Malignant hyperthermia: Difference between revisions
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==Background== | ==Background== | ||
*Inherited disorder of skeletal muscles triggered most often by anesthesia inhalation agents | *Inherited disorder of skeletal muscles triggered most often by anesthesia inhalation agents, succinylcholine, heat or exercise<ref>Denborough, M. (1998) ‘Malignant hyperthermia’, The Lancet, 352(9134), pp. 1131–1136. doi: 10.1016/s0140-6736(98)03078-5</ref> | ||
*Results in hypermetabolism, skeletal muscle damage, hyperthermia, and death if not treated quickly | *Results in hypermetabolism, skeletal muscle damage, hyperthermia, and death if not treated quickly | ||
*GENERALIZED rigidity NOT always present; if it occurs, MH is almost certain | *GENERALIZED rigidity NOT always present; if it occurs, MH is almost certain | ||
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*Increased time from 1st sign to 1st dantrolene | *Increased time from 1st sign to 1st dantrolene | ||
**For every 30 minute increase in the interval, complication likelihood increases x 1.6 | **For every 30 minute increase in the interval, complication likelihood increases x 1.6 | ||
* Increased maximal temperature | *Increased maximal temperature | ||
**For every 2°C increase in max temp, complication likelihood increases x 2.9 | **For every 2°C increase in max temp, complication likelihood increases x 2.9 | ||
== | ==Clinical Features== | ||
*Muscle contraction | *Muscle contraction | ||
*Fever | *Fever | ||
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*26% Metabolic Acidosis | *26% Metabolic Acidosis | ||
*80% Muscular Abnormalities | *80% Muscular Abnormalities | ||
Watch for it with succinylcholine use. | Watch for it with [[succinylcholine]] use. | ||
===Types=== | ===Types=== | ||
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**All patients demonstrate elevated CK and often gross myoglobinuria | **All patients demonstrate elevated CK and often gross myoglobinuria | ||
**CK >20,000IU = high likelihood of MH | **CK >20,000IU = high likelihood of MH | ||
* Late onset MH | *Late onset MH | ||
**Uncommon, may begin shortly after anesthesia termination (usually within first hour) | **Uncommon, may begin shortly after anesthesia termination (usually within first hour) | ||
==Differential Diagnosis== | ==Differential Diagnosis== | ||
{{ | {{AMS and fever DDX}} | ||
==Evaluation== | |||
*Core temperature | |||
*CBC | |||
*Chem 7 | |||
*Total CK | |||
*PT/PTT | |||
*ABG | |||
== | ==Management== | ||
*Discontinue Triggering Agents | |||
*100% Oxygen at High Flow | |||
*Give Dantrolene | |||
*Provide [[bicarbonate]] for metabolic acidosis temporization | |||
*Actively cool the patient | |||
*** | *Treat any dysrhythmia | ||
===Dantrolene=== | |||
*60ml sterile water into each vial of [[dantrolene;]] may need up to 36 vials | |||
*If using Dantrium® (20mg/vial), each vial contains 3 g of mannitol (renal vasodilation); newer nanocrystalline dantrolene (250mg/vial) has 250mg mannitol per vial and requires mannitol supplementation | |||
*'''2.5mg/kg IV push''' | |||
*Titrate to effect; may need more than 10mg/kg | |||
*Call MHAUS Hotline if needed: 1-800-644-0737 | |||
*Continued Care | *Continued Care | ||
**Dantrolene | **Dantrolene 1mg/kg every 4-6 hours for 24–48 hours | ||
**Monitor for recrudescence (rate is 25%) | **Monitor for recrudescence (rate is 25%) | ||
**Follow electrolytes, blood gases, CK, core temperature, urine output and color, coagulation studies | **Follow electrolytes, blood gases, CK, core temperature, urine output and color, coagulation studies | ||
===Bicarb=== | |||
*1-2 mEQ/kg if blood gas values not yet available | |||
===Cooling Measures=== | |||
*Most patietns will have a core temperature >39 deg C (102.2 deg F) | |||
*Stop cooling when temperature reaches 100.4 | |||
===Dysrhythmic therapy=== | |||
*Dysrhythmias usually respond to treatment of acidosis and hyperkalemia | |||
*AVOID CA CHANNEL BLOCKERS as they may cause hyperkalemia or cardiac arrest in presence of dantrolene | |||
===Hyperkalemia=== | |||
