Peripheral neuropathy is a condition of damage to peripheral nerves. They are the ones that carry sensation from the outside to the brain. They are part of a very efficient fool proof circuit where even a wisp of hair touching the foot can be perceived by the individual in less than a fraction of a second.
Unfortunately, these nerves can be damaged by various reasons resulting in altered or impaired sensations or loss of sensation. Altered sensations can be in the form of tingling, sensation of ants crawling, burning pain, cramps, and etcetera. If the sensations on feet are impaired, while walking, one feels as if they are walking on wool. Loss of sensation also becomes a source of trauma to the hands and feet as affected person is not able to feel pain or prick, hence, is not able to withdraw limb while encountering a sharp object or something hot or harmful.
The site of problem depends on the nerve or nerves affected. A single nerve may be affected causing loss of sensation and or paralysis. Classic example is if someone sleeps in a stupor over a chair with arm hanging over it and wakes up to find one hand being paralysed. A “glove and stocking” peripheral neuropathy is the one where both hands and feet are affected.
Peripheral neuropathy can be due to many reasons. Diabetic patients are very vulnerable to it as high blood glucose damages the peripheral nerve fibres. It is one of the main reasons for development of diabetic foot. Here, due to peripheral neuropathy, a person has repeated trauma and infections that can result in deformities of the feet in severe cases.
Chronic Vitamin B complex deficiency, particularly B1 (thiamine), B6 (pyridoxine) and B12 (cobalamin) results in peripheral neuropathy. Alcohol depletes Vitamin B complex of the body and is also toxic to the peripheral nerves. People consuming alcohol can develop features of damage to peripheral nerves which increases in severity as consumption continues.
Peripheral neuropathy is one of the manifestations of chronic liver and kidney diseases.
Infectious diseases like herpes zoster, HIV and leprosy, cause chronic inflammation and damage to the peripheral nerves resulting in chronic disability to the sufferer.
Some drugs also cause peripheral neuropathy. Among them, fluoroquinolones like ciprofloxacin, anti-tubercular drugs like isoniazid, metronidazole used for intestinal protozoal infections, and etcetera, are some of the drugs which can cause peripheral neuropathy as adverse effect. Withdrawal of the offending drug helps in improvement of the symptoms.
Radiation therapy and chemotherapy used to treat any malignancy can damage the peripheral nerves along with malignant cells resulting in abnormal or impaired sensations.
Desk workers, people using computers for long hours, become prone to develop peripheral neuropathy.
Exposure to chemicals like mercury, lead, arsenic and thallium in industrial settings results in peripheral neuropathy in the workers. Insecticides also contain chemicals leading to damage to nerves. Workers dealing with them on a daily basis are the ones who are mostly affected. Chemicals toxic to the nerves, like mercury and arsenic, are also present in certain herbal products. People use these products innocently considering them to be a safe alternative to modern medicine which does produce some secondary effects. Inadvertently, they suffer from peripheral neuropathy.
It is a troublesome condition, when one has abnormal or reduced sensations anywhere in the body. Often, sleep is disturbed due to burning sensation in the hands and or feet. Due to severe paraesthesia, a person finds it difficult to work or even walk at times.
Taking a nutritious diet rich in vitamin B. complex helps to prevent neuropathy due to vitamin B. complex deficiency. It also helps to minimise the suffering due to peripheral nerve damage. Such a diet should include whole grains, cereals, nuts, red meat, and etcetera.
Those who suffer from diabetes need to keep blood glucose levels well controlled by means of diet and drugs to avoid peripheral neuropathy. In early stages, neuropathy is reversible in diabetic patients.
Alcohol is best avoided.
Treatment consists of drugs like gabapentin and carbamazepine to provide symptomatic relief in troublesome neuropathy. Antidepressant drugs are also used for the same purpose. Supplements of vitamin B complex are also given sometimes.
Whenever a person develops recurrent or persistent altered sensations in the limbs or any part of the body, they should seek medical treatment before the problem is aggravated.
Dr Rachna Pande,
Specialist, internal medicine