39. Gigantism FIGURE 25.6-7 A case of simple (primary) gigantism. The Austrian giant, Winkelmeyer, 7 ft. 6 in. tall. (Reprinted with permission from Douthwaite AH, editor: French's Index of Differential Diagnosis, ed 7. Williams & Wilkins, Baltimore, 1954.)
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42. FIGURE 25.6-8 A phenotypic female with abdominal testes and an XY chromosomal karyotype. Note the excellent breast development and the absence of pubic hair. A normal blind vagina was present without clitoral enlargement. (Courtesy of R.B. Greenblatt, M.D., and V.P. McNamara, M.D.)
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Notas del editor
Endocrinology Horm productn: 1.concentration of hormones 2.activity of the hormones themselves 3.hormones from other sites common medical conditions esp. in the elderly adults Lab evaluation: Evaluation of endocrine function (initial) Serum electrolytes Fasting blood sugar TSH Calcium
result from excessive or deficient amounts or resistance These latter cases are primarily hereditary and are characterized by normal or elevated concentrations of a hormone despite an absence or deficiency of the hormone's action. Increased concentrations result from the lack of normal negative feedback on the hormone's production, a consequence of the failure or deficiency of the hormone's action. f hormone or from resistance to a hormone’s action
Of all the endocrine disorders, disorders of the thyroid are the most common
Also called “ thyrotoxicosis ” results from overproduction of thyroid hormone by the thyroid gland most common cause is Graves' disease (exophthalmic goiter) Patients with Graves' disease produce thyroid-stimulating antibodies thyroid storm “ thyrotoxic crisis” develop following withdrawal of antithyroid drugs a life-threatening syndrome usually precipitated by illness or injury marked tachycardia weakness fever altered mental status
overt - symptomatic abnormally low thyroid hormone concentration elevated TSH subclinical Asymptomatic normal thyroid hormone concentration elevated TSH idiopathic atrophy endemic hypothyroidism from iodine deficiency in the diet hypopituitarism like from postpartum pituitary necrosis hypothalamic disease iatrogenic hypothyroidism caused by drugs such as lithium or anti-thyroid drugs or from chemical or surgical thyroidectomy
Bipolar: may have lithium-induced hypothyroidism
Levothyroxine it provides the most uniform thyroid replacement doses are typically between 50 and 200 mg a day replacement of thyroid hormone should be gradual patients over age 50 history of cardiac disease to avoid precipitating angina or cardiac arrhythmias the starting dose should not exceed 0.05 mg daily TSH concentrations should be measured 6 weeks after initiation of thyroid hormone treatment have a serum TSH concentration above 10 mU/L exhibit deficits in memory or cognitive functioning have a rapid-cycling bipolar disorder
Epidemiology and Etiology prevalence of Cushing's disease = 40 per million; women(3rd and 4th decades of life) ACTH-producing pituitary adenoma most common cause of spontaneous Cushing's syndrome Adrenal adenoma/adrenocortical carcinoma/nodular adrenal hyperplasia ACTH-independent causes of increased cortisol concentrations.
manic and psychotic symptoms (less frequently than depression) Cushing’s syndrome plasma and urine concentration of cortisol is increase normal circadian rhythms of cortisol secretion are blunted or absent Administration of metyrapone blocks cortisol synthesis followed by increased cortisol production which does not occurs in cases of adrenal or ectopic origin postmetyrapone response is augmented in cases of pituitary origin Dexamethasone (Decadron) Suppression Test (DST) another test that distinguishes pituitary from adrenal cause of Cushing’s syndrome involves administering 1 mg dexamethasone at midnight and determining the plasma cortisol concentration the following morning Diagnosis and Clinical Features Steroids withdrawal depression, weakness, anorexia, and arthralgia Withdrawal symptoms can persist for up to 8 weeks following corticosteroid withdrawal.
