Hypokalemic periodic paralysis due to factitious thyrotoxicosis

Introduction:Hypokalemic periodic paralysis (hypoPP) is characterized by episodes of sudden-onset muscle weakness associated with low plasma potassium (<3.5 mmol/l).Secondary hypoPP can be due to diverse etiologies; one of the most common identifiable causes is thyrotoxicosis that named as thyrotoxic periodic paralysis (TPP). This condition is rare complication of hyperthyroidism that most often affects young East Asian males but increasingly also in other ethnic groups. We present patient with hypokalemic periodic paralysis and history of hypothyroidism.Case report:A 40 years old female with generalized weakness and inability to walk came to our hospital. On neurological examination, there was generalized decrease in muscle strength (muscle power: grade 3/5 in all four limbs). From 1.5 years ago hypertension and hypothyroidism was diagnosed for the patient. She was under treatment with 40 mg furosemide daily, 50 mg methoral daily and 100 mcg levothyroxine one and half day. The primary lab tests showed normal CBC diff and sever hypokalemia K= 2.2 mmol/L, Na=135 mmol/L, Urea=28 mmol/L, Cr=1.7mmol/L and Arterial blood gas analysis showed respiratory alkalosis (pH=7.43, PCO2: 32.8 mm Hg; and HCO3: 22.3 mmol/L). Our diagnosis was factitious hyperthyroidism due to over dose of levothyroxine.Discussion and Conclusion:As we know hypokalemia is one of the most frequently encountered fluid and electrolyte abnormalities in clinical medicine and an important cause of acute flaccid paralysis in adults. It can result from reduced potassium intake, transcellular potassium uptake, and extrarenal or renal potassium loss. Diagnosis of factitious thyrotoxicosis requires high index of suspicion, without which misdiagnosis and mismanagement are common. The work-up for diagnosis of factitious thyrotoxicosis should include careful history, physical examination, laboratory tests. Although hypokalaemic paralytic attack happened due to thyrotoxicosis following of hyperthyroidism but in hypothyroid patients it can happened due to factitious thyrotoxicosis.