Module 4: Weakness 2

Question 0

Antibodies to acetylcholine receptors least common in what form of myasthenia gravis?

Answer 0

Ocular

Question 1

Types of myasthenia gravis?

Answer 1

#Generalized – involves limited facial muscles
#Ocular – involves eye muscles (ptosis, diplopia)
#Bulbar myasthenia – dysarthria, dysphasia

Question 2

If myasthenia gravis is confirmed, should do what test?

Answer 2

Chest CT to evaluate for thymoma

Question 3

MG:Treatment for underlying immune mediated process?

Treatment for symptoms?

Treatment for crisis?

Answer 3

Steroids, and immunosuppressants, thymectomy

Pyridostigmine

IVIG or plasma exchange

Question 4

Mechanism of botulinum toxin? Symptoms? How to test? Tx?

Answer 4

Prevents release of acetylcholine vesicles

Descending paralysis with diplopia, dysarthria, respiratory weakness

Stool testing

Antitoxin

Question 5

Lambert-Eaton syndrome – pathophysiology? Usually associated with (be specific)? Symptoms? Uncommonly affects? Test what? Treatment?

Answer 5

Antibodies against presynaptic calcium channels

Small cell lung cancer

Proximal limb weakness, autonomic symptoms (try mouth, constipation)

Uncommonly presents with ocular involvement

Test serum

Treat Cancer, plasma exchange, suppression

Question 6

Etiologies of myopathy?

Answer 6

(#Vascular)
#Infection – HAV, viral, parasites
(#Neoplastic)
#drugs – toxins
#Inflammatory – polymyositis, dermatomyositis, inclusion body myositis
(# trauma)
#Inherited – mitochondrial, distrophin
# metabolic – thyroid, parathyroid, adrenal

Question 7

Polymyositis – time course? Affected muscles? Labs? Pathology? Antibodies? Treatment?

Answer 7

Weeks/months

Proximal muscles – leaving-girdle muscles, neck flexors

CK

Inflammatory cells among muscle fibers

Anti-Jo-1 or anti-SRP

Prednisone 1-2 mg/kg/day

Question 8

Dermatomyositis – time course? Affected muscles? Other signs? Labs? Pathology? Antibodies? Treatment?

Answer 8

Weeks/months

Proximal muscle – limb-girdle muscles, neck flexors

Anti-Jo-1 and anti-Mi-2
Heliotrope rash, shawl side, Bouchard’s nodules

CK

Perivascular and interfasicular inflammatory cells

Question 9

Inclusion body myositis – time course? Affected muscles? Labs? Pathology? Antibodies? Treatment?

Answer 9

Months/years

Proximal and distal involvement

Dysphasia

CK

Rimmed vacuoles, basophilic inclusions, inflammatory cells

Does not respond to Prednisone, IV IG

Question 10

Drugs that can cause muscle dysfunction?

Answer 10

#Steroids – painless proximal muscle weakness
#Statins – painful necrotizing myopathy
#Alcohol
#gemfibrozil

Question 11

Slowly progressive proximal muscle weakness with respiratory involvement begins in the 30s-40s?

Answer 11

Late-onset acid Maltese deficiency

Question 12

Upper motor neurons – location of cell body? Axon path?

Answer 12

Cortex/prefrontal gyrus

Internal capsule to 
brainstem to 
Pyramidal tract to 
contralateral medulla to 
corticospinal tract to 
anterior horn cell

Question 13

Path of lower motor neuron?

Answer 13

Anterior horn cell to
Ventral route to
Peripheral nerve

Question 14

Upper motor neuron lesion - atrophy? Tone? Fasciculations? Weakness of? Reflexes? Babinski?

Answer 14

None

Spastic

None

Focal/Fine movements

Increased

Present

Question 15

Lower motor neuron lesion – atrophy? Tone? Fasciculations? Weakness of? Reflexes? Babinski?

Answer 15

Yes

Decreased

Present

Distal

Absent or decreased

Negative

Question 16

Neuromuscular junction – atrophy? Tone? Fasciculations? Weakness of? Reflexes? Babinski?

Answer 16

None

Normal

None

Cranial muscles, proximal muscles, fatigue

Normal

Negative

Question 17

Primary muscle disease – atrophy? Tone? Fasciculations? Weakness of? Reflexes? Babinski?

Answer 17

Mild

Normal

Proximal

Normal

Negative