Presentation
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]
As described in the present case, however, patients with recessive MC can experience severe myotonia, which hinders their daily activities. [checkorphan.org]
Guidelines on clinical presentation and management of non-dystrophic myotonias. [institut-myologie.org]
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]
The different clinical presentations of myotonic dystrophy type 2 and its main differential diagnostic options are also discussed. [journals.lww.com]
Entire Body System
- Weakness
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]
A cold-induced attack of weakness can last for several hours even after return to a warm environment. Weakness can also be induced in some cases by potassium intake. Further attacks of weakness can be focal or generalized attacks of weakness. [neupsykey.com]
It also significantly improved pain, weakness, fatigue and quality of life. It was well tolerated with no serious cardiac events. Gastrointestinal side effects were reported by 15%. [jnnp.bmj.com]
- Pain
However, while mexiletine is very effective in reducing muscle stiffness, it is less effective at treating the pain associated with NDM and some SCN4A genotypes may not respond to mexiletine treatment. [tandfonline.com]
Patients experience delayed muscle relaxation causing functionally limiting stiffness and pain. [moh-it.pure.elsevier.com]
Adults living with the condition have told us first-hand how much pain and disruption muscle stiffness causes them each day, but that symptoms improve when taking the drug. [musculardystrophyuk.org]
Patients experience delayed muscle relaxation that causes impaired physical activity, stiffness, and pain. [ega-archive.org]
- Fatigue
It also significantly improved pain, weakness, fatigue and quality of life. It was well tolerated with no serious cardiac events. Gastrointestinal side effects were reported by 15%. [jnnp.bmj.com]
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]
Secondary Outcome Measures: a) patient-assessed pain, weakness, and fatigue as measured by IVR; b) clinical myotonia assessment; c) quality of life as measured by INQoL, SF36; d) a quantitative measure of grip myotonia; e) measurement of CMAP after short [ega-archive.org]
- Falling
Patients experience stiffness, pain, weakness, impaired mobility, fatigue, disability, falls, problems with speech, chewing and swallowing. [omicsonline.org]
It can lead to increased falls. Nonpharmacologic ways to help include: Changing positions slowly and employing physical countermaneuvers to prevent fainting (syncope). [healthblog.uofmhealth.org]
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]
Symptoms often begin in the lower limbs between the ages of 4 and 12 years, and there is often a history of freezing and falls. [checkorphan.org]
The muscles that pick up the foot when walking may weaken, allowing the foot to flop down and cause tripping and falling (foot drop). [mda.org]
- Unable to Stand
Patients commonly recall having played with friends during school lunch break, returning to sit at a desk for lessons, and then being unable to stand or walk. [pn.bmj.com]
Patients are unable to stand or raise a limb against gravity during an episode of paralysis. The diaphragm and bulbar muscles are spared, and respiratory failure does not occur. [kidney-international.org]
Respiratoric
- Respiratory Distress
Congenital disease (15% of cases) is the most severe form and includes severe generalized weakness at birth with respiratory distress, hypotonia, and feeding difficulty. [orpha.net]
In neonates, it is characterised by hypotonia and respiratory distress often leading to death 1. The disease has a variable onset as it can be seen in adults (adult-onset) and children (congenital form). [radiopaedia.org]
These conditions may also be associated with intermittent or permanent mild to severe muscle weakness, and respiratory distress has been reported in some individuals. [invitae.com]
The patient was observed in the recovery room for four hours during which time she was doing well without any signs or symptoms of respiratory distress. Her only complaint was about the brief shivering episode after waking up. [hindawi.com]
In young children with hypokalaemic periodic paralysis respiratory muscle weakness can cause respiratory distress and hypoxia. This is much less common in teenagers and adults but can occur in severe episodes with tetraparesis. [pn.bmj.com]
- Dyspnea
However, she abruptly complained of dyspnea accompanied with a decrease of SpO2 to 90% with a non-rebreather mask on 10 L/min of oxygen, and she required reintubation on the 8th day. [jaclinicalreports.springeropen.com]
Affected dogs usually present with non-painful muscle spasms, stridor, dyspnea, dysphonia, stiff-stilted gait, bunny-hopping and collapse associated with exercise and activity. [vetbook.org]
