Lithium and Hypothyroidism

Sir, Ethanol, the intoxicant that has plagued civilization down the ages, is metabolized into acetaldehyde by the enzyme alcohol dehydro-genase. In this connection, a medical student recently posed a humorous but interesting question : "Ethanol does not occur naturally in the body; so, why did Nature provide us with alcohol dehydrogenase unless she meant us to drink?" A diligent search through the medical library revealed that there are several possible answers to this question. We wish to share these with the readers of the Indian Journal of Psychiatry, for their interest and edification-(i) Ethanol does occur naturally in the body; it is formed in tiny quantities as a normal by-product of the catabolism of carbohydrates. Alcohol dehydrogenase metabolizes this ethanol (Mcllwain & Bachelard, 1985). (2) Small quantities of ethanol are also produced by fermentation of sugars by intestinal flora in the gut; alcohol dehydrogenase metabolizes this ethanol, too (Lieber, 1984). (3) Alcohol is a generic term, used to describe aliphatic (straight chain) or aromatic (ringed) compounds with an-(OH) [hydroxy] group. Ethanol is not the only alcohol metabolized by alcohol dehydrogenase; certain other alcohols occur in the body and are metabolized by this enzyme. For example, alcohol dehydrogenase is responsible for the conversion of 11-cis-retinol to 11-cis-retinal (Hubbard & Wald, 1952). Alcohol dehydrogenase is also involved in the catabolism of catecholamines; it metabolizes 3-methoxy 4-hydroxyphenylethanol to 3-methoxy 4-hydroxy phenylacetaldehyde (Mcllwain & Bachelard, 1985). (4) Alcohol dehydrogenase has several other substrates as well, and is involved in the dehydrogenation of steroids, and in the omega LITHIUM AND HYPOTHYROIDISM Sir, A male of 32 years already on lithium maintenance (900 mg per day) for twelve months, came with complaints of lethargy, weakness, tiredness, sleepiness, not liking to do routine work and easy irritability On examination he had about fifteen kg. weight gain, oedema feet, puffy face, change of voice and coarse dry scaly skin On investigation-haemoglobin was 11.0 gm%, serum creatinine-1.6 mg%, blood urea 56 mg%, serum cholesterol 265 mg/dl, TSH 110 mU/ml, T3-0 4 ng/L, T4-4.0 ug/dL, S.G.P.T. 23 I.U./ml and serum lithium 0.6 meq/L of blood. Other investigations and examinations were inconclusive including fundus, echocardiography, ultrasonography of abdomen, E.C.G , serum protein, urine and blood A provisional diagnosis of hypothyroidism was made and lithium was stopped. Thyroxine 50 ugm on empty stomach and sodium valproate was started with other symptomatic management. Periodically patient was investigated and within nine months he lost …