The patient will most commonly present with muscle hypertrophy, a positive family history, and muscle stiffness with repeated activity. The creatine kinase may be elevated. Abnormal thyroid function should be ruled out due to a similar presentation. [statpearls.com]

[…] symptoms in 80-99% of the cases: Hypertonia Myotonia Frequently present symptoms in 30-79% of the cases: Elevated serum creatine phosphokinase EMG abnormality Feeding difficulties in infancy Flexion contracture Gait disturbance Myalgia Occasionally present [dovemed.com]

Still, she had never presented any similar periodic paralysis. [ncbi.nlm.nih.gov]

[…] type II, which may be very mild and not present until the third or fourth decade of life. [britannica.com]

Cold sensitivity is not systematic but when present, it can be of varying severity. Myotonia is rarely associated with attacks of weakness. Some patients describe a warm-up phenomenon while others report an exacerbation with exercise. [orpha.net]

• Pain

  PMID 17998485 2007 A novel founder SCN4A mutation causes painful cold-induced myotonia in French-Canadians. PMID 9392583 1997 A novel muscle sodium channel mutation causes painful congenital myotonia. [xcode.life]

  Episodic pain syndromes are genetic disorders including: Familial episodic pain syndrome Paroxysmal extreme pain disorder Inherited erythromyalgia Congenital insensitivity to pain PNH disorders can be genetic or may be acquired e.g. related to an autoimmune [stgeorges.nhs.uk]

  In acetazolamide-responsive myotonia, stiffness is often painful and myotonia is triggered by fasting and mildly by exercise and cold exposure. [orpha.net]

  The typical presentation is that of a painful myotonia that fluctuates and is aggravated by exercise or rest after exercise, potassium loads, and exposure to depolarizing neuromuscular blocking agents. [humpath.com]

  The complications of Potassium-Aggravated Myotonia may include: Severe cramping Incapacitating pain Severe shortness of breath Decreased quality of life Complications may occur with or without treatment, and in some cases, due to treatment also. [dovemed.com]

• Fatigue

  Chronic Fatigue Syndrome Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here. [meta.org]

  During brief exercise, overexcitation of muscles can cause stiffness, and with prolonged exercise, the overexcitation can occasionally lead to a fatigue-like weakness or even complete paralysis. [mda.org]

  Additional common symptoms include pain, weakness and fatigue. They are considered to be distinct from myotonic dystrophy because of the absence of progressive weakness and systemic features. [genome.jp]

  Clinically, they are characterized by myotonia, defined as delayed muscle relaxation after voluntary contraction, which leads to symptoms of muscle stiffness, pain, fatigue, and weakness. [institut-myologie.org]

  The patient may also describe symptoms such as pain, weakness, and fatigue due to prolonged muscle contraction. [statpearls.com]

• Falling

  KEVEYIS may increase your risk of falling. Tell your healthcare provider right away if you experience a fall while taking KEVEYIS. The risks of falls and acid buildup are greater in elderly patients. [strongbridgebio.com]

  Dr Levitt: People with PP are at high risk for falling because they can’t support themselves, either while trying to move during an acute attack, or tripping in the context of PMW of the quadriceps. [neurologyadvisor.com]

  The Stem A 59 year-old white woman with a history of hypertension and hyperlipidemia, suffered a left femur fracture following a fall. For three days after the fall, she was awake but was unable to move. [renalfellow.org]

  Any variants that fall outside these regions are not analyzed. Any limitations in the analysis of these genes will be listed on the report. Contact client services with any questions. [invitae.com]

  Children may appear clumsy and fall frequently, even after walking is established. Patients may also exhibit difficulty in opening eyes during prolonged contraction, such as crying. [statpearls.com]

• Respiratory Distress

  When the infant develops respiratory symptoms, it is usually from severe hypoxemia or acidosis. The infant who is cyanotic with respiratory distress and does not respond to supplemental oxygen. [lafemmemusic.com]

  (Outcomes/Resolutions) The prognosis of Potassium-Aggravated Myotonia is good, with many affected individuals gaining control over their signs and symptoms over time However, complications such as respiratory distress may reduce one’s quality of life. [dovemed.com]

  During neonatal period he presented paroxysms of laryngospasm and respiratory distress, depicting the peculiar features of severe neonatal episodic laryngospasm (SNEL) phenotype (7). [frontiersin.org]

  She was admitted to the intensive care unit (ICU) for 2 months on mechanical ventilation, due to a respiratory distress syndrome, secondary systemic infections and developed a critical illness neuropathy. [ncbi.nlm.nih.gov]

• Dysphagia

  A Sodium Channel Myotonia Presenting with Intermittent Dysphagia as a Manifestation of a Rare SCN4A Variant. [link.springer.com]

  […] myotonias: a double-blind randomized study. 61 Andersen G...Vissing J 29050397 2017 22 Spectrum of Nondystrophic Skeletal Muscle Channelopathies in Children. 61 Al-Ghamdi F...Ghosh PS 28325641 2017 23 A Sodium Channel Myotonia Presenting with Intermittent Dysphagia [malacards.org]

