Myasthenia Gravis:
A Nursing Perspective
On-line Continuing Education Program
MGFA: Nurses Advisory Board
Authors: Wilma Koopman, RN (EC), MScN, TCNP, CNN(C)
Marilyn Ricci, RN, MS, CNS, CNRN
Continuing Nursing Education Approval
Registered Nurses who complete this continuing nursing
education program and achieve an 70% score on the post test
will earn 2 contact hours.
This continuing nursing education activity was approved by the
American Association of Neuroscience Nurses, an accredited approver by the
American Nurses Credentialing Center’s COA.
Program Instructions
•
•
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•
Study the Myasthenia Gravis Continuing Education Program.
To receive CE contact hours:
– Complete the Post Test, recording your answers in the test answer section. Each
question has only 1 correct answer.
– Complete the Program Evaluation Form.
Email the Post Test Answers and the Evaluation Form to Kday@kellencompany.com
A passing score is 70% (20 correct answers)
You will be notified of your test results.
If you pass, a CE Certificate and an answer key will be returned to you within 4 – 6
weeks.
If you do not pass, you have the opportunity to retake the test.
Disclosure Statement:
The authors and the Myasthenia Gravis Foundation have no significant
relationship or financial interest in any commercial companies that pertain to this
educational activity.
Program Objectives
Upon completion of this program, the participant will be able to:
1. Define Myasthenia Gravis (MG).
2. Discuss the epidemiology of myasthenia gravis.
3. Discuss the predisposing factors and environmental issues that may
contribute to the onset of MG.
4. Explain the pathophysiological mechanisms and autoimmune basis of
acquired MG.
5. Describe the common clinical presentations of patients with MG.
6. Discuss the classification system used to characterize the distinct
clinical features and severity of MG.
7. Compare the procedures used in the diagnosis of MG.
8. Discuss the medical and surgical therapeutic modalities used in the
treatment of MG and compare the side effects and risk factors associated with
each treatment option.
Program Objectives (continued):
9. Identify the nursing implications associated with the various treatment
options.
10. Describe a comprehensive nursing assessment of the patient with MG.
11. Identify the potential patient problems, expected outcomes, and the
appropriate interventions used to manage MG.
12. Discuss the factors that have an adverse effect and contribute to worsening
of MG.
13 Differentiate between Myasthenic Crisis and Cholinergic Crisis and identify
the appropriate management strategies.
14. Discuss the impact of MG on the patient and the family members.
15. Demonstrate knowledge of myasthenia gravis and the appropriate
patient and family management.
Myasthenia Gravis (MG)
Acquired Autoimmune MG is –
• a chronic, neuromuscular, autoimmune disease that results
in muscle weakness
• induced by T-cell dependent, antibody-mediated
deterioration of the neuromuscular junction (NMJ)
• an alteration in the transmission of nerve impulses
(Mays, Butts. 2011)
MG in Childhood
•
Congenital MG –
– an autosomal recessive genetic mutation
– synaptic malformation involving nerve cell, muscle cell or space between
each
– not associated with an autoimmune process
– present at birth but may not manifest itself until several years later
– mild to severe weakness that usually does not progress
•
Neonatal Transient MG –
– infants born to mothers with autoimmune MG
– placental passage of autoantibodies
– symptoms occur within hours of birth
• generalized weakness, facial weakness
• weak cry, suck, swallow
• Respiratory distress
– may last several weeks to months
(Howard, 2008)
Types of Acquired MG
•
Ocular versus Generalized
– Ocular - limited to eyes with no other involvement
– Generalized – involves eyes with progression to bulbar and limb muscles
•
Seropositive versus Seronegative
– AChR antibodies
– No AChR antibodies but MuSK or titin antibodies
– No antibodies identified
•
Juvenile – early age, onset before adolescence
•
Early Onset versus Late Onset
– Early onset – after adolescence & before age 50, more women than men
– Late onset – presents at 40 or 50 years – few more men than women
•
