Malignant hyperthermia: Difference between revisions
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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 | ||
Line 37: | Line 37: | ||
**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) | ||
Line 54: | Line 54: | ||
*Initial | *Initial | ||
**Declare MH Emergency: (call OR for anesthesia to bring MH cart) | **Declare MH Emergency: (call OR for anesthesia to bring MH cart) | ||
** Discontinue Triggering Agents | **Discontinue Triggering Agents | ||
** 100% Oxygen at High Flow | **100% Oxygen at High Flow | ||
** Give Dantrolene | **Give Dantrolene | ||
***Designate 2 or 3 people to mix sterile water into Dantrolene \ | ***Designate 2 or 3 people to mix sterile water into Dantrolene \ | ||
****60ml sterile water into each vial of dantrolene; may need up to 36 vials | ****60ml sterile water into each vial of dantrolene; may need up to 36 vials | ||
****If using Dantrium® (20 mg/vial), each vial contains 3 g of mannitol (renal vasodilation); newer nanocrystalline dantrolene (250 mg/vial) has 250 mg mannitol per vial and requires mannitol supplementation | ****If using Dantrium® (20 mg/vial), each vial contains 3 g of mannitol (renal vasodilation); newer nanocrystalline dantrolene (250 mg/vial) has 250 mg mannitol per vial and requires mannitol supplementation | ||
*** '''2.5 mg/kg IV push''' | ***'''2.5 mg/kg IV push''' | ||
*** Titrate to effect; may need more than 10 mg/kg | ***Titrate to effect; may need more than 10 mg/kg | ||
**Bicarb for metabolic acidosis | **Bicarb for metabolic acidosis | ||
*** 1-2 mEQ/kg if blood gas values not yet available | ***1-2 mEQ/kg if blood gas values not yet available | ||
** Cool the patient if core temp >39 deg C (102.2 deg F) | **Cool the patient if core temp >39 deg C (102.2 deg F) | ||
*** Stop cooling when temp reaches 100.4 | ***Stop cooling when temp reaches 100.4 | ||
** Dysrhythmias usually respond to treatment of acidosis and hyperkalemia | **Dysrhythmias usually respond to treatment of acidosis and hyperkalemia | ||
*** Standard therapy EXCEPT NO CA CHANNEL BLOCKERS: | ***Standard therapy EXCEPT NO CA CHANNEL BLOCKERS: | ||
****may cause hyperkalemia or cardiac arrest in presence of dantrolene | ****may cause hyperkalemia or cardiac arrest in presence of dantrolene | ||
** Treat hyperkalemia: standard treatment, remember to check glucose levels q1h after treatment with insulin/glucose | **Treat hyperkalemia: standard treatment, remember to check glucose levels q1h after treatment with insulin/glucose | ||
** Call MHAUS Hotline if needed: 1-800-644-0737 | **Call MHAUS Hotline if needed: 1-800-644-0737 | ||
*Continued Care | *Continued Care | ||
**Dantrolene 1 mg/kg every 4-6 hours for 24–48 hours | **Dantrolene 1 mg/kg every 4-6 hours for 24–48 hours |
Revision as of 13:41, 4 July 2016
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
Diagnosis
- Core temperature
- CBC
- Chem 7
- Total CK
- PT/PTT
- ABG
Treatment
- Initial
- Declare MH Emergency: (call OR for anesthesia to bring MH cart)
- Discontinue Triggering Agents
- 100% Oxygen at High Flow
- Give Dantrolene
- Designate 2 or 3 people to mix sterile water into Dantrolene \
- 60ml sterile water into each vial of dantrolene; may need up to 36 vials
- If using Dantrium® (20 mg/vial), each vial contains 3 g of mannitol (renal vasodilation); newer nanocrystalline dantrolene (250 mg/vial) has 250 mg mannitol per vial and requires mannitol supplementation
- 2.5 mg/kg IV push
- Titrate to effect; may need more than 10 mg/kg
- Designate 2 or 3 people to mix sterile water into Dantrolene \
- Bicarb for metabolic acidosis
- 1-2 mEQ/kg if blood gas values not yet available
- Cool the patient if core temp >39 deg C (102.2 deg F)
- Stop cooling when temp reaches 100.4
- Dysrhythmias usually respond to treatment of acidosis and hyperkalemia
- Standard therapy EXCEPT NO CA CHANNEL BLOCKERS:
- may cause hyperkalemia or cardiac arrest in presence of dantrolene
- Standard therapy EXCEPT NO CA CHANNEL BLOCKERS:
- Treat hyperkalemia: standard treatment, remember to check glucose levels q1h after treatment with insulin/glucose
- Call MHAUS Hotline if needed: 1-800-644-0737
- Continued Care
- Dantrolene 1 mg/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
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