  […] hypertrophy Increased skeletal muscle cells 0003712 Percent of people who have these symptoms is not available through HPO Autosomal dominant inheritance 0000006 Autosomal recessive inheritance 0000007 Childhood onset Symptoms begin in childhood 0011463 Dysphagia [rarediseases.info.nih.gov]

  Gastrointestinal complaints are also frequent and may be severe, often requiring GI specialist, speech therapist, and nutritionist input for dysphagia, constipation or diarrhea. [now.aapmr.org]

  A sodium channel myotonia presenting with intermittent dysphagia as a manifestation of a rare SCN4A variant. J Mol Neurosci. 2017;61:312–14. [www-ncbi-nlm-nih-gov.ezproxy.u-pec.fr]

• Muscle Rigidity

  In the two sisters described, exposure to succinylcholine resulted in generalized muscle rigidity without a rise in body temperature. [rarediseases.org]

• Myalgia

  Myalgias and cramps are frequent. Intensity and topography of myotonic symptoms may vary. In myotonia fluctuans, episodes of stiffness vary in severity and frequency, and occur during the resting period following exercise. [orpha.net]

  \n\n https://medlineplus.gov/genetics/condition/potassium-aggravated-myotonia From HPO Myalgia MedGen UID: 68541 •Concept ID: C0231528 • Sign or Symptom Pain in muscle. [ncbi.nlm.nih.gov]

  Very frequently present symptoms in 80-99% of the cases: Hypertonia Myotonia Frequently present symptoms in 30-79% of the cases: Elevated serum creatine phosphokinase EMG abnormality Feeding difficulties in infancy Flexion contracture Gait disturbance Myalgia [dovemed.com]

  […] creatine phosphokinase [ more ] 0003236 EMG abnormality 0003457 Feeding difficulties in infancy 0008872 Flexion contracture Flexed joint that cannot be straightened 0001371 Gait disturbance Abnormal gait Abnormal walk Impaired gait [ more ] 0001288 Myalgia [rarediseases.info.nih.gov]

• Muscle Cramp

  cramps Muscle weakness Ophthalmoparesis Respiratory insufficiency Skeletal muscle hypertrophy (Source: Potassium-Aggravated Myotonia; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), [dovemed.com]

  Definition of Myotonie in the German dictionary Muscle cramp. Muskelkrampf. Click to see the original definition of «Myotonie» in the German dictionary. Click to see the automatic translation of the definition in English. [educalingo.com]

  Five were interviewed; their symptoms began in early childhood, and included muscle cramping induced by exposure to cold or exertion (both in most cases). Face and hand muscles were predominantly affected. [mja.com.au]

  Patient II.1 from family 6 complained of contractures and muscle cramps not related to exercise or cold temperature from the age of 20 (Figure 1F). Clinical myotonia was not detected but EMG showed myotonic discharges. Muscle biopsy was normal. [frontiersin.org]

• Flexion Contracture

  […] following information may be noted: Very frequently present symptoms in 80-99% of the cases: Hypertonia Myotonia Frequently present symptoms in 30-79% of the cases: Elevated serum creatine phosphokinase EMG abnormality Feeding difficulties in infancy Flexion [dovemed.com]

  contracture Flexed joint that cannot be straightened 0001371 Gait disturbance Abnormal gait Abnormal walk Impaired gait [ more ] 0001288 Myalgia Muscle ache Muscle pain [ more ] 0003326 5%-29% of people have these symptoms Asthma 0002099 Chest pain 0100749 [rarediseases.info.nih.gov]

• Clumsiness

  On direct questioning, however, his parents reported that his movements appeared “clumsy” from the time he began to walk and that the symptoms related to his eyes were already present when he was an infant. [content.iospress.com]

  Children may appear clumsy and fall frequently, even after walking is established. Patients may also exhibit difficulty in opening eyes during prolonged contraction, such as crying. [statpearls.com]

• Dysarthria

  Dysphagia and dysarthria were also present only when he was exposed to cold. Muscle manual testing was normal at ordinary temperatures. Fig. 1 a The parents are consanguineous and the family has no neuromuscular disease. b Pictures at age of 22. [bmcneurol.biomedcentral.com]

  Periodic paralysis was not associated with dyspnea or dysarthria. Her father (V: 7) was definitively diagnosed with hypokalemic periodic paralysis in his twenties. Her mother (V: 6) suffered from myotonia and muscle hypertrophy from childhood. [journals.plos.org]

However, the patient would again not likely suffer such a condition on an episodic basis over an extended period of time, and further workup may reveal a source of electrolyte disturbance. [statpearls.com]

Diagnostic workup should be considered even if patients are taking medications with known myotonia-aggravating potential as they can unmask an underlying disease. Cataracts and diabetes at a young age should prompt consideration. [now.aapmr.org]

• Creatine Phosphokinase Increased

  […] circulating creatine phosphokinase Elevated creatine kinase Elevated serum CPK Elevated serum creatine phosphokinase High serum creatine kinase Increased CPK Increased creatine kinase Increased creatine phosphokinase Increased serum CK Increased serum [rarediseases.info.nih.gov]