Thymoma associated – peak onset 30’’s to 50’’s often having antibodies to several
muscle proteins including titin
(Howard, 2008)
Epidemiology:
• Prevalence rate: 20 per 100,000 in the US
• Peak incidence:
– Women –
• 20 to 40’
’s
• Average – 28 years of age
– Men – have 2 peaks
• 30’
’s
• 60’
’s
• Average – 42 years of age
– Late Onset – after 50 years
•
•
•
•
Women 3:2 men
Mortality: less than 5%
Full remission: Uncommon
Races: Caucasian, African American, Japanese
(Angelini, 2011, MDA, 2009)
Predisposing Factors/Risk Factors
•
Familial myasthenia gravis:
– genetic predisposition – 5%
•
Drug Induced:
– D-penicillamine
•
Other Autoimmune Diseases:
–
–
–
–
–
•
Thyroid Disease
Diabetes Mellitus, Type I
Rheumatoid Arthritis (RA)
Lupus Erythematosus (SLE)
Demyelinating CNS Diseases: Amyotrophic Lateral Sclerosis (ALS)
Hormonal Status:
– Pregnancy
– Post partum
(Grob et al, 2008, Mays et al, 2011)
Differential Diagnoses
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•
•
•
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Lambert Eaton Myasthenic Syndrome
Amytrophic Lateral Sclerosis (ALS)
Brainstem glioma
Multiple Sclerosis (MS)
Thyroid disease –
– Hyperthyroid
– Hypothyroid
• Botulinism
• Stroke
• Muscular Dystrophy
(Keesey, 2004)
Pathophysiology of
Acquired Autoimmune MG
• Involves the specific components of the nervous system,
the immune system and the interaction between the
following:
– Neuromuscular Transmission Mechanisms
– Autoimmune Processes
– Thymus Gland
Neuromuscular Transmission
Mechanisms:
• Neuromuscular Junction
• Neurotransmitters
• Physiology of Neurotransmission
Neuromuscular Transmission:
• Neuromuscular Junction (NMJ) also known as the motor end-plate is
composed of:
– Motor Nerve Terminal
• Highly specialized region containing synaptic vesicles
• Collects acetylcholine (ACh) & packages in vesicles for release into
the synaptic cleft
–
Synaptic Cleft
• Separates motor nerve terminal from post-junctional region
–
Post synaptic membrane
• Enfolds to increase surface area
• Contains ACh receptors (AChR)
(Howard, 2008)
Neuromuscular Transmission:
• Neurotransmitters: Chemicals released by the neurons to signal other
structures
• Neurotransmitters at the neuromuscular junction
– Acetylcholine (ACh)
•
•
•
•
Synthesized at the nerve terminal from choline and acetate
Stored in vesicles
Released in response to nerve activation
Binds with ACh receptors
– Acetylcholinesterase (AChE)
• Located in the synaptic clefts
• Hydrolyzes ACh into choline and acetate
• Choline and acetate taken back into the nerve terminal for resynthesis
into ACh
(Howard, 2008)
Physiology of Neurotransmission:
(pre & post synaptic depolarization)
• Acetylcholine (ACh) Pathway
– released in presence of Calcium into cleft
– binds with postsynaptic AChR receptors
– Na and K channels open ►► ►►
– depolorization produces action potential and
firing of post synaptic cell (muscle contraction)
– diffuses out of cleft
– hydrolized into choline and acetate
(Howard, 2008)
NMJ Figure from Howard 2008
Immune System Mechanisms
• Protects self from non- self :
- ability to recognize self, and not attack
- thought to develop during fetal life as immature
leukocytes are exposed to self
• Is lymphocyte driven:
- have surface receptors for a large array of possible
antigens (all are protein fragments of some kind
that are not recognized as self)
(Smeltzer & Bare, 2007 )
Immune System Mechanisms
(continued)
• Several primary organs are involved
– Bone marrow
– Thymus
• Consists of both humoral and cellular components
– Humoral immunity – B lymphocytes
- Cell-mediated immunity - T lymphocytes/cells
- Natural killer cells
(Smeltzer & Bare, 2007)
Humoral Immunity:
Antibody-mediated immunity
• B cells are:
– derived from the bone marrow
– precursors of plasma cells (differentiated B cells)
• Plasma cells:
– are found in the plasma
– produce antibodies which are immunoglobulins (Igs)
• Antigens bind to the lymphocytes which has surface
antibodies
• Some B cells remain as memory cells
• Effective against bacteria
(Smeltzer & Bare, 2007)
Cell-mediated Immunity
• T cells differentiate and mature in the thymus
• Types of T cells:
– Cytotoxic T cells (CD8) – kill target cells
– T helper cells (CD4) – assist in antibody formation
Implicated in the formation of antibodies against ACh
receptors.
