Thyrotoxic periodic paralysis (TPP) is a notable and potentially lethal complication of thyrotoxicosis, and Graves' disease is the most common cause of TPP. TPP is commonly reported in Asian males between 20–40 years of age, but it is rare in children and adolescents. We report 2 Korean adolescents (a 16-year-old male and a 14-year-old female) with episodes of TPP who were previously diagnosed with Graves' disease. These 2 patients presented with lower leg weakness in the morning after waking up. They were diagnosed with TPP-associated with thyrotoxicosis due to Graves' disease. After they were initially treated with potassium chloride and antithyroid drugs, muscle paralysis improved and an euthyroid state without muscle paralytic events was maintained during follow-up. Therefore, clinicians should consider TPP when patients have sudden paralysis and thyrotoxic symptoms such as goiter, tachycardia, and hypertension.
Adolescent ; Antithyroid Agents ; Asian Continental Ancestry Group ; Child ; Follow-Up Studies ; Goiter ; Graves Disease ; Humans ; Hypertension ; Hypokalemia ; Hypokalemic Periodic Paralysis ; Leg ; Male ; Paralysis ; Potassium Chloride ; Tachycardia ; Thyrotoxicosis

No abstract available.
Acetazolamide ; Acidosis ; Acidosis, Renal Tubular ; Hypokalemic Periodic Paralysis ; Muscle Weakness

Adult ; Female ; Humans ; Hypokalemic Periodic Paralysis ; genetics ; Infant, Newborn ; Male ; NAV1.4 Voltage-Gated Sodium Channel ; genetics ; Pedigree ; Potassium Channels, Voltage-Gated ; genetics ; Young Adult

No abstract available.
Electrodiagnosis ; Hypokalemic Periodic Paralysis ; Neural Conduction* ; Paralysis* ; Thyrotoxicosis

Channelopathies are a heterogeneous group of disorders resulting from the dysfunction of ion channels located in the membranes of all cells and many cellular organelles. These include diseases of the nervous system (e.g., generalized epilepsy with febrile seizures plus, familial hemiplegic migraine, episodic ataxia, and hyperkalemic and hypokalemic periodic paralysis), the cardiovascular system (e.g., long QT syndrome, short QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia), the respiratory system (e.g., cystic fibrosis), the endocrine system (e.g., neonatal diabetes mellitus, familial hyperinsulinemic hypoglycemia, thyrotoxic hypokalemic periodic paralysis, and familial hyperaldosteronism), the urinary system (e.g., Bartter syndrome, nephrogenic diabetes insipidus, autosomal-dominant polycystic kidney disease, and hypomagnesemia with secondary hypocalcemia), and the immune system (e.g., myasthenia gravis, neuromyelitis optica, Isaac syndrome, and anti-NMDA [N-methyl-D-aspartate] receptor encephalitis). The field of channelopathies is expanding rapidly, as is the utility of molecular-genetic and electrophysiological studies. This review provides a brief overview and update of channelopathies, with a focus on recent advances in the pathophysiological mechanisms that may help clinicians better understand, diagnose, and develop treatments for these diseases.
Ataxia ; Bartter Syndrome ; Brugada Syndrome ; Cardiovascular System ; Channelopathies* ; Diabetes Insipidus, Nephrogenic ; Diabetes Mellitus ; Endocrine System ; Epilepsy, Generalized ; Genetics ; Hypoglycemia ; Hypokalemic Periodic Paralysis ; Immune System ; Ion Channels ; Isaacs Syndrome ; Long QT Syndrome ; Membranes ; Migraine with Aura ; Myasthenia Gravis ; Nervous System ; Neuromyelitis Optica ; Organelles ; Polycystic Kidney Diseases ; Respiratory System ; Seizures, Febrile

Hypokalemic periodic paralysis is a rare disorder characterized by sudden onset of weakness and low serum potassium levels. We report a case provoked by combination chemotherapy including prednisolone. A 23-yr-man, diagnosed with diffuse large B-cell lymphoma, received chemotherapy. He developed significant weakness in upper and lower extremities during chemotherapy, and his serum potassium level was 1.7 mmol/L. Potassium replacement restored the weakness. Further workup revealed that prednisolone had provoked hypokalemic paralysis. As prednisolone triggered an attack of hypokalemic periodic paralysis, it should be administered with caution, particularly in patients with periodic paralysis.
Drug Therapy ; Drug Therapy, Combination ; Humans ; Hypokalemic Periodic Paralysis ; Lower Extremity ; Lymphoma, B-Cell* ; Paralysis* ; Potassium ; Prednisolone