Plasma cortisol concentrations above 200 nmol/L indicate a high likelihood of Cushing's syndrome vary considerably during the day Differential Diagnosis Similarities of Cushing’s syndrome and Major depressive disorder: with mood changes with shortened rapid eye movement (REM) latency increased cortisol concentration abnormal findings on DSTs
PRIMARY autoimmune disease infection idiopathic atrophy metastatic tumor ACTH and CRH concentrations increase in response to low concentrations of adrenal steroids Adrenal aldosterone production tends to be less affected by secondary or tertiary forms of adrenal insufficiency. Etiology Secondary and tertiary adrenal insufficiency result primarily from withdrawal of exogenous corticosteroids or ACTH, as their administration suppresses the hypothalamic-pituitary-adrenal axis Other causes pituitary tumors, trauma, infectious disease (e.g., human immunodeficiency virus [HIV]), infarction, and surgical ablation.
A normal test and stimulated cortisol concentrations of more than 7 μg per 100 mL stimulated cortisol concentration above 18 μg per 100 m Low cortisol responses to this test indicate adrenal insufficiency.
Primary adrenal insufficiency ACTH concentration rises cortisol concentration does not rise following ACTH stimulation Adrenal insufficiency resulting from pituitary disease, ACTH concentrations are low or normal, and the response to CRH is blunted
MOST COMMON PROLACTINOMAS ALL ANTIPSYCHOTICS RAISE EXCEPT CLOZAPINE AND OLANZAPINE
GH, produced by the anterior pituitary, stimulates protein synthesis, lypolysis, and growth of skeletal cartilage. Its production is stimulated by GH-releasing factor and inhibited by somatostatin, both of hypothalamic origin. If GH concentrations are excessively high in childhood, gigantism may develop.
Acromegaly results from an excess of GH in adulthood, after fusion of the epiphyses of the long bones, so that height is not affected. The prevalence of acromegaly is approximately 4 in 100,000. Other causes include ectopic production or excessive hypothalamic production of growth hormone releasing factor. Organ enlargement can lead to congestive heart failure. No specific psychiatric symptoms have been consistently associated with acromegaly or gigantism, or with elevated GH levels. Adjustment disorder may occur from changes in physical appearance and from living with a chronic illness. Laboratory studies show high GH concentrations. The most reliable test for acromegaly is measurement of GH following an oral glucose tolerance test. In acromegalic patients, GH secretion does not show the normal suppression by glucose. Brain imaging studies may show a pituitary tumor. Treatment involves pituitary ablation through surgery or radiation. Dopamine agonists such as bromocriptine and apomorphine, which normally increase GH levels, have the opposite effect in patients with acromegaly. The serotonin antagonist cyproheptadine may also reduce GH levels.
is a rare X-linked recessive disorder that produces a variable appearance of external genitalia depending on the degree of androgen receptor defectiveness patients with a 46 XY karyotype are phenotypically female.
The vagina, however, is short and blind or may be absent altogether. An inguinal hernia is a common clinical presentation in prepubertal children, and the diagnosis may not be made until surgical repair of the hernia reveals a testis. Postpubertally, primary amenorrhea is a common presentation. With the exception of the undescended testes, internal genitalia are absent. Surgical removal of the testes is recommended, as the development of gonadal tumors is a concern. The psychosexual development is feminine, and it is therefore recommended that these individuals be raised as females. In patients with incomplete testicular feminization, the appearance of external genitalia is more virilized and ambiguous.
most widespread endocrine disorders in women Prevalence: women of reproductive age autosomal dominant Dysregulation of the rate-limiting enzyme involved in androgen biosynthesis in the ovaries
LH concentrations usually high FSH concentrations are low or normal elevated concentrations of androstenedione, testosterone, estrone, prolactin
Initiation of oral contraceptive treatment has been reported to improve mood, possibly by the reduction in androgen concentration that results from suppression of ovarian activity. Differential Diagnosis pituitary and adrenal disorders such as: Hyperprolactinemia Acromegaly Congenital adrenal hyperplasia
Hirsutism may respond to spironolactone, an androgen receptor antagonist