Hypothyroidism Deficit secretion of thyroid hormones
Pathophysiology
- Primary hypothyroidism : the most cases :
- Fails to produce enough TH that stimulate TSH is secreted by the pituitary gland
- Secondary hypothyroidism :
- low levels of TSH which fail to stimulate release of TH
- Tertiary hypothyroidism :
- inadequate release of TRH(thyrotropin-releasing hormone) secreted by hypothalamus low level of hormones that slow metabolism
Etiology
Primary hypothyroidism : congenital ,inflammation or iodine deficiency, autoimmune disorder (Hashimoto’s thyroiditis) ,thyroid surgery, radiation therapy
Secondary or tertiary : pituitary or hypothalamic lesion or postpartum pituitary necrosis or treatment of hyperthyroidism
Risk factor
woman age 50 and over, man age 60 and over
high cholesterol
autoimmune disease such as , rheumatoid arthritis or lupus.
Signs and symptom
- Cardiovascular: Bradycardia , decreased cardiac output , cool skin , cold intolerance, fatigue
- Neurologic: Lethargy , slowed movements , loss concentration , confusion, depression, muscles weakness, hoarse voice
- Pulmonary : Dyspnea , hypoventilation
- Integumentary : cool, dry skin, brittle , dry hair hair loss (eyebrow)
- Gastrointestinal : Decreased appetite , weight gain , constipation , increased serum lipid levels
- Reproductive : Decreased libido , erectile dftitl
Complications
.1- Myxedema coma
- Hypothermic , decreased respiration
- Depressed mental function and lethargy • Blood glucose drops , cardiac output drops
- Reduced perfusion of kidney , non pitting edema
- Death from respiratory failure
2- Cretinism a decreased
production of T4 and results
in mental retardation
Diagnostic test
- Level of T3&T4 are low
- Level of TSH low or high depend on cause
- Serum cholesterol and triglycerides are elevated
- Antibodies present in autoimmune disease
- ↓Radioactive iodine uptake test
Therapeutic measure
- 1- thyroid replacement hormone (Levothyroxine )
- Doses are started low and are slowly increased to prevent symptoms of hyperthyroidism or cardiac complication
- 2- Iodine Deficiency
- Iodized Salt
- Increase intake of seafood
- SSKI- saturated solution of potassium iodide
- 3. Nutritional Therapy A low-calorie diet to promote weight loss or prevent weight gain
Hyperthyroidism Excess secretion of thyroid
hormones
Pathophysiology
- Primary hyperthyroidism problem within thyroid gland causes excess hormone release
- Secondary hyperthyroidism Excess TSH from pituitary so overstimulation of thyroid gland
- Tertiary hyperthyroidism Excess TRH
- High level of thyroid hormone increase the metabolic rate
Etiology
- Graves disease :autoimmune disorder (hereditary )
- Thyroid nodules , inflammation or tumor , medication
- Secondary Malfunctioning pituitary Malfunctioning hypothalamus Risk factor . iodine intake, cigarett common in the 30's and 40's women . excessive doses of thyroid hormone
Signs and
symptom
- Tachycardia , palpitation , increased cardiac out put , warm skin , heat intolerance, chest pain
- Fatigue , restlessness , exophthalmose, hyperactive reflexes , tremor , insomnia , emotional instability
- Dyspnea
- Diaphoresis , warm , moist skin , fine soft hair, Hair loss, goiter
- Increased appetite ,weight loss , frequent stools , decreased serum lipid levels
- Decreased libido , erectile dysfunctionamonorrhea
Complications
1. Thyrotoxic crisis
(thyroid storm) is
severe hyperthyroidism
- Death in as little as 2 hrs if untreated (high fever , tachycardia 130 , hypertension , dehydration , restlessness and coma
2.Hypothyroidism long
term disease as result of
treatment
Diagnostic test
- Level of T3&T4are high
- Level of TSH low in primary hyperthyroidism or high on cause of pituitary
- ↑Radioactive iodine uptake test
- Palpation of thyroid gland
- TSI(thyroid stimulating immunoglobulin) is present in Graves disease
Therapeutic measure
- 1- anti-thyroid drug •Propylthiouracil (PTU) And methimazole (Tapazole) continue for 12-18 months 2- beta-blocker Propranol (indral)
- 3- Radioactive iodine
- 4- Surgery (thyroidectomy)
- 5-. Nutritional Therapy
- High-calorie, high-protein diet, carbohydrates
- Frequent meals
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