Medical Care
If the neuropathy is due to thiamine deficiency in an alcohol-dependent patient, consider instituting an alcohol-withdrawal protocol and providing seizure prophylaxis if indicated.
Surgical Care
Prevent trophic changes to the skin and ulceration of the feet with orthotics.
Consider surgical prophylaxis of osseous deformities.
Consultations
Refer the patient to an orthopedic surgeon for evaluation of osseous deformities.
Diet
Establishing an exact nutritional deficiency is often difficult. Many etiologies are often present simultaneously, especially in patients with malnutrition. Nutritional supplements are relatively innocuous. Therefore, for many nutritional neuropathies, the treatment is empirical and establishes the diagnosis. The further the disease has progressed, the lower the likelihood of reversing the symptoms.
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Alcohol: Discontinue alcohol; give folate 1 mg intramuscularly (IM) once daily (qd) for 3 days and thiamine (vitamin B 1) 50 mg IM qd and/or 50 mg orally (PO) 3 times daily (tid) for 3 days followed by a maintenance dose of 5-10 mg PO qd.
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Thiamine (vitamin B 1) deficiency: Administer parenteral B-complex vitamins, then oral thiamine, 50 mg IM qd for 3 days or 50 mg PO tid for 3 days; the maintenance dose is 5-10 mg PO qd. A maintenance dose of 0.5 mg/100 kcal is required.
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Niacin (vitamin B 3) deficiency: The peripheral neuropathy of pellagra does not respond to niacin supplements alone; both niacin and pyridoxine must be added to the diet. Niacin causes a vasocutaneous flush; therefore, administer nicotinamide 100 mg IM or intravenously (IV), followed by 200 mg PO tid. The RDA is 11.3-13.3 niacin equivalents, so named because tryptophan is a niacin precursor such that 60 mg tryptophan is equivalent to 1 mg niacin. This RDA is increased in pregnant women and in those with diets high in leucine (eg, millet).
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Pyridoxine (vitamin B 6) deficiency: Treat with excessive amounts of pyridoxine. Be careful of competitive inhibition with thiamine.
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Cyanocobalamin (vitamin B 12) deficiency: Give cyanocobalamin (vitamin B 12) supplementation and treat the underlying disease responsible for the deficiency state. Administer IM injections 1 mg/day for 1 week followed by 1 mg/week for 1 month. If malabsorption is the etiology, prescribe 1 mg/mo for life. Oral supplementation of 1 mg/d is acceptable if the integrity of the GI tract is preserved; this yields absorption of 10 mcg/d.
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Folate deficiency: Give 1 mg PO qd. Do not give folate until cyanocobalamin (vitamin B 12) deficiency has been positively excluded. Folate corrects the hematologic abnormalities but worsen the neurologic dysfunction.
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Alpha-tocopherol (vitamin E) deficiency: Treatment varies depending on the cause, as follows:
Cystic fibrosis - 5-10 IU/kg qd
Cholestatic disease - 15-25 IU/kg qd
Abetalipoproteinemia - 100-200 IU/kg qd in divided doses with vitamin A 15,000-20,000 IU qd
Short bowel syndrome - 200-3600 IU qd
Vitamin E transporter deficiency - 800-3500 IU qd
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Gluten sensitivity: The ideal management is unclear, but a gluten-free diet appears prudent.
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Malnutrition: Thiamine replenishment alone is usually not sufficient to cause resolution of the symptoms; increase the protein in the diet slowly to 1.5-2 g/kg body weight qd.
Activity
Physical therapy is recommended to prevent joint contractures. Therapy consists of daily exercises though full range of motion, the use of splints to prevent foot drop, and the use of orthotics to minimize ulceration at denervated pressure points.
Prevention
Pyridoxine (vitamin B6) deficiency
Patients receiving isoniazid should receive pyridoxine 30 mg/d as prophylaxis.
Those receiving penicillamine should receive pyridoxine 100 mg/d.
Doses of more than 0.2 g/d have been associated with chronic sensory neuropathy.
The recommended daily allowance for men is 2 mg/d.
Alpha-tocopherol (vitamin E)
In patients with cystic fibrosis, short-bowel syndrome, or deficiency of vitamin E transporter, monitor the serum a-tocopherol level.
In those with cholestatic disease, monitor the ratio of serum a-tocopherol level to total serum lipid level.
For those with abetalipoproteinemia, use the adipose tissue percentage or results of erythrocyte hydrogen peroxide assay. (Serum a-tocopherol measurements are inaccurate in this disorder.)
Bariatric surgery
The chance of developing peripheral neuropathy is less in those who have surgery performed at the Mayo Clinic, do not have a jejunoileal bypass, take vitamin and calcium supplements, and attend nutritional clinics postoperatively.
Increased risk is associated with greater and faster weight loss; lower postsurgery BMI; lower serum albumin and transferrin; prolonged postoperative nausea, vomiting, diarrhea, and dumping; postoperative complications requiring rehospitalization; inadequate vitamin and calcium supplementation; and poor compliance. Accentuated and rapid weight loss appears to be the crucial risk factor.
Unrelated factors appear to be age, weight and BMI, diabetes, HgA1C, cholesterol, triglycerides, and length of hospitalization.
In the absence of a deficit, monitoring every 6 months for the first 2 years then annually after that is appropriate, giving oral B 12 supplementation when it is in the low-normal range.
In the presence of a deficit, give 0.5 mg/d oral B 12 supplementation, switching to 1.0 g/mo IM if the deficits are not corrected in 3 months or if anemia is also present.
Copper deficiency can present decades following surgery, so should be considered as a potential cause for neuropathy in anyone with even a remote history of bariatric surgery.
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Pernicious anemia. Characteristic lemon-yellow–tinged pallor with raw-beef tongue lacking filiform papillae. Used with permission from Forbes and Jackson.
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Ischemic retinopathy caused by severe megaloblastic anemia.
