Hypothyroidism
In medicine, hypothyroidism is "a syndrome that results from abnormally low secretion of thyroid hormones from the thyroid gland, leading to a decrease in basal metabolic rate. In its most severe form, there is accumulation of mucopolysaccharides in the skin and edema, known as myxedema."[1]
Thyroid stimulating hormone levels of less than 10 may not be important.[2]
Diagnosis
Because the manifestations of hypothyroidism in the typical patient do no present the physician with a specific set of signs and symptoms, diagnosis of the disease usually requires laboratory tests.
Primary hypothyroidism
If the initiating pathological process greatly affects the thyroid gland as its primary target, the thyroid hormone, thyroxin (T4), will show abnormally low concentrations in blood, while the pituitary hormone, thyrotropin (TSH), which normally stimulates the thyroid gland to secrete thyroid hormones, shows abnormally high concentrations in the blood, due to lack of the normal physiological feedback inhibition of TSH secretion by T4. In a sense, the pituitary gland, through excess TSH secretion 'tries' to compensate for the the low blood T4 concentrations by excess stimulation of the diseased thyroid gland.
if it appears that the elevated TSH concentration can maintain a normal or near normal T4 concentration, the physician renders a diagnosis of subclinical hypothyroidism.
Central hypothyroidism
in some cases of hypothyroidism, referred to as central hypothyroidism, the hypothalamus, which normally produces a hormone to stimulate the pituitary gland to secrete TSH, is abnormal, in which case the laboratory results will show and abnormally low T4 concentration in the blood without an appropriate compensatory increase in TSH concentration. In other cases of so-called central hypothyroidism, the primary problem may reside in the pituitary gland itself, also giving on laboratory testing a low T4 concentration and an inappropriately high TSH concentration.
Symptoms
Symptoms may not be accurate.[3][4] The symptoms that may be distinguish between hypothyroid and normal patients are hoarse voice, dry skin, and muscle cramps.[4]
Treatment
About thirty[5] to forty[3][6] percent of patients taking thyroid hormone replacement may not have appropriate values of thyroid stimulating hormone (TSH).
Taking replacement hormone at night may be better.[7]
References
- ↑ Anonymous (2024), Hypothyroidism (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ Rodondi N, den Elzen WP, Bauer DC, Cappola AR, Razvi S, Walsh JP et al. (2010). "Subclinical hypothyroidism and the risk of coronary heart disease and mortality.". JAMA 304 (12): 1365-74. DOI:10.1001/jama.2010.1361. PMID 20858880. Research Blogging.
- ↑ 3.0 3.1 Canaris GJ, Manowitz NR, Mayor G, Ridgway EC (2000). "The Colorado thyroid disease prevalence study.". Arch Intern Med 160 (4): 526-34. PMID 10695693. [e]
- ↑ 4.0 4.1 Canaris GJ, Steiner JF, Ridgway EC (1997). "Do traditional symptoms of hypothyroidism correlate with biochemical disease?". J Gen Intern Med 12 (9): 544-50. DOI:10.1046/j.1525-1497.1997.07109.x. PMID 9294788. PMC PMC1497160. Research Blogging.
- ↑ Ross DS, Daniels GH, Gouveia D (1990). "The use and limitations of a chemiluminescent thyrotropin assay as a single thyroid function test in an out-patient endocrine clinic.". J Clin Endocrinol Metab 71 (3): 764-9. PMID 2394778. [e]
- ↑ Okosieme OE, Belludi G, Spittle K, Kadiyala R, Richards J (2011). "Adequacy of thyroid hormone replacement in a general population.". QJM 104 (5): 395-401. DOI:10.1093/qjmed/hcq222. PMID 21109503. Research Blogging.
- ↑ Bolk N, Visser TJ, Nijman J, Jongste IJ, Tijssen JG, Berghout A (2010). "Effects of evening vs morning levothyroxine intake: a randomized double-blind crossover trial.". Arch Intern Med 170 (22): 1996-2003. DOI:10.1001/archinternmed.2010.436. PMID 21149757. Research Blogging.