Hypokalemia

Background

Low = <3.5meq/L

Low! = <2.5meq/L

Diagnosis

Symptoms:

1. CNS (weakness, cramps, hyporeflexia)
2. GI (ileus)
3. CV (dysrhythmia, dig tox, U waves, ST depression, prolonged QT)
4. Renal (met alkalosis)

DDX

1. Shift
   1. Increased pH
   2. B-agonist, inuslin
2. Reduced intake
3. Increased loss
   1. Renal
      1. Primary (hyperaldos, osmotic diuresis)
      2. Secondary (diuretics, malignant HTN, renal art stenosis)
      3. Misc
         1. Licorice
         2. HyperCa
         3. HypoMg
         4. RTA
         5. Leukemia
4. Drugs
   1. PCN
   2. Lithium
   3. L-dopa
   4. Theophyline
5. GI Loss (v/d/fistula)

Treatment

20meq/h KCl IV or PO

every 10meq should inc serum by ~0.1meq/L)

treat hypomag if present

Source

2/7/06 DONALDSON (adapted from Tintinalli)