Hypothyroid

Thyroid-stimulating hormone can be used clinically to test thyroid function but has not found practical apphcation in the treatment of human thyroid insufficiency. Direct replacement therapy with thyroid hormone is easy and effective, owing to a simple molecular stmcture. TSH has been used in the veterinary treatment of hypothyroidism, and preparations of TSH ate produced by Cooper Animal Health, Inc. and Armour Pharmaceuticals. 

Iodine. Of the 10—20 mg of iodine in the adult body, 70—80 wt % is in the thyroid gland (see Thyroid and antithyroid preparations). The essentiahty of iodine, present in all tissues, depends solely on utilisation by the thyroid gland to produce thyroxine [51-48-9] and related compounds. Well-known consequences of faulty thyroid function are hypothyroidism, hyperthyroidism, and goiter. Dietary iodine is obtained from eating seafoods and kelp and from using iodized salt. 

Treatment of Manic—Depressive Illness. Siace the 1960s, lithium carbonate [10377-37-4] and other lithium salts have represented the standard treatment of mild-to-moderate manic-depressive disorders (175). It is effective ia about 60—80% of all acute manic episodes within one to three weeks of adrninistration. Lithium ions can reduce the frequency of manic or depressive episodes ia bipolar patients providing a mood-stabilising effect. Patients ate maintained on low, stabilising doses of lithium salts indefinitely as a prophylaxis. However, the therapeutic iadex is low, thus requiring monitoring of semm concentration. Adverse effects iaclude tremor, diarrhea, problems with eyes (adaptation to darkness), hypothyroidism, and cardiac problems (bradycardia—tachycardia syndrome). 

Myxedema and goiter are the main conditions for which thyroid preparations are indicated. The treatment of cretinism is difficult because it is recognized only at or after birth. Even if this disease could be diagnosed m utero, thyroid hormones do not readily cross the placental barrier. In addition, the fetus, as does a premature infant, rapidly deactivates the thyroid hormones. The halogen-free analogue DlMlT [26384-44-7] (3), which is resistant to fetal deiodinases, may prove useful for fetal hypothyroidism (cretinism). 

Lithium. In the lithium carbonate treatment of certain psychotic states, a low incidence (3.6%) of hypothyroidism and goiter production have been observed as side effects (6,36) (see Psychopharmacologicalagents). It has been proposed that the mechanism of this action is the inhibition of adenyl cyclase. Lithium salts have not found general acceptance in the treatment of hyperthyroidism (see Lithiumand lithium compounds). 

The thyroid gland, located in the base of the neck, exerts i key role on growth and metabolism. In contrast with that of some of the other endocrine glands, this control is effected Ihrough a pair of relatively simple molecules, thyroxine, and its close congener, triiodothyronine. Cases of thyroid deficien-cy (hypothyroidism) are common enough to warrant the production... 

MMI and PTU can lead to methimazole embryopathy with choanal or esophageal atresia. In pregnant women the antithyroid diug dose should be minimized to prevent fetal hypothyroidism by maintaining the maternal free thyroxine serum level slightly above the upper limit of normal. 

Decreased activity of the thyroid gland results in hypothyroidism and, in severe cases, myxoedema. It is often of immunological origin and the manifestations are low metabolic rate, slow speech, lethargy, bradycardia, increased sensitivity to cold, and mental impairment. Myxoedema includes a characteristic thickening of the skin. Therapy of thyroid tumours is another cause of hypothyroidism. Thyroid deficiency... 

Disorders of lipoprotein metabolism involve perturbations which cause elevation of triglycerides and/or cholesterol, reduction of HDL-C, or alteration of properties of lipoproteins, such as their size or composition. These perturbations can be genetic (primary) or occur as a result of other diseases, conditions, or drugs (secondary). Some of the most important secondary disorders include hypothyroidism, diabetes mellitus, renal disease, and alcohol use. Hypothyroidism causes elevated LDL-C levels due primarily to downregulation of the LDL receptor. Insulin-resistance and type 2 diabetes mellitus result in impaired capacity to catabolize chylomicrons and VLDL, as well as excess hepatic triglyceride and VLDL production. Chronic kidney disease, including but not limited to end-stage... 

Other causes of shock include anaphylaxis, hypoglycemia, hypothyroidism, or Addison s disease. 

To be classified as a major depression, these symptoms should occur daily or nearly every day for a period of 2 weeks or more. The symptoms of major depression should not be the result of normal bereavement, such as the loss of a loved one, or disease, such as hypothyroidism. 

Ovarian enlargement, hemoperitoneum, febrile reactions, multiple pregnancies, hypersensitivity Failure to respond to therapy due to development of antibodies, hypothyroidism, insulin resistance, swelling of the joints, joint and/or muscle pain Same as somatropin... 