– T supressor cells – inhibit immune responses
– T- delayed hypersensitivity cells
(Smeltzer & Bare, 2007)
Role of the Thymus
• Central organ for immunological self-tolerance, the capacity to
recognize self from non-self with the appropriate immunological
response
• Contains myoid cells that express the AChR antigen, antigen
presenting cells, immunocompetent T cells
• Normally targets and deletes AChR-specific T cells before they enter
the periphery
• Abnormal thymus results in loss of tolerance and development of
antibodies AChR and other proteins at the NMJ
• Abnormal in many patients with acquired MG
• B lymphocytes may be found in patients with MG
(Mays et al, 2011)
Autoimmune Processes in MG
• Antibody-mediated attack and complement-mediated destruction of the
post-synaptic membrane (striated/voluntary muscles)
• AChRs degraded by auto-antibodies and complement activity
• Immunoglobin G (IgG) and complement components attach to and
damage the muscle membrane resulting in loss of it’
’s normal fold
• Synaptic junction distance is increased
• Reduced concentration of AChR’
’s on muscle endplate membrane
• Antibodies block AChR binding sites
• ACh release is normal but post-synaptic membrane less sensitive
• Reduced probability that nerve impulses will be followed by a muscle
action potential (AP)
(Mays et al, 2011, Howard, 2008)
Antibodies in MG
• Acetylcholine Receptor (AChR) Antibodies:
– Found in 90% with generalized MG
– Found in 70% with ocular MG
– Synthesis of AChR antibodies is regulated by AChR-specific T-helper
cells (CD4) which react primarily with the α subunits of the receptor
• Anti-MuSK Antibodies (10%)
– postsynaptic membrane expresses muscle-specific receptor tyrosine
kinase ( MuSK)
– present as an antigen in 38 to 50 % of patients with generalized MG
who are AChR antibody negative
• Muscle protein antibodies
– Striated muscle antigens - titin
– Ryanodine & ryanodine receptors (RyR)
(Chan et al, 2007, Mays et al, 2011)
Thymus Gland in MG
• Hyperplasic cells
– 60 - 70% of myasthenics
– B cells interact with helper T- cells
resulting in antibody production
• Thymoma
– 10-15% of myasthenics
– age 30 to 60
– more severe disease
– higher levels of AChR antibodies
Typical MG Events
• Clinical Course:
– Restricted to eyes only (ocular MG) in 10%
– Progressive if not treated
– Generally weakness spreads to involve oropharyngeal muscles and limb
muscles in 66 % within the first year
– Maximal weakness is reached in the first 2 - 3 years (Grob et al, 2008,
Mantegazza, 1990)
• Initial Symptoms:
– Ptosis or diplopia (double vision) - 2/3 of patients
– Difficulty chewing, swallowing - 16%
– Limb weakness - 10% (Howard, 2009)
• Minimal Precipitating Factors:
–
–
–
–
Infection, emotional stress(4%)
Physical trauma ( 3%)
Thyroid disease (1%)
Pregnancy/delivery (1%) (Grob et al 2004)
Ptosis in MG
Hallmark Characteristics of
“Muscle Weakness” in MG
• Fatigability
• Fluctuates & asymmetrical – worse with
use, particularly at end of day
• Variable location of muscles involved
and severity of weakness within each myasthenic and
among myasthenics
• Weakness increases with repeated activity, after effort
and/or repeated testing
• Strength improves after rest
• Periods of worsening and remissions
Classic Clinical Features:
Weakness in MG
• Eyes – double vision (diplopia). droopy eye lids (ptosis)
• Face – facial weakness (flat smile, drooping lips, poor brow movement,
weak pucker, unable to puff cheeks out or suck)
• Speech – slurred (dysarthria), nasal or hoarse
• Oropharyngeal - chewing fatigue and dysphagia - swallowing problems
may include gagging, choking, nasal regurgitation, difficulty clearing
