05-28-2003, 02:25 AM
Dr.Heart
PHYSIOLOGY
(Add Cardio, Pulmonary, GI)
Renal Acid/Base
1. Most tubular reabsorption occurs as a result of the active transport of Na+ basolaterally. Glucose, lactate, many amino acids, phosphate, H+ and Cl- are co-transported with Na+ as it diffuses down its concentration gradient into the tubule cell.
Most substances secreted by the tubules enter the tubule lumen via active transport.
Passive diffusion of CO2 and H20 allow for reabsorption of bicarbonate.
2. Central diabetes insipidus ? lack of production of ADH due to:
Tumors of pituitary/hypothalamus
Posttraumatic
Idiopathic
Vascular lesions
Infection
Nephrogenic diabetes insipidus ? lack of kidney response to ADH:
Congenital
Drugs ? lithium, demeclocycline
Endocrine/Reproductive
1. Hypoparathyroidism is most commonly caused by damage or removal during thyroid surgery or it is congenital.
Steady decline in serum Ca2+ levels show signs of increasing neuromuscular hyperexcitability followed by hypocalcemic tetany.
Lab values: Decreased serum Ca2+
Increased serum phosphate
Decreased urinary phosphate excretion
2. 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.
3. Dwarfism (insufficient GH) and giantism (excessive GH) have body habituses that remain proportional.
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.
4. 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. See figure 7-21 of BRS physiology.
5. 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).
6.
PHYSIOLOGY
(Add Cardio, Pulmonary, GI)
Renal Acid/Base
1. Most tubular reabsorption occurs as a result of the active transport of Na+ basolaterally. Glucose, lactate, many amino acids, phosphate, H+ and Cl- are co-transported with Na+ as it diffuses down its concentration gradient into the tubule cell.
Most substances secreted by the tubules enter the tubule lumen via active transport.
Passive diffusion of CO2 and H20 allow for reabsorption of bicarbonate.
2. Central diabetes insipidus ? lack of production of ADH due to:
Tumors of pituitary/hypothalamus
Posttraumatic
Idiopathic
Vascular lesions
Infection
Nephrogenic diabetes insipidus ? lack of kidney response to ADH:
Congenital
Drugs ? lithium, demeclocycline
Endocrine/Reproductive
1. Hypoparathyroidism is most commonly caused by damage or removal during thyroid surgery or it is congenital.
Steady decline in serum Ca2+ levels show signs of increasing neuromuscular hyperexcitability followed by hypocalcemic tetany.
Lab values: Decreased serum Ca2+
Increased serum phosphate
Decreased urinary phosphate excretion
2. 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.
3. Dwarfism (insufficient GH) and giantism (excessive GH) have body habituses that remain proportional.
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.
4. 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. See figure 7-21 of BRS physiology.
5. 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).
6.