Periodic paralysis: clinical evaluation in 20 patients

Abstract

Twenty patients with periodic paralysis were evaluated and the aspects studied included epidemiological data, clinical manifestations, ancillary tests, treatment and evolution. Sixteen patients had the hypokalemic form (5 familiar, 5 sporadic, 5 thyrotoxic and 1 secondary). No patient with the normokalemic form was detected. Predominance of men was found (14 patients), especially in the cases with hyperthyroidism (5 patients). No thyrotoxic patient was of oriental origin. Only 4 patients had the hyperkalemic form (3 familiar, 1 sporadic). Attacks of paralysis began during the first decade in the hyperkalemic form and up to the third decade in the hypokalemic. In both forms the attacks occurred preferentially in the morning with rest after exercise being the most important precipitating factor. Seventy five percent of the hyperkalemic patients referred brief attacks (< 12 hours). Longer attacks were referred by 43% of the hypokalemic patients. The majority of the attacks manifested with a generalized weakness mainly in legs, and its frequency was variable. Creatinokinase was evaluated in 10 patients and 8 of them had levels that varied from 1.1 to 5 times normal. Electromyography was done in 6 patients and myotonic phenomenon was the only abnormality detected in 2 patients. Carbonic anhydrase inhibitors, especially acetazolamide, were used for prophylactic treatment in 9 patients with good results in all. Although periodic paralysis may be considered a benign disease we found respiratory distress in 5 patients, permanent myopathy in 1, electrocardiographic abnormalities during crises in 4; death during paralysis occurred in 2. Therefore correct diagnosis and immediate treatment are crucial. This study shows that hyperthyroidism is an important cause of periodic paralysis in our country, even in non oriental patients. Hence endocrine investigation is mandatory since this kind of periodic paralysis will only be abated after return to the euthyroid state.

Toxic Thyroid Adenoma Presenting as Hypokalemic Periodic Paralysis

“…Similarly, although most of studies failed to detect mutations of the Na v 1.4 and K v 3.4 genes [13,14,41,43], one pediatric Caucasian patient with TTP had an R672G mutation of the Na v 1.4 and one TPP patient of Portuguese descent had an R83H mutation in the K v 3.4 gene. However, the R672G mutation of the Na v 1.4 was also carried by the family members who had hypokalemic paralysis without thyrotoxicosis and the patient with R83H mutation in the K v 3.4 seems to have been also reported as FHPP [14,44]. In addition, the R83H mutation in the K v 3.4 gene was present at frequency of 1-5% in the Caucasian population [45] while it was not detected in the Asian population [14].…”

No mutation in the KCNE3 potassium channel gene in Chinese thyrotoxic hypokalaemic periodic paralysis patients

“…(2002a) is a Brazilian patient with a Portuguese descent. Both familial HOKPP and TPP have been reported in this ethnic group (Tengan et al ., 1994). An alternative explanation for their observation is that this was a case of familial HOKPP suffering from a coincidental hyperthyroidism.…”

Thyrotoxic Periodic Paralysis

“…The mutations for FHPP have been linked to three mutations in the calcium channel alpha-1 subunit (CACN1AS) [2][3][4], one in the sodium channel alpha subunit (SCN4A) [5] and one in the human skeletal muscle voltage-gated potassium channel (KCNE3) [6], none of which has been detected in HTPP patients. A solitary HTPP case in a patient of Portuguese descent in whom KCNE3 mutation has been described [7] but it is still probable that this particular patient has coexisting HTPP and FHPP, as previously reported in the same group of patients [8]. Kung et al [4] also failed to detect any association with the microsatellite markers that mapped to chromosome 1 where the genes for the a-1, a-2 and b-1 subunits for the Na-K-ATPase pump are located.…”