K Basics Flashcards
Abnormalities of serum K have a major effect on…
Cell Excitability (Esp. nerve/muscle)
Hyperkalemia is almost always caused by..
Hypokalemia is almost always caused by…
Reduced renal K excretion
Diuretics or Vomiting
Major causes of Hypokalemia
Decreased intake
Increased cell entry (basic pH, insulin, beta adrenergics)
Increased GI/Urinary/Sweat Loss
Dialysis/Plasmaphoresis
Best test in a patient with hypokalemia for no clear reason?
24 hour urine K+
Kidney will want to minimize K loss. normally, will be under 20 meq/24 hrs
If the value is over 20, renal cans save it – renal source of loss
If patient is hypokalemia with high urine K+ AND HTN, what should be be thinking of
High renin/aldosterone (RA stenosis, paraneoplastic) Normal RA (Adrenal adenoma/hyperplasia) Low RA (Cushings, 11bhydroxylase def, Liddle)
If patient is hypokalemia with high urine K+ AND NO HTN, what should be be thinking of
Low Bicarb (Renal tubular acidosis) Normal Bicarb -- Diuretics, Mg def. Gitelman syndrome, vomiting
Effects of hypokalemia
Cardiac arrythmias Neuromuscular weakness/ GI Illeus Metabolic Alkalosis Lowered Na, Mg, Cl- High ammonium
What is pseudohyperkalemia
Serum K more than 0.5 mEq/L above the plasma K
Which drugs most commonly cause hyperkalemia
Aldosterone downregulators (ACE, etc), Antagonists Collecting Tubule Na channel blockers
Clinical manifestations of hyperkalemia
Weakness –> paralysis/hypoventilation
Metabolis Acidosis (inhib. renal ammoniagenesis)
Arrhythmias
How to treat GI K+ loss
Kayexalate
How to treat Renal K loss
Diuretics
How to treat too much K being in the cells
Glucose+Insulin
Nebulized beta agonists
How to protect the heart against arrhythmia from hyperkalemia
IV Ca
