Management of Hyperthyroid Hypokalemic Periodic Paralysis
The management of thyrotoxic hypokalemic periodic paralysis (THPP) should focus on acute potassium replacement, non-selective beta-blockers, and definitive treatment of the underlying hyperthyroidism to prevent recurrence. 1
Acute Management
First-line treatment: Administer non-selective beta-blockers (such as propranolol) as they simultaneously decrease sodium-potassium ATPase activity, limit insulin secretion, and address the underlying thyrotoxicosis 2
Cautious potassium replacement: Provide intravenous potassium chloride for severe weakness, but limit to <50 mEq to prevent rebound hyperkalemia when potassium shifts back from cells to extracellular space 2, 1
Monitor cardiac status: Perform ECG monitoring in hyperkalemic patients to detect arrhythmias or conduction abnormalities 3
Avoid glucose-containing solutions: These can stimulate insulin release and worsen hypokalemia 1
Definitive Management
Control hyperthyroidism: Initiate anti-thyroid medications (such as methimazole) to achieve euthyroid state, which will completely abolish attacks 1, 4
Long-term beta-blockade: Continue propranolol until euthyroidism is achieved to prevent recurrent attacks 4
Regular potassium monitoring: Check serum potassium levels periodically during treatment 5
Clinical Pearls and Pitfalls
Diagnostic clues: THPP typically presents in adult males with no family history of periodic paralysis, often with systolic hypertension, tachycardia, and characteristic ECG findings 1
Avoid excessive potassium: Administration of >50 mEq of exogenous potassium places patients at risk of dysrhythmias from rebound hyperkalemia once the paralytic attack resolves 2
Consider THPP in normokalaemic paralysis: Some patients may present with normal potassium levels (thyrotoxic normokalaemic periodic paralysis) but still require the same management approach 6
Recognize risk factors: Patients of East Asian descent and those with obesity (due to underlying insulin resistance) are at higher risk for THPP 2, 1
Look beyond obvious symptoms: Many patients with THPP may not have obvious symptoms of hyperthyroidism, requiring high clinical suspicion 1
Preventive measures: Advise patients to avoid precipitating factors such as high-carbohydrate meals, alcohol, and strenuous exercise until definitive treatment of hyperthyroidism 1
Complete resolution: Definitive control of hyperthyroidism (through medication, radioactive iodine, or surgery) will completely eliminate attacks of periodic paralysis 1, 4