MH and Inherited Disorders

Question 0

What are the clinical features of MH?

Answer 0

• Elevated EtCO2 despite hyperventilation
• tachycardia and tachypnea
• HTN
• Cardiac dysrhythmias
• muscle rigidity
• temp elevation (1-2 degrees C q5min)
• peripheral mottling, sweating, cyanosis

Question 1

What is Malignant Hyperthermia?

Answer 1

• Hyper metabolic syndrome
• Uncontrolled Ca release from the sarcoplasmic reticulum-> sustained myofibril contraction-> cells run out of ATP-> cell death

Question 2

What are the late clinical features of MH?

Answer 2

• Rhabdomyolysis
• Renal Failure (secondary to myoglobin from rhabdo)
• DIC
• Multi-system organ failure

Question 3

What are 7 considerations in the differential diagnosis of MH?

Answer 3

1. Neuroleptic Malignant Syndrome
2. Pheochromocytoma
3. Thyrotoxicosis
4. Sepsis
5. Heat stroke
6. mitochondrial myopathy
7. Rhabdomyolysis

Question 4

Name 3 differences in NMS and MH.

Answer 4

NMS is not associated with Sux, it is not inherited, and it develops over hours to days

Question 5

What causes NMS? How do you treat it?

Answer 5

Depletion of dopamine in the CNS - can be caused by antipsychotics or withdrawal from Parkinson’s meds

Tx - bromocriptine (DA agonist) - dantrolene? looks like MH - give it

Question 6

How do you treat MH?

Answer 6

Call for help! Discontinue triggering agent. Hyperventilate. 100% O2 high flows. Dantrolene 2.5mg/kg. cool. monitor labs.

Question 7

What is MMR?What is the correlation between Masseter Muscle Rigidity and MH. What should you do if your pedi pt has MMR?

Answer 7

MMR is rigidity of jaw muscles after sux. Pedi pts w/MMR have a 25-50% MH susceptibility.

What to do. Cancel case. monitor for 24hrs after. check myoglobin and CK levels. give Dantrolene if high suspicion of MH

Question 8

What is the best test for MH?

Answer 8

CHCT - Caffeine-Halothane Contracture Test
-high sensitivity but low specificty
Genetic testing - highly specific but poor sensitivity

Question 9

List 5 MH associated Disorders.

Answer 9

• Central Core Disease (myopathy, autosomal dominant, ryanodine receptor mutation)
• Myotonias
• Osteogenesis imperfecta
• hypokalemic periodic paralysis
• Duchenne’s MD (not MH related but mjr rxn w/sux)

Question 10

What are porphyrias?

Answer 10

defects of heme synthesis - overproduction of aminolevulinic acid
- autosomal dominant

Question 11

What are the clinical presentations of porphyrias?

Answer 11

• abdominal pain, N/V
• psychiatric disturbance
• quad-or hemiplegia
• electrolyte disturbance
• skin fragility

Question 12

List the 8 safe drugs/ drug classes for porphyria management.

Answer 12

• propofol
• versed
• ketamine
• opioids
• N2O
• MRs
• IAs
• Reversal agents
• RAs

Question 13

What is Mucopolysaccharidoses? What are the clinical features?

Answer 13

Defect of mucopolysaccharide metabolism.
Clinical features: Gargoylism (Hurler’s), limited joint movement, cardiac and hepatic dysfunction, difficult airways, unstable c-spine

Question 14

Which glucose storage disease is characterized as drug-induced hemolytic anemia? List 4 drugs that cause this.

Answer 14

Type 1: G6PD (glucose-6-phosphate dehydrogenase)

methyldopa, hydralazine, ASA, methylene blue

Question 15

What is Riley-Day Syndrome? What are the clinical features?

Answer 15

Defect of NE synthesis.

• copious secretions, recurrent pneumonia
• dysphagia
• no pain/temp sensation
• vasomotor lability
• sensitivity to vasopressors

Question 16

What is osteogenesis imperfecta? What are the clinical features?

Answer 16

Defect of collagen synthesis
Clinical Features
-brittle teeth and bones
-blue sclera
-joint laxity
-aortic and mitral valve regurg
-platelet dysfunction
-MH susceptible