[Clinical features of hypokalemic periodic paralysis]

To explore the clinical features of hypokalemic periodic paralysis, and compare clinical features of primary group with those of thyrotoxicosis secondary group.

Clinical data of 44 patients with hypokalemic periodic paralysis in Peking University First Hospital from 1996 December to 2008 December were retrospectively analyzed.

There were 22 patients in primary group, and 22 in thyrotoxicosis group. Identical clinical features of both the groups: (1)It had a predilection in young men. (2)Main symptoms were limb movement disorder and fatigue, and paralysis recurrent attacked in most patients. (3) 40.9% to 68.2% patients had obvious incentives, and the common ones were a heavy meal, sweet drinks, or strenuous exercise. (4) Serum potassium levels of the two groups were obviously lower than the normal range. (5)In 20% patients of primary group and 25% patients of thyrotoxicosis secondary group, CK levels were higher than normal, while LDH and HBDH levels were normal. (6)The doses of potassium replishment were not correlated to serum potassium levels at the onset. Different clinical features of the two groups: (1) Patients of thyrotoxicosis group had hypermetabolism symptoms and thyroid dysfunction. Patients of primary group had no hypermetabolism symptoms, and all of them were euthyroid. (2)Serum potassium levels of thyrotoxicosis secondary group were lower than those of primary group significantly [(2.25 +/- 0.67) vs (2.78 +/- 0.49) mmol/L, P=0.007]. (3) Hyperkalemia is easier than primary group to rebound in thyrotoxicosis secondary group, after replenishment of potassium.

Hypokalemic periodic paralysis has its clinical features, and patients with early diagnosis and replenishment of potassium in time have good prognosis. The doses of potassium replenishment are not determined by serum potassium levels at the onset. Hyperkalemia is easier to rebound in thyrotoxicosis secondary group after replenishment of potassium, serum potassium levels should be monitored closely, and hyperthyrosis radically cured.