new_n_lost
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A 54-year-old alcoholic presents with complaints of tremors and muscle twitching. Physical examination reveals the presence of Trousseau's sign.
Laboratory data show that serum magnesium is < 1 mEq/L (normal, 1.4 - 2.2 mEq/L).
Which of the following findings would be most consistent with this information?
A. Decreased serum calcium
B. Decreased serum phosphate
C. Increased bone density
D. Increased plasma parathyroid hormone concentration
E. Increased urinary cAMP concentration
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| Addicudo
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A. Decreased serum calcium And could someone tell me the Clinical Relevance of Mg .. too !! and its relation to any hormone..
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| mytime
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A U know what i think this is a trick q.....D?????????
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| Luckyall
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Absolutelly & unequivocally DECR serum CA due to
Mg is a cofactor of Adenylate cyclase ----> generating cAMP----> req. for PTH activation
hypo Mg emia---> inhibits synth & release of PTH----> excluding D&E options
 -----> hupo PTH----> hypo CA emia
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| mytime
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OH God I really need that sleep.!!!!! LUCKY GOOD JOB,girl!
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| Luckyall
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after all if i get any endo Qs wrong...im going crazyyyyyyy
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| Medusin
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A.
Mg acts as a cofactor for many intracellular enzyme reactions, including those related to transfer of phpsphate groups.
Magnesium deficiency can result from any condition that directly limits intake such as malnutrition, starvation, etc. A common cause of Mg deficiency is chronic alcoholism (low intake, diarrhea). This problem is exacerbated with calcium and potassium deficiency. (Trousseaus sign, Chvosteks sign, muscle twitching, arrythmias, etc)
Clinical characteristics of Mg deficiecy are usually respsented with hypocalcemia and hypokalemia. Most patients with hypomagnesemia related hypocalcemia have decreased PTH levels as a result of impaired magnesium dependant mechanism that control PTH release and synthesis.
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| keepgoing
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good question..agree with a
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| new_n_lost
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| new_n_lost
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The correct answer is A.
Malnutrition associated with chronic alcoholism can lead to a severe magnesium deficiency. The effect of low serum magnesium on parathyroid hormone secretion (PTH) depends on severity and duration. An acute decrease in serum magnesium will increase PTH secretion, while a prolonged severe deficiency results in decreased PTH secretion. There is also evidence that the action of PTH is decreased with chronic magnesium deficiency. Hence, this patient is suffering from "functional" hypoparathyroidism. The low serum calcium can produce weakness, tremors, muscle fasciculations, and seizures. A positive Trousseau's sign indicates the presence of latent tetany. It is observed by inflating a blood pressure cuff above systolic blood pressure for at least 2 minutes. A positive reaction consists of the development of carpal spasm, with relaxation occurring within seconds after deflating the cuff. In patients with magnesium deficiency, magnesium administration will produce a prompt rise in plasma PTH with subsequent restoration of serum calcium concentration to normal.
With functional hypoparathyroidism bone density would be decreased (not increased, choice C).
The combination of decreased PTH secretion (not increased, choice D) and decreased effectiveness of PTH produce hypocalcemia and hyperphosphatemia (not hypophosphatemia, choice B).
Urinary cAMP would probably be decreased (not increased, choice E), given the low PTH.
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FORUM RULES-- Those who believe in telekinesis, raise my hand. I get enough exercise just by pushing my luck --P4U World.." The pure and simple truth is rarely pure and never simple."
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