secretions
• Diaphragm - breathing shallow, decreased chest expansion,
short of breath, increased difficulty breathing bending over
or supine
• Neck and Proximal Limb Muscles –
- Head - dropped
- Arms – difficulty carrying, lifting, gripping
- Legs – difficulty climbing stairs, getting out of chairs/bed
(Howard, 2008)
Clinical Classification of MG
• Designed to identify subgroups of patients with
MG who share distinct clinical features or severity
of disease that may indicate different prognoses or
responses to therapy
• Classes I through V
(Jaretzki A et al. 2000)
Clinical Classification of MG
• Class I:
• Class II:
• Class IIa:
• Class IIb:
• Class III:
• Class IIIa:
Any ocular weakness, may have weakness of eye
closure, all other muscle strength is normal
Mild weakness affecting other than ocular muscles,
may also have ocular weakness of any severity
Predominantly affecting limb, axial muscles or both,
may also have lesser involvement of oropharyngeal
weakness
Predominantly affecting oropharyngeal, respiratory
muscles or both, may also have lesser or equal
involvement of limb, axial muscles or both
Moderate weakness affecting other than ocular
muscles
Predominantly affecting limb, axial muscles, or both;
may also have lesser involvement of oropharyngeal
weakness
Clinical Classification of MG
• Class IIIb: Predominantly affecting oropharyngeal, respiratory
muscles or both; may also have lesser or equal
involvement of limb, axial muscles or both
• Class IV: Severe weakness affecting other than ocular muscles;
may also have ocular weakness of any severity
• Class IVa: Predominantly affecting limb and/or axial muscles
• Class IVb: Predominantly affecting oropharyngeal, respiratory
muscles or both; Use of feeding tube; May also have
lesser or equal involvement of limb, axial muscles or
both.
• Class V: Defined by intubation, with or without mechanical
ventilation, except when employed during routine
postoperative care. Use of a feeding tube without
intubation places the patient in class IVb.
Diagnostic Testing for MG
• Edrophonium (Tensilon) test – rarely used
• Ice Pack Test
• Serology: Auto-antibody Tests
– AChR antibody
– MuSK antibody, if AChR seronegative
– Anti-titin antibodies
– Anti RyR antibodies
• Electrodiagnostic Studies:
– Single fiber EMG
– Nerve Conduction Studies (NCS)
• Imaging Tests of the Chest:
– Computerized Tomography (CT)
– Magnetic Resonance Imaging (MRI)
Edrophonium (Tensilon )Test:
•
•
•
•
A cholinesterase inhibitor: inhibits the action of AChE - slowing the breakdown of
ACh which then prolongs the diffusion of ACh in synapatic cleft to allow
interaction with AChR’
’s resulting in endplate depolarization
MG weakness improves after tensilon administration ..minutes
Positive:
– 60-95% (ocular MG)
– 72-95% (generalized MG)
Procedure:
– Select a weak muscle and test it
– Inject 0.1 cc Tensilon IV and look for improvement or adverse effects
• Excessive cholinergic stimulation of the heart with resulting bradycardia
is possible– Atropine at bedside
– If no improvement or adverse effects, inject a further 0.9 cc slowly IV
– Retest the preselected muscle group
– Ideally, have someone else do the muscle testing to control for bias
(Pascuzzi, 2003)
Ice Pack Test
• Used in patients with ptosis especially if Tensilon test risky
• Based on the physiologic principle of improving neuromuscular
transmission at lower muscle temperatures, the eyelid muscles are the
most easily cooled by the application of ice
• Procedure:
– a bag (or surgical glove) is filled with ice and placed on the closed
(ptotic) lid for two minutes.
– The ice is then removed and the extent of ptosis is immediately
assessed.
