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

BACKGROUND AND PURPOSE: Hyperkalemic periodic paralysis (hyperKPP) is a muscle sodium-ion channelopathy characterized by recurrent paralytic attacks. A proportion of affected individuals develop fixed or chronic progressive weakness that results in significant disability. However, little is known about the pathology of hyperKPP-induced fixed weakness, including the pattern of muscle involvement. The aim of this study was to characterize the patterns of muscle involvement in hyperKPP by whole-body magnetic resonance imaging (MRI). METHODS: We performed whole-body muscle MRI in seven hyperKPP patients carrying the T704M mutation in the SCN4A skeletal sodium-channel gene. Muscle fat infiltration, suggestive of chronic progressive myopathy, was analyzed qualitatively using a grading system and was quantified by the two-point Dixon technique. RESULTS: Whole-body muscle MRI analysis revealed muscle atrophy and fatty infiltration in hyperKPP patients, especially in older individuals. Muscle involvement followed a selective pattern, primarily affecting the posterior compartment of the lower leg and anterior thigh muscles. The muscle fat fraction increased with patient age in the anterior thigh (r=0.669, p=0.009), in the deep posterior compartment of the lower leg (r=0.617, p=0.019), and in the superficial posterior compartment of the lower leg (r=0.777, p=0.001). CONCLUSIONS: Our whole-body muscle MRI findings provide evidence for chronic progressive myopathy in hyperKPP patients. The reported data suggest that a selective pattern of muscle involvement-affecting the posterior compartment of the lower leg and the anterior thigh-is characteristic of chronic progressive myopathy in hyperKPP.
Channelopathies ; Humans ; Leg ; Magnetic Resonance Imaging* ; Muscles ; Muscular Atrophy ; Muscular Diseases* ; Paralysis, Hyperkalemic Periodic* ; Pathology ; Thigh

In cases of hyperkalemia with preserved renal function, the differential diagnoses that should be considered are drug-related disorders, primary tubular disease, and hormonal diseases including primary adrenal insufficiency. Addison's disease represents a rare disorder characterized by primary adrenal failure, general weakness, poor appetite, nausea, dizziness, and hyperpigmentation. It may also cause fatal adrenal crisis, involving hypotension, loss of consciousness, hyperkalemia, or hyperkalemic periodic paralysis under stressful conditions. We describe herein the case of a 54-year-old Korean male who developed Addison's disease, due to adrenal tuberculosis, in addition to painless thyroiditis, which led to hyperkalemic periodic paralysis.
Addison Disease* ; Appetite ; Diagnosis, Differential ; Dizziness ; Humans ; Hyperkalemia ; Hyperpigmentation ; Hyperthyroidism ; Hypotension ; Male ; Middle Aged ; Nausea ; Paralysis, Hyperkalemic Periodic* ; Thyroid Gland* ; Thyroiditis* ; Tuberculosis ; Unconsciousness

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

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

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