Scott Belliston

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Transcript Scott Belliston

Grand Rounds Presentation
By Scott Belliston DO PGY2
• Elderly. right handed male with PMH of HTN,
HLD, aneurysm in stomach 3cm, and GERDwas
transferred from OSH for further evaluation of
• Hx of dysphagia 3 years ago improved after
esophageal dilatation
• No pain with swallowing
• Corticobulbar Tracts
– Motor strip
– Medulla
– Nuclei of Lower Cranial Nerves
• Esophagus C-Spine
• Neuromuscular Junction
– Presynaptic
– Postsynaptic
Stroke ischemic or hemorrhagic
Intracerebral mass (tumor, abscess, lesion, aneurysm)
Amyotrophic lateral sclerosis
Myasthenia Gravis
Lambert-Eaton Myasthenic syndrome
Multiple sclerosis
Parkinson’s disease
Toxins/Drugs (Botulism, snake venom, anticholinergics,
antimuscarinics, tetrodotoxin…)
• Foreign body internal or external compression
More history
• 3 years ago developed dysphagia was diagnosed with
allergies to ragweed. GI procedure improved
• One week before admission was eating and choked on
a sandwich hasn’t been able to eat or drink since. GI
doctor told him no stricture that he had ALS.
• OSH neurology workup
– MRI brain no stroke, EMG of facial muscles and tongue
negative. Acetylcholine receptor antibodies pending. Video
swallow failed. Pt on TPN refusing PEG tube.
Hbg 16.5
WBCs 7.4
Platelets 166
INR 1.1
UDS positive benzos
Sodium 132
Potassium 3.8
Chloride 106
CO2 22
BUN 12
Creatinine 0.72
Glucose 85
HgbA1c 5.3
TSH 1.980
CPK 297
• General exam unremarkable
• Neuro exam
Mental status alert and oriented x 4
Speech moderate to severe flaccid dysarthria and
Dysphagia to solids and liquids
CN mild right eye ptosis, Obicularis oculi 3/5 Obicularis
oris 2/5, unable to protrude tongue or place in cheek
Motor Neck flexor 4/5 wrist flexors and hip flexors 4+/5
Edrophonium test
• Tensilon test (No longer available in US)
– Edrophonium a short acting IV
acetylcholinesterace inhibitor
• Risks/Side effects
Edrophonium Test (cont)
• Prior to injection
• After second dose of
5 mg
Other studies
• Acetylcholine receptor antibodies
– Acetylcholine Binding AB 37.0, Acetylcholine
Blocking AB 29, Acetylcholine Modulating AB 34
– 85% of MG
• MuSK antibodies not checked
– 40-70% of AChR-Ab negative
• CT chest for thymoma negative
– 10–15% have a thymoma
Myasthenia Gravis
10 to 125 of every 1 million people worldwide
Bimodal distribution 2nd and 3rd decades (mainly
women) and 6th through 8th decades (mainly
Antibodies to the muscle type of nicotinic
cholinergic receptors
Increased incidence of RA, SLE, and polymyositis
Common Presenting Symptoms
Occular symptoms
• Ptosis and or diplopia over 50%
Bulbar symptoms
• Dysarthria, dysphagia and fatigable
• chewing about 15%
Proximal limb weakness alone less than 5%
• May get other isolated muscle weakness but are
much less common
• Myasthenia crisis is when the respiratory muscles
are involved
Neuromuscular Junction
Watch out for!
• Crisis!
• When to intubate?
– VC < 20ml/kg or NIF <-30ccH2O
– ABGs insensitive for respiratory weakness
• Drugs to avoid in MG
– Antibiotics (aminoglycosides, erythromycin, and
– Cardiac drugs (beta-blockers, procainamide, and
– Magnesium
– Glucocorticoids
• Anticholinesterace (Mestinon)
Chronic immunomodulating
• Glucocorticoids
• Immunosuppression
Rapid immunomodulating
• Plasmapheresis
• IV immune globulin
• Thymectomy (reduction in symptoms of 70% of pts
without thymoma)
Balzer, KM, PharmD, “Drug-Induced Dysphagia”, International Journal of MS Care, page 6, Volume 2
Issue 1, March 2000. (
Barohn, RJ, “Update on Myasthenia Gravis: Diagnosis, Measurement, and Treatment”, PowerPoint,
Accessed October 07, 2012.
Bird, SJ. Myasthenic Crisis. In: UpToDate, Dashe, JF (Ed), UpToDate,
Waltham, MA, 2012.
Brunton LL, Chabner BA, Knollmann BC: Goodman & Gilman's The Pharmacological Basis of
Therapeutics, 12th Edition:
National Institute of Mental Health, Electron micrograph of neuromuscular junction:
Ropper AH, Samuels MA. Chapter 53. Myasthenia Gravis and Related Disorders of the
Neuromuscular Junction. In: Ropper AH, Samuels MA, eds. Adams and Victor's Principles of
Neurology. 9th ed. New York: McGraw-Hill; 2009. Accessed
October 11, 2012.
Taylor P. Chapter 10. Anticholinesterase Agents. In: Brunton LL, Chabner BA, Knollmann BC,
eds. Goodman & Gilman's The Pharmacological Basis of Therapeutics. 12th ed. New York: McGrawHill; 2011.
Accessed October 11, 2012.