We also discuss the reasons for the shift in typical clinical presentation. [ncbi.nlm.nih.gov]

The clinical presentation may vary from abortive MH to the fulminant MH crisis. [link.springer.com]

• Fever

  In both cases, the discontinuation of rocuronium therapy was followed by the rapid diminution of fever over 12-36 hours. [ncbi.nlm.nih.gov]

  J Pediatr Orthop 1994; 14:799–801Angel, JD Blasier, RD Allison, R Lenhardt R, Negishi C, Sessler DI: Perioperative fever. [doi.org]

  After 4 h of operation, the child went through convulsions, high fever and succumbed within a few hours. High fever was not detected in a timely manner, which is one of the main symptoms of MH. [spandidos-publications.com]

• High Fever

  After 4 h of operation, the child went through convulsions, high fever and succumbed within a few hours. High fever was not detected in a timely manner, which is one of the main symptoms of MH. [spandidos-publications.com]

  fever, which, if not immediately reversed, can lead to tissue damage or death. [science.sciencemag.org]

  This exposure can lead to muscle rigidity, very high fever, failure of other organs (kidney, lung), abnormal blood clotting and other life-threatening complications. [wakehealth.edu]

  He later developed high fever with core temperature reaching a peak of 42.2°C, rapid breathing, and died after unsuccessful attempts to stabilize him. [ncbi.nlm.nih.gov]

  Muscle rigidity, breakdown of muscle fibers ( rhabdomyolysis ), a high fever, increased acid levels in the blood and other tissues (acidosis), and a rapid heart rate are some of the effects of this potentially life-threatening condition. [medicinenet.com]

• Asymptomatic

  In the mildest form (the heterozygote, i.e. where only one abnormal gene is inherited) patients may be asymptomatic. However, under certain circumstances the patient may experience significant problems. [mhaus.org]

  Affected patients have an asymptomatic but potentially lethal hypermetabolic reaction after contact with volatile anesthetics or succinylcholine. Classic symptoms include hemodynamic instability, combined with acidosis, rigor, and hyperthermia. [circuit.perfusion.com]

  […] mechanism of RYR1 mutants using Ca2+ imaging and molecular dynamics. 61 Yamazawa T...Iino M 31841587 2020 44 Personalized pediatric anesthesia and pain management: problem-based review. 61 Packiasabapathy S...Sadhasivam S 31849281 2020 45 Significance of Asymptomatic [malacards.org]

  Such studies would be difficult to perform because they would require an IVCT to determine the MH status prior to the onset of EHS; however, IVCT is an invasive and ethically unacceptable procedure among asymptomatic patients. [journals.plos.org]

  Liver side effects may be seen either as asymptomatic elevation of liver enzymes and/or bilirubin or, most severe, as fatal and nonfatal liver inflammation. [en.wikipedia.org]

• Rigor

  1.75% halothane or an ambient temperature of 42 degrees C characterized by increased rectal temperature, respiratory rate, and inspiratory effort, with significant blood biochemical changes indicating metabolic acidosis, ending in death and hyperacute rigor [ncbi.nlm.nih.gov]

  1.25–1.75% halothane or an ambient temperature of 42°C characterized by increased rectal temperature, respiratory rate, and inspiratory effort, with significant blood biochemical changes indicating metabolic acidosis, ending in death and hyperacute rigor [doi.org]

  We observed severe generalized rigors, hyperthermia, tachycardia, and a respiratory rate of 50 breaths per minute. [hindawi.com]

  Classic symptoms include hemodynamic instability, combined with acidosis, rigor, and hyperthermia. During cardiopulmonary bypass, these signs may be obscured, delaying correct diagnosis and lifesaving treatment. [circuit.perfusion.com]

• Chills

  Other measures to reduce core body temperature include administering chilled 0.9% sodium chloride solution I.V.; placing ice packs at his groin, axillae, and neck; and applying a temperature-regulating blanket. Monitor his core body temperature. [journals.lww.com]

  For example, active-liquid systems operate by chilling water and circulating it through a garment; the skin surface area is thereby cooled through conduction. [en.wikipedia.org]

• Tachypnea

  In response to the acidosis, patients breathing spontaneously develop tachypnea that only partially compensates. [msdmanuals.com]

  Many features of a typical malignant hyperthermia episode were present, including tachydysrhythmia, tachypnea, and fever in association with metabolic acidosis, hyperCKemia, myglobinemia, and rapid recovery without residual effects upon administration [ncbi.nlm.nih.gov]

