A Case of Addison's Disease Accompanied by Painless Thyroiditis and Hyperkalemic Periodic Paralysis / 대한내과학회지

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.

Whole-Body Muscle MRI in Patients with Hyperkalemic Periodic Paralysis Carrying the SCN4A Mutation T704M: Evidence for Chronic Progressive Myopathy with Selective Muscle Involvement

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.

Management of a patient with hyperkalemic periodic paralysis requiring coronary artery bypass grafts.

Hyperkalemic periodic paralysis (HPP) is an autosomal-dominant inherited muscle disease characterized by episodes of flaccid weakness and intermittent myotonia. There are no previous reports in the literature about anesthesia for cardiac surgery with cardiopulmonary bypass in this disorder. We describe perioperative anesthetic management for on-pump coronary artery bypass grafting in a 75-year-old man with a history of hyperkalemic periodic paralysis. This case report outlines our management strategy and the issues encountered during the perioperative period.

A Case of Hyperkalemic Periodic Paralysis Induced by Diabetic Nephropathy / 대한내과학회지

Hyperkalemic periodic paralysis is characterized by episodic flaccid paralysis of the skeletal muscles due to an increase in serum potassium concentrations. Primary hyperkalemic periodic paralysis is caused by point mutations in SCN4A, encoding a voltage-gated skeletal muscle sodium channel. However, hyperkalemia-related diseases, such as renal failure, adrenal insufficiency, hypoaldosteronism, and chronic diuretic use, can induce secondary hyperkalemic periodic paralysis. Diagnosis of this disease is based on clinical features, nerve conduction studies, and a DNA sequence analysis. In cases of diagnostic uncertainty, a provocation test can be used to ensure the correct diagnosis. Here, we report a case of secondary hyperkalemic periodic paralysis with hyperkalemia that was induced by diabetic nephropathy, and review the relevant literature.

Familial hyperkalemic periodic paralysis caused by a de novo mutation in the sodium channel gene SCN4A / 소아과

Familial hyperkalemic periodic paralysis (HYPP) is an autosomaldominant channelopathy characterized by transient and recurrent episodes of paralysis with concomitant hyperkalemia. Mutations in the skeletal muscle voltage-gated sodium channel gene SCN4A have been reported to be responsible for this disease. Here, we report the case of a 16-year-old girl with HYPP whose mutational analysis revealed a heterozygous c.2111C>T substitution in the SCN4A gene leading to a Thr704Met mutation in the protein sequence. The parents were clinically unaffected and did not have a mutation in the SCN4A gene. A de novo SCN4A mutation for familial HYPP has not previously been reported. The patient did not respond to acetazolamide, but showed a marked improvement in paralytic symptoms upon treatment with hydrochlorothiazide. The findings in this case indicate that a de novo mutation needs to be considered when an isolated family member is found to have a HYPP phenotype.

Familial hyperkalemic periodic paralysis caused by a de novo mutation in the sodium channel gene SCN4A / 소아과

Familial hyperkalemic periodic paralysis (HYPP) is an autosomaldominant channelopathy characterized by transient and recurrent episodes of paralysis with concomitant hyperkalemia. Mutations in the skeletal muscle voltage-gated sodium channel gene SCN4A have been reported to be responsible for this disease. Here, we report the case of a 16-year-old girl with HYPP whose mutational analysis revealed a heterozygous c.2111C>T substitution in the SCN4A gene leading to a Thr704Met mutation in the protein sequence. The parents were clinically unaffected and did not have a mutation in the SCN4A gene. A de novo SCN4A mutation for familial HYPP has not previously been reported. The patient did not respond to acetazolamide, but showed a marked improvement in paralytic symptoms upon treatment with hydrochlorothiazide. The findings in this case indicate that a de novo mutation needs to be considered when an isolated family member is found to have a HYPP phenotype.

Electrodiagnostic Findings and Clinical Characteristics of Familial Hyperkalemic Periodic Paralysis With a SCN4A Met1592Val Mutation

BACKGROUND: Hyperkalemic periodic paralysis (HYPP) is characterized by episodic flaccid paralysis of skeletal muscles that is exacerbated by the consumption of potassium-containing foods, fasting, or rest following exercise. HYPP is largely diagnosed based on clinical features and electrodiagnostic findings. METHODS: Seven patients from three families were assessed by interviews and clinical examinations. Standardized protocols comprising short and long exercise tests were applied to 15 unaffected control subjects and the 7 patients with familial HYPP. RESULTS: Exercise of short duration induced an immediate increase in the amplitude of the compound motor action potential (CMAP) in the patients, and this was significantly larger and lasted longer than that observed in controls within 50 seconds (p<0.05). A long exercise test induced a large increase in the CMAP amplitude in patients immediately after exercise completion, which decreased to normal values with 1 minute. In contrast, controls showed a decreased CMAP amplitude immediately after exercise, which subsequently also returned to the normal value. Precipitants of attacks were vigorous exercise and hunger in all patients, and cold and potassium-rich foods in five patients. All patients experienced clinical myotonia at the eyelids or lips. CONCLUSIONS: We conclude that exercise tests may be helpful in confirming abnormal excitability of muscle membranes in patients with HYPP. We have described the clinical and electromyographic characteristics in familial HYPP with the Met1592Val mutation in the SCN4A gene.

Electrophysiological Changes by Exercise and Cold Provocation Test in a Patient with Hyperkalemic Periodic Paralysis

Hyperkalemic periodic paralysis and paramyotona congenita share common clinical manifestations, such as autosomal dominant diseases with missense mutations at a gene encoding alpha-subunit of skeletal muscle voltage sensitive sodium channel (SCN4A). Exercise and cold provocation tests are physiological phenomena of clinical characteristics of these diseases. The authors experienced a case with hyperkalemic periodic paralysis and performed these tests comparing them with a patient with hypokalemic periodic paralysis and a normal person. Significant decremental changes of CMAPs were found by both tests in the case with hyperkalemic periodic paralysis, compared with those in a case of hypokalemic periodic paralysis or normal control. In conclusion, we suggest that exercise and cold provocation tests may be useful for the differential diagnosis between hyperkalemic periodic paralysis and hypokalemic periodic paralysis.

Screening SCN4A gene for mutations in a Chinese family with hyperkalemic periodic paralysis / 中华神经科杂志

Objective To study the clinical features of hyperkalemic periodic paralysis (hyperKPP) and the relationship with SCN4A gene in a Chinese family Methods The clinical features of 7 patients in a Chinese family with hyperKPP were summarized All 24 exons of SCN4A gene were screened with denaturing high performance liquid chromatography (DHPLC) technology, and then sequence analysis was performed on those with abnormal elution peak Results This family showed typical clinical features of hyperKPP but without myotonia Three mutations were found in exon 13, 23 and 24 respectively Linkage analysis and direct sequencing showed the mutation in exon 24 was a synonymous mutation The mutation in exon 23 was a missense mutation, but proved to be a benign polimophism; the mutation in exon 13 was proved leading to the best known amino acid exchange Thr704Met Conclusion SCN4A gene should be related to hyperKPP, and Thr704Met be responsible for hyperKPP in this Chinese family