ABSTRACT
Objective: To explore the clinical features of hypokalemic periodic paralysis, and compare clinical features of primary group with those of thyrotoxicosis secondary group. Methods: Clinical data of 44 patients with hypokalemic periodic paralysis in Peking University First Hospital from 1996 December to 2008 December were retrospectively analyzed. Results: 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±.67) vs (2.78±.49) mmol/L, P=0;007]. (3) Hyperkalemia is easier than primary group to rebound in thyrotoxicosis secondary group, after replenishment of potassium. Conclusion: 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.
ABSTRACT
Objective To report clinical symptoms of a Chinese pedigree of familial paramyotonia congenital (PMC) with progressive myopathy (PM), and investigate the mutations of hot spots in the adult skeletal muscle sodium channel α-subunit (SCN4A). Methods The medical history and clinical phenotype of the patients from this large family with PMC were collected. Insertional and spontaneous activity were recorded by routine electromyograph (EMG), and the exercise test (ET) and cool water test were also performed on some patients during episodes. The mutations of SCN4A were screened by PCR-SSCP and DNA sequencing in affected and unaffected members. Results The family is a four-generation kindred with 15 members affected by severe, homogeneous paralysis periodiea paramyotoniea pheuotype. The onset was early, and almost all patients developed severe progressive myopathy by middle age. Routine EMG shows myotonia discharge in all affected subjects. The compound remarkably motor action potential (CMAP) decreased more than 40% after ET with greater decreases in cool water test than in ET. The mutation screening study revealed a missense mutation (Met1592Val) in SCN4A in patients. Conclusions Autosomal dominant inheritance pattern with complete penetrance was observed in this family. The phenotype is in accord with that reported in other ethnic populations with more severe symptoms. The ET and cool water tests may be used as an easy and reliable diagnostic method. Our research supports that periodic paralysis and paramyotonia can be caused by the same mutation in SCN4A. Mutation Met1592Val is a hotspot for mutation screening in patients with PMC accompanied by PM in the Chinese population.