Step I How do electrolytes change with bulimia?

[studylol]

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Besides the obvious hypochloremia. I'm specifically looking at phosphate, sodium and potassium. I know K becomes low (hypokalemia) but i'm having trouble figuring out why.

Thanks!

 

[TheNsg300]

In the purging type of BN,,u wud expect hypochloremic metabolic alkalosis, hypokalemia nd possibly hypophosphatemia((xcpt this wud be more common in Anorexia or de restrictive type of BN)). The hypokalemia cud be explained by the transcelluar shift dat occurs with K entry into cells in exchange for H+ or de increased K loss in urine becuz of increased tubular secretion. I wud think Na levels wud be normal or slightly hyponatremic cuz Na controls plasma volume nd iz rapidly adjusted for by RAA,,which cud also contribute for the hypokalemia,,

 

[Phloston]

Besides the obvious hypochloremia. I'm specifically looking at phosphate, sodium and potassium. I know K becomes low (hypokalemia) but i'm having trouble figuring out why.

Thanks!

Volume loss stimulates renin-angiotensin system, and the renal tubules will secrete K+ and H+ (and Cl- follows H+ in the cortical collecting duct), in addition to the HCl lost via emesis.

The secretion of K+, H+ and Cl- is more important than the stomach losses in terms of why you have the hypochloraemic-hypokalaemic metabolic alkalosis.

Phosphate would theoretically be lower because it's an additional anion that can be paired with K+ in the urine. But phosphate depletion is classically a sign of rapid refeeding following ongoing, nutritional deficiency, rather than a direct result of acute losses. That's why refeeding syndrome we notably look at phosphate levels.

 

[studylol]

Thanks a lot for the reply makes sense! Great explanation Phloston.

 

[worldbeater]

Your vomiting, meaning your losing fluids, which makes it a low volume state. That means a loss of Na, Cl, K, but an increase in a total sodium in your cell.

Also the patient is losing H+ ions, which increases her pH. Losing volume will also increase her blood pressure.