Kvalsund studies neuropathy in Zambia
by Laura Probyn
In the U.S., we often associate neuropathy with diabetes, but the sometimes debilitating condition has numerous causes. The Neuropathy Association says that about 30 percent of neuropathies have unknown causes. In addition to diabetes, other known causes include autoimmune disorders, nutritional deficiencies, infections or toxins.
Neuropathy affects the peripheral nerves—the ones that connect the spinal cord to muscles, skin and internal organs—and often causes tingling, weakness and pain in the hands and feet. People can also have the condition without showing symptoms.
Neuropathy can come and go, it can progress slowly or it can become extremely debilitating. The good news is that if it is diagnosed early, it can often be controlled.
MSUCOM clinical instructor and neuro-epidemiology fellow Michelle Kvalsund is looking at neuropathy from a global health perspective, with help from two grants. One is a Practice Research Training Fellowship from the American Brain Foundation, and the second is a Fogarty Global Health Fellowship.
Kvalsund, who is also an MSUCOM alumna (Class of 2009), is using these grants to examine the possible connections between neuropathy and two possible causes: nutritional deficiencies or toxins. She’s conducting this work in two locations in Zambia. One is rural Chikankata Mission Hospital in Mazabuka and the other is in urban Lusaka, Zambia’s capital city.
Her interest in exploring the topic grew from a previous project. While working with HIV-positive patients in Zambia—and assuming a link between HIV and neuropathy—Kvalsund discovered connections between the neurological disorder and other conditions.
“We did some work on this subject as part of a study in rural anti-retroviral adherence in Zambia. We asked a group of participants if they had symptoms of neuropathy and 75 percent said that they did,” Kvalsund said. “Even more interesting, we found that among patients with food insecurity, the odds of having neuropathy were 2 to 1, compared to patients that were not defined as being food insecure.”
That suggested to Kvalsund that there was more than just HIV behind the prevalence of neuropathy.
“When we look at other studies, it’s clear that a lot of times it’s just presumed that HIV infection is the cause of neuropathy in HIV patients, but there may be nutritional factors that are playing a role based on our finding about the food insecurity,” she said.
There have also not been extensive investigations into whether a lot of the medications that HIV patients receive may affect neuropathy prevalence. Other common medications that are used to treat all sorts of infections have been linked to neuropathy, as has Isoniazid, a medication commonly prescribed for tuberculosis. Kvalsund says that there are no population-based data to show how common neuropathy is in Zambia in general, as all of the current studies have been done in the context of HIV.
During her 18 months in Zambia, Kvalsund will look at HIV-positive patients who are either newly diagnosed or who have not yet begun a course of treatment for the virus and she’ll examine them for signs of neuropathy. She’ll look at whether they are asymptomatic, exhibit symptoms or if their neuropathy is progressing. She’ll then try to correlate the conditions with medications or nutritional deficiencies.
“We are trying to quantify how many times they’ve been exposed to those medications and see if neurotoxic exposures are also playing a role in the high prevalence that we saw in our cohort,” she said.
If she can link the neuropathy with nutrition, it is possible to treat and potentially reverse further progression of the disorder and prevent disability.
“As far as the toxic exposures, those could be avoided if it was recognized as an important cause; but as of now, we really don’t know what the impact is—if [a medication] should be avoided if there are alternatives,” Kvalsund notes.
If her studies point to treatable causes of neuropathy, efforts can be made to address them. “There may need to be policy discussions about that based on what we find. If there are frequent vitamin deficiencies that are treatable, then resources to make sure that patients are able to be adequately screened for those nutritional deficiencies and treated for them would be very important to prevent progression of the disorder,” she adds.
The results of this work will add to a limited but growing knowledge base and give Kvalsund a basis upon which to expand her research, but it may also have possibilities for broader applications later.
“We hope to improve the care of patients with neuropathy in sub-Saharan Africa, but we would also very much like for this — research to benefit a global community — by better understanding how having numerous infectious, nutritional, and frequent neurotoxic exposures impact the progression of neuropathy.”