  Clinical signs include unexplained elevation of end-tidal carbon dioxide, muscle rigidity, acidosis, tachycardia, tachypnea, hyperthermia, and evidence of rhabdomyolysis. [doi.org]

• Tachycardia

  Pathologic response in MH include increase in oxygen consumption, increase in endtidal CO2, tachycardia, hyperthermia, hyperkalemia and muscle rigidity. Immediate recognition and treatment are crucial to avoid lethal outcome. [ncbi.nlm.nih.gov]

  Early diagnosis can be facilitated by prompt recognition of jaw rigidity, tachypnea, tachycardia, and increased end-tidal CO2. [msdmanuals.com]

• Hypertension

  He showed the earlier clinical signs, such as elevation of end-tidal $CO_2$, tachycardia, and hypertension. After prompt administration of dantrolene, operation was continued with profopol and midazolam. [chikd.org]

  After a preprocedural pain block for elective right shoulder arthroscopy, a 53-year-old hypertensive white man developed chest pain. In the operating room, he had increased blood pressure. [ncbi.nlm.nih.gov]

  Disease (1) increased ETCO2 (2) tachycardia (3) tachypnoea (4) masseter spasm (if develops this convert to a MH safe anaesthetic) (5) muscle rigidity (6) temp increase (late) – 1 C\15min intra-op & 4\24 post op tachyarrhythmia difficulty ventilation hypertension [lifeinthefastlane.com]

  Just click on your patient’s weight and you have many categories to choose from: Blades/Tubes/LMA/Gases All our Anesthesia Drugs Local Anesthetics Labor and Delivery (detailed) Antihypertensive Meds Beta Blockers Hypertensive Meds/Pressors Asthma (Mild [play.google.com]

• Hypotension

  Later signs include complex arrhythmias, cyanosis, hypoxia, hypotension, electrolyte abnormalities, rhabdomyolysis and severe hyperthermia. Hyperthermia is a late sign. Rhabdomyolysis is a sign of the severity of the condition. [patient.info]

  After 10 minutes of halothane anesthesia, the patient became tachycardic, hypotensive, hypoxemic, and hyperthermic, and the halothane was discontinued. He was packed in ice and subsequently recovered uneventfully. [newswise.com]

  •Bradycardia •Bronchiolitis •Burns •Cardiac Arrest •Coma •Congenital Heart Disease •Croup •Diabetic Ketoacidosis •Fever •Head Injury •Hyperkalaemia •Hypertensive Crises •Hypoglycaemia •Hypokalaemia •Hypomagnesaemia •Hypophosphataemia •Hyponatraemia •Hypotension [play.google.com]

  Signs and Symptoms Approximate number of patients (when available) Abnormality of the coagulation cascade - Autosomal dominant inheritance - Elevated serum creatine phosphokinase - Fever - Hyperkalemia - Hyperphosphatemia - Hypotension - Malignant hyperthermia [web.archive.org]

  CPK Elevated serum creatine phosphokinase High serum creatine kinase Increased CPK Increased creatine kinase Increased creatine phosphokinase Increased serum CK Increased serum creatine kinase Increased serum creatine phosphokinase [ more ] 0003236 Hypotension [rarediseases.info.nih.gov]

• Sweating

  Clinical manifestations include: CO 2 increase, tachycardia, haemodynamic instability, metabolic and respiratory acidosis, profuse sweating, hyperpyrexia, CPK increase, myoglobinuria, kidney failure, disseminated intravascular coagulation (DIC), and ending [ncbi.nlm.nih.gov]

  […] signs Inappropriately elevated carbon dioxide production, which is manifested as raised end-tidal CO on capnography or as tachypnea if the patient is breathing spontaneously Increased oxygen consumption Mixed metabolic and respiratory acidosis Profuse sweating [revonto.com]

  […] increased ETCO2 (2) tachycardia (3) tachypnoea (4) masseter spasm (if develops this convert to a MH safe anaesthetic) (5) muscle rigidity (6) temp increase (late) – 1 C\15min intra-op & 4\24 post op tachyarrhythmia difficulty ventilation hypertension sweating [lifeinthefastlane.com]

  The main risk factor for hyperthermia is the lack of ability to sweat. People that are dehydrated or who are older in age may not produce the sweat they need to regulate their body temperature[26]. [en.wikipedia.org]

• Erythema

  Less than twenty minutes after initiation of volatile anesthesia, profound skin erythema and hyperthermia were installed, with the body temperature reaching 41 Celsius degrees. [pubs.sciepub.com]

