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Old 08-23-2011
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Default S.Calcium

a 45 yr old female with cirrhosis secondary to auto immune hepatitis is coming to u for regular follow up. she reports that she has been relatively well lately,and complains of only mild fatigue.her medical history is otherwise unremarkable. her medications include lactulose, spironolactone, propranolol and furosamide.her vital signs are stable. her lab values are given below.

sodium -132 mEq/l
potassium - 4.1 mEq/l
chloride - 100 mEq/l
bicarbonate - 24 mEq/l
Glucose - 102 mg/dl
creatinine - 0.9 mg/dl
calcium - 7.4 mg/dl
total protein - 6.1 g/dl
albumin 2.5 g/dl
total bilirubin - 2.1 mg/dl
AST - 80 u/l
ALT - 102 U/l

what is the most approprate next step in the management of this patient's calcium status?
a) calcium gluconate infusion
b) measurement of VIT D levels
C) replace furosimide with hydrochlorothiazide
d) initiate oral calcium and vitamin replacement
e) No intervention required


Explanation PLZ
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Old 08-23-2011
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c) replace Furocemide w.Hydrochlorthiazide
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Old 08-23-2011
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I Think the answer is E
Ca exists in protein bound as well as free form
so Total Ca = Bound Ca + Free Ca
The serium calcium is low coz of the fact that decreased Albumin leads to decrease in the bound form of calcium leading to decrease in total calcium conc.
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Old 08-23-2011
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Correct Answer good job dude !!!

Quote:
Originally Posted by usmle2011 View Post
I Think the answer is E
Ca exists in protein bound as well as free form
so Total Ca = Bound Ca + Free Ca
The serium calcium is low coz of the fact that decreased Albumin leads to decrease in the bound form of calcium leading to decrease in total calcium conc.
The answer is EE
The reason is that the serum calcium level in this patient is actually normal.

1) Calcium exists both in free and bound form (45%free & 40% bound to albumin) (note 15% bound to citrates and other salts)

2) For every 0.8 mg drop in albumin concentration the calcium concentration drops by 1

3) Under normal conditions the average albumin concentration is =4
So now lets calculate corrected value of calcium for our patient here

Corrected Ca =0.8 (normal albumin - measured albumin)+ measured ca

0.8 (4.0-2.5)+7.4 =8.8mg/dl


Please note that serum calcium of 8.6mg/dl is normal so no intervention is required for calcium.
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jahn77 (08-23-2011), jaimin (08-23-2011), riya_rai84 (08-23-2011), usmle2011 (08-23-2011), yasirsattar75 (08-23-2011)



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