Muscle Weakness

Question 1

What is Critical illness myopathy

Answer 1

seen in ICU pts who develop muscle weakness after being intubated for a prolonger period of time. Seen more often with systemic steroids neuromscular blocking agents or sepsis.

Question 2

Symptoms of critical illness myopathy

Answer 2

flaccid quadriparesis (proximal > distal mm) and failure to wean from mechanical ventilation. Sensation is normal but has decreased reflexes

Question 3

diagnosis of CIM or critical illness myopathy

Answer 3

EMG or NCS. Serum creatine kinase are normal or mildly elevated.
muscle biopsy shows myopathy with loss of myosin.

Question 4

Treatment of CIM is

Answer 4

stopping or reducing steroids ASAP, aggressive management of underlying medical conditions and PT/OT

good prognosis but reversal of symptoms over weeks to months

Question 5

GBS (acute inflammatory demyelinating polyneuropathy)

Answer 5

diffuse weakness and develops within 1-2 days

absent reflexes and ascending sensory loss

Question 6

prolonged neuromsuclar blockade disorder

Answer 6

from prolonged paralytic agents (Days) in setting of hepatic or renal insufficiency that leads to prolonged circulation of drug metabolites.

Question 7

Rhabdomyolysis clinical features

Answer 7

elevated serum creatine kinase levels >5000 and intact tendon refluxes.

Question 8

clinical features of myasthenia crisis

Answer 8

increased generalized and oropharyngeal weakness and respiratory insufficiency/dyspnea (worse when supine)

Question 9

Precipitating factors for myasthenia crisis

Answer 9

infection or surgery
pregnancy or childbirth
tapering of immunosuppressive drugs
medications (aminoglycosides and beta blockers)

Question 10

treatment of myasthenic crisis

Answer 10

measurement of vital capacity every 2 hours in ICU
elective intubation for: respiratory distress and difficulty with oral secretions or speaking
VC<20 ml/kg or MIF>-30 cm H20
withdrawal of acetylcholinesterase inhibitors
plasma exchange (plasmapheresis) or IVIG plus high dose steroids
weaning and extubation with improved muscle strength

Question 11

Respiratory parameters to follow with myasthenia gravis crisis

Answer 11

2-4 hr vital capacity <20 needs intubation

Maximal inspiratory force MIF > -30 (normal is 0 to -30) needs intubation.

Question 12

how much high dose steroids to give people who have myasthenia gravis crisis

Answer 12

prednisone 60-80 mg daily. If cannot tolerate steroids need to be started on azathioprine, mycophenolate mofetil or cyclosporine.

Question 13

when to wean and extubate people with myasthenia gravis crisis

Answer 13

improved muscle strength (able to lift head off bed or VC>20 ml/kg or MIF