Clinical Perspective - Disorders of Potassium Flashcards
True/False. Aldosterone excess is a cause of hypokalemia.
True - aldosterone increases Na reabsorption via ENaCs, thus increasing K+ secretion
How is most K+ excreted from the body?
90% via urina, 10% via stool
What are common causes of hyperkalemia?
Hyperosmolarity, low insulin, non-anion gap metabolic acidosis, NSAIDs
What foods have the highest K+ content?
Dried figs, molasses, seaweed
Where is most K+ stored in the body?
Intracellularly - primarily in myocytes
Where is most K+ reabsorbed in the kidney?
PCT
What changes would be seen on an ECG of a patient with hypokalemia?
ST depression, flatted T wave, U wave
What drug is given to stabilize the heart rhythm in hyperkalemia?
Calcium Gluconate - note this does not treat hyperkalemia, only prevents arrhythmias
What is the treatment for Bartter’s syndrome?
ACEI or ARB
What is the treatment for Liddle’s syndrome?
Amiloride, triameterne (K+ sparing diuretics)
What findings would be seen on an ECG of a patient with hyperkalemia?
Prolonged PR, peaked T waves, sine waves, asystole
What is the treatment to remove excess K+ in cases of hyperkalemia?
Lactulose, loop diuretics, dialysis
This autosomal recessive disease affects the thick ascending loop, causing NaCl wasting, hypokalemia, and metabolic alkalosis.
Bartter’s Syndrome
This autosomal recessive disease affects the DCT causing mild NaCl wasting and hypokalemia.
Gitelman’s Syndrome
What is the only location of K+ excretion in the kidney?
Collecting duct
True/False. A patient with decreased kidney function is at higher risk of hypokalemia.
False - they are at risk of hyperkalemia. This is because the kidneys excrete 90% of K+ via urine
What is the treatment of hypokalemia?
Replete Mg (if low) and K+ supplementation
What drugs are used to increase intracellular K+ uptake?
Insulin, Albuterol - note these are only temporary fixes and do not remove excess K+ from the body
Liddle’s and Bartter’s syndromes both cause hypertension. How do the causes differ?
In Liddle’s syndrome, HTN is due to NaCl reabsorption and H2O retention.
In Bartter’s syndrome, HTN is due to NaCl wasting and hyperactivation of the RAAS system
This disease causes persistent ENaC activation in the collecting duct leading to hypertension and hypokalemia.
Liddle’s Syndrome
