Electrolyte Abnormalities

Question 1

What are the ECG features of hyPOkalemia? (5) What are the causes of arrythmias in hypokalemia? (4)

Answer 1

Flattened T wave
U wave
Depressed ST
QT prolongation
Arrythmia -- VF, TdP
-- generally not caused by hypoK itself, but exacerbating hypoMg, MI, cong long QT, drugs (digox, QT prolong'g)

Question 2

What are clinical features of hypokalemia? (7)

Answer 2

• Muscle weak/cramps
• Paralysis (may occur if K< 2.5), typically lower limbs 1st can progress to UE, resp
• Rhabdomyolysis
• Decreased GI motility (in abscence of diarrheal dx, can get constipation, ileus)
• Bladder dysfxn (retention)
• Polyuria, dipsia – can result in nephrogenic DI if chronic hypoK
• renal impairment (interstitial nephritis, renal cysts)
• worsening of hepatic encephalopathy via renal ammonia production