These hormones cause few adverse reactions when administered as directed. Antibodies to somatropin may develop in a small number of patients, resulting in a failure to experience response to therapy, namely, failure of the drug to produce growth in the child. Some patients may experience hypothyroidism or insulin resistance Swelling, joint pain, and muscle pain may also occur. 

The glucocorticoids are administered with caution to patients with renal or hepatic disease hypothyroidism, ulcerative colitis, diverticulitis, peptic ulcer disease, inflammatory bowel disease hypertension, osteoporosis, convulsive disorders, or diabetes. The glucocorticoids... 

Hypothyroidism—a decrease in the amount of tiiyroid hormones manufactured and secreted. 

The symptoms of hypothyroidism and hyperthyroidism are given in Table 51-1. A severe form of hyperthyroidism, called thyrotoxicosis or tiiyroid storm, is characterized by high fever, extreme tachycardia, and altered mental status. Thyroid hormones are used to treat hypothyroidism and antithyroid... 

Thyroid hormones are used as replacement therapy when the patient is hypothyroid. By supplementing the decreased endogenous thyroid production and secretion with exogenous thyroid hormones, an attempt is made to create a euthyroid (normal thyroid) state Levotliyroxine (Synthroid) is the drug of choice for hypothyroidism because it is relatively inexpensive, requires once-a-day dosages, and lias a more uniform potency than do other thyroid hormone replacement drugs. 

Myxedema is a severe hypothyroidism manifested by lethargy, apathy, memory impairment, emotional changes, slow speech, deep coarse voice, thick dry skin, cold intolerance, slow pulse, constipation, weight gain, and absence of menses. 

These drugp are contraindicated in patients with known hypersensitivity to the drug or to any constituents of the drug, after a recent myocardial infarction (heart attack), or in patients with thyrotoxicosis. When hypothyroidism is a cause or contributing factor to a myocardial infarction or heart disease, the physician may prescribe small doses of thyroid hormone... 

After a patient receives a diagnosis of hypothyroidism and before therapy starts, the nurse takes vital signs and weighs the patient. A history of the patient s signs and symptoms is obtained. The nurse performs a general physical assessment to determine outward signs of hypothyroidism. 

The symptoms of hypothyroidism maybe confused with symptoms associated with aging, such as depression, cold intolerance, weight gain, confusion, or unsteady gait. The presence of these symptoms should be thoroughly evaluated and documented in the preadministration assessment and periodically throughout therapy. 

Replacement therapy is for life, witii the exception of transient hypothyroidism seen in those with tiiy-roiditis. 

Once a euthyroid state is achieved, tlie primary health care provider may add a thyroid hormone to tlie therapeutic regimen to prevent or treat hypothyroidism, which may develop slowly during long-term antithyroid drug therapy or after administration of 131I. 

Ms. Hartman, age 47 years, has been prescribed leuothyroxine (Synthroid) for hypothyroidism. Develop a teaching plan for Ms. Hartman that would provide her with the knowledge she needs to maintain a therapeutic treatment regimen. 

Hypothyroid myopathy occurs in about 30% of patients with hypothyroidism irrespective of its cause. Muscle pain, cramps, and stiffness may be seen, and are often exacerbated by cold weather. Pseudomyotonic features of delayed muscle contraction and relaxation are common. Myoedema (the mounding phenomenon) is due to the painless, electrically silent contracture produced on direct percussion. Muscle biopsy often shows a predominance of type 1 (slow-twitch) fibers, again analogous to that seen in experimental hypothyroidism (Figure 22). Muscle hypertrophy with weakness and slowness of movement occurs in the Debre-Semelaigne syndrome seen in severely hypothyroid children, and Hoffman s syndrome is a similar condition seen in adults with hypothyroidism, but is also accompanied by painful spasms. 

Figure22. (a) Euthyroid(normal)ratmuscleshowingmixtureoftype1 (slow-twitch) and type 2 (fast-twitch) fibers, (b) Hypothyroid rat muscle showing uniformly type 1 (slow-twitch) histochemical profile myofibrillar ATPase after alkaline preincubation.

Clofibrate causes a necrotizing myopathy, particularly in patients with renal failure, nephrotic syndrome or hypothyroidism. The myopathy is painful and myokymia of unknown origin is sometimes present. The mechanism of damage is not known, but p-chlorophenol is a major metabolite of clofibrate and p-chlorophe-nol is a particularly potent uncoupler of cellular oxidative phosphorylation and disrupts the fluidity of lipid membranes. Muscle damage is repaired rapidly on the cessation of treatment. 

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