Thyrotoxic periodic paralysis: correct hypokalemia with caution.

Abstract

BACKGROUND:

Thyrotoxic periodic paralysis is rare in Caucasian populations, but affects approximately 2% of East Asians with thyrotoxicosis (13% of males, 0.17% of females). The presentation is characterized by abrupt-onset hypokalemia and profound proximal muscular weakness, and commonly occurs after carbohydrate loading or exercise.

OBJECTIVES:

To raise awareness of this condition through the description of a typical case of thyrotoxic periodic paralysis; to remind readers that, despite intravascular hypokalemia, total body potassium is normal and that correction must be done with caution; to highlight the differences in treatment compared to familial hypokalemic periodic paralysis.

CASE REPORT:

We describe the presentation of a 36-year-old Filipino man with a background history of Graves disease. Over-administration of intravenous potassium was narrowly averted in this case.

CONCLUSION:

It may be important to check thyroid function in patients presenting with acute paralysis, especially those of Asian origin. In patients with thyrotoxic periodic paralysis, administration of potassium, with cardiac monitoring and a total dose of <50 mmol, limits the dysrhythmia risk. Patients are likely to benefit from the prescription of non-selective beta-blockers until they become euthyroid. In contrast to familial periodic paralysis, regular oral potassium supplementation is ineffective in thyrotoxic periodic paralysis, and acetazolamide precipitates, rather than prevents, attacks.

• Authors: Thomas E Cope, Amal P R Samaraweera, David J Burn
• Journal: The Journal of emergency medicine (J Emerg Med) Vol. 45 Issue 3 Pg. 338-40 (Sep 2013) ISSN: 0736-4679 [Print] United States
• PMID: 23849367 (Publication Type: Case Reports, Journal Article)
• Copyright: Copyright © 2013 Elsevier Inc. All rights reserved.

Chemical References

• Adrenergic beta-Antagonists
• Antithyroid Agents
• Propylthiouracil
• Propranolol
• Potassium

Topics

• Adrenergic beta-Antagonists (therapeutic use)
• Adult
• Antithyroid Agents (therapeutic use)
• Graves Disease (complications, drug therapy)
• Humans
• Hypokalemia (blood, drug therapy, etiology)
• Male
• Muscle Weakness (etiology)
• Potassium (administration & dosage, blood)
• Propranolol (therapeutic use)
• Propylthiouracil (therapeutic use)
• Thyrotoxicosis (diagnosis, drug therapy, etiology)