  […] reconstitution, dantrolene is stable at room temperature for 6 hours when protected from light. 18 Adverse effects associated with dantrolene include loss of grip strength, muscle weakness, drowsiness, dizziness, and injection site reactions, including pain, erythema [healio.com]

• Myalgia

  We present four recently referred cases to illustrate this point: one late-onset case, two patients with slowly progressive hypercapnia as the sole sign and a fourth patient with postoperative myalgias and elevated creatine kinase. [ncbi.nlm.nih.gov]

  Before an anaesthetic ask about unclear complications from previous anaesthesia, muscle disorders in the family, myalgia, muscle cramps and dark urine. If there is suspicion, check CK. If in doubt, use a trigger-free anaesthetic. [patient.info]

  Jungbluth, Mutations in RYR1 are a common cause of exertional myalgia and rhabdomyolysis, Neuromuscular Disorders, 10.1016/j.nmd.2013.03.008, 23, 7, (540-548), (2013). Allison Billings, Skeletal Muscle, Equine Clinical Pathology, (153-179), (2013). [doi.org]

• Muscle Spasticity

  It is also used in the management of neuroleptic malignant syndrome, muscle spasticity (e.g. after strokes, in paraplegia, cerebral palsy, or patients with multiple sclerosis), and 2,4-dinitrophenol poisoning,[2][3] and the related compounds dinoseb and [en.wikipedia.org]

  [Spasticity 2006] Spasticity refers to the often painful involuntary tensing, stiffening or contracting of muscles. [medmk.com]

• Dark Urine

  Before an anaesthetic ask about unclear complications from previous anaesthesia, muscle disorders in the family, myalgia, muscle cramps and dark urine. If there is suspicion, check CK. If in doubt, use a trigger-free anaesthetic. [patient.info]

  A person may have: Fever higher than 105°F (40.6°C) Stiff muscles Muscle spasms, mainly in the face Fast breathing Fast or irregular heartbeat Dark urine An uneven skin color Muscle Fibers Copyright © Nucleus Medical Media, Inc. [winchesterhospital.org]

  urine (myoglobinuria) Severe cardiac arrhythmia and cardiac arrest Disseminated intravascular coagulation Treatment should be started as soon as an MH crisis is suspected. 4 Treatment Immediate discontinuation of all trigger agents Administration of [revonto.com]

  Symptoms Symptoms may begin after medication is given and include: Fever - often more than 40.6°C (105°F) Stiff muscles Muscle spasms, especially the facial muscles Fast breathing Fast or irregular heartbeat Dark urine An uneven skin color Diagnosis Malignant [cancercarewny.com]

• Seizure

  Acute toxic effects include agitation, hypertensive crisis, coronary or cerebral vasospasm, cardiac dysrhythmias, metabolic acidosis, seizures, and hyperkalemia. [calpoison.org]

  Seizures. Coma. Death. Is malignant hyperthermia fatal? If untreated, malignant hyperthermia is almost always fatal. The death rate is 3% to 5%, even when the condition is properly treated. [my.clevelandclinic.org]

  She was treated for presumed seizures with midazolam (Versed; Roche Laboratories Nutley, NS, New Jersey) and propofol (Diprivan; AstraZeneca, Wilmington, Delaware). The pediatric service was consulted. [academic.oup.com]

  Nevertheless, severe CNS impairment, such as confusion, delirium, coma or seizures, was required in all cases. [journals.plos.org]

  […] citation needed] Adverse effects[edit] Central nervous system side effects are quite frequently noted and encompass speech and visual disturbances, mental depression and confusion, hallucinations, headache, insomnia and exacerbation or precipitation of seizures [en.wikipedia.org]

• Confusion

  Signs of an MH reaction are non-specific and may be confused with the presentation of other problems such as sepsis and overheating of a patient. A high index of suspicion is needed to be aware of an early presentation of MH. [ncbi.nlm.nih.gov]

  Some degree of increased muscular tone is usually present, which may be confused with the lead-pipe rigidity seen with NMS. [calpoison.org]

  Nevertheless, severe CNS impairment, such as confusion, delirium, coma or seizures, was required in all cases. [journals.plos.org]

  Flushed skin Sweating An abnormally rapid or irregular heartbeat Rapid breathing or uncomfortable breathing Brown or cola-colored urine Very low blood pressure (shock) Confusion Muscle weakness or swelling after the event Many people who carry a gene [drugs.com]

  Hyperthermia from neurological disease may include little or no sweating, lack of heart rate change, and confusion or delirium. Other signs and symptoms vary. [en.wikipedia.org]

