2012 Gemc Res Oppong Myasthenia Gravis Oer
description
Transcript of 2012 Gemc Res Oppong Myasthenia Gravis Oer
![Page 1: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/1.jpg)
Project: Ghana Emergency Medicine Collaborative
Document Title: Myasthenia Gravis (Case of the Week)
Author(s): Chris Oppong, BSc, MBChB
License: Unless otherwise noted, this material is made available under the terms of the Creative Commons Attribution Share Alike-3.0 License: http://creativecommons.org/licenses/by-sa/3.0/
We have reviewed this material in accordance with U.S. Copyright Law and have tried to maximize your ability to use, share, and adapt it. These lectures have been modified in the process of making a publicly shareable version. The citation key on the following slide provides information about how you may share and adapt this material.
Copyright holders of content included in this material should contact [email protected] with any questions, corrections, or clarification regarding the use of content.
For more information about how to cite these materials visit http://open.umich.edu/privacy-and-terms-use.
Any medical information in this material is intended to inform and educate and is not a tool for self-diagnosis or a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional. Please speak to your physician if you have questions about your medical condition.
Viewer discretion is advised: Some medical content is graphic and may not be suitable for all viewers.
1
![Page 2: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/2.jpg)
Attribution Key
for more information see: http://open.umich.edu/wiki/AttributionPolicy
Use + Share + Adapt
Make Your Own Assessment
Creative Commons – Attribution License
Creative Commons – Attribution Share Alike License
Creative Commons – Attribution Noncommercial License
Creative Commons – Attribution Noncommercial Share Alike License
GNU – Free Documentation License
Creative Commons – Zero Waiver
Public Domain – Ineligible: Works that are ineligible for copyright protection in the U.S. (17 USC § 102(b)) *laws in your jurisdiction may differ
Public Domain – Expired: Works that are no longer protected due to an expired copyright term.
Public Domain – Government: Works that are produced by the U.S. Government. (17 USC § 105)
Public Domain – Self Dedicated: Works that a copyright holder has dedicated to the public domain.
Fair Use: Use of works that is determined to be Fair consistent with the U.S. Copyright Act. (17 USC § 107) *laws in your jurisdiction may differ
Our determination DOES NOT mean that all uses of this 3rd-party content are Fair Uses and we DO NOT guarantee that your use of the content is Fair.
To use this content you should do your own independent analysis to determine whether or not your use will be Fair.
{ Content the copyright holder, author, or law permits you to use, share and adapt. }
{ Content Open.Michigan believes can be used, shared, and adapted because it is ineligible for copyright. }
{ Content Open.Michigan has used under a Fair Use determination. }
2
![Page 3: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/3.jpg)
CASE OF THE WEEK
BY CHRIS K. OPPONG,
BSc HUMAN BIOLOGY, MBChB
EMERGENCY MEDICINE RESIDENT-KATH
3
![Page 4: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/4.jpg)
CASE OF THE WEEK
A 17 year old female presented to KATH ED with a 3 day history of difficulty in swallowing , drooling ,dysphasia and shortness of breath.
Differential diagnosis??
4
![Page 5: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/5.jpg)
PmHx: mother claims she has been treated for chronic tonsillitis recently and has been having non-specific recurrent illnesses which has been managed on OPD basis
Drug hx: iv ceftriazone 2g, iv amoksiklav 1.2g Social hx: SHS 3 , boarding house
5
![Page 6: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/6.jpg)
O/E
Lethargic Weak respiratory effort Drooling Afebrile
Vital signs:Bp-130/95, pulse-105bpmRGV, RR-30cpm, temp.-36.8oC, Spo2-62% room air. GCS m-6, v-5, e-3. any concerns??
6
![Page 7: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/7.jpg)
Admission Day 1
UPPER AIRWAY OBSTRUCTION ?cause
ABC’s Normal throat examination :tonsils , soft
palate Consult to ENT CBC, ABG’s, LFT ,RFT, pregnancy test Chest x-ray, lateral neck x-ray, ECG
7
![Page 8: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/8.jpg)
Lab results
Wbc-15, Hb-10.1, ESR-18 ABG- pH-7.1, pCo2-42.9, HCO3- 15.8, pO2-
29, Na-149.4, Cl-111.4 AST 275, ALT-294 UREA-6.02,CRT-67, BUN /CRT-42
8
![Page 9: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/9.jpg)
DAY 2
ENT consult : acute laryngitis Patient transferred to ENT ward
9
![Page 10: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/10.jpg)
DAY 3
Improvement in patients condition on the ward.
Feeding again Mother expressed concern to doctors that her
condition keeps fluctuating, worse in the evening???hysteria
Ward cover doctor called to see patient who had become restless.
