Hyperkalemia - causes
Pseudohyperkalemia:
Hemolysis during blood drawing
Excessive clenching of fist with tourniquet on during blood drawing
Platelet >1,000,000
WBC >200,000
Mononucleosis
Familial pseudohyperkalemia (potassium efflux from cells)
Redistribution (potassium shifts out of cells)
Acidosis (metabolic and respiratory)
Hypertonic states
Massive digitalis overdose
Autosomal dominant hyperkalemic periodic paralysis
Tumor lysis syndrome
Aldosterone deficiency/unresponsiveness
Primary adrenal failure (autoimmune, TB, hemorrhage, tumor infiltration)
Syndrome of hyporeninemic hypoaldosteronism
Accounts for many cases of unexplained hyperkalemia
GFR is generally >20%
May have associated NAGMA
Caused by a variety of interstitial renal diseases
Diabetes is the most common cause
RTA-4
Tubular unresponsiveness to aldosterone
Caused by a variety of interstitial renal diseases
Very similar to SHH but does not respond to fludrocortisone
Renal failure
GFR is typically reduced to <10 - 20% of normal.
Hyperkalemia may develop rapidly from exogenous potassium in patients with renal failure.
RTA - type 4
Drugs that can cause or aggravate hyperkalemia (multiple mechanism)
Potassium soruces
IV potassium solutions
Penicillin VK
Potassium citrate
Salt substitutes
Foods: dried fruits, nuts, bananas, oranges, potatoes, spinach.
Redistribution hyperkalemia
Arginine and lysine HCl (rarely used)
Beta2-adrenergic blockers
Succinylcholine
Digitalis (massive overdose)
Hypertonic mannitol (osmotic effect)
Aldosterone deficiency/unresponsiveness
NSAIDs
ACE-I
A2RB
Heparin
Cyclosporine (also causes hypetriglyceridemia and hypercholesterolemia)
FK 506
Aminoglutethimide
Potassium-sparing diuretics
TMP
Pentamidine
Nefamostat mesilate