*Not always present but can occur | |||
*Treat hyperkalemia with standard treatment, remember to check glucose levels q1h after treatment with insulin/glucose | |||
* | |||
==Prognosis== | ==Prognosis== | ||
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*Relapse | *Relapse | ||
*Death | *Death | ||
==References== | |||
<references/> | |||
==See Also== | ==See Also== | ||
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*[[Toxidromes]] | *[[Toxidromes]] | ||
[[Category: | [[Category:Toxicology]] |
Revision as of 17:21, 8 May 2019
Background
- Inherited disorder of skeletal muscles triggered most often by anesthesia inhalation agents, succinylcholine, heat or exercise[1]
- Results in hypermetabolism, skeletal muscle damage, hyperthermia, and death if not treated quickly
- GENERALIZED rigidity NOT always present; if it occurs, MH is almost certain
Likelihood of Complications
- Increased time from 1st sign to 1st dantrolene
- For every 30 minute increase in the interval, complication likelihood increases x 1.6
- Increased maximal temperature
- For every 2°C increase in max temp, complication likelihood increases x 2.9
Clinical Features
- Muscle contraction
- Fever
- First signs
- Hypercarbia
- Sinus tachycardia
- Masseter spasm
- Temperature abnormalities (may be early)
- Most common pattern
- Respiratory acidosis and muscular abnormalities
Presentations
- 99% Respiratory Acidosis
- 26% Metabolic Acidosis
- 80% Muscular Abnormalities
Watch for it with succinylcholine use.
Types
- Fulminant MH
- muscle rigidity, high fever, increased HR shortly after induction of anesthesia
- Masseter muscle rigidity
- jaw muscle rigidity after succinylchoine
- More common in children
- Presages MH in 20-30% cases
- All patients demonstrate elevated CK and often gross myoglobinuria
- CK >20,000IU = high likelihood of MH
- Late onset MH
- Uncommon, may begin shortly after anesthesia termination (usually within first hour)
Differential Diagnosis
Altered mental status and fever
- Infectious
- Sepsis
- Meningitis
- Encephalitis
- Cerebral malaria
- Brain abscess
- Other
Evaluation
- Core temperature
- CBC
- Chem 7
- Total CK
- PT/PTT
- ABG
Management
- Discontinue Triggering Agents
- 100% Oxygen at High Flow
- Give Dantrolene
- Provide bicarbonate for metabolic acidosis temporization
- Actively cool the patient
- Treat any dysrhythmia
Dantrolene
- 60ml sterile water into each vial of dantrolene; may need up to 36 vials
- If using Dantrium® (20mg/vial), each vial contains 3 g of mannitol (renal vasodilation); newer nanocrystalline dantrolene (250mg/vial) has 250mg mannitol per vial and requires mannitol supplementation
- 2.5mg/kg IV push
- Titrate to effect; may need more than 10mg/kg
- Call MHAUS Hotline if needed: 1-800-644-0737
- Continued Care
- Dantrolene 1mg/kg every 4-6 hours for 24–48 hours
- Monitor for recrudescence (rate is 25%)
- Follow electrolytes, blood gases, CK, core temperature, urine output and color, coagulation studies
Bicarb
- 1-2 mEQ/kg if blood gas values not yet available
Cooling Measures
- Most patietns will have a core temperature >39 deg C (102.2 deg F)
- Stop cooling when temperature reaches 100.4
Dysrhythmic therapy
- Dysrhythmias usually respond to treatment of acidosis and hyperkalemia
- AVOID CA CHANNEL BLOCKERS as they may cause hyperkalemia or cardiac arrest in presence of dantrolene
Hyperkalemia
- Not always present but can occur
- Treat hyperkalemia with standard treatment, remember to check glucose levels q1h after treatment with insulin/glucose
Prognosis
Stable to Transfer Criteria
- ETCO2 is declining or normal
- HR is stable or decreasing
- No ominous dysrhythmias
- Temperature is declining
- Generalized muscular rigidity is resolving (if present)
- IV dantrolene administration has begun
Complications
- Consciousness Level Change/Coma
- Cardiac Dysfunction
- Pulmonary Edema
- Renal Dysfunction
- Disseminated Intravascular Coagulation
- Hepatic Dysfunction
- Relapse
- Death
References
- ↑ Denborough, M. (1998) ‘Malignant hyperthermia’, The Lancet, 352(9134), pp. 1131–1136. doi: 10.1016/s0140-6736(98)03078-5