• The sensitivity appears to be about 80 percent in those with prominent
ptosis. The predictive value of the test has not yet been established.
(Golnik et al , 1999)
Serology:
Anti-acetylcholine receptor antibodies
• Titres in one individual do not correlate with clinical severity
– Over time will change in parallel with disease
– Repeated testing is rarely needed - use clinical and
sometimes electrodiagnostic examinations to follow
longitudinally
• If positive - confirms the diagnosis of MG
– But does not mean symptoms are due to MG
Seronegative MG
• Undetectable antibodies against the acetylcholine receptor
– 50% of ocular MG
– 15% of generalized MG
– In generalized MG individuals with clinical history and
examination consistent with possible MG may be MuSK
antibody positive
– MuSK Ab positive MG patients have characteristic clinical
features that are different from features of the remaining
seronegative MG patients
(Meriggioli & Sanders, 2009)
Electrodiagnostic Tests
• Electromyography (EMG) and Nerve Conduction studies (NCS)
• Tests used to evaluate nerve conduction and muscle function
• NCS measure the nerve conduction time and amplitude of the
stimulated muscle in response to an electrical stimulus
• EMG records the rate of firing, shape and dimension of the potentials
• Single Fiber EMG (SFEMG) is a specific test of neuromuscular
transmission
(Angelini, 2011)
Normal Nerve conduction
As seen on an oscilloscope during testing
Repetitive Nerve Stimulation
Decremental
response
as seen
in MG
(Oh et al, 1992)
Imaging Studies (CT or MRI) of the Chest :
Visualization of the Thymus
• Thymic Hyperplasia:
– 65% of MG patients
– Mainly early onset (arbitrarily less than 50 years of age)
– Not necessarily visible on CT
• Thymoma:
– 30% of late onset greater than 50 years of age
– Visible on CT of the chest
– Always seropositive for AChR antibodie
(Howard, 2008)
Therapeutic Modalities
• Medications:
– Symptomatic
• Anti-Cholinergic Agents
– Immunosuppressive agents
– Immunomodulatory agents
• Immunomodulatory Therapies
– Plasmapheresis (TPE/PLEX)
– Immune Gamma Globulin (IVIg)
– Thymectomy
Anti-cholinergic Agents:
Acetylcholinesterase Inhibitors
• Pyridostigmine bromide (Oral)
– Mestinon (short-acting)
– Mestinon Time Span (long-acting)
• Neostigmine bromide (Oral)
• Neostigmine methylsulfate (IM, SC)
Pyridostigmine bromide (Mestinon)
•
•
Most commonly used acetylcholinesterase inhibitor
Action
– Increases the amount of acetylcholine available at the NMJ to make the
muscles contract
– If it works, improvement within hours
– Symptomatic treatment only; doesn’
’t treat underlying problem with the
immune system
•
Advantages
– Inexpensive
– Few serious side effects
•
Side Effects/Risk Factors
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Diarrhea, abdominal cramps
Nausea & vomiting
Urinary urgency, frequency
Muscle twitching, cramps
Muscle weakness at high doses
Overdose (Cholinergic Crisis) particularly if S & S occur within 15 – 60
minutes after dosing
Immunosuppressive Therapy
• General – short or long term use
– Glucocorticosteroids (Prednisone, methylprednisolone)
• Targeted – long term use
Not FDA approved for MG
“Off-label”
” drugs
Used as steroid sparing option
Available for non responders, in severe MG, or with
intolerable side effects
– Typically used in
–
–
–
–
• Cancer therapy
• Prevention of transplant rejection
Prednisone
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General immunosupression
Works in most people - Smallest dose for shortest time possible
Works quickly but high doses can induce an exacerbation of weakness
to respiratory failure
Takes months
– 1 month minimum
– 3-6 months optimum
– Sometimes 12 months
Many side effects/Risk Factors - some serious
