Myotonia

Prolonged failure of muscle relaxation after contraction. This may occur after voluntary contractions, muscle percussion, or electrical stimulation of the muscle. Myotonia is a characteristic feature of MYOTONIC DISORDERS.

Also Known As:

Networked: 578 relevant articles (39 outcomes, 53 trials/studies)

Relationship Network

Disease Context: Research Results

Related Diseases

1.	Myotonic Dystrophy (Dystrophia Myotonica)
2.	Neuralgia (Stump Neuralgia)
3.	Myotonia Congenita (Thomsen Disease)
4.	Myotonia
5.	Paralysis (Palsy)

Experts

1.	Takahashi, Masanori P: 14 articles (05/2015 - 02/2006)
2.	Hanna, Michael G: 10 articles (12/2014 - 10/2010)
3.	Sternberg, Damien: 8 articles (01/2015 - 11/2004)
4.	Thornton, Charles A: 8 articles (11/2013 - 10/2002)
5.	Cannon, Stephen C: 7 articles (03/2014 - 12/2004)
6.	Griggs, Robert C: 6 articles (01/2015 - 10/2008)
7.	Fontaine, B: 6 articles (11/2014 - 08/2000)
8.	Desaphy, Jean-François: 6 articles (05/2014 - 01/2004)
9.	Sakoda, Saburo: 6 articles (06/2012 - 02/2006)
10.	Lehmann-Horn, F: 6 articles (10/2011 - 08/2000)

Drugs and Biologics

Drugs and Important Biological Agents (IBA) related to Myotonia:

