Neuropathy, thiamin

Rice bran is the richest natural source of B-complex vitamins. Considerable amounts of thiamin (Bl), riboflavin (B2), niacin (B3), pantothenic acid (B5) and pyridoxin (B6) are available in rice bran (Table 17.1). Thiamin (Bl) is central to carbohydrate metabolism and kreb s cycle function. Niacin (B3) also plays a key role in carbohydrate metabolism for the synthesis of GTF (Glucose Tolerance Factor). As a pre-cursor to NAD (nicotinamide adenine dinucleotide-oxidized form), it is an important metabolite concerned with intracellular energy production. It prevents the depletion of NAD in the pancreatic beta cells. It also promotes healthy cholesterol levels not only by decreasing LDL-C but also by improving HDL-C. It is the safest nutritional approach to normalizing cholesterol levels. Pyridoxine (B6) helps to regulate blood glucose levels, prevents peripheral neuropathy in diabetics and improves the immune function. 

Neuropathy can result from deficiency of vitamins or hormones. Alcoholics often obtain a large proportion of their caloric needs from ethanol, and hence become thiamine-deficient. Alcoholic neuropathy results from a combination of thiamine deficiency, which impairs... 

Koike, H., Iijima, M., Sugiura, M. et al. Alcoholic neuropathy is clinicopathologically distinct from thiamine-deficiency neuropathy. Ann. Neurol. 54 19-29,2003. 

Thiamine deficiency is commonly seen in alcoholics, who may develop a complex of symptoms associated with Wernicke peripheral neuropathy and Korsakoff psychosis. Alcohol interferes with thiamine absorption from the intestine. Symptoms include ... 

Beriberi (infantile and adult) and Wernicke s encephalopathy (WE) are clinical manifestations attributed to thiamine deficiency. Beriberi is characterized by peripheral neuropathy including sensory, motor, and reflex functions affecting the distal segments of limbs more severely than proximal ones (TanPhaichitr, 1985). WE is a metabolic disease due to thiamine deficiency and is characterized by lesions in the thalamus, hypothalamus (including mammillary nuclei), and cerebellum (Victor et al., 1971 Harper and Butterworth, 1997). 

The earliest symptoms of thiamin deficiency include constipation, loss of appetite, nausea as well as mental depression, peripheral neuropathy and fatigue. 

In a case of a rapidly progressive neuropathy with arsenic, a contributory role of thiamine deficiency was implied (18). 

Suzuki S, Kumanomido T, Nagata E, Inoue J, Niikawa O. Optic neuropathy from thiamine deficiency. Intern Med I997 36(7) 532. 

Vitamin B complex is the collective term for a number of water-soluble vitamins found particularly in dairy products, cereals and liver.Vitamin B (thiamine) is used by mouth for dietary supplement purposes and by injection in emergency treatment of Wernicke-Korsakoff syndrome. Vitamin B2 (riboflavin) is a constituent of the coenzyme FAD (flavine adenine dinucleotide) and FMN (flavine mononucleotide) and is therefore important in cellular respiration. Vitamin Be (pyridoxine) is a coenzyme for decarboxylases and transamination, and is concerned with many metabolic processes. Overdose causes peripheral neuropathy. It may be used medically for vomiting and radiation sickness and for premenstrual tension. Pyridoxine has a negative interaction with the therapeutic use of levodopa in parkinsonism by enhancing levodopa decarboxylation to dopamine in the periphery, which does not then reach the brain. The antitubercular drug isoniazid interferes with pyridoxine, and causes a deficiency leading to peripheral neuritis that may need to be corrected with dietary supplements. Vitamin B ... 

Adverse reactions Pyridoxine Occasional Stinging at IM injection site Rare headache, nausea, somnolence high doses cause sensory neuropathy (paresthesia, unstable gait, clumsiness of hands) Thiamine Rare anaphylaxis after a large IV dose Riboflavin None known... 

