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HYPOTHYROIDISMHypothyroidism results from suboptimal levels of thyroid hormone.Thyroid deficiency can affect all body functions and canrange from mild, subclinical forms to myxedema, an advancedform. The most common cause of hypothyroidism in adults isautoimmune thyroiditis (Hashimoto’s disease.Thyroid HormoneThe two separate hormones, thyroxine (T4) and triiodothyronine(T3), that are produced by the thyroid gland and that make up thyroidhormone, are amino acids that have the unique property of T4contains four iodine atoms in each molecule, and T3 contains onlythree. These hormones are synthesized and stored bound to proteinsin the cells of the thyroid gland until needed for release into thebloodstream.REGULATION OF THYROID HORMONEThe secretion of T3 and T4 by the thyroid gland is controlled bythyroid-stimulating hormone (TSH, or thyrotropin) from the anteriorpituitary gland. TSH controls the rate of thyroid hormone release.In turn, the level of thyroid hormone in the blood determinesthe release of TSH. If thyroid hormone concentration in the blooddecreases, the release of TSH increases, which causes increased outputof T3 and T4.Calcitonin, or thyrocalcitonin, is another important hormone secretedby the thyroid gland. It is secreted in response to highplasma levels of calcium, and it reduces the plasma level of calciumby increasing its deposition in boneCauses of hypothyroidismChronic lymphocytic thyroiditis (Hashimoto’s thyroiditis)Atrophy of thyroid gland with agingTherapy for hyperthyroidismRadioactive iodine (131I)ThyroidectomyMedicationsLithiumIodine compoundsAntithyroid medicationsRadiation to head and neck for treatment of head and neckcancers, lymphomaInfiltrative diseases of the thyroid (amyloidosis, scleroderma)Iodine deficiency and iodine excessTHYROID SCAN, RADIOSCAN, OR SCINTISCANUltrasound, CT scans, and MRI may be used to clarify or confirmthe results of other diagnostic studies. Thyroglobulin (Tg),a precursor for T3 and T4, can be measured reliably in the serumby radioimmunoassay.Clinical ManifestationsEarly symptoms of hypothyroidism are nonspecific, but extremefatigue makes it difficult for the person to complete a full day’swork or participate in usual activities. Reports of hair loss, brittlenails, and dry skin are common, and numbness and tingling of thefingers may occur. On occasion, the voice may become husky, andthe patient may complain of hoarseness. Menstrual disturbancessuch as menorrhagia or amenorrhea occur, in addition to loss oflibido. Hypothyroidism affects women five times more frequentlythan men and occurs most often between 30 and 60 years of age.Severe hypothyroidism results in a subnormal temperature andpulse rate. The patient usually begins to gain weight even withoutan increase in food intake, although severely hypothyroid patientsmay be cachectic. The skin becomes thickened because of an accumulationThe hair thins and falls out;the face becomes expressionless and masklike. The patient oftencomplains of being cold even in a warm environment.At first, the patient may be irritable and may complain of fatigue,but as the condition progresses, the emotional responses aresubdued. The mental processes become dulled, and the patientappears apathetic. Speech is slow, the tongue enlarges, and handsand feet increase in size. The patient frequently complains of constipation. Deafness may also occur.NURSING ALERT In all patients with hypothyroidism, the effectsof analgesic agents, sedatives, and anesthetic agents are prolonged;particular caution is necessary in administering theseagents to elderly patients because of concurrent changes in liverand renal function.Medical ManagementThe primary objective in the management of hypothyroidism is torestore a normal metabolic state by replacing the missing hormone.PHARMACOLOGIC THERAPYSynthetic levothyroxine (Synthroid or Levothroid) is the preferredpreparation for treating hypothyroidism and suppressingnontoxic goiters.NURSING ALERT Medications are administered to the patientwith hypothyroidism with extreme caution because of the potentialfor altered metabolism and excretion and depressed metabolic rateand respiratory status.?Nursing diagnosisSee page 1219HyperthyroidismEtiology and Pathophysiology■ Diffuse toxic goiter (Graves’ disease) or autoimmune condition secondaryto infection, crisis or stress. This leads to ↓thyroid-specific suppressorT-cell lymphocytes, which leads to ↑T3 (triiodothyronine) and/or ↑T4(thyroxine). The result is an ↑metabolic rate and sensitivity tocatecholamines■ Sudden severe hyperthyroidism is called thyrotoxicosis or thyroid storm■ Hyperthyroidism generally occurs between 20 and 40yr old and is morecommon in femalesSigns and Symptoms■ ↑T, ↑P, ↑R, and ↑BP; heart failure, enlargement of gland■ Hunger, diarrhea, ↓weight■ Tremors, nervousness, bulging eyes (exophthalmos)■ Osteoporosis, amenorrhea■ ↑Sweating, flushed skin, heat intolerance■ ↑Radioactive iodine uptake, ↑T3, ↑T4, ↓TSH■ Thyrotoxicosis: ↑T, P _120, delirium, comaTreatmentThe most commonlyused medications are propylthiouracil (Propacil, PTU) or methimazole(Tapazole) until the patient is euthyroid (ie, neitherhyperthyroid nor hypothyroid). These medications block extrathyroidalconversion of T4 to T3■ Radioactive iodine destroys thyroid cells■ Propylthiouracil or methimazole to ↓T4■ Subtotal thyroidectomy (iodide before to ↓vascularity)NURSING DIAGNOSESBased on all the assessment data, the major nursing diagnoses ofthe patient with hyperthyroidism include the following:? Imbalanced nutrition, less than body requirements, relatedto exaggerated metabolic rate, excessive appetite, and increasedgastrointestinal activity? Ineffective coping related to irritability, hyperexcitability,apprehension, and emotional instability? Low self-esteem related to changes in appearance, excessiveappetite, and weight loss? Altered body temperature Page 1224 detail nursing careNursing■ Monitor for S&S of thyrotoxicosis■ Provide calm, cool environment■ ↑Protein, ↑calorie diet■ Teach S&S of hypothyroidism, which may occur with treatment■ Give eye care (drops, patches) prn■ Thyrotoxicosis: Hypothermia blanket, oxygen, propranolol, steroids,propylthiouracil, iodide ................
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