Electrolyte imbalance
| Condition | Clinical Presentation | EKG Findings |
|---|---|---|
| Hypokalemia | Neuromuscular: Muscle weakness, cramping, fasciculations, paralysis, respiratory failure, ileus, rhabdomyolysis. Other: Polyuria, polydipsia, metabolic alkalosis. | - Flattened or inverted T waves - U waves (prominent) - ST depression - Apparent prolonged QT interval (actually QU interval) - Can lead to Torsades de Pointes, VT/VF |
| Hyperkalemia | Neuromuscular: Muscle weakness, paralysis, paresthesias. Often asymptomatic until severe. GI: Nausea, vomiting, abdominal pain. | - Tall, peaked T waves (earliest sign) - PR interval prolongation - P wave flattening or loss - QRS widening - "Sine wave" pattern in severe cases, preceding cardiac arrest. |
| Hypocalcemia | Neuromuscular: Tetany (perioral numbness, tingling in fingers/toes), muscle cramps, carpopedal spasm. Signs: Chvostek's sign (facial muscle twitch), Trousseau's sign (carpal spasm). Other: Seizures, laryngospasm. | - Prolonged QT interval (due to ST segment lengthening) - T wave may be normal or inverted. - Can lead to Torsades de Pointes (less common than with hypokalemia). |
| Hypercalcemia | "Stones, bones, groans, thrones, and psychiatric overtones": - Stones: Renal stones, polyuria, polydipsia. - Bones: Bone pain (from PTH or malignancy). - Groans: Abdominal pain, constipation, nausea, pancreatitis. - Thrones: Polyuria leading to dehydration. - Psychiatric: Confusion, depression, lethargy, coma. Other: Muscle weakness. |
- Shortened QT interval - PR interval prolongation - T wave flattening or inversion. - Bradycardia, heart block in severe cases. |