Vitamin Deficiencies and Myeloneuropathy

Vitamin deficiencies can cause many different neurological problems. One of the most striking is a myeloneuropathy, meaning problems with the spinal cord and the peripheral nervous system.

Patients with myeloneuropathy may experience ataxia  with clumsiness due to lack of ability to tell where their body parts are in space (proprioception). They may also develop weakness and/or numbness in affected limbs. On exam, reflexes are likely to be abnormally brisk.

One of the best known of myeloneuropathy is the one caused by low vitamin B12. But other vitamin deficiencies like copper, folate, or vitamin E can also cause problems with the spinal cord.

Vitamin B12 Deficiency

B12 deficiency can cause a wide number of different neurological problems, but the best known is the myeloneuropathy called subacute combined degeneration. B12 deficiency causes disease of the posterior columns of the spinal cord, which carry information about light touch, vibration and the position of the body in space (proprioception) from the body to the brain. As a result of this myeloneuropathy, numbness and weakness result. The numbness develops in a "stocking-glove pattern" which means that it moves gradually and evenly up the arms and legs (after starting in the feet and hands).

Copper Deficiency

Copper deficiency resembles that of B12 deficiency. The most common cause is malabsorption, such as after bariatric surgery, or malabsorption syndromes like celiac disease. Excess zinc intake can also lead to copper deficiency. In addition to zinc supplements, some denture creams also contain excessive levels of zinc. The diagnosis of copper deficiency can be made by testing for copper levels in the blood -- and usually, a healthcare provider will check zinc levels too. 

The treatment of copper deficiency is by supplementing with oral copper and, if necessary, reducing zinc consumption.

Folate Deficiency

Folate (tetrahydroflic acid) is found in citrus fruits and green leafy vegetables. It may be low in alcoholics or malabsorptive syndromes. In pregnancy, low folate levels may lead to fetal spinal malformations, which has led to general recommendations that women supplement with this vitamin if they are considering pregnancy.

Folate deficiency is usually accompanied by other vitamin deficiencies that can cause neurological patterns. That said, patterns similar to subacute combined degeneration have been described with folate deficiency, with cognitive changes, as well as numbness and weakness, and most healthcare providers still test for folate levels in the blood if these symptoms are present and suggest a myeloneuropathy.

Folic acid is easily taken by mouth but can also mask an underlying vitamin B12 deficiency and actually worsen a person's myeloneuropathy. This is why healthcare providers will rule out a vitamin B12 deficiency before starting folic acid supplementation. 

Vitamin E Deficiency

While the primary neurologic deficit in vitamin E deficiency is a spinocerebellar syndrome, there is often a concomitant large fiber sensory-predominant axonal peripheral neuropathy. Vitamin E deficiency occurs in the setting of severe fat malabsorption (eg, biliary dysfunction, cystic fibrosis) or genetic disorders (eg, ataxia with vitamin E deficiency or abetalipoproteinemia). Strategies to treat vitamin E deficiency include improving fat absorption and oral vitamin E supplementation.

Vitamin E is a fat-soluble vitamin found in seeds, grains, and wheat germ. It's rare that vitamin E deficiency is due to dietary deficiencies, but it may result from conditions that cause significant fat malabsorption. Appropriate digestion of vitamin E requires pancreatic enzymes and bile salts from the liver. Sometimes there are inherited disorders of vitamin E metabolism which can cause problems, especially in children.

The symptoms of vitamin E deficiency include eye movement abnormalities, vision changes, cerebellar ataxia, and peripheral neuropathy, in addition to signs of posterior column sensory loss in a manner reminiscent of the other vitamin deficiencies discussed.

Vitamin E levels can be directly measured in the blood, though these levels can be affected by levels of cholesterol and lipids in the bloodstream. Treatment of vitamin E deficiency is with oral vitamin E supplements and improving fat absorption (treating the underlying medical condition, if possible). 

Bottom Line

While the myeloneuropathy caused by these vitamin deficiencies can be severe, the good news is the symptoms can improve or even resolve with proper treatment.

If your healthcare provider does test you for a myeloneuropathy, he may order a magnetic resonance imaging (MRI), which can show lesions in the posterior part of the spinal cord and an electromyogram (EMG) and nerve conduction study (NCS), which show slowing.