Neuropathy in chemotherapy or Chemotherapy-induced peripheral neuropathy is a condition wherein the peripheral nervous system is damaged. This nervous system transmits information from the central nervous system i.e. the brain and spinal cord to the rest of the body and vice versa.

Causes of Peripheral Neuropathy

Some of the chemotherapy drugs damage the myelin sheath, which is a protective covering on the neuron or the nerve cell. This is as good as an insulated electrical wire that is nibbled. The nibbled wire would be unprotected and cause a short circuit.

Chemotherapy drugs are toxic to cancerous cells as well as any fast growing cells including the nerve cells. When these nerves are damaged, all their functions are affected. Loss of sensation in the hands and feet makes it difficult to pick up objects, walk comfortably and balance your body. It also makes you clumsy.

Many types of chemotherapy drugs especially platinum compounds like cisplatin, carboplatin, vincristine and paclitaxel tend to degenerate the myelin sheath coating on the nerves especially from the nerves in hands and feet. The higher the drug dose greater will be the neuropathic effect.

Although peripheral neuropathy can be a side effect of chemotherapy, it can also be aggravated by pre-existing neuropathy, underlying inherited or inflammatory neuropathy .

Symptoms of Peripheral Neuropathy in Chemotherapy

• Burning
• Tingling in hands and feet
• Muscle shrinkage
• Weakness
• Problem in balancing yourself
• Dizziness
• Numbness in hands and feet
• Weak reflexes
• Increased sensitivity to cold temperature
• Constipation
• Trouble passing urine
• Blood pressure fluctuations
• Trouble in swallowing
• Pain
• Impaired sense of touch

Treatment for Peripheral Neuropathy

Vitamin B is the most important factor in reducing neuropathy. Thiamine or vitamin B1 in bloodstream reduces or reverses neuropathy. Vitamin B12 supports sheathing around the neuron and hence vitamin B12 supplements also help in regeneration of the nerve cells.

However, oral intake of vitamin B1 does not quite elevate the levels of vitamin B1 in the blood. Thiamine a form of vitamin B1 is water-soluble and if taken orally gets flushed out of the body through urine. Hence, if the patient takes huge amounts of this vitamin, the urine appears yellow. Due to this limitation, vitamin B1 is given intravenously.

Vitamin B12 deficiency also causes neuropathy. However, even if the patient takes vitamin B12 supplements, it is stored in the body but not easily absorbed into the bloodstream. Hence, vitamin B12 injections directly in the bloodstream are recommended more than oral doses. A common source of vitamin B12 is cyanocobalamine, which is used in most supplements. However, the absorption of this in the blood is very limited. Most common type of vitamin B12 used in supplements is called Cyanocobalamine. Additionally, the body converts cyanocobalamine into a usable form called methylcobalamine. However, with old age the body loses this ability of conversion.

However, nowadays a fat-soluble vitamin B1 is available. This can be consumed orally and is as effective as when given intravenously. This is called benfotiamine. The body does not flush it out like thiamine. This is effective in reducing peripheral neuropathy. In addition, an oral form of vitamin B12 called methylcobalamine is available where the body does not have to convert it to a usable version. This can be directly absorbed by the body and has the same effect like the vitamin B12 given intravenously.

Neuropathy in chemotherapy or chemotherapy-induced neuropathy can be tackled although it cannot be prevented. Prevention is possible only if drugs that do not damage the neuron are developed.