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The Role of the ECG in Acute Nontraumatic BLE Weakness
Acute bilateral lower extremity paralysis
Hypokalemic periodic paralysis
I. Familial hypokalemic periodic paralysis
Hyperkalemic paralysis
ECG signs of severe hyperkalemia
Acute bilateral lower extremity paralysis
- The differential diagnosis of acute nontraumatic bilateral weakness is broad
- Most causes have unique manifestations and symptoms
- The two most common cluster of causes of acute nontraumatic BLE weakness without significant associated symptoms: spinal cord disease and periodic paralysis
- Patients with periodic paralysis have unique ECG manifestations
Hypokalemic periodic paralysis
I. Familial hypokalemic periodic paralysis
- Mostly Caucasian men
- First attack at age <25
- Most patients have family history
- Most patients have repetitive attacks
- Mostly Asian and Latino men
- First attack later (20s – 30s)
- Attacks only occur when hyperthyroid
- No family history of periodic paralysis
- Hyperthyroidism frequently indolent, easy to miss the diagnosis
- Large distant U waves frequently reaching the next P waves
- Tall QRS complexes
- Slight PR prolongation
- Terminal notching of QRS complexes in anterior chest leads (rsR’ pattern)
- Propranolol
- Use caution with potassium replacement
Hyperkalemic paralysis
- Almost always acquired and/or iatrogenic
- Only occurs with severe, extreme hyperkalemia
- Wide bizarre QRS complexes, sine-wave appearance
- Usually no P waves present
- Most patients do not have PEA
ECG signs of severe hyperkalemia
- The more severe the hyperkalemia, the less you can expect peaking of the T waves
- Widened QRS complexes, new axis shifts
- Widened QRS complexes with ST-segment elevation in V1-V2
- Widened QRS complexes with the Brugada pattern in V1-V2
- Double counting of heart rate by the ECG interpretation software
- Sine-wave appearance