10
![Page 11: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/11.jpg)
Day 4
Better in the morning c/o diffiulty in swallowing Ward cover doctor called in the evening to
see patient who had become restless again
11
![Page 12: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/12.jpg)
Day 5
15:35 GMT , doctor called to see patient who had become unresponsive with a GCS of 8/15
Physician consult; epiglotitis with sepsis+ adrenal insufficiency, requested head CT-scan
21:30 GMT, patient rushed to RED by ENT ward nurses with no cardio respiratory activity and brownish secretions from mouth and nostrils
12
![Page 13: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/13.jpg)
CPR Patient revived after 3 cycles and intubated ICU ventilators were malfunctioning so
patient was kept at RED on the transport ventilator
CXR- aspiration
13
![Page 14: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/14.jpg)
Day 6
Patient transferred to ICU Physician consult; atypical
pneumonia(mycoplasma pneumonia) Rapid HIV test ?positive ELISA-negative
14
![Page 15: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/15.jpg)
Day 7
Massive subcutaneous emphysema ??barotrauma
RT pneumothorax
15
![Page 16: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/16.jpg)
Source Undetermined16
![Page 17: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/17.jpg)
Day 10
Source Undetermined17
![Page 18: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/18.jpg)
Hypopyon Ophthalmology consult Ophthalmologist recognizes patient and
discloses he had treated her for ocular myasthenia gravis
MYASTHENIC CRISIS now the working diagnosis
18
![Page 19: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/19.jpg)
Day 18 post admission
Patient is still on a ventilator on CPAP Being treated with pyridostigmine,
azathioprine and iv immunoglobulin Significant improvement, , GCS m-5, e-2
v-Intubated
19
![Page 20: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/20.jpg)
Myasthenia Gravis
20
![Page 21: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/21.jpg)
MYASTHENIC CRISIS
21
![Page 22: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/22.jpg)
Outline
Background Anatomy Pathophysiology Epidemiology Clinical Presentation Work-up Treatment Rehabilitation
Posey & Spiller, Wikimedia Commons
22
![Page 23: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/23.jpg)
Background
Acquired autoimmune disorder Clinically characterized by:
Weakness of skeletal muscles Fatigability on exertion.
First clinical description in 1672 by Thomas Willis
23
![Page 24: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/24.jpg)
Anatomy
Neuromuscular Junction (NMJ) Components:
Presynaptic membrane Postsynaptic membrane Synaptic cleft
Presynaptic membrane contains vesicles with Acetylcholine (ACh) which are released into synaptic cleft in a calcium dependent manner
ACh attaches to ACh receptors (AChR) on postsynaptic membrane
24
![Page 25: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/25.jpg)
Nrets, Wikimedia Commons 25
![Page 26: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/26.jpg)
Anatomy
Neuromuscular Junction (NMJ) The Acetylcholine receptor (AChR) is a sodium
channel that opens when bound by ACh There is a partial depolarization of the postsynaptic
membrane and this causes an excitatory postsynaptic potential (EPSP)
If enough sodium channels open and a threshold potential is reached, a muscle action potential is generated in the postsynaptic membrane
26
![Page 27: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/27.jpg)
Pathophysiology
In MG, antibodies are directed toward the acetylcholine receptor at the neuromuscular junction of skeletal muscles
Results in: Decreased number of nicotinic acetylcholine
receptors at the motor end-plate Reduced postsynaptic membrane folds Widened synaptic cleft
27
![Page 28: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/28.jpg)
Pathophysiology
Anti-AChR antibody is found in 80-90% of patients with MG
MG may be considered a B cell-mediated disease Antibodies
28
![Page 29: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/29.jpg)
Pathophysiology
T-cell mediated immunity has some influence Thymic hyperplasia and thymomas are
recognized in myasthenic patients*
Source UndeterminedSource Undetermined 29
![Page 30: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/30.jpg)
Epidemiology Frequency
Annual incidence in US- 2/1,000,000 Worldwide prevalence 1/10,000
Mortality/morbidity Recent decrease in mortality rate due to advances in treatment
3-4% (as high as 30-40%) Risk factors
Age > 40 Thymoma
Sex F-M (6:4) Mean age of onset (M-42, F-28) Incidence peaks- M- 6-7th decade F- 3rd decade
30
![Page 31: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/31.jpg)
Clinical Presentation
Fluctuating weakness increased by exertion Weakness increases during the day and improves
with rest Extraocular muscle weakness
Ptosis is present initially in 50% of patients and during the course of disease in 90% of patients
