[Hypokalemic Paresis in Adolescent: A Case Report].

Familial hypokalaemic periodic paralysis is a rare autosomal dominant neuromuscular disease characterized by episodic attacks of flaccid paralysis with concomitant hypokalaemia. We present a case of a 15-year-old male adolescent observed in the pediatric emergency department by flaccid paresis of the 4 limbs of sudden onset and progressive worsening. In the anamnesis, corticosteroid and antihistamine intake were observed on the previous day for urticaria and family history of transient episodes of flaccid paralysis in adolescence, asymptomatic after the fourth decade of life, without an established diagnosis. Diagnostic tests revealed hypokalaemia (K + < 2.4 mEq/L), without hypokaluria and without other changes. Symptomatology resolution after supplementation with potassium was verified until normalization of kaliemia. Flaccid paralysis is a rare form of presentation of hypokalaemia. Several etiologies may be involved in the child or adolescent presenting with acute flaccid paralysis. The description of this case draws attention to the importance of the knowledge of this entity, because if recognized and treated properly, patients usually recover without sequelae.