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29 Jul 2005

thyroid
i think i might have an underactive throid. both my mother and my father had thyroid problems. (my mom's was radiated a couple of years ago and she uses eltroxin now. her's was overactive with underactive symptoms! hair falling out, tired, but losing weight at a pace )
i had a blood test a couple of years ago, but it didn't state any abnormal figures. is there perhaps another way to test it? what are the exact symptoms? i am not massively overweight (6kg's or so), but have to eat almost nothing if i want to lose any weight whatsoever. i pick up weight easily. maybe my thyroid is not that underactive, just sluggish, but i'd like to get it tested. for 2 weeks now i've tried my best to eat healthily, I even started jogging and i picked up weight! i'm 25 now.
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CyberDoc
CyberDoc

01 Jan 0001


Beula, it is important to differentiate secondary from primary hypothyroidism; while secondary hypothyroidism is uncommon, it often involves other endocrine organs affected by the hypothalamic-pituitary axis. In a woman with known hypothyroidism, the clues to secondary hypothyroidism are a history of amenorrhea rather than menorrhagia and some suggestive differences on physical examination. In secondary hypothyroidism, the skin and hair are dry but not as coarse; skin depigmentation is often noted; macroglossia is not as prominent; breasts are atrophic; the heart is small without accumulation of the serous effusions in the pericardial sac; blood pressure is low; and hypoglycemia is often found because of concomitant adrenal insufficiency or growth hormone deficiency.
Laboratory evaluation demonstrates a low level of circulating TSH in secondary hypothyroidism (although serum TSH may be normal by immunoassay but with decreased bioactivity), whereas in primary hypothyroidism there is no feedback inhibition of the intact pituitary, and serum TSH levels are elevated. The serum TSH is the simplest and most sensitive test for the diagnosis of primary hypothyroidism. Serum cholesterol is usually high in primary hypothyroidism but less so in secondary hypothyroidism. Other pituitary hormones and their corresponding target tissue hormones may be low in secondary hypothyroidism.
The TRH test may be useful in distinguishing between hypothyroidism secondary to pituitary failure and hypothyroidism caused by hypothalamic failure. In the latter, TSH is released in response to TRH.
The determination of total serum T3 levels in hypothyroidism deserves mention. In addition to primary and secondary hypothyroidism, other conditions are characterized by decreased circulating levels of total T3; these include decreased serum TBG, the effects of some drugs (overtreatment with propylthiouracil, methimazole, and iodide), and the euthyroid sick syndrome due to acute and chronic illness, starvation, and low carbohydrate diets.
In more severe hypothyroidism, both serum T3 and T4 levels are decreased. However, many patients with primary hypothyroidism (elevated serum TSH, low serum T4) may have normal circulating levels of T3 probably caused by sustained TSH stimulation of the failing thyroid, resulting in preferential synthesis and secretion of the biologically active hormone T3.

The symptoms and signs of primary hypothyroidism are generally in striking contrast to those of hyperthyroidism and may be quite subtle and insidious in onset. The facial expression is dull; the voice is hoarse and speech is slow; facial puffiness and periorbital swelling occur due to infiltration with the mucopolysaccharides hyaluronic acid and chondroitin sulfate; cold intolerance may be prominent; eyelids droop because of decreased adrenergic drive; hair is sparse, coarse, and dry; and the skin is coarse, dry, scaly, and thick. Weight gain is modest and is largely the result of decreased metabolism of food and fluid retention. Patients are forgetful and show other evidence of intellectual impairment, with a gradual change in personality. Some appear depressed. There may be frank psychosis (myxedema madness).
There is often carotenemia, particularly notable on the palms and soles, caused by deposition of carotene in the lipid-rich epidermal layers. Deposition of proteinaceous ground substance in the tongue may produce macroglossia. A decrease in both thyroid hormone and adrenergic stimulation causes bradycardia. The heart may be enlarged, partly because of dilation but chiefly because of the accumulation of a serous effusion of high protein content in the pericardial sac. Pleural or abdominal effusions may be noted. The pericardial and pleural effusions develop slowly, and only rarely result in respiratory or hemodynamic distress. Patients generally note constipation, which may be severe. Paresthesias of the hands and feet are common, often due to carpal-tarsal tunnel syndrome caused by deposition of proteinaceous ground substance in the ligaments around the wrist and ankle, producing nerve compression. The reflexes may be very helpful diagnostically because of the brisk contraction and the slow relaxation time. Women with hypothyroidism often develop menorrhagia, in contrast to the hypomenorrhea of hyperthyroidism. Hypothermia is commonly noted. Anemia is often present, usually normocytic-normochromic and of unknown etiology, but it may be hypochromic owing to menorrhagia, and sometimes macrocytic because of associated pernicious anemia or decreased absorption of folic acid. In general, the anemia is rarely severe (Hb > 9 g/dL). As the hypometabolic state is corrected, the anemia subsides, sometimes requiring 6 to 9 mo.
Let me know as a new question if you have more questions. Good luck.
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