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

• Shift
  • Increased pH
  • B-agonist, inuslin
• Reduced intake
• Increased loss
  • Renal
    • Primary (hyperaldos, osmotic diuresis)
    • Secondary (diuretics, malignant HTN, renal art stenosis)
    • Misc
      • Licorice
      • HyperCa
      • HypoMg
      • RTA
      • Leukemia
• Drugs
  • PCN
  • Lithium
  • L-dopa
  • Theophyline
• 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)