1.	Mexiletine (Mexitil)FDA LinkGeneric 10/03/2012 - "Mexiletine improved the INQOL-QOL score (mexiletine, 14.0 vs placebo, 16.7; difference, -2.69; 95% CI, -4.07 to -1.30; P < .001) and decreased handgrip myotonia on clinical examination (mexiletine, 0.164 seconds vs placebo, 0.494 seconds; difference, -0.330; 95% CI, -0.633 to -0.142; P < .001). " 01/01/2015 - "Combined N-of-1 trials to investigate mexiletine in non-dystrophic myotonia using a Bayesian approach; study rationale and protocol." 05/01/2014 - "Considering the limits of mexiletine tolerability and the occurrence of non-responders, this study proposes an arsenal of alternative drugs, which may prove useful to increase the quality of life of individuals suffering from non-dystrophic myotonia. " 10/01/2009 - "A randomized controlled trial has been initiated for the study of mexiletine in nondystrophic myotonias. " 10/01/2008 - "For myotonia, there is only anecdotal evidence for treatment, but a controlled trial of mexiletine versus placebo is currently being funded by a Food and Drug Administration-orphan products grant and is scheduled to begin in late 2008. "
2.	Phenytoin (Dilantin)FDA LinkGeneric 10/01/1978 - "Myotonia induced by ACA is inhibited by concentrations of diphenylhydantoin that are clinically effective in controlling hereditary myotonia in humans." 12/01/1988 - "Effects of phenytoin on in vitro muscle twitch and clinical signs of CIR and myotonia were evaluated in these same horses. " 08/01/1980 - "A report is given on the possible therapeutic influence of diphenylhydantoin on dystrophic myotonia. " 09/01/1979 - "Suppression of myotonia in dystrophic chicken muscle by phenytoin." 09/01/1976 - "[Effects of diphenylhydantoin on myotonia and biopsy findings of the muscle]."
3.	Flecainide (Tambocor)FDA LinkGeneric 02/17/2006 - "Considering the slow recovery from block and the specific action against repetitive depolarization, flecainide may represent a potent therapeutic agent for myotonia." 09/01/2003 - "The antiarrhythmic agent flecainide appears beneficial for painful congenital myotonia and LQT-3/DeltaKPQ syndrome. " 02/17/2006 - "When pulses of brief depolarization simulating myotonia were applied from a holding potential of -90 mV, flecainide at therapeutic concentrations significantly blocked sodium currents. " 02/17/2006 - "Flecainide, a class Ic antiarrhythmic drug, has been anecdotally reported to improve myotonia, but little is known about its kinetics on human skeletal muscle sodium channels applicable in vivo. " 04/09/1999 - "Our findings demonstrate the unique pattern of sodium channel dysfunction associated with a D1/S6 myotonia-producing sodium channel mutation, and provide a mechanism for the beneficial effects of flecainide in this setting."
4.	Chloride Channels (Chloride Channel)IBA 11/27/2012 - "New immunohistochemical method for improved myotonia and chloride channel mutation diagnostics." 01/01/2014 - "Studies in mice, dogs, humans and goats confirmed myotonia associated with functional defects in chloride channels and mutations in a skeletal muscle chloride channel (CLCN1). " 10/01/1996 - "Physiologic study of these mutations may lead to better understanding of the pathophysiology of myotonia in these patients and of voltage-gated chloride channel structure/function relationships in skeletal muscles." 04/01/2015 - "Ovine congenital myotonia associated with a mutation in the muscle chloride channel gene." 01/01/2015 - "Impaired surface membrane insertion of homo- and heterodimeric human muscle chloride channels carrying amino-terminal myotonia-causing mutations."
5.	Acetazolamide (Diamox)FDA LinkGeneric 03/01/1987 - "Acetazolamide was dramatically effective in alleviating myotonia in all patients and was more effective than other antimyotonic agents." 05/01/1987 - "Myotonia was effectively treated with a very low dose of acetazolamide and no weakness developed. " 01/01/1980 - "6. In our study, the diuretic, acetazolamide, unmasked subthreshold myotonia. " 06/01/2015 - "Becker myotonia-a recently identified mutation in iberian descendants with apparent acetazolamide-responsive phenotype." 10/01/2014 - "Based on this clinical experience and the favorable pharmacologic profile of acetazolamide, it may be a good treatment option for children with nondystrophic myotonias."
6.	Sodium Channels (Sodium Channel)IBA 07/01/2011 - "In this study, we characterize the functional consequences of the new A799S Na+ channel mutation that is associated with sodium channel myotonia in newborn babies. " 07/01/1993 - "Furthermore, in support of previous studies on myotonic muscle from patients, this model provides direct evidence that only a small proportion of sodium channels needs to function abnormally to cause myotonia." 11/01/2015 - "A myotonia-like symptom without myotonic discharge may present as an early neurological sign of SBMA, which possibly reflects a sodium channel dysfunction in skeletal muscles. " 10/01/2015 - "The clinical follow-up led us to the diagnosis of sodium channel myotonia with atypical neonatal onset. " 10/01/2015 - "Mutations of the skeletal muscle sodium channel gene SCN4A are associated with several neuromuscular disorders including sodium channel myotonias. "
7.	Lidocaine (Xylocaine)FDA LinkGeneric 07/01/2002 - "Muscle stiffness and myotonia improved after infusion of lidocaine. " 04/01/2012 - "We describe a Polish patient with severe myotonia, transient weakness, and muscle cramps who only responds to lidocaine. " 01/01/1980 - "Improved therapy of myotonia with the lidocaine derivative tocainide." 03/23/2001 - "Na(+) channel blockers like lidocaine and mexiletine, suggested for therapy of myotonia, do not reconstitute inactivation in channels with defective inactivation in vitro. " 04/01/2010 - "Lidocaine is also an important anesthetic and topical agent that is useful in the treatment of multiple pain disorders, and mexiletine is commonly used for neuropathic pain and myotonia. "
8.	PotassiumIBA 02/01/1981 - "Experiments were conducted to study the effect of altering external potassium on in vitro induction of myotonia in rat diaphragm using 2,4-dichlorophenoxy acetate (2,4-D). " 01/01/2012 - "These data suggested that KCNQ openers prevent the myotonia induced by 9-AC, at least partly through enhancing potassium conductance in skeletal muscle. " 10/01/2011 - "We report a 4-generation Turkish family with 10 affected members presenting with myotonia and potassium- and exercise-induced paralytic attacks. " 12/01/1998 - "All the changes are consistent with the hyperexcitability of the muscle fibers observed in patients affected by potassium-aggrevated myotonia (PAM)." 01/01/1994 - "During the treatment of this episode, as soon as serum potassium levels were restored to normal values, a marked increase in muscular excitability with an electromyographic picture of myotonia was observed. "
9.	Tocainide (Tonocard)FDA Link 03/27/2014 - "The results provide additional indications about the structural requirement of pharmacophores for further increasing potency and state-dependent block and allowed us to identify a new tocainide analogue (6f) with a favorable pharmacodynamic profile to be proposed as a valid candidate for studies aimed at evaluating its usefulness in the treatment of myotonias. " 05/01/1986 - "Successful treatment with tocainide of recessive generalized congenital myotonia." 12/01/1983 - "Tocainide prevented myotonia and weakness induced by cooling, but failed to prevent hyperkalemic weakness. " 01/01/1985 - "Therefore, the authors recommend symptomatic therapy with tocainide for myotonia and paramyotonia congenita, as well as in myotonic dystrophy patients suffering from marked myotonic stiffness. " 01/01/1980 - "Improved therapy of myotonia with the lidocaine derivative tocainide."
10.	SodiumIBA 04/01/2013 - "The physiological basis for myotonia lies in well-established deficiencies of skeletal muscle chloride and sodium conductances. " 01/01/2013 - "Non-dystrophic myotonias (NDM) are characterised by muscle stiffness during voluntary movement owing to delayed skeletal muscle relaxation caused by mutations in the chloride (CLCN1) and sodium (SCN4A) skeletal muscle channel genes. " 07/01/2008 - "Mutations in the genes encoding chloride (ClC-1) or sodium (SCN4A) channels expressed exclusively in skeletal muscle cause nondystrophic myotonias. " 03/01/1975 - "Further, myotonia can be prevented by reducing peak membrane sodium permeability or by shifting the voltage dependency of the membrane rate constants for sodium in a depolarizing direction. " 01/01/2015 - "Needle electromyography was performed by an electromyographer blinded for genetic diagnosis in 66 non-dystrophic myotonia patients (32 chloride and 34 sodium channelopathy). "