Head extension and flexion weakness Weakness may be worse in proximal muscles
31
![Page 32: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/32.jpg)
Clinical presentation
Progression of disease Mild to more severe over weeks to months
Usually spreads from ocular to facial to bulbar to truncal and limb muscles
Often, symptoms may remain limited to EOM and eyelid muscles for years
The disease remains ocular in 16% of patients
Remissions Spontaneous remissions rare Most remissions with treatment occur within the first three
years
32
![Page 33: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/33.jpg)
Clinical presentation
Basic physical exam findings Muscle strength testing Recognize patients who may develop respiratory
failure (i.e. difficult breathing) Sensory examination and DTR’s are normal
33
![Page 34: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/34.jpg)
Clinical presentation
Muscle strength Facial muscle weakness Bulbar muscle weakness Limb muscle weakness Respiratory weakness Ocular muscle weakness
34
![Page 35: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/35.jpg)
Clinical presentation
Facial muscle weakness is almost always present Ptosis and bilateral facial muscle
weakness Sclera below limbus may be exposed due
to weak lower lids
Cumulus, Wikimedia Commons 35
![Page 36: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/36.jpg)
Clinical presentation
Bulbar muscle weakness Palatal muscles
“Nasal voice”, nasal regurgitation Chewing may become difficult Severe jaw weakness may cause jaw to hang open Swallowing may be difficult and aspiration may
occur with fluids—coughing and choking while drinking
Neck muscles Neck flexors affected more than extensors
36
![Page 37: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/37.jpg)
Clinical presentation
Limb muscle weakness Upper limbs more common than lower limbs
Upper ExtremitiesDeltoidsWrist extensorsFinger extensorsTriceps > Biceps
Lower ExtremitiesHip flexors (most common)QuadricepsHamstringsFoot dorsiflexorsPlantar flexors
37
![Page 38: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/38.jpg)
Clinical presentation
Respiratory muscle weakness Weakness of the intercostal muscles and the diaghram
may result in CO2 retention due to hypoventilation May cause a neuromuscular emergency(myasthenic crisis)
Weakness of pharyngeal muscles may collapse the upper airway Monitor negative inspiratory force, vital capacity and tidal
volume Do NOT rely on pulse oximetry
Arterial blood oxygenation may be normal while CO2 is retained
38
![Page 39: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/39.jpg)
Clinical presentation
Occular muscle weakness Asymmetric
Usually affects more than one extraocular muscle and is not limited to muscles innervated by one cranial nerve
Weakness of lateral and medial recti may produce a pseudointernuclear opthalmoplegia Limited adduction of one eye with nystagmus of the
abducting eye on attempted lateral gaze Ptosis caused by eyelid weakness Diplopia is very common
39
![Page 40: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/40.jpg)
Clinical presentation
Co-existing autoimmune diseases Hyperthyroidism
Occurs in 10-15% MG patients Exopthalamos and tachycardia point to hyperthyroidism Weakness may not improve with treatment of MG alone in
patients with co-existing hyperthyroidism
Rheumatoid arthritis Scleroderma Lupus
40
![Page 41: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/41.jpg)
Clinical presentation
Causes Idiopathic Penicillamine
AChR antibodies are found in 90% of patients developing MG secondary to penicillamine exposure
Drugs
41
![Page 42: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/42.jpg)
Clinical presentation
Causes Drugs
Antibiotics (Aminoglycosides, ciprofloxacin, ampicillin, erythromycin)
B-blocker (propranolol) Lithium Magnesium
Procainamide Verapamil Quinidine Chloroquine Prednisone Timolol Anticholinergics
42
![Page 43: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/43.jpg)
Differentials
Amyotropic Lateral Sclerosis
Basilar Artery Thrombosis
Brainstem gliomas Cavernous sinus
syndromes Dermatomyositis Lambert-Eaton
Myasthenic Syndrome
Multiple Sclerosis Sarcoidosis and
Neuropathy Thyroid disease Botulism Oculopharyngeal
muscular dystrophy Brainstem syndromes
43
![Page 44: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/44.jpg)
Work-up
Lab studies Anti-acetylcholine receptor antibody
Positive in 74% 80% in generalized myasthenia 50% of patients with pure ocular myasthenia
Anti-striated muscle Present in 84% of patients with thymoma who are
younger than 40 years
44
![Page 45: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/45.jpg)
Work-up
Lab studies Interleukin-2 receptors
Increased in generalized and bulbar forms of MG Increase seems to correlate to progression of disease
45
![Page 46: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/46.jpg)
Work-up
Imaging studies Chest x-ray
