One out of every two people in India suffers from neuropathy — a disease caused by changes in the nerve cells. These changes may be age related. The degeneration is accelerated and aggravated if the patient suffers from diabetes, hypertension or has an abnormal lipid profile. Neuropathy can affect all three nervous systems — central, peripheral and autonomous.
If the central nervous system is affected, memory and cognitive skills decline. Forgetfulness becomes an accepted way of life. Peripheral neuropathy produces the most obvious, incapacitating, and distressing symptoms.
In some, the affected nerves may produce symptoms that are symmetrical (occurring in both limbs) and appear first in the furthest extremity. There may be paraesthesia (tingling, burning or numb sensation), hyperalgesia (abnormally acute pain sensation to innocuous stimuli) or deep aching. The symptoms tend to get worse at night and interfere with sleep.
In others, the sensation of and response to pain may be lost. Injuries can occur unnoticed. Infection may set in and be neglected because there is no warning pain. Healing may be delayed as unnoticed micro trauma continues to occur. Ulcers become chronic.
The nerves supplying the muscles can also be affected, leading to weakness and atrophy. Muscles visibly shrink, resulting in hammer toes (toes curve downwards) or drop foot (moving toes and ankle become difficult). Weak muscles cannot hold the joints in place efficiently, leading to sprains and fractures.
The symptoms of autonomic neuropathy are not as clear-cut. Patients complain about unrelated symptoms such as dizziness, poor balance and frequent falls, fainting spells, nausea, abdominal pain and bloating, attacks of “gas” or sexual (especially erectile) dysfunction. These symptoms are difficult to objectively evaluate or substantiate. The condition is ignored and under-diagnosed. Such patients can die suddenly because of malfunction of the autonomic nerves supplying the heart.
Neuropathy is more likely in people with the metabolic syndrome. This is diagnosed when there is increased level of fasting glucose, elevated triglycerides, decreased high-density lipoprotein-C (HDL-C), central obesity, and hypertension. At least three of the five should be present.
Thirty per cent of the people affected by peripheral neuropathy are diabetics. Of these, 20 per cent are unaware of their elevated blood sugar level, which is diagnosed during the blood tests done for the evaluation of neuropathy.
Smoking or the use of tobacco in any form is an independent risk factor. The cancer-causing chemicals in tobacco enter the blood stream and affect the brain and the lining of the nerves.
Alcohol acts as a direct poison on the nerves. It also interferes with the absorption of the B group of vitamins. A neuropathy results, which does not respond to treatment until alcohol consumption is stopped.
Diseases of the intestines that cause malabsorption can lead to vitamin deficiency and from there to neuropathy. Surgery to remove portions of the intestine can have the same effect.
Keeping blood sugar, weight, hypertension under control and regularising lipid profile reduce the symptoms of peripheral neuropathy. The damage to the nerves is reversible in the early stages. Once neuropathy is established, however, response to treatment is unsatisfactory.
Many adjuvant medications have been tried, such as mega doses of vitamins, iron, zinc, calcium, alpha lipoic acid, acetyl-L carnitine. Increasing doses of painkillers like tramadol are also used. Sometimes they are combined with anti histamines like diphendydramnine (Benadryl) and pain modifying drugs. Combinations with anti epileptics such as gabapentin and anti depressants like amitriptyline reduce the intensity of symptoms. None of these treatments has been 100 per cent successful. The pain is still present in 80 per cent of the patients 5-10 years later.
The intensity of the pain can be reduced by soaking the legs up to the knees in warm salted water for 10 minutes, half-an-hour before bed. Application of pain relieving ointments that contain capsaicin also provides relief. The ointment should be applied every 3-4 hours. Do not rub the ointment in too vigorously as it will damage the skin.
Dr Gita Mathai is a paediatrician with a family practice at Vellore. Questions on health issues may be emailed to her at firstname.lastname@example.org