The treatment is usually given to manage the signs and symptoms and any complication that develops. [dovemed.com]

Management and treatment Management of patients consists in medical therapy and avoidance of triggering factors (such as potassium-rich food). [orpha.net]

Treatment Treatment for myotonia may include mexiletine, quinine, phenytoin, and other anticonvulsant drugs. [ninds.nih.gov]

[…] begins with avoiding foods that contain large amounts of potassium; other treatments may include physical therapy (stretching or massages to help relax muscles) or certain medications (such as mexiletine, carbamazapine, or acetazolamide).[5170] For more [rarediseases.org]

Patients who prior to the study receive treatment, with drugs that can potentially influence myotonia, must stop the treatment during the study. [clinicaltrials.gov]

Prognosis Prognosis is good with stability of symptoms during life but respiratory function may be compromised in severe myotonia permanens. The documents contained in this web site are presented for information purposes only. [orpha.net]

Prognosis Myotonia is a chronic disorder. Symptoms may improve later in life. x Prognosis Myotonia is a chronic disorder. Symptoms may improve later in life. Prognosis Myotonia is a chronic disorder. Symptoms may improve later in life. [ninds.nih.gov]

However, it is often necessary to use molecular analysis to be able to diagnose the disease correctly, make a prognosis and predict the risk of recurrence as well as to formulate a treatment plan. Ned Tijdschr Geneeskd. 2006;150:2501-6 [ntvg.nl]

Prognosis:- The long-term outlook (prognosis) for each person with myotonic dystrophy (including life expectancy) may depend on the type of myotonic dystrophy and the specific medical problems present. [samarpanphysioclinic.com]

Etiology Myotonia permanens is a muscle sodium channelopathy due to missense mutations of the SCN4A gene encoding the alpha subunit of the skeletal muscle voltage-gated sodium channel Nav1.4. Genetic counseling Transmission is autosomal dominant. [orpha.net]

Many etiologies result in myotonia, including dystrophic and non-dystrophic myotonias. [statpearls.com]

ETIOLOGY:- The presentation of myotonia can result from a diverse array of etiologies. [samarpanphysioclinic.com]

Myotonic disorders have multiple etiologies and some disorders may be considered a channelopathy if ion channel conductance is the culprit in the disease, but the most common cause myotonia is not due to an ion channelopathy but a defect in the protein [accessanesthesiology.mhmedical.com]

Summary Epidemiology Prevalence is unknown. Clinical description Continuous and severe myotonia begins during childhood (usually before 10 years of age) and involves mainly the face, neck, limbs, and thoracic muscles. [orpha.net]

Epidemiology Paramyotonia congenita is considered an extremely rare disorder, though little epidemiological work has been done. Prevalence is generally higher in European-derived populations and lower among Asians. [findzebra.com]

Epidemiological estimates have been provided for the German population. [bionity.com]

Pathophysiology A defect in chloride channels results in decreased conductance of chloride into the muscle cell, resulting in a slowed repolarization of the cell membrane. Diagnosis is made clinically and confirmed with genetic studies. [accessanesthesiology.mhmedical.com]

INTRODUCTION In this chapter, we describe the pathophysiology, clinical presentation, laboratory findings, and treatment of the nondystrophic myotonias and periodic paralyses (Table 31-1). [neurology.mhmedical.com]

Abstract and Introduction Clinical Features Clinical Electrophysiology Genetics Genotype–Phenotype Correlations Molecular Pathophysiology Animal Models Treatment References Table 1. [medscape.com]

Neuropharmacology 4:123–8 CrossRef Google Scholar Rudel R (1986) The pathophysiologic basis of the myotonias and the periodic paralysies. In: Engel AG, Banker BQ (eds.) [link.springer.com]

Myotonia Evaluated Using Aggregated N-of-1 Trials. 61 Stunnenberg BC...van der Wilt GJ 30535218 2018 14 Skeletal Muscle Channelopathies. 61 Phillips L...Trivedi JR 30341599 2018 15 Multiple sclerosis and non-dystrophic myotonias: do they share a common pathophysiology [malacards.org]

Currently, Potassium-Aggravated Myotonia may not be preventable, since it is a genetic disorder. [dovemed.com]

Beginning in childhood or adolescence, people with this condition experience bouts of sustained muscle tensing (myotonia) that prevent muscles from relaxing normally. [rarediseases.oscar.ncsu.edu]

The abnormal channels change the normal flow of sodium ions, which prevents muscles from contracting normally. Low potassium levels also contribute to this problem. [medlineplus.gov]

[…] in an autosomal dominant manner Potassium-aggravated myotonia is a rare genetic disorder that affects skeletal muscle. [2]Beginning in childhood or adolescence, people with this condition experience bouts of sustained muscle tensing (myotonia) that prevent [en.wikipedia.org]

If you child has club foot, gentle passive stretching will help realign the foot and ankle and prevent deformities. This may be used in combination with plaster casting. [samarpanphysioclinic.com]