RENAL PHYSIOLOGY-VOLUME CONTRACTION

SUMMARY

1. Vomiting causes metabolic alkalosis and low serum Cl^- (losing stomach HCl in the emesis­), hypokalemia from renal K⁺ wasting mediated by aldosterone.

2. Diarrhea causes metabolic acidosis (NAGMA) and an appropriately high serum Cl^- (bicarbonate is lost in the stool, and chloride is reabsorbed to increase intravascular volume).

3. Thiazide diuretics, like vomiting, cause a metabolic alkalosis with low serum cr, but, unlike vomiting, cause a high urinary Cl.

4. Diabetes insipidus (nephrogenic or neurogenic) may cause hypernatremia and volume con­traction.

5. Osmotic diure­sis (mannitol, hyperglycemia) causes a high urine output with a normal urine osmolality.

Reference(s)

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Therapeutic Guidelines. Melbourne: Therapeutic Guidelines Limited. https://www.tg.org.au [Accessed 2021].