Endocrine

Question 1

Name 8 common medications that can exacerbate myasthenia gravis

Answer 1

New medications: ABCDF - aminoglycosides, BB, CCB, dilantin, fluroquinolones

1. Magnesium
2. Antibiotics
   - floroquinolones
   -macrobids
   -amino-glycosides
3. Statins
4. Steroids
5. BB
6. CCB
   7.lidocaine
7. procainamide
8. phenytoin
9. neuromuscular blockers

Question 2

What is the pathophysiology of myasthenia gravis?

Answer 2

Weakness and fatigue result from circulating autoantibodies against nicotinic ACh receptors on postsynaptic membrane

Question 3

Define myasthenia crisis

Answer 3

Defined as diagnosis of MG with respiratory failure requiring mechanical ventilation

Question 4

What are the treatments for myasthenia crisis

Answer 4

1. Intubate
2. Steroids- Prednisone 60mg daily
   -(give with IVIG or PLEX, but not alone as can worsen weakness)
   3.PLEX = first line
3. IVIG 2g/kg in divided doses over several days

Question 5

How is MG managed in the outpatient setting

Answer 5

1. Pyridostigmine - acetylcholinesterase inhibitor
   Dose: 60-120mg PO q4-6h
   Prolongs the presence and activity of ACh in synaptic cleft
   Side effect: excessive cholinergic stimulation
2. Thymectomy
3. Steroids
4. Rituximab
5. Eculizumab

Question 6

What is forced vital capacity?

What is normal?

What FVC is a consideration for intubation for
a. MG
b. GBS

Answer 6

FVC is the total amount of air a person can forcefully exhale from their lungs after a deep breath

Normal is 60 ml/kg or 3-5L

MG <15 ml/kg –> intubate
GBS <15 ml/kg –>intubate

Question 7

What is MIPS?

What is normal?

What MIP is a consideration for intubation in neuromuscular disease

Answer 7

Mean Inspiratory Pressure

Normal 60-100 mmH2O

MIP <30 –> intubate

Question 8

Name 5 clinical features of MG

Answer 8

1. Ocular muscle weakness (1st sign of MG in up to 40% of patients
2. Ptosis (worse towards the end of the day)
3. New-onset diplopia
4. Bulbar weakness - dysarthria, dysphagia
5. Facial/extremity muscle weakness
6. Difficulty combing hair, brushing teeth
7. Weakness of muscles of head –> “dropped head appearance”