HYPOKALEMIC PERIODIC PARALYSIS DISCLOSING THYROTOXICOSIS

BACKGROUND: Hypokaliemic periodic paralysis is an uncommon complicatio n of hyperthyroidism occurring sporadically almost exclusively in youn g Asian men. The clinical presentation is the same as in familial hypo kaliemic periodic paralysis. Treatment consists of conventional manage ment for thyrotoxicosis. CASE REPORT: A Laotian man aged 42 years had suffered episodes of pain and fatigue in the lower limbs lasting 2 to I days over the last few months. The patient was hospitalized with sev ere limb pain. Clinical examination found severe motor deficit involvi ng ail four limbs. laboratory findings included hypokaliemia (1.8 mmol /l) and hyperthyroidism (free thyroxin 36 pmol/l, TSH < 0.005 mlU/l). Thyroid echography revealed multinodular goitre with two heterogeneous nodules. Strong uptake was seen on the scintigram. The motor deficit regressed within 8 hours and the kaliemia was restored with 1.50 g KCI . The patient was discharged with carbimazole (30 mg/d). Three months later he was euthyroid and symptom free. Total thyroidectomy was perfo rmed and thyroxin prescribed. The patient remains symptom-free at the last follow-up, 5 months after thyroidectomy. DISCUSSION: The pathogen esis of hypokaliemic periodic paralysis involves the ATPase-dependent sodium-potassium pump whose activity is stimulated by thyroid hormones . The reasons for the ethnic and male predominance are poorly elucidat ed.