Renal Case: 22-year-old Woman Complaining of Weakness

00:01 Let's go to our next case.

00:03 We have a 22 year old woman who presented to her primary care provider complaining of weakness.

00:07 Her exam is significant for a blood pressure of 105 over 70.

00:11 Her laboratory evaluation demonstrated a potassium of 2.9 milli equivalents per liter.

00:16 Her serum bicarbonate was 14 and we can see the normal is between 22 and 25.

00:23 A potassium to creatinine ratio was 12 milliequivalents per gram.

00:28 So the question is what is the most likely etiology of this woman's hypokalemia? Let's again go through our diagnostic algorithm to see if we can figure this out.

00:38 So our first step we want to check the acid-based status.

00:42 Is she alkalimic or is she acidemic? She has a serum bicarbonate of 14, so she has an acidosis.

00:48 So I'm already thinking potential causes could either be a renal tubular acidosis.

00:52 I cannot on reabsorbable anion or GI losses from the stool.

00:58 So my second step I want to check that potassium to creatinine ratio.

01:02 Here she's actually less than 15 Milli equivalents per gram of creatinine.

01:06 Our kidneys are trying to conserve potassium.

01:09 So this has to be a extrarenal loss.

01:12 So if I think about extrarenal losses in association with a metabolic acidosis, then I really think about stool losses.

01:19 So in this particular setting this patient likely has two losses and she could have potential laxative abuse.