Lab values: Decreased serum Ca2+
Increased serum phosphate Decreased urinary phosphate excretion
Clinical tests for endocrine abnormalities:
Radioimmunoassays for T4, T3, TSH, cortisol, Ca2+ , etc.
Glucose Tolerance test: Check a fasting blood sugar level, then have patient drink a 75 g glucose solution. Re-draw blood at 30 min, 1 hr., and 2 hrs. If blood glucose level is >200 mg/dl at 2 hrs, then highly suggestive of diabetes.
Dexamethasone suppression test: Dexamethasone, a synthetic steroid, is given to the patient at 11 p.m. The following day blood samples are collected at 4 p.m. and 11 p.m. The normal response is a decrease in circulating adrenal steroid hormones. Those with Cushing’s will have continued elevated levels.
Radioiodine injection: Hyperthyroidism will show an increase uptake.
Acromegaly (excessive GH after epiphyseal plate closure) results in soft tissue overgrowth. Signs include prominent forehead, nose, mandible, ears, and enlarged hands and feet.
Grave’s disease (hyperthyroidism)- heat intolerance, weight loss, increased sweating, nervousness, tremor, exophthalmos.
Hashimoto’s thyroiditis (hypothyroidism) – myxedema, lethargy, mental sluggishness, weight gain, cold intolerance.
Cushing’s syndrome (hypercortisolism) – Moon facies, buffalo hump, central obesity, thin arms and legs, striae, osteoporosis, acne, and hirsutism.
Addison’s disease (hypoadrenalism) – Anorexia, weight loss, hypoglycemia, weakness, hypotension, hyperkalemia, metabolic acidosis, hyperpigmentation.
Conn’s syndrome (hyperaldosteronism) – Hypertension, hypokalemia, metabolic alkalosis, decreased renin.
Syncytiotrophoblast cells release hCG which stimulates the corpus luteum to increase its secretion of estrogen and progesterone. By week 6, the placenta is making hormones and by week 9 it takes over for the corpus luteum and makes the majority of the estrogen and progesterone.
Prolactin secretion is tonically inhibited by the hypothalamus by dopamine. Hyperprolactinemia occurs due to a prolactin secreting tumor or when the dopamine inhibition is lost. Also, when assessing hyperprolactinemia, always remember to check TRH levels, as TRH stimulates prolactin secretion. Treat with dopamine agonists (bromocriptine).
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