Hi Lindon,
I’m sorry, you sound very unwell. But are they treating you for TB? TB can affect the lining of the brain, it’s called TB meningitis. But treating TB and HIV when you have a very low CD4 count is complex. It should be treated by specialist doctors. What country do you live in? Do you have access to treatment?
Hi I have tb in my brain and I am HIV positive and my cd4 count is 20, i sleep whole day and don’t eat please help me.
Hi Lerato,
What medication are you taking? What was your CD4 count when you started?
Hi i have been in hiv meds for half a year now but i hv memory loss m felling sleepy n m always tired can that be the meds
Hi Robert, thanks for your comment and question. It is really good that your treatment is now stable – and also easier to take. You are right that the injections were called Fuzeon (also called T-20 or enfuvirtide). At the time, these injections are likely to have saved your life, but newer drugs are luckily now much easier to take.
What has your doctor said about the memory changes. As 52 is still young it is important that your doctor checks your symptoms. This might be with a short set of questions, or a more detailed set of tests, possible including a brain scan. These will be to find out more about the symptoms and how serious they are.
The meds are not likely to be causing the problems, but they might be linked to being HIV positive for such a long time, and to how low your CD4 count went before you started effective treatment.
I have been on HIV medication from 1989 and just recently my memory has been short circuiting. Names, words, things that I know like the back of my hand or better vacate my mind and I can not pull them up even if I just said them a few minutes ago. I am only 52 but do the math, I have been on these drugs more than half my life. I am undetectable now and have been for a very long time but I have been through the gammet of treatment including taking shots twice a day for 5 years plus (Fuzeon?). See, even that is hard for me to recall the name of the drug. Any thoughts? By “just recently” I am talking about the last couple of years after ending Fuzeon and starting new drug routine.
Hi Mbali, Do you mean you’ve been taking HIV meds for a month? If so then it’s a good idea to talk to the doctor about it. Memory loss and feeling tired should be checked out by the doctor because the symptoms might not be because of HIV or HIV meds.
hi its a month now has memory loss .and I feel so tired sometimes
Hi R,
Please see here:
http://i-base.info/qa/6637
Hi My boyfriend is hiv positive and experiencing memory loss, he was was in prison when he was told about his status and only started taking meds late, im not sure what meds he’s on but what can possibly cause the memory loss?