• Altered Mental Status

  Serotonin toxicity is characterized by a triad of altered mental status, autonomic effects, and neuromuscular excitation. [calpoison.org]

  Neuroleptic malignant syndrome is characterized by muscle rigidity, hyperthermia, hyperkalemia, acidosis, autonomic instability, and altered mental status most often occurring after the use of neuroleptic agents such as haloperidol, but it has also been [healio.com]

• Agitated Delirium

  Cocaine-associated agitated delirium and the neuroleptic malignant syndrome. Am J Emerg 1996;14:425-428 51.-TSAI G. et al: Neuroleptic Malignant Syndrome Associated with clozapine treatment. [uninet.edu]

• Flaccid Paralysis

  Seizures, flaccid paralysis, respiratory depression, and coma may ensue. Anticholinergic effects delay gastric emptying, resulting in a prolonged duration of action. Patients may be amnestic to the events. [calpoison.org]

Neurology workup revealed the presence of a known causative ryanodine receptor (RYR1) mutation for MH, c.7522C>T; p.R2508C. Furthermore, the neurology workup diagnosed the child with King-Denborough syndrome (KDS). [ncbi.nlm.nih.gov]

She was administered 2 liters of normal saline and a workup for possible infection ensued. Her sister later arrived and stated that her paroxetine dose was doubled from 20 to 40 mg last week and that she may have taken a few extra pills. [calpoison.org]

• Hypercapnia

  The following tachycardia, hypercapnia and hyperthermia led to the diagnosis of malignant hyperthermia. Symptoms were relieved dramatically after the discontinuation of sevoflurane. [ncbi.nlm.nih.gov]

• Creatine Phosphokinase Increased

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

If these complications occur even with initial treatment with dantrolene, our experiences may be useful adjunctive treatments to consider. [ncbi.nlm.nih.gov]

FDA-Approved Treatments The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. [web.archive.org]

Quarterly drills on reconstitution of dantrolene and treatment of malignant hyperthermia were also deemed to be necessary. [doi.org]

Prognosis The syndrome is likely to be fatal if untreated but thanks to the dramatic progress in understanding the clinical manifestations and pathophysiology of the syndrome, the mortality from MH has dropped from over 80%, thirty years ago, to less [orpha.net]

[…] inotropes as needed HCO3 2-4mEq/kg Dantrolene 2.5mg/kg every 5min (total dose 10mg/kg/day – continuous infusion or treat recurrence (25%)) cardiac arrhythmias -> beta blockers & lignocaine. high K+ -> glucose-insulin & frusemide watch for DICCK Q6hrly PROGNOSIS [lifeinthefastlane.com]

[…] in 291 MH episodes recorded in the North American Malignant Hyperthermia Registry database between 1987 and 2006, there were eight cardiac arrests and four deaths, and the median age of patients experiencing cardiac arrest or death was 20 years. [7] Prognosis [emedicine.medscape.com]

DNA samples were collected from 885 patients in 4 groups: severe statin myopathy (n=197), mild statin myopathy (n=163), statin-tolerant controls (n=133), and non-drug-induced myopathies of unknown etiology characterized by exercise-induced muscle pain [ncbi.nlm.nih.gov]

References:[1][2][4] Malignant hyperthermia Summary Epidemiology Etiology Pathophysiology Clinical features Diagnostics Differential diagnoses Treatment [amboss.com]

Epidemiology References:[1][2] Epidemiological data refers to the US, unless otherwise specified. [amboss.com]

Epidemiologic data on the geographic variation in MH prevalence is scant. The objective of this study is to examine the prevalence of recorded MH diagnosis in patients discharged from hospitals in four states in the United States. [ncbi.nlm.nih.gov]

Our aim was to present the most recent data concerning epidemiology, genetics, pathophysiology, clinical course, treatment, and diagnosis of MH. [termedia.pl]

Increased understanding of the clinical manifestation and pathophysiology of the syndrome, has lead to the mortality decreasing from 80 % thirty years ago to <5 % in 2006. [ncbi.nlm.nih.gov]

The pathophysiologic changes of MH are due to an uncontrolled rise in myoplasmic calcium, which activates biochemical processes related to muscle activation. [orpha.net]

This prevented us from making a definitive diagnosis in our patient. [ncbi.nlm.nih.gov]

Dantrolene sodium for injection can be used preoperatively, and sometimes postoperatively, to prevent or attenuate the development of clinical and laboratory signs of MH in individuals judged to be susceptible to MH.³ Early recognition and prompt treatment [revonto.com]