Hypokalaemia Flashcards
What is a Mallory-Weiss tear and how does it form
longitudinal muscle tear near gastro-oesophageal junction often with severe retching or vomitting after alcohol intoxication
Diagnosis suggested if haematamesis occurs after bouts non-bloody vomitting
if the tear perforate into mediastinum can lead to Boerhaave syndrome
The tear occurs, as during vomitting there is a reflax relaxation of gastrooesphageal musculature leading to anti-peristalsic wave, however with prolongued vomitting this relaxation fails, which causes refluxing gastric contents to overwhelm gastric inlet causing a tear
What are common ways for increased renal potassium loss
enhanced sodium delivery to collecting ducts (diuretics)
mineralcorticoid excess
hyperaldosteronism
increase urine flow (osmotic diuretics)
How does prolongued vomitting cause low K+
vomitting causes loss of gastric fluid causing vol depletion + metabolic alkalosis
vol depletion- leads to secondary hypoaldosteronism, causing enhance cortical collecting tubule secretion of K+ in response to enhance Na+ reabsorbtion
Metabolic alkalosis- decreased availability of H+ for secretion in response to Na+ reabsorbtion so increase collecting tubule K+ secretion
What is the treatment for hypokalaemia
measure K+ to find out pathophys behid the low levels
treatment involves either reducing further loss of K+ or replenishing K+
Reducing loss:
-discontinue diuretics/laxatives
-potassium-sparing diuretics instead
-treat diahrrhoea/vomitting
Replenishing:
-oral K replacement
- IV K+
What is the SCOFF questionaire
-do you make yourself sick because you feel uncomftorbly full
-do you worry you have lost control ober how much you eat
-have you lost >1 stone in last 3 months
-do you believe you are fat when other say you are too thin
-does food dominate your life
> 2= likely case of anorexia nervosa/ bulimia
MOA of furosemide
blocks NKCC2 transporters collecting tubules and thick asceding loop causing less Na+ reabsorbtion, meaning more water and electrolytes excreted
