A Real Pain
Positive Living article • Graham Stocks •
28 November 2011
PERIPHERAL NEUROPATHY IS A COMMON COMPLAINT OF MANY PEOPLE LIVING WITH HIV.
The symptoms vary but usually consist of unpleasant ‘stabbing’ pains or tingling, burning, numbness or cramps in the hands and feet. It can make walking or placing weight on your feet quite painful. And it can have a huge negative impact on your quality of life.
Those of us who have lived with HIV through the 1990s remember it as one of the more unpleasant side effects of the older nucleoside reverse transcriptase inhibitors (NRTIs) like d4T (stavudine) and ddI (didanosine), both of which are now rarely used in Australia.
But HIV itself can also cause peripheral neuropathy (PN). Even people on effective treatment with undetectable viral loads can still experience nerve tissue damage. The cause is not fully known but it may relate to macrophage cells in the nervous system and associated small blood vessels being infected with HIV. This might then stimulate the production of chemicals which causes inflammation that damages nerve fibres, particularly the longer ones in the feet and arms.
The other factors associated with PN are increasing age, height, high intakes of alcohol and the extent to which your immune system was damaged before starting treatment (sometimes measured by your lowest CD4 count or ‘nadir’).
STUDIES + LINKS
A recent study called ALLRT (AIDS Clinical Trials Group Longitudinal Linked Randomized Trials) followed more than 2000 PLHIV for seven years after they had started on treatment. It revealed that 30% of them had some HIV-associated peripheral nerve damage and up to 20% of them experienced some pain in their feet. Nerve function was measured by assessing the signs (vibration sensation at the feet and ankle reflexes) and symptoms (pain, ‘pins and needles’ sensation and numbness). All these people were being effectively treated and their median CD4 cell count was around 500.
Another study of 436 PLHIV in California (between 2000 and 2008) found some interesting associations between PN and levels of triglycerides (one of the lipids or ‘fats’ we regularly monitor in blood tests). In this study, almost everyone had an undetectable viral load and their current median CD4 cell count was around 460.
Amongst them, nearly 30% had some signs of PN. They may not have experienced pain or other symptoms, but they were judged to have nerve damage by signs such as reduced vibration or sharp sensation and reduced ankle reflexes. Like the larger ALLRT study, the same factors (age, height, nadir CD4) were also associated with PN. And there was some suggestion that those who took a protease inhibitor showed higher rates.
The important finding in this study was that people with higher triglycerides were also more likely to have PN.
People who had levels in the range of 1.6 to 2.75mmol/L were one and a half times more likely of having PN and the probability was 2.6 times higher for those with triglyceride levels greater than 2.75 (compared to people with levels below 1.6).
The National Heart Foundation of Australia advises that triglyceride levels greater than 2.0 bring increased risk of heart and other diseases. A lot of PLHIV have trig levels higher than this, and it is often combined with lower levels of HDL or ‘good’ cholesterol.
It is thought that high levels of triglycerides alter the way mitochondria function and increase the release of chemicals which can damage nerve fibres.
Triglycerides also affect blood flow in very small blood vessels which may also result in nerve damage.
In diabetics there is accumulating evidence that oxidative stress (through production of free radicals) is part of diabetic neuropathy.
Diabetics often have elevated triglycerides which contribute to their peripheral neuropathy. It is thought that damage to the blood vessels supplying oxygen to nerve tissues starves them of sufficient oxygen and thus damages them. Antioxidant treatment with Alpha Lipoic Acid has been shown to prevent these abnormalities.
So, both HIV itself and high levels of triglycerides are factors linked to inflammation in the peripheral nerves and associated blood vessels.
Clearly, reducing the inflammation associated with HIV is the first step to minimising the risk of acquiring peripheral neuropathy. Treating HIV itself will reduce this inflammation, and so, consistent with Australian Antiretroviral Guidelines, starting HAART should be considered in all PLHIV when their CD4 counts fall to less than 500, and definitely started by the time CD4 count reaches 350. Using dietary supplements of 3 to 5 grams per day of omega-3 fatty acids (fish oils) have been shown to be highly effective in reducing triglyceride levels. As have drug-based therapies using niacin and/or fibrates.
http://napwa.org.au/pl/2011/12/a-real-pain
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