A Quick Overview of Hypokalemic Periodic Paralysis

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1) Patient has "attacks" of weakness and/or floppy paralysis.

2) First attacks occur by the age of 16 in 65% of patients.

3) Attacks follow triggering events (vigorous exercise, intense stress, fright) or a meal high in carbohydrate and/or sodium (baked goods, pizza, Chinese food, sugar-sweetened soda, beer, etc.). Often a first attack occurs in a teenager who has participated in a sporting event and celebrated afterward with pizza and beer or soda. Attacks also frequently occur after dental work or stitching of minor wounds, triggered by the epinephrine in the local anaesthetic. Heat stress and chilling are reported triggers in many patients.

4) Attacks usually begin in early morning hours before waking so patient awakens weak/paralyzed.

5)  Potassium level in the blood falls in the hours leading up to the attack. In teenagers this fall may be dramatic, even to 1.8 or 2.0, older patients usually experience less drop from normal. Potassium level normalizes well before strength returns, so the drop in potassium may not always be evident if blood is drawn toward the end of the attack.  

6) Patients do not lose potassium (or other electrolytes) in the urine during paralytic attack. Low serum levels due to excretion immediately prior to or during attacks suggests another diagnosis. See: Determining the Origin of Hypokalemic Paralysis

7) Patients should not be started on medication which modifies/manipulates acid-base balance or  potassium levels until a 24 hour urine examination has been conducted to rule out kidney, endocrine and digestive disorders.