Cirrhosis, alcoholic hepatitis, pancreatitis, gastric or duodenal ulcer, esophageal varices, middle-age onset of diabetes, gastrointestinal cancer, hypertension, peripheral neuropathies, myopathies, cardiomyopathy, cerebral vascular accidents, erectile dysfunction, vitamin deficiencies, pernicious anemia, and brain disorders including Wemicke-Korsakoff syndrome (mortality rate of untreated Wernicke is 50% treatment is with thiamine)... 

The nervous system consists of various cell types that are functionally interconnected so as to allow efficient signal transmission throughout the system (see Chapter 48). The cells of the central nervous system are protected from potentially toxic compounds by the blood-brain barrier, which restricts entry of compounds into the nervous system (ammonia, however, is a notable exception). The brain cells communicate with each other and with other organs, through the synthesis of neurotransmitters and neuropeptides. Many of the neurotransmitters are derived from amino acids, most of which are synthesized within the nerve cell. Because the pathways of amino acid and neurotransmitter biosynthesis require cofactors (such as pyridoxal phosphate, thiamine pyrophosphate, and vitamin BI2), deficiencies of these cofactors can lead to neuropathies (dysfunction of specific neurons within the nervous system). 

CNS Peripheral neuropathies are the most common neurologic abnormalities in chronic alcoholics. More rarely, thiamine deficiency—along with ethanol use—leads to the Wer-nicke-Korsakoff syndrome, which is characterized by ataxia, confusion, and paralysis of the extraocular muscles. Prompt treatment with parenteral thiamine is essential to prevent... 

Adverse reactions Thiamine rare anaphylaxis after a large IV dose Riboflavin none known Niacin or nicotinic acid Cardiac arrythmias may occur rarely Pyridoxine Lxmg-term megadoses may produce sensory neuropathy... 

Following thiamine therapy in the acute state, one may obtain a dramatic response, which essentially confirms the diagnosis (Squirrell, 2004). Improvement in ophthalmoplegia is often the first sign of treatment benefit and may occur within hours (Koontz et al, 2004 Doherty et al, 2002). Ataxia may take days to weeks but 25% of cases may not improve at all. Residual peripheral neuropathy is also not... 

Nerve tissue is mainly dependent for ATP production on glucose metabolism via glycolysis to produce acetyl CoA by the PDH reaction for oxidation in Krebs cycle. Since thiamin is essential for PDH activity, thiamin deficiency, which can occur in malnourished alcoholics, results in PDH dysfunction and an energy deficit in nerve tissue. This causes hyperlactataemia and neuropathy, which can progress to Wernicke s encephalopathy and Korsakoff s psychosis (Chapter 53). 

Concomitant deficiencies of other B vitamins, notably thiamine and pyridoxine, probably participate in the pathogenesis of the dementia of pellagra. Pyridoxine deficiency is associated with a peripheral neuropathy in adults and seizures in infants. Victor and Adams (1956) found that pyridoxine-depleted monkeys develop diffuse cerebral pathology similar to, but not absolutely the same as, that found in human pellagra. 

Poupon, R.E., Gervaise, G., Riant, P., Houin, G., and Tillement, J.P., 1990. Blood thiamine and thiamine phosphate concentrations in excessive drinkers with or without peripheral neuropathy. Alcohol and Alcoholism. 25 605-611. 

Apart from some conflicting therapeutic cltiims there is, however, little if any, convincing evidence of an associated thiamine deficiency in this condition. Goodhart and Sinclair [28] found that the levels of cocarboxylase in the blood were normal in four out of the five patients studied by them, the fifth patient, in whom a low level was found, being also an alcohol addict. Martin [29] carried out pyruvate tolerance tests following the intravenous injection of pyruvate to a series of diabetic subjects and concluded that pyruvate metabolism was normal. Thompson, Butterfield and Kelsey-Fry [30] reported on the blood pyruvate levels in glucose-insulin tests performed on a series of diabetic patients with and without neuropathy, and found that the levels were no higher in patients with neuropathy than in the other diabetics. 

The clinical syndrome of beri-beri is seen sporadicedly in Nigeria, and an aetiological relationship to thiamine deficiency presumed from the therapeutic response to this vitamin. An implied relationship to the W. African ataxic neuropathy is sometimes suggested, but has been rejected because abnormalities of pyruvate metabolism are usually slight [39]. 

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