Malignant hyperthermia (MH) is a rare, inherited muscle disorder triggered by
certain types of anaesthesia that may cause a fast-acting, life-threatening crisis.
MH-susceptible persons have a mutation that results in the presence of
abnormal proteins in the muscle cells of their body. Although normal in
everyday life, when these patients are exposed to certain anaesthetic agents, or
in rare cases when exposed to high environmental heat or strenuous exercise, it
causes an abnormal release of calcium from the sarcoplasmic reticulum (a
storage site for calcium) in the muscle cell, which results in a sustained muscle
contraction and thus an abnormal increase in metabolism and heat production.
The general signs of the MH crisis include increased heart rate, greatly
increased body metabolism, muscle rigidity and/or fever that may exceed 110°
F along with muscle breakdown, derangements of body chemicals and increased
acid con - ANSWER Malignant Hyperthermia. rapid rise in temperature,
autosomal dominant - use of dantrolene sodium, a drug specific for the
treatment of MH. (MHAUS) has names of on-call physicians available for
consultation in MH emergencies at 1-800-644-9737. Calcium accumulation in
skeletal cells, sustains skeletal muscle contractions
inherited disorder MH - ANSWER MH is inherited with an autosomal
dominant inheritance in humans. All closely related members of a family in
which MH has occurred must also be considered MH susceptible and managed
accordingly, unless proven otherwise
Risk Factors: definite association with central core disease (CCD), an inherited
neuromuscular disorder. Both CCD and MH are caused by a genetic mutation in
the skeletal muscle ryanodine receptor type 1 - ANSWER CCD:experience
persistent, mild muscle weakness that does not worsen with time. Central core
disease is also associated with skeletal abnormalities such as curvature of the
spine (scoliosis), hip dislocation, joint deformities-"contractures" that restrict
the movement of certain joints.
Other neuromuscular disorders that may be associated with MH include:
, Duchenne muscular dystrophy
King-Denborough syndrome
Hypokalemic and hyperkalemic Periodic paralysis
Osteogenesis imperfecta
Myotonic patients
Carnitine palmityl transferase deficiency
Multiminicore disease - ANSWER Mitochondrial Myopathy (MM)
MM involve acidosis that is of a chronic nature and hypotonia of varying
severity, literature suggests no or weak association between MM and MH.
Caution be used when using succinylcholine in myopathic patients due to
evidence suggestive of succinylcholine-induced hyperkalemia in such patients,
and MHAUS recommends that volatile agents should not be avoided out of
concern for possible MH susceptibility
Neuroleptic Malignant Syndrome (NMS): is a syndrome that resembles MH but
is precipitated by drugs acting centrally on dopaminergic pathways in the brain.
- ANSWER Patients who develop documented recurrent rhabdomyolysis after
exercise or with heat stroke should be referred to a neuromuscular specialist for
evaluation.
Patients with any of these muscle disorders or incidents of heat stroke or
hyperthermia should be carefully evaluated by their anesthesiologist prior to
surgery.
Signs and Symptoms of Malignant Hyperthermia - ANSWER Unexplained
tachycardia is often the first sign of an acute MH episode. This sign can be
mistaken for light anesthesia. Other early signs include:
Sudden unexplained end tidal carbon dioxide
Tachypnea
Cardiac arrhythmias
Decreased peripheral oxygen saturation/mottled skin/Cyanosis
Unstable B/P
Muscle rigidity
Later symptoms as the episode continues:
Elevated body temperature
Respiratory and metabolic acidosis
Hyperkalemia
certain types of anaesthesia that may cause a fast-acting, life-threatening crisis.
MH-susceptible persons have a mutation that results in the presence of
abnormal proteins in the muscle cells of their body. Although normal in
everyday life, when these patients are exposed to certain anaesthetic agents, or
in rare cases when exposed to high environmental heat or strenuous exercise, it
causes an abnormal release of calcium from the sarcoplasmic reticulum (a
storage site for calcium) in the muscle cell, which results in a sustained muscle
contraction and thus an abnormal increase in metabolism and heat production.
The general signs of the MH crisis include increased heart rate, greatly
increased body metabolism, muscle rigidity and/or fever that may exceed 110°
F along with muscle breakdown, derangements of body chemicals and increased
acid con - ANSWER Malignant Hyperthermia. rapid rise in temperature,
autosomal dominant - use of dantrolene sodium, a drug specific for the
treatment of MH. (MHAUS) has names of on-call physicians available for
consultation in MH emergencies at 1-800-644-9737. Calcium accumulation in
skeletal cells, sustains skeletal muscle contractions
inherited disorder MH - ANSWER MH is inherited with an autosomal
dominant inheritance in humans. All closely related members of a family in
which MH has occurred must also be considered MH susceptible and managed
accordingly, unless proven otherwise
Risk Factors: definite association with central core disease (CCD), an inherited
neuromuscular disorder. Both CCD and MH are caused by a genetic mutation in
the skeletal muscle ryanodine receptor type 1 - ANSWER CCD:experience
persistent, mild muscle weakness that does not worsen with time. Central core
disease is also associated with skeletal abnormalities such as curvature of the
spine (scoliosis), hip dislocation, joint deformities-"contractures" that restrict
the movement of certain joints.
Other neuromuscular disorders that may be associated with MH include:
, Duchenne muscular dystrophy
King-Denborough syndrome
Hypokalemic and hyperkalemic Periodic paralysis
Osteogenesis imperfecta
Myotonic patients
Carnitine palmityl transferase deficiency
Multiminicore disease - ANSWER Mitochondrial Myopathy (MM)
MM involve acidosis that is of a chronic nature and hypotonia of varying
severity, literature suggests no or weak association between MM and MH.
Caution be used when using succinylcholine in myopathic patients due to
evidence suggestive of succinylcholine-induced hyperkalemia in such patients,
and MHAUS recommends that volatile agents should not be avoided out of
concern for possible MH susceptibility
Neuroleptic Malignant Syndrome (NMS): is a syndrome that resembles MH but
is precipitated by drugs acting centrally on dopaminergic pathways in the brain.
- ANSWER Patients who develop documented recurrent rhabdomyolysis after
exercise or with heat stroke should be referred to a neuromuscular specialist for
evaluation.
Patients with any of these muscle disorders or incidents of heat stroke or
hyperthermia should be carefully evaluated by their anesthesiologist prior to
surgery.
Signs and Symptoms of Malignant Hyperthermia - ANSWER Unexplained
tachycardia is often the first sign of an acute MH episode. This sign can be
mistaken for light anesthesia. Other early signs include:
Sudden unexplained end tidal carbon dioxide
Tachypnea
Cardiac arrhythmias
Decreased peripheral oxygen saturation/mottled skin/Cyanosis
Unstable B/P
Muscle rigidity
Later symptoms as the episode continues:
Elevated body temperature
Respiratory and metabolic acidosis
Hyperkalemia
