Okay, most HIV patients who also have neuropathy, try to change their lifestyle in some way, to try reduce some of the worst effects of the disease. That's normal; it's not obligatory, it's just a normal reaction to try something out if someone advises you that it will help...so how does a bad diet, drinking and recreational drug use affect people's neuropathy? These are just some of the questions in this interview for Aidsmap.com files (see link below) with Dr Hadi Manji, one of only a handful of neurologists in the UK with extensive clinical experience of HIV-related neuropathy.
ATU: How can you tell whether the neuropathy is caused by HIV or by the medicines used to treat it?
Dr Hadi Manji:The presentation of HIV neuropathy is very similar to drug-related neuropathy, but there are some clues to tell whether it is the drugs or not. Sometimes the drug-related neuropathies come on very rapidly, almost explosively.My impression is that drug-related neuropathies may also be more painful. And if there's involvement of the fingers, that, to my mind, would be more drug – than HIV-related.
ATU: How many people have both HIV and drug-related neuropathy together?
HM: In my experience, a lot of people – up to 60% – who develop neuropathy that is attributed to the drugs are still left with neuropathy when they stop the offending drug, despite some improvement. My feeling is that these individuals probably had asymptomatic HIV related neuropathy that was unmasked by the drugs.
ATU:What other factors can make neuropathy worse?
HM:The bottom line is, if you've got nerve -related problems for whatever reason – HIV or antiretrovirals – and you add another factor that damages nerves, you are more likely to cause further damage. For example, when I see patients, I ask about alcohol intake, because alcohol damages nerves, making you more vulnerable to neuropathy.
ATU: How much alcohol is too much?
HM: It would seem reasonable that anyone who drinks more than the recommended 21 units a week for men [14 for women] may be more vulnerable. It's impossible to be categorical about these things because the other factor in alcohol-related neuropathy is vitamin B deficiency due to poor diet.
ATU: Does that also mean that people who use recreational drugs, and have a poor diet, could get neuropathy?
HM:There's no evidence that recreational drugs themselves cause neuropathy. However, the poor nutrition that can accompany drug-taking could certainly be a factor, since it is deficiency of the B vitamins which is important for nerve function.The cause of neuropathy in people who eat badly for any reason is usually thiamine (vitamin B1) deficiency.
ATU:Would you suggest that people whose diet is likely to be poor, for whatever reason, supplement with a vitamin B-complex tablet?
HM: I think that's reasonable, but with a caveat. One of the B-complex vitamins, B6, if taken in excess, causes neuropathy. At one stage in New York, B6 overdose was a common cause of neuropathy, because people were taking too much in their supplements. It's also worth checking B12 levels if you're a vegetarian, or if you have chronic diarrhoea.
ATU:What else do you check for when you see your patients for the first time?
HM: Diabetes is a cause of neuropathy, so I always check my patients' blood sugar. I also check to see if there are any other drugs that could cause neuropathy. For example, isoniazid, which is used to treat TB, can cause neuropathy.
ATU: What about co-infection with hepatitis C?
HM: Although there is a mechanism by which hepatitis C can cause neuropathy, it is very rare. I haven't seen more neuropathy in coinfected patients.
ATU: Are all the d-drugs equally likely to cause neuropathy, and of all the HAART medications, is it only d-drugs that can cause neuropathy?
HM: Of the antiretrovirals, only ddC, ddI and d4T are associated with neuropathy.The others aren't. ddC used to be the worst offender, but use of that drug has reduced significantly. In fact, compared with the early studies, incidence of neuropathy from all of these drugs is reducing for two reasons. First, lower drug doses are being used. Secondly, people aren't quite so immunosuppressed when they start the drugs, so they don't run the risk of this asymptomatic HIV-related neuropathy, as it is less likely to occur in people with higher CD4 counts.
ATU: How do you treat people with neuropathy who have no option but to
remain on d-drugs?
HM: Often, if the person is doing well as far as CD4 count and viral load are concerned, both the patient and HIV doctor are not that keen on stopping the d-drug.You could consider reducing the dose of the offending drug, but then there are concerns about resistance. Otherwise, all we can do then is to control the symptoms by using other drugs to make life a bit more bearable.
ATU: Do you prescribe antidepressants?
HM: I think they have a role to play, so I wouldn't write them off completely. I tend to use one of the tricyclics, amitryptyline.The crucial
thing is to start at the lowest possible dose (10mg), since it causes drowsiness. However,this does work in the patients' favour,particularly if they take it at night, because they can get a decent night's sleep.
ATU: Given the promising pain-reducing qualities of smoked marijuana presented at the recent Retroviruses Conference, would you support its use in the UK?
HM: In terms of other neuropathies, I have had patients who have said that smoking cannabis may be helpful.These results from San Francisco are preliminary, and it's never been trialled in a formal setting. Since there is no definite evidence to its benefit, I currently wouldn't be able to recommend it.
ATU: Before HAART, about one third of people reported HIV-related neuropathy. Why hasn't the incidence of neuropathy decreased in the HAART era?
HM: It's a combination of people living longer, and use of the d-drugs.We may see even more neuropathies appear as people with HIV are living longer.This is because there may well be increased risks for other causes of neuropathy that we currently see in non-HIV peripheral nerve clinics – diabetes, for example. So, when doctors see patients who are ageing with HIV, they will have to consider not just HIV or the drugs they take, but the other causes, too.
http://www.aidsmap.com/files/file1000724.pdf
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