Early to recognize and Early to recover: A case series on Thyrotoxic periodic paralysis

Thyrotoxic periodic paralysis (TPP) is a rare disease of muscle, presenting with sudden onset weakness of muscles with or without features of hyperthyroidism. The disease most commonly occurs in the Asian population representing about 1.9% of thyrotoxic patients. It involves a predominantly male population with no family history, with or without hypokalemia. Pathophysiology is still not clearly understood. We are describing, a case series of two different patients of TPP presented to our emergency department (ED). One patient presented with classical episodic weakness of both lower limbs specifically during the night times with spontaneous reversal of weakness early in the morning. Another patient presented with complete weakness of both lower limbs for the past 1 day. Both of them had a history of weight loss and intermittent palpitations. They were promptly diagnosed in the ED and successfully treated. We recommend evaluating thyroid function status in the emergency room with the aforementioned clinical features, as early recognition and correction of thyrotoxic state are the definitive treatment helping in a complete reversal of weakness. Potassium supplements, beta-blockers, and antithyroid medications are used in treating acute attacks and preventing recurrence

Debilidad muscular con hipokalemia e hipertiroidismo en un adolescente con síndrome de Down / Muscle weakness with hypokalemia and hyperthyroidism in an adolescent with Down syndrome

La hipokalemia aguda es una causa poco frecuente de debilidad muscular. La parálisis periódica tirotóxica es una complicación infrecuente de la tirotoxicosis, en sus diferentes etiologías, en la cual se produce hipokalemia por un flujo masivo de potasio al compartimiento intracelular, que provoca parálisis muscular, que afecta, principalmente, la musculatura proximal de los miembros inferiores. Es importante reconocer esta entidad para instaurar un tratamiento adecuado que incluya el rápido suplemento de potasio y el uso de beta-bloqueantes no selectivos. El tratamiento del hipertiroidismo subyacente y el retorno al estado eutiroideo es imprescindible para la resolución de los episodios de parálisis periódica tirotóxica. Aquí se presenta a un paciente de 13 años de edad con síndrome de Down que consultó por debilidad muscular de los miembros inferiores y trastorno de la marcha, asociada a hipokalemia aguda, en el que se realizó el diagnóstico de hipertiroidismo por enfermedad de Graves.

Acute hypokalemic paralysis is a rare cause of acute weakness. Thyrotoxic periodic paralysis (TPP) is an unusual complication of hyperthyroidism. It is characterized by sudden onset of hypokalemia condition resulting from a shift of potassium into cells and paralysis that primarily affects the lower extremities. Failure to recognize TPP may lead to improper management. Treatment of TPP includes replacing potassium rapidly, using nonselective beta-blockers and correcting the underlying hyperthyroidism as soon as possible. TPP is curable once euthyroid state is achieved. We describe a 13-year-old male with Down syndrome who presented with acute onset of lower extremity weakness secondary to acute hypokalemia and was found to have new onset Graves' disease.

Analysis of 8 Children with Familial Periodic Paralysis and Literature Review / 实用儿科临床杂志

Objective To understand well this disease,8 children with familial periodic paralysis(FPP) were reported and the(rela)-ted literatures were reviewed.Methods The hereditary characters,clinical manifestations,auxiliary examination and managements were summarized retrospectively in 8 cases of FPP patients hospitalized from January 1996 to December 2005,and etiopathogenis and diagnosis were also analyzed.Results Six cases of FPP were diagnosed as hypokalemic periodic paralysis,and all occured as an autosomal dominant condition.During paralytic episodes,the patients showed obviously low serum potassium levels [1.9-2.8 mmol/L,(2.4?0.38) mmol/L)] and hypokalemic electrocardiogram findings,such as U-wave.The level of blood glucose was lower than normal range.Other 2 cases with normal serum potassium ion level at attack were diagnosed as normokalemic periodic paralysis with autosomal dominant pattern.One of the two cases,the level of blood glucose was lower.Thyroid functions,renal functions and electromyograms were all normal in 8 cases.Conclusions FPP is a group of relatively uncommon inherited disorders known as the skeletal muscle channelophathies.It can be diagnosed by hereditary characters,clinical manifestataions,auxiliary examinations.

Genetics of Channelopathy: Familial Periodic Paralysis

Familial periodic paralysis (FPP) is inherited as a dominant trait, and the intermittent failure to maintain the skeletal muscle resting potential is due to mutations in the genes coding for the voltage-gated ion channels. Because several variants of FPP have been delineated on the bases of clinical features, the expectation was that these variants might be due to involvement of different classes of ion channels. The reality of the situation has proven to be more complicated. Mutation-induced defects in the same channel may give rise to diverse phenotypes (phenotypic heterogeneity) and, conversely, mutation in different channel genes may produce a common phenotype (genetic heterogeneity). Regardless of which type of ion channel is defective, the final common pathway is the depolarization-induced loss of muscle excitability; gain-of-function defect in voltage-gated Na channel may cause myotonia, periodic paralysis or both, clinical features of hyperkalemic periodic paralysis and paramyotonia congenita, and loss-of-function defects in voltage-gated Na and Ca channel and K channel may be responsible for periodic paralysis, cardiac arrhythmia or both in hypokalemic periodic paralysis or Andersen's syndrome, respectively. This review focuses on the clinical features, molecular genetic defects, and pathophysiologic mechanisms that underlie FPP.