Due to her history of exertional dyspnea (on walking less than two blocks) associated with fatigue and exertional chest pain, her cardiologist decided to do cardiac nuclear stress test with lexiscan, which was negative for ischemia. [hindawi.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]
Gastrointestinal
- Dysphagia
dysarthria, irritable bowel-like symptoms (e.g., abdominal pain, bloating), impaired sleep, daytime somnolence are common Mild clinical myotonia Uncommon symptoms: respiratory muscle involvement, dysphagia, dysarthria, irritable bowel-like symptoms [www-amboss-com.db.rsu.lv]
Therefore, you may also see a physical therapist, occupational therapist, and, if you have trouble swallowing (dysphagia), you may also see a speech-language pathologist. [understandingmyositis.org]
Because of involuntary muscle involvement, patients with DM 1 may also have dysphagia and constipation; uterine muscle abnormalities may cause problems for women during labor and delivery. [msdmanuals.com]
- Choking
In some patients, weakness in muscles required for breathing and swallowing increases the risk of sleep apnea, choking, and aspiration (breathing in food or liquids). [musculardystrophynews.com]
As the condition progresses symptoms can include: Mobility and balance issues, including falls Digestive problems leading to incontinence, constipation Issues with speech and swallowing, such as a weak voice, slurred speech or frequent choking on food [theloopcommunity.org]
Swallowing muscles, if weakened, can lead to choking or “swallowing the wrong way” (called aspiration), with food or liquid going down the trachea (windpipe) to the lungs instead of down the esophagus to the stomach. [mda.org]
[…] when they are repeated Frequent falling Difficulties opening eyelids after strenuous contraction or crying (von Graefe's sign)[5] Possible complications may include:[citation needed] Aspiration pneumonia (caused by swallowing difficulties) Frequent choking [en.wikipedia.org]
- Muscle Rigidity
In the two sisters described, exposure to succinylcholine resulted in generalized muscle rigidity without a rise in body temperature. [rarediseases.org]
If the rigidity includes the jaw muscles, intubation may be impossible.41 Suxamethonium can also induce hyperkalaemia and ventricular arrhythmia, which can be fatal.42 Emergency treatment for a myotonic crisis is with intravenous sodium channel blockers [pn.bmj.com]
- Gagging
[citation needed] Early symptoms in a child may include:[citation needed] Difficulty swallowing Gagging Stiff movements that improve when they are repeated Frequent falling Difficulties opening eyelids after strenuous contraction or crying (von Graefe's [en.wikipedia.org]
Musculoskeletal
- Myopathy
Dystrophinopathies (Becker’s and Duchenne’s muscular dystrophy), nutritional myopathies, and endocrine myopathies are outside the scope of this review. [practicalneurology.com]
Immune-Mediated Necrotizing Myopathy (IMNM), also referred to as Necrotizing Autoimmune Myopathy (NAM), one of the Inflammatory Myopathies, is a rare, thought to be complement-mediated muscle disease. [understandingmyositis.org]
The myopathy can also have different forms: (1) adult onset distal myopathy (distal leg weakness and intrinsic hand muscles); (2) subacute myopathy of the respiratory muscles; (3) severe generalised myopathy; and (4) minimal variant myopathy. [neuroweb.us]
Myotonia congenita is an inherited myopathy, a disease that causes problems with the tone and contraction of skeletal muscles. [mda.org]
Proximal myotonic myopathy: a syndrome with a favourable prognosis? J Neurol Sci. 2002; 193:89-96 Day JW, Ricker K, Jacobsen JF, Rasmussen LJ, Dick A, Kress W. Myotonic dystrophy type 2: molecular, diagnostic and clinical spectrum. [medigraphic.com]
- Muscle Cramp
Symptoms can become considerable to the extent that they disturb daily activities, and patients sometimes notice an exacerbation of their myotonia during cold or wet weather when they can also suffer from muscle cramps. [checkorphan.org]
Your healthcare provider may prescribe a medication that blocks the sodium channel that’s on your muscle membrane. This can help with muscle cramps and stiffness. [my.clevelandclinic.org]
Presenting during brief periods of high-intensity exercise, glycogen storage diseases cause muscle cramps within seconds to minutes of exercise. [practicalneurology.com]
Additionally, about 30–40% of patients reported muscle cramps with no significant differences between both types. Dysphagia and dysphonia were only rarely reported and mostly mild. [link.springer.com]
is often described by patients as muscles ‘locking’, ‘sticking’ or ‘cramping’. [pn.bmj.com]
- Myalgia
The most frequent symptom at onset was myotonia (74.1%), followed by myalgia (16.1%) and muscle weakness (14.5%). [link.springer.com]
[…] dystrophy type I (DM1, Curschmann-Steinert disease) Myotonic dystrophy type II (DM2, proximal myotonic myopathy) Clinical features Myotonia: delayed muscle relaxation following normal muscle contraction Skeletal muscle weakness(due to muscle atrophy) Myalgia [www-amboss-com.db.rsu.lv]
Other associated symptoms often include muscle pain (myalgia) and extreme fatigue. [understandingmyositis.org]
It is quite common for DM2 patients to experience muscle pain (myalgia). Only a minority have cataracts. In common with DM1 patients, some DM2 patients may experience heart conduction defects and diabetes. [treat-nmd.org]
- Muscle Spasm
Care must be taken with the use of depolarizing muscle relaxants such as suxamethonium during anesthesia, because they can cause adverse events such as life-threatening muscle spasms and ventilation difficulties following a preoperative injection. [checkorphan.org]
Affected dogs usually present with non-painful muscle spasms, stridor, dyspnea, dysphonia, stiff-stilted gait, bunny-hopping and collapse associated with exercise and activity. [vetbook.org]
Myotonia Congenita is a hereditary disorder affecting the tone and contraction of skeletal muscle. The characteristic symptom of Myotonia Congenita is muscle spasm whereby muscles are unable to relax quickly after contracting. [scirp.org]
Other agents with reported benefit in some patients are tizanidine, methocarbamol, vigabatrin, and valproate (mainly for spasms). Botulinum toxin has been used occasionally for severe muscle spasms with dystonia. [neuroweb.us]
It was a muscle biopsy under ether general anesthesia [16, 36]. Operation was complicated by muscle spasm induced by surgical incision, leading to inadequate ventilation and cyanosis. 3.3.1. [hindawi.com]
Eyes
- Strabismus
Myotonia congenita with strabismus in a large family with a mutation in the SCN4A gene. Eye. 2012; 26: 1039-1043 Caietta E Milh M Sternberg D Lépine A Boulay C McGonigal A et al. [nmd-journal.com]
Multiple cases of bilateral adduction restriction have been reported, as well as those with divergent strabismus and convergence paralysis. The abducting eye does not present with nystagmus. [eyewiki.aao.org]
Journal of American Association for Pediatric Ophthalmology and Strabismus. 12 (3): 294–6. doi:10.1016/j.jaapos.2007.12.002. PMID 18313341. ^ Basu, A.; Nishanth, P.; Ifaturoti, O. (2010). "Pregnancy in Women with Myotonia Congenita". [en.wikipedia.org]
For example, involvement of muscles that control movements of the eyeballs (extraocular muscles) may lead to temporary episodes of double vision or abnormal deviation of one eye in relation to the other (strabismus). [rarediseases.org]
Onset
- Onset in Infancy or Childhood
There are also less common forms of myotonic dystrophy with onset in infancy or childhood. The condition tends to be more severe and have an earlier age of onset with each generation in a family. [mda.org.au]
Neurologic
- Neonatal Hypotonia
We observed the I693T mutation linked to spontaneously resolving neonatal hypotonia with variable feeding and respiratory difficulties in four unrelated families (Matthews et al., 2008a). [ncbi.nlm.nih.gov]
- Dysarthria
irritable bowel-like symptoms (e.g., abdominal pain, bloating), impaired sleep, daytime somnolence are common Mild clinical myotonia Uncommon symptoms: respiratory muscle involvement, dysphagia, dysarthria, irritable bowel-like symptoms (e.g., abdominal [www-amboss-com.db.rsu.lv]
She developed dysarthria, dysphasia, and severe weight loss. At age 59, she died from asphyxia. An autopsy was not performed. [e-jmd.org]
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]
Difficulty with speech (dysarthria), hearing problems, and problems with coordination may also occur. Heart issues including heart rhythm disturbances and irregular heartbeats (arrhythmias) have been reported. [rarediseases.org]
- Slurred Speech
Also, affected people may have slurred speech or temporary locking of their jaw. [medlineplus.gov]
As the condition progresses symptoms can include: Mobility and balance issues, including falls Digestive problems leading to incontinence, constipation Issues with speech and swallowing, such as a weak voice, slurred speech or frequent choking on food [theloopcommunity.org]
This may cause slurred speech if the lower face and tongue are weak or for there to be eye closure weakness. [pn.bmj.com]
Some individuals may have slurred speech because of weakness of muscles required to speak. Many people with DM1 have conduction defects of the heart. [rarediseases.org]
- 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]
Parents reported that the child has improved strength when walking upstairs and less clumsiness and stiffness on initiation of movement. [hkjpaed.org]
- Hyporeflexia
Hyporeflexia is also seen in a large percentage of patients. Weakness, when present, tends to be in the distal lower extremities. Autonomic involvement may also be seen with hyperhidrosis and tachycardia. [neuroweb.us]
Workup
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]
Typical facial features and examination findings should prompt a focused genetic workup for these individuals. [practicalneurology.com]
Clinical Testing and Workup Molecular genetic testing can confirm a diagnosis of DM1 or DM2. Molecular genetic testing looks for changes or alterations in the DMPK gene known to cause DM1, or in the CNBP gene for DM2. [rarediseases.org]
Serum
- Hypercapnia
Ventilatory response to carbon dioxide is reduced and chronic hypercapnia is a common finding.(c)Cardiac: Conduction defects are common in patients with DM [31]. [hindawi.com]
Treatment
[…] with a lack of treatment evidence, the validation of innovative trial designs is urgently needed. [nof1sced.org]
Participants and investigators were all blinded to treatment until the end of the trial. [healthyaging.ku.dk]
Patients preferred mexiletine treatment over placebo treatment in 26 of the 31 treatment sets (84%). [jamanetwork.com]
“The approval and commercialization of NaMuscla brings to an end the difficult off-label treatment challenges faced by these patients. With no licensed antimyotonic drug being available to date, many patients have lived without treatment. [globenewswire.com]
Prognosis
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]
Because of the diverse clinical manifestations of channelopathies the prognosis of the disease is difficult to predict. Keywords: apnoea, myotonia, SCN4A mutation. [thieme-connect.com]
Prognosis Some cases are severe and may have an impact on life expectancy, particularly early-onset cases caused by massive gene expansions. The prognosis in adult-onset cases is mainly dependent on the severity of cardiac manifestations. [orpha.net]
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
Many etiologies result in myotonia, including dystrophic and non-dystrophic myotonias. [statpearls.com]
- DM2 results from an unstable tetranucleotide (CCTG) repeat expansion in the intron 1 of ZNF9 on chromosome 3q21. 15 16 Etiology Source: Science (2001) 293: 17 Etiology The cause of the unstable CTG repeat expansion is unknown; however, it is thought [slideplayer.com]
ETIOLOGY:- The presentation of myotonia can result from a diverse array of etiologies. [samarpanphysioclinic.com]
Primary Periodic Paralyses: A Review of Etiologies and Their Pathogeneses. Farooque U, Cheema AY, Kumar R, Saini G, Kataria S. Farooque U, et al. Cureus. 2020 Aug 29;12(8):e10112. doi: 10.7759/cureus.10112. Cureus. 2020. [pubmed.ncbi.nlm.nih.gov]
Etiology The disease is due to abnormal CTG expansion in the non-translating region of the DMPKgene (19q13.3). Disease severity generally correlates with the number of DNA repeats. More than 2000 CTG repeats may be found. [orpha.net]
Epidemiology
Neuromuscular Centre Nijmegen, Department of Neurology, Radboud University Nijmegen, Medical Centre, Nijmegen, The Netherlands 3 Department of Human and Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands 4 Department of Clinical Epidemiology [jnnp.bmj.com]
Summary Epidemiology It is the most frequent adult muscular dystrophy and has an estimated prevalence ranging from 1/215,000 in Taiwan to 1/5,500 in Croatia. [orpha.net]
The Epidemiology of Neuromuscular Disorders: A Comprehensive Overview of the Literature. Journal of neuromuscular diseases 2015;2(1):73-85. Hughes MI, Hicks EM, Nevin NC, Patterson VH. [now.aapmr.org]
Pathophysiology
Udgivet Facioscapulohumeral Muscular Dystrohpy and Non-dystrophic Myotonia: Pathophysiology, outcome measures, and exercise and drug therapies Publikation: Bog/antologi/afhandling/rapport › Ph.d.-afhandling Oversigt Citationsformater [research.regionh.dk]
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]
Introduction to DM Etiology and pathophysiology of DM Model mechanisms for myotonic dystrophy: Haploinsufficiency of DMPK Haploinsufficiency of SIX5 and neighboring genes RNA pathogenesis 3 Learning Objective Introduction to repeat expansion disorders [slideplayer.com]
View Large Image Figure Viewer Download (PPT) PATHOPHYSIOLOGIC BASIS FOR MYOTONIA AND PERIODIC PARALYSIS Animal models and computer simulations have been used to explore the pathophysiologic mechanisms by which defects in mutant Na channel gating give [kidney-international.org]
Prevention
In addition, gastrointestinal discomfort is frequent and may prevent adequate dose titration. Since the designation of mexiletine as an orphan drug for NDM, level 1 evidence for the antimyotonic effect of lamotrigine has emerged. [tandfonline.com]
Early pharmacological therapy can reduce the frequency of episodes, symptoms, and prevent intensive care procedures. Because of the diverse clinical manifestations of channelopathies the prognosis of the disease is difficult to predict. [thieme-connect.com]
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]
Beginning in childhood, people with this condition experience bouts of sustained muscle tensing (myotonia) that prevent muscles from relaxing normally. [medlineplus.gov]