Plain anteroposterior and lateral views may identify a thymoma as an anterior mediastinal mass
Chest CT scan is mandatory to identify thymoma MRI of the brain and orbits may help to rule out
other causes of cranial nerve deficits but should not be used routinely
46
![Page 47: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/47.jpg)
Work-up
Electrodiagnostic studies Repetitive nerve stimulation Single fiber electromyography (SFEMG)
SFEMG is more sensitive than RNS in MG
47
![Page 48: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/48.jpg)
Electrodiagnostic studies:Single-fiber electromyography
Generalized MG Abnormal extensor digiti minimi found in 87% Examination of a second abnormal muscle will
increase sensitivity to 99% Occular MG
Frontalis muscle is abnormal in almost 100% More sensitive than EDC (60%)
48
![Page 49: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/49.jpg)
WorkupPharmacological testing
Edrophonium (Tensilon test) Patients with MG have low numbers of AChR at
the NMJ Ach released from the motor nerve terminal is
metabolized by Acetylcholine esterase Edrophonium is a short acting Acetylcholine
Esterase Inhibitor that improves muscle weakness
Evaluate weakness (i.e. ptosis and opthalmoplegia) before and after administration
49
![Page 50: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/50.jpg)
WorkupPharmacological testing
Before After
Source Undetermined
50
![Page 51: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/51.jpg)
WorkupPharmacological testing
Edrophonium (Tensilon test) Steps
0.1ml of a 10 mg/ml edrophonium solution is administered as a test
If no unwanted effects are noted (i.e. sinus bradychardia), the remainder of the drug is injected
Consider that Edrophonium can improve weakness in diseases other than MG such as ALS, poliomyelitis, and some peripheral neuropathies
51
![Page 52: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/52.jpg)
Treatment
AChE inhibitors Immunomodulating therapies Plasmapheresis Thymectomy
Important in treatment, especially if thymoma is present
52
![Page 53: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/53.jpg)
Treatment
AChE inhibitor Pyridostigmine bromide (Mestinon)
Starts working in 30-60 minutes and lasts 3-6 hours Individualize dose Adult dose:
60-960mg/d PO 2mg IV/IM q2-3h
Caution Check for cholinergic crisis
Others: Neostigmine Bromide
53
![Page 54: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/54.jpg)
Treatment
Immunomodulating therapies Prednisone
Most commonly used corticosteroid in US Significant improvement is often seen after a
decreased antibody titer which is usually 1-4 months No single dose regimen is accepted
Some start low and go high Others start high dose to achieve a quicker response
Clearance may be decreased by estrogens or digoxin Patients taking concurrent diuretics should be
monitored for hypokalemia
54
![Page 55: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/55.jpg)
TreatmentBehavioral modifications
Diet Patients may experience difficulty chewing and
swallowing due to oropharyngeal weakness If dysphagia develops, liquids should be thickened
Thickened liquids decrease risk for aspiration
Activity Patients should be advised to be as active as
possible but should rest frequently and avoid sustained activity
Educate patients about fluctuating nature of weakness and exercise induced fatigability
55
![Page 56: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/56.jpg)
Complications of MG
Respiratory failure Dysphagia Complications secondary to drug treatment
Long term steroid use Osteoporosis, cataracts, hyperglycemia, HTN Gastritis, peptic ulcer disease Pneumocystis carinii
56
![Page 57: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/57.jpg)
Prognosis
Untreated MG carries a mortality rate of 25-31%
Treated MG has a 4% mortalitiy rate 40% have ONLY occular symptoms
Only 16% of those with occular symptoms at onset remain exclusively occular at the end of 2 years
57
![Page 58: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/58.jpg)
Rehabilitation
Strategies emphasize Patient education Timing activity Providing adaptive equipment Providing assistive devices Exercise is not useful
58
![Page 59: 2012 Gemc Res Oppong Myasthenia Gravis Oer](https://reader036.fdocuments.in/reader036/viewer/2022062407/55cf8f06550346703b98245a/html5/thumbnails/59.jpg)
References
1. Delisa, S. A., Goans, B., Rehabilitatoin Medicine Principles and Practice, 1998, Lippencott-Raven
2. Kimura, J., Electrodiagnosis in Diseases of Nerve and Muscle, F.A.Davis Company, Philadelphia
3. Rosenberg, R. N., Comprehensive Neurology, 1991, Raven Press Ltd
4. O’sullivan, Schmidtz, Physical Medicine and Rehabilitation Assessment and Treatment, pg. 151-152
5. Grabois, Garrison, Hart, Lehmke, Neuromuscular Diseases, pgs. 1653-1655
6. Shah, A. K., www.emedicine.com, Myasthenia Gravis, 2002, Wayne State University
7. Tensilon test pictures http://www.neuro.wustl.edu/neuromuscular/mtime/mgdx.html
59