Risks Factors:
– Infection
– Weight gain (Obesity)
– Hyperglycemia, Type II Diabetes
– Hypertension
– Osteopenia/Osteoporosis
– Avascular necrosis of hip joint
– Cataracts, glaucoma
– Insomnia
– Psychosis – depression,
Targeted Immunosuppressive Long Term Therapies
(Off-Label)
• Azathioprine (Imuran) – B cells and T cells
• Mycophenolate (Cell Cept) – B cells and T cells
• Cyclosporin (Neoral or Sandimmune) NB: Not to be
interchanged) – T cells
• Tacrolimus (Prograf) – T cells and IL2
• Cyclophosphamide (Cytoxan) – B cells
• Methotrexate – T cells
(Mays et al, 2011)
Azathioprine (Imuran)
•
•
•
•
•
Most frequently used
Works well in MG with improvement after 6 – 12 months
Allows the use of lower doses of prednisone
Required monitoring: liver function tests (LFT’
’s); blood counts
Side effects:
– Flu-like symptoms
–
–
–
–
–
•
Increased liver enzymes
Decreased WBC
Bleeding, bruising
GI upset, loss of appetite, nausea
Rash, darkened skin, hair loss
Risks:
–
–
–
–
Hepatotoxic, Nephrotoxic
Bone marrow suppression – leukopenia, anemia
Cancer – lymphoma, skin cancer
Infertility
Targeted Immunosuppressive
Long Term Therapies
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•
•
•
•
Effectiveness - Weeks to months
Not compatible with pregnancy
Typical Use:
– Cancer therapy
– Prevent transplant rejection
Indications in MG:
– Steroid sparing
– Inhibit production of B cells and/or T cells
– Limit antibody production by B cells
Common Risk Factors:
– Many drug – drug interactions including OTC
– Hepatotoxicity
– Nephrotoxicity
– Bone marrow suppression – leukopenia, anemia etc.
– Cardiopulmonary dysfunction
Other Drug Therapy in MG
• Rituximab (Rituxan) –
–
–
–
–
–
Monoclonal antibody
Destroys B lymphocytes
Used in MG refractory to other long term immunosuppressive therapy
Weight based infusions for 10 – 12 weeks for up to 2 years
Advantage:
• Lower steroid dose required
• Good with MuSK AB positive
• May result in sustained remission
– Risks:
• Infusion reactions
• Neutropenia
• Progressive Multifocal Encepholopathy (PML)
Immunomodulatory Therapy
• Plasmaphoresis (TPE/PLEX) - depletes antibodies
by the bulk removal of anti-AChR & other
antibodies
• IVIG Infusions – neutralize the blocking effects of
antibodies by infusion of human polyclonal
immunoglobulin
• Thymectomy – remove the source
of dysregulated Tcells
(Angelini, 2011)
Plasmaphoresis (TPE/PLEX)
• Indications:
– Acute myasthenic crisis
– Uncontrolled MG with medications
– Pre-thymectomy
• Benefits in 70% of patients within 2 weeks
• Risks:
– Venous access – infection, pain, nerve damage, thrombosis, perforation,
hematoma
– Paresthesia, muscle cramps
– Electrolyte imbalance
– Reduced coagulation factors
– Cardiac events and stroke
(Howard, 2008)
Immune Gamma Globulin
Intravenous (IVIg)
• Indications:
– Acute intervention
– Chronic maintenance
• Risk Factors:
–
–
–
–
–
Chills & fever (pretreat with antihistamine, antipyretic and/or steroids)
Headache, aseptic meningitis
Fluid overload
Anaphylaxis
DVT, PE
(Howard, 2008)
Thymectomy
• Indications:
– MG age 10 – 50 (except Ocular, MUSk +)
– Thymoma
– Non-thymomatous autoimmune MG – option to increase
the probability of remission or improvement
• Approaches:
– Transsternal
– Transcervical
– Endoscopic (video-assisted thorascopic)
• Note: Post operative increase in symptoms of MG may
occur
(Angelini, 2011, Howard, 2008)
Comprehensive
Nursing Assessment:
• Patient History
• Neurological Examination
– Muscle Strength
– Muscle Fatigability
Patient History
• Provides direction to guide the neurological
examination
• Aids in Identifying:
– Specific patient problems
– Health strengths
– Health weaknesses
– Reason for exacerbation of symptoms
• Aids in development of individualized care plan
Symptoms of MG??
