Vitamin B6 and polyneuropathy

Vitamin B6 is usually available in food and does not require additional intake. However, vitamin B6 is used in the prevention of polyneuropathy and in the treatment of tuberculosis. In addition, excess or deficiency of vitamin B6 also leads to polyneuropathy.

Vitamin B6 or pyridoxine is a water-soluble vitamin that is available in many foods, especially cereals, fruits, chicken,... The active form of vitamin B6 is pyridoxal phosphate. It is a coenzyme that metabolizes the amino acids, methionine and tryptophan, and plays a role in amino acid metabolism and decarboxylation. In addition, pyridoxine is involved in the biosynthesis of neurotransmitters such as dopamine, GAGB, catecholamines and serotonin.
Pyridoxine is used for the prevention of peripheral polyneuropathy. However, vitamin B6 is very special because if it is too much or too little, it leads to peripheral polyneuropathy. This is a double-edged sword if used indiscriminately. The recommended daily dose of vitamin B6 for adults is 2mg and for children is 0.9 - 1.6mg.

2.1 Polyneuropathy Polyneuropathy is a diffuse peripheral neuropathy that is usually bilaterally symmetrical and is not limited to one nerve or one limb. Polyneuropathy is often classified according to the area of ​​dysfunction including:
Myelinpathy Blood vessels supplying axons Polyneuropathy often presents with sudden onset or slow progression, become chronic depends on the cause. The disease affects mainly sensory and motor fibers, and may affect the cranial nerves. Polyneuropathy can be acquired or inherited.
2.2 Polyneuropathy due to vitamin B6 deficiency Vitamin B6 deficiency often occurs when undernutrition, alcoholism, vitamin B6 deficiency in mothers will lead to infant deficiency. In addition, it may be seen in some patients taking B6 antagonists such as hydralazine, isoniazid, and D-penicillamine.
Vitamin B6 deficiency polyneuropathy is common in patients being treated with isoniazid for tuberculosis and can be prevented by concurrent supplementation with vitamin B6. Vitamin B6 deficiency causes motor and sensory polyneuropathy, symmetrical on both sides, patients have symptoms of pain and numbness, followed by muscle weakness and atrophy. Tendon reflexes in the distal extremities are lost and all sensations are also lost. Electrodiagnostic method showed polyneuropathy with more axonal damage. Alternatively, the diagnosis can be made by quantifying the serum pyridoxine concentration.
2.3 Polyneuropathy due to vitamin B6 toxicity Polyneuropathy occurs due to excessive intake of vitamin B6 in drug form. Many patients with polyneuropathy are treated with vitamin B6 supplements, but high doses of vitamin B6 should not be taken because it can make the condition worse.

The mechanism of polyneuropathy caused by vitamin B6 toxicity is currently unknown. Prolonged use of oral doses of 1-6g of pyridoxine per day for 12-40 months will cause sensory polyneuropathy and worsening. The disease is characterized by sensory disturbances, which can occur in both hands and feet. The patient walks in a staggered, staggered manner due to loss of sensation, however, muscle strength is usually normal. On neurologic examination, decreased vibratory and somatosensory sensations were observed. Tendon reflexes are reduced or absent, and some patients have lhermitte's sign. The severity of symptoms depends on the dose used, and symptoms will improve or stop if the drug is stopped.
In addition, other symptoms of vitamin B6 overdose include:
Pain Skin deformity lesions Increased sensitivity to light Nausea, vomiting, belching. Polyneuropathy due to vitamin B6 toxicity is usually sensory axonal. Nerve biopsies revealed that all fibers of different diameters were damaged, leading to degeneration of both the peripheral and central sensory bundles.
In short, vitamin B6 is available in food and the average person does not need to take vitamin B6 supplements. Only people who are being treated for tuberculosis, and for the prevention of polyneuropathy, need vitamin B6 supplements. The dosage of vitamin B6 used to prevent polyneuropathy is 25-100 mg/day. If used in too high a dose and for a long time, it also leads to polyneuropathy. Vitamin B6 deficiency leads to polyneuropathy with axonal damage, both sensory and motor. Vitamin B6 excess polyneuropathy is characterized by sensory axonal polyneuropathy.

To know if your health status and your body are deficient in vitamin B6, you need to go to the hospital for regular health check-ups. Currently, Vinmec International General Hospital has been implementing a lot of periodic health checkup packages suitable for each age, gender and individual needs of customers with a very preferential price policy, including:
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