A 26 year old woman presents to the ER with generalized weakness associated with perioral numbness. She is moderately built and looks slightly depressed. On physical exam, she has mild pallor. She denies use of any medications. BP 120/88 mmHg and physical exam is normal. Lab data: Cr 1.2mg/dL, BUN 15mg/dLNa 136 , K 2.8 , Cl 88 , HCO3 38. Urine Na 45 meq/L, Urine K 35 meq/L, Urine Cl 8 meq/L, Urine specific gravity 1.010, Urine pH 7.
Most likely diagnosis is :
A)Laxative Abuse
B)Surreptious vomiting
C)Licorice abuse
D)Malabsorption Syndrome
E)Hyporeninemic Hypoaldosteronism
q21) Most appropriate next step in the management:
A)IV normal saline
B)Spronolactone
C)Amiloride
D)Psychiatry consult
E)Reassurance because this is self limiting beca
COPY RIGHTS: ARCHER USMLE REVIEWS
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B Surreptious vomiting metabolic alkalosis
D
B, D
b,d
e a
B
A
B
D
BD
bbb?
aaa
B
saline sensitive metabolic alklosis due to induced vomiting by anorexic woman.
D
patient hemodynamically stable so no need of saline only consult psychiatry.
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ITS
A
A
The patient has metabolic alkalosis which is mostly saline responsive.
In Dr.Red’s lecture, Met alkalosis has been divided in to two types : saline responsive and saline resistant.
Contraction metabolic alkalosis that is secondary hypovolemia will always respond to NS.
Normally, we check urine Na+ Level to see if there is hypovolemia. If urine NA+ is less than 10 it is more consistent with hypovolemia. However, metabolic alkalosis
spuriously increases Urine NA+ level. Therefore, urine NA+ is not a reliable predictor for volume status in met.alkalosis. Hence, urine chloride is the most important result here and a urine chloride < 10 suggest hypovolemia here. Once you know that urine cl- is low, next step is to give NS to correct this hypovolemia induced metabolic alkalosis.
The answer is B and D
When potassium is low and there is no other medical explanation, it is almost certain that the patient is either vomiting or abusing laxatives or diuretics.
Purging also throws the body’s acid-base balance off-kilter, which is reflected in another type of electrolyte disturbance, elevated bicarbonate levels in the blood. These laboratory values of low potassium and elevated bicarbonate levels could, to the unsuspecting or inexperienced doctor, incorrectly indicate a kidney problem, not surreptitious vomiting.
Although elevated serum bicarbonate is not as serious as the low potassium that can accompany purging behaviors, it is something that can be tested for, and is a much more reliable marker than potassium for purging behaviors. For this reason, some doctors order a serum bicarbonate test when they suspect purging, even though potassium levels are normal.
A and D, pt has perioral numbnes, fatigue and depression which could imply that she has hypocalcemia- more common with laxative abuse.
Ans. B
Ans. A
Key concepts : Recognize the etiologies of metabolic alkalosis. Understand the concept of urinary chloride level in identifying the etiology of metabolic alkalosis. If urinary chloride is less than 10meq/L, it indicates Saline responsive alkalosis. A higher than 10 value indicates Saline resistant alkalosis.
Ans. B is the correct choice because the patient has hypokalemic, hypocholremic metabolic alkalosis. Urinary chloride less than 10 indicate that this is a saline responsive metabolic alkalosis and hence, should be treated with IV normal saline. NS can correct this metabolic alkalosis.
Ans. A incorrect because diarrhea due to laxative abuse should cause non anion gap metabolic acidosis.
Ans. C is incorrect. The active component in licorice is glycyrrhizic acid which inhibits 11B-HSD2, the enzyme that inactivates cortisol to cortisone in the collecting duct. Inhibition or deficiency of 11B-HSD2 causes cortisol to remain active and like aldosterone, cortisol binds to aldosterone receptors causing hypokalemia, metabolic alkalosis and low-renin and low-aldosterone hypertension. This is not licorice abuse because this patient does not have hypertension. Also, urinary chloride will be higher than 10 in licorice induced metabolic alkalosis
Ans. D is incorrect because it should cause chronic diarrhea and non-gap metabolic alkalosis.
Ans. E is incorrect because hyporeninemic hypoaldosteronism causes hyperkalemia and metabolic acidosis
( Type IV RTA)
Report
If she is sureptous vomiting, you will need to correct the electrolytes b/c there is danger of her getting cardiac,seizueres, or any life threatening situation. This is an emergency! Treat!
Hi Stefan …….
I would really appreciate your help if you take some time to answer the remaining questions if possible,because we find your explanations really useful and helpful….
thanks
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b,a