• Location (where/what is the
weakness – eyes, speech, swallow, breathing,
upper/lower limbs, etc.)
• Quality or character
• Quantity or severity
• Timing (onset, duration, frequency)
• Setting
• Aggravating/alleviating factors
• Associated factors
•
•
•
•
Disease Process
Treatment regimen
Concurrent Illness
Psychosocial Issues
Myasthenia Gravis ??
•
•
•
•
•
•
Newly or previously diagnosed
Duration of diagnosis
Previously in remission
Symptoms increase after activity or stress
Knowledge of the disease process
Coping with the diagnosis
Treatment Regimen ??
Prescribed medications & treatments
Dosing and frequency schedule
Knowledge of the medication regimen rationale
Compliance issues
Unpleasant side effects
Response after taking the medications
Fatigue/weakness noticeable before and/or after taking the
medication
• Weakness after taking the medication
• New medications or other treatments
•
•
•
•
•
•
•
Concurrent Illness??
• Recent infection or illness
• Medications –
– Prescribed
– OTC
• Recent surgery
Concurrent Illness??
• Other long-standing illness – Primary disease process
– Secondary to MG medications
Psychosocial Issues ??
•
•
•
•
•
Patient’
’s and family learning level
Available family support
Cultural issues that can affect compliance
Religious issues that can affect compliance
Stressful events
Muscle Strength Testing
•
•
•
•
Eye & Eyelid Movements
Facial Movements
Speech & Swallowing
Muscle Strength Testing
(Proximal & Distal Muscles)
• Breathing Patterns
Eye & Eyelid Movements
Facial Movements
Speech, Swallowing &
Breathing Patterns
Muscle Strength Testing
(Proximal & Distal Muscles)
Grade 5 = normal muscle power
Grade 4 = movement against gravity
and against resistance
Grade 3 = movement against gravity
without resistance
Grade 2 = movement in the plane of
action with gravity eliminated
Grade 1 = flicker of muscle movement in
gravity eliminated position
Grade 0 = no muscle movement
Physical Assessment:
MG Focus for Fatigability
•
•
•
•
•
•
•
Eye Lids and Movement
Facial Muscles
Swallowing
Speech
Head Control
Arms and legs including grip
Respiratory
Physical Assessment:
Muscle Fatigue of Eyes & Lids
• Eye Movement - Looking straight ahead, right, left and down
– Reduced extraocular movements
– Diplopia occurs with prolonged gaze > 45 seconds: lateral and
upward gaze
– Downward gaze may be normal
– Pattern of weakness does not map to one nerve
– No eye movement
– Pupillary response normal
• Eye Lids – Looking straight ahead
– Ptosis
• With upward gaze in > 45 seconds
• Upper lid touches pupil
– Lid droop in seconds
Physical Assessment:
Muscle Fatigue of Face
• Facial Muscles – Close lids
– Reduced forced eye closure (unable to bury eyelashes
– Unable to keep eyelids squeezed shut
– Reduced ability to puff cheeks, lip seal, ability to spit
• Jaw opening and closure
– Unable to open and close jaw against resistance
– Reduced ability with repetitive attempts
Physical Assessment:
Muscle Fatigue of Pharynx/Larynx
• Speech –
– Count 1 – 50 noting the number at which
dysarthria begins
– Observe for nasal, soft and/or slurred speech
– Worsens with repetition
• Swallowing –
– May test with 4 oz of water (no ice); if clinically safe ask patient to drink as
usual
– Observe for coughing, throat clearing, double swallows, fatiguing of
swallow, choking, nasal regurgitation
Physical Assessment:
Testing for Muscle Fatigue
•
Head Control
– Observe head position in upright position
– Test neck flexion and extension
– Lift head off the table while in supine position
•
Upper limbs
–
–
–
–
Arms extended in sitting position
Both arms at 90°
°, palms down
Unable to maintain at least 240 sec.
Strength in proximal muscles (deltoid, triceps) most affected
•
Grip
•
– Compare strength (right vs left, male vs female)
– Test distal muscles (finger extensors) against resistance
Lower limