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]

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

Present Absent May be present Paradoxical myotonia Absent Absent Present May be present Delayed onset myotonia after exercisea Absent Absent Absent May be present Characteristic of myotonia fluctuans Episodic muscle weakness Common, develops on initiation [medscape.com]

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

There are patients in whom features of both hyperKPP and PC are present. These diseases result from molecular alterations in the adult skeletal muscle sodium channel. [n.neurology.org]

• Weakness

  It has been proven to reduce weakness attacks. [periodicparalysis.org]

  Open symbols depict mutations for which paralytic weakness is a prominent clinical finding. 34 Figure 2. Slow inactivation is impaired by mutations associated with periodic paralysis (T704M, M1592V) or cold-induced weakness (I693T). [slideplayer.com]

  Unlike some other forms of myotonia, potassium-aggravated myotonia is not associated with episodes of muscle weakness. [rarediseases.oscar.ncsu.edu]

  There was no significant clinical weakness or increase in myotonia in the limb on cooling. [jnnp.bmj.com]

• 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]

• 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]

  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]

  Slowed recovery of mutant EDL and susceptibility to delayed weakness after fatigue. [jci.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]

• Falling

  Older goats try to avoid falls by spreading their legs or leaning against walls. This implies that they do not want to fall. Therefore, even if it is painless, deliberately trying to make them fall just for a laugh is wrong. [owlcation.com]

  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]

  If the individuals are standing up, they’ll fall over, as the kittens in the video do. Startle reflexes can cause sudden muscle contraction, hence startles can induce falling in these individuals. [sciblogs.co.nz]

  However, a fall into cold water may render the person unable to move for the duration of submergence. As with myotonic goats, children are more prone to falling than adults, due to their impulsivity. [en.wikipedia.org]

  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]

• Episodic Weakness

  We also report the putative disease-causing mutation in acetazolamide-responsive myotonia congenita, a related disease in which myotonia is worsened by potassium but in which episodic weakness does not occur. [n.neurology.org]

  These patients do not experience episodic weakness or progressive myopathy. This disease is caused by mutations of the sodium channel SCN4A gene on chromosome 17q. See also channelopathies [humpath.com]

  Unlike some other forms of myotonia, potassium-aggravated myotonia is not associated with episodes of muscle weakness. [rarediseases.oscar.ncsu.edu]

  SCM is a diverse group of disorders characterized by clinical and electrical myotonia and occasionally episodic weakness. If episodic weakness is absent, SCM may closely mimic myotonia congenita. [now.aapmr.org]

  […] by a marked worsening of myotonia by cold and by the presence of clear episodes of weakness; Group 2 Sodium channel myotonia—notable for the absence of episodic weakness but may have cold sensitivity. [medscape.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]

  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]

  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]

• Muscle Rigidity

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

  Jedlicka, et al., Masseter muscle rigidity associated with glycine1306 to alanine mutation in the adult muscle sodium channel alpha-subunit gene. Anesthesiology 82 (1995), 1097–1103. 96. D. C. Aberfeld, L. P. Hinterbuchner, M. [cambridge.org]

  […] relaxants, opiates, and barbiturates with surgery Cataract removal; occasional need for pacemaker; antimyotonia therapy often not necessary (mexiletine); monitor carefully during and after surgery for muscle rigidity and rhabdomyolysis The existence [clinicalgate.com]

  Patients with malignant hyperthermia are susceptible to severe muscle rigidity and fevers when exposed to depolarizing anesthetic agents. [ncbi.nlm.nih.gov]

• Diarrhea

  The most common side effects were gastrointestinal, such as diarrhea, nausea, and heartburn. Click here to read an abstract of the article. This study echoes findings on mexiletine and its beneficial effects on myotonia published in 2010 by Drs. [myotonic.org]

  Increased GI or kidney loss of potassium Check for a history of GI losses (diarrhea, vomiting, feeding tube output, ostomy output etc). Our patient did not have any of the above. [renalfellow.org]

  Syndromes Constipation or diarrhea Problems producing urine Moderate to severe pain around a skin injury Wasting away of muscle and loss of body fat 7 - 12 months: 20 mcg/day Bleeding will not stop Pain and stiffness are worse at night, in the morning [lafemmemusic.com]

  Side effects seen more often in people taking CBD included diarrhea, vomiting, fatigue, fever, sleepiness and abnormal results on liver function tests. [epilepsy.com]

  This regimen appreciably reduced myotonia, but had to be interrupted due to the appearance of diarrhea. Consequently, the previous mexiletine regimen was restarted. [frontiersin.org]

• Nausea

  The most common side effects were gastrointestinal, such as diarrhea, nausea, and heartburn. Click here to read an abstract of the article. This study echoes findings on mexiletine and its beneficial effects on myotonia published in 2010 by Drs. [myotonic.org]

  Other features include sinus tachycardia, weight loss, nausea, and vomiting. Thyrotoxic HypoKPP resolves without morbidity after treatment of the thyroid disease. [annalsofian.org]

  Side-effects include kidney stone formation, parasthesia, nausea, confusion, mood irritability, depression, rash and liver function abnormalities. Regular monitoring of complete blood count and liver functions is recommended. [neurologyindia.com]

  Other adverse events were headache, palpitations, nausea and syncope but there were no serious adverse events and all side effects resolved when medication was discontinued [34, 35]. [link.springer.com]

• Vomiting

  Only 5% were found to have hypokalemia and all of those had bulimia with either diuretic, cathartic or self-induced vomiting causing increased potassium losses. [renalfellow.org]

  Side effects seen more often in people taking CBD included diarrhea, vomiting, fatigue, fever, sleepiness and abnormal results on liver function tests. [epilepsy.com]

  Other features include sinus tachycardia, weight loss, nausea, and vomiting. Thyrotoxic HypoKPP resolves without morbidity after treatment of the thyroid disease. [annalsofian.org]

• Myopathy

  INTRODUCTION Ion channel myopathies consist of disorders featuring paralysis and hypotonia. [accessanesthesiology.mhmedical.com]

  Lammens M, Schoser B (2009) Metabolic myopathies – an overview. [link.springer.com]

  These patients do not experience episodic weakness or progressive myopathy. This disease is caused by mutations of the sodium channel SCN4A gene on chromosome 17q. See also channelopathies [humpath.com]

  MDA supports ongoing research into the molecular bases of inherited myopathies and to find effective treatments. For more, see Research. [mda.org]

  Feb 16» Solidarité Téléthon 2015 : le marathon du don bat son plein à ... ... myopathies (AFM), pour financer des projets de recherche sur les maladies génétiques neuromusculaires (Myopathies, myotonie de Steinert) principalement, ... [educalingo.com]

• 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]

  […] 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]

  Paramyotonia Congenita Eulenburg first used the term paramyotonia congenita in 1886 to describe a syndrome of episodic muscle cramps and paralysis profoundly exacerbated by cold and exercise in six generations of a German family (Eulenburg, 1886). [medscape.com]

  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]

• Leg Cramp

  The use of Quinine is also well documented for both idiopathic leg cramps and the sustained muscle contractions in some myotonic conditions including Myotonia Congenita, with a direct effect on muscle cell membrane sodium channels as the proposed mechanism [scirp.org]

• Seizure

  Mutant GABA(A) receptor gamma2-subunit in childhood absence epilepsy and febrile seizures. Nat Genet 2001; 28: 49–52. 71. BianchiMT, SongL, ZhangH, MacdonaldRL. [cambridge.org]

  Seizure disorder is a common erroneous diagnosis. Apnoeas are effectively reduced or abolished by appropriate treatment with anti-myotonic agents. [discovery.ucl.ac.uk]

  CK is a non-specific test which can be raised in non-neuromuscular disease e.g. post seizure and seizure disorder is a common differential diagnosis postulated in SNEL cases 19. [ncbi.nlm.nih.gov]

• 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]

  Patients have prominent wasting and weakness of superficial facial muscles, levator palpebrae superioris, temporalis, masseter and palate with resultant ptosis, dysarthria and myopathic face. Swallowing may be impaired early in the disease. [neurologyindia.com]

  Quinidine, fluoxetine, Worsening with pyridostigmine AD (rare)/AR Fast-channel CMS (CMS1B) 608,930 Infancy non-specific Neonatal hypotonia; ocular, bulbar (dysarthria), neck, recurrent respiratory crises, and limb progressive muscle weakness and fatigability [mdpi.com]

• 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]

  The later, childhood-onset form usually is evident from nonmuscular manifestations of the disease, such as intellectual deficiency, difficulty with speech or hearing, clumsiness, or, rarely, with a cardiac dysrhythmia or postoperative apnea [Harper, 2001 [clinicalgate.com]

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]

Table 4-1 Muscle Channelopathies Discussed in This Review Table 4-1 Continued ELECTRODIAGNOSTIC TESTING IN CHANNELOPATHIES When a patient presents with concerns of episodic symptoms consistent with myotonia or paralysis, the initial workup traditionally [ncbi.nlm.nih.gov]

• 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]

[…] 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]

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

[…] term for treatment variable. [jamanetwork.com]

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]

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

Etiology PAM is a sodium muscle channelopathy due to missense mutations of the SCN4A gene encoding the alpha subunit of the skeletal muscle voltage-gated sodium channel Nav1.4. [orpha.net]

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 These diseases are very rare and their prevalence is unknown. Clinical description Myotonia develops during childhood or adolescence and is, by definition, aggravated by potassium ingestion. [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]

However, other mutations may be due to different pathophysiological mechanisms, such as the defect of protein trafficking to membranes. [hindawi.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]

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]

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]

[…] 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]