Hypokalemic periodic paralysis is a rare disorder characterized by sudden onset of weakness and low serum potassium levels. We report a case provoked by combination chemotherapy including prednisolone. A 23-yr-man, diagnosed with diffuse large B-cell lymphoma, received chemotherapy. He developed significant weakness in upper and lower extremities during chemotherapy, and his serum potassium level was 1.7 mmol/L. Potassium replacement restored the weakness. Further workup revealed that prednisolone had provoked hypokalemic paralysis. As prednisolone triggered an attack of hypokalemic periodic paralysis, it should be administered with caution, particularly in patients with periodic paralysis.
Drug Therapy ; Drug Therapy, Combination ; Humans ; Hypokalemic Periodic Paralysis ; Lower Extremity ; Lymphoma, B-Cell* ; Paralysis* ; Potassium ; Prednisolone

PURPOSE: Familial hypokalemic periodic paralysis (HOKPP) is an autosomal dominant channelopathy characterized by episodic attacks of muscle weakness and hypokalemia. Mutations in the calcium channel gene, CACNA1S, or the sodium channel gene, SCN4A, have been found to be responsible for HOKPP; however, the mechanism that causes hypokalemia remains to be determined. The aim of this study was to improve the understanding of this mechanism by investigating the expression of calcium-activated potassium (KCa) channel genes in HOKPP patients. METHODS: We measured the intracellular calcium concentration with fura-2-acetoxymethyl ester in skeletal muscle cells of HOKPP patients and healthy individuals. We examined the mRNA and protein expression of KCa channel genes (KCNMA1, KCNN1, KCNN2, KCNN3, and KCNN4) in both cell types. RESULTS: Patient cells exhibited higher cytosolic calcium levels than normal cells. Quantitative reverse transcription polymerase chain reaction analysis showed that the mRNA levels of the KCa channel genes did not significantly differ between patient and normal cells. However, western blot analysis showed that protein levels of the KCNMA1 gene, which encodes KCa1.1 channels (also called big potassium channels), were significantly lower in the membrane fraction and higher in the cytosolic fraction of patient cells than normal cells. When patient cells were exposed to 50 mM potassium buffer, which was used to induce depolarization, the altered subcellular distribution of BK channels remained unchanged. CONCLUSION: These findings suggest a novel mechanism for the development of hypokalemia and paralysis in HOKPP and demonstrate a connection between disease-associated mutations in calcium/sodium channels and pathogenic changes in nonmutant potassium channels.
Blotting, Western ; Calcium ; Calcium Channels ; Channelopathies ; Cytosol ; Humans ; Hypokalemia ; Hypokalemic Periodic Paralysis* ; Large-Conductance Calcium-Activated Potassium Channels ; Membranes ; Muscle Weakness ; Muscle, Skeletal ; Paralysis ; Polymerase Chain Reaction ; Potassium ; Potassium Channels ; Potassium Channels, Calcium-Activated* ; Reverse Transcription ; RNA, Messenger ; Sodium Channels

Thyrotoxic periodic paralysis (TPP) is a rare disease of muscle paralysis associated with hypokalemia and thyrotoxicosis. Hypokalemic periodic paralysis can be caused by potassium channelopathy or thyroid dysfunction. Thyrotoxic hypokalemic periodic paralysis is far more common in Asian males aged between 20 to 40 years and rare in children and adolescents. Clinical symptoms with motor paralysis were recovered just after treatment of potassium, propranolol, and methimazole. However, thyroid function tests were not normalized until 3 month treatment of methimazole and propranolol. We report a 17-year-old patient diagnosed with Graves' disease with TPP. Thyroid function test should including in periodic paralysis patient's evaluation.
Adolescent ; Aged ; Asian Continental Ancestry Group ; Channelopathies ; Child ; Graves Disease ; Humans ; Hyperthyroidism ; Hypokalemia ; Hypokalemic Periodic Paralysis ; Male ; Methimazole ; Muscles ; Paralysis ; Potassium ; Propranolol ; Rare Diseases ; Thyroid Function Tests ; Thyroid Gland ; Thyrotoxicosis

Familial hypokalemic periodic paralysis (HOPP) is an autosomal dominant disorder characterized by episodic attacks of muscle weakness with concomitant hypokalemia (<3.5 mEq/L). The onset of HOPP usually occurs within the first and second decade of life. Mutations in the skeletal muscle calcium (CACNL1A3) and sodium channel (SCN4A) genes have been reported to be responsible for familial HOPP. Voltage-sensitive ion channels mediate action potentials in electrically excitable cells and play important roles in signal transduction in other cell types. Therefore, abnormalities in a channel's function lead to disarray of signal transduction and thus various neurological symptoms. Those are called channel diseases, which include familial HOPP. We report a 14-year-old boy with HOPP from a family in which two members of two generations are affected. Genetic examination identified a mutation causing a codon change from arginine to histidine at the amino acid portion #528 (R528H) in the calcium channel gene CACNL1A3.
Action Potentials ; Adolescent ; Arginine ; Calcium ; Calcium Channels ; Codon ; Family Characteristics ; Histidine ; Humans ; Hypokalemia ; Hypokalemic Periodic Paralysis ; Ion Channels ; Muscle Weakness ; Muscle, Skeletal ; Signal Transduction ; Sodium Channels