Therapies and Procedures

1.	Activities of Daily Living (ADL) 08/01/1998 - "After DHEAS, activities of daily living improved, muscle strength increased, and myotonia decreased. " 12/01/2005 - "In myotonic dystrophy dehydroepiandrosterone is low in the serum and it has been reported that intravenous injections of DHEAS to human cases improves myotonia and activities of daily living. " 12/01/1999 - "Recently dehydroepiandrosterone sulfate which is a male hormone secreted from the adrenal cortex has been used for myotonic dystrophy and the drug reduces myotonia and improves activities of daily living. "
2.	Cholecystectomy 05/01/1948 - "Myotonia acquisita due to chronic calculous cholecystitis and cured by cholecystectomy."
3.	Aftercare (After-Treatment) 06/01/2012 - "Finally, the scale was sensitive to clinical changes disclosing a significant improvement after treatment in the items assessing myotonia, and also to disease progression showing a significant worsening in all areas but myotonia in untreated patients. "
4.	Denervation 09/01/1977 - "Denervation and diazacholesterol myotonia: a study of the isometric twitch of the rat." 10/01/2004 - "Effects of acute and chronic denervation on human myotonia." 08/01/1988 - "Facilitation of electrical myotonia and denervation fibrillation by direct current stimulation." 06/01/1988 - "Facilitation of electrical myotonia and denervation fibrillation by direct current stimulation." 05/01/1986 - "All the rats gradually became amyotonic following denervation; myotonia reappeared during reinnervation. "
5.	Microelectrodes 01/01/1984 - "Myotonia induced by low chloride solution: intracellular studies by Cl liquid ion exchanger microelectrode." 12/01/2005 - "In mto mice insertion myotonia was recorded as soon as the microelectrode was inserted in the muscle cells. " 06/01/1997 - "6. Measurements made using microelectrodes showed that the conditions under which myotonia either did not develop or was significantly reduced, i.e. " 10/01/1990 - "Intracellular recordings from the mdx mouse hemidiaphragm preparations revealed low resting membrane potentials and electrical myotonia which occurred at the time of microelectrode insertion and withdrawal. " 09/01/1981 - "Analysis of the membrane current densities using voltage clamps with 3 microelectrodes revealed that in paramyotonic patients at 37 degrees C all component conductances were normal, except for a decreased Cl conductance in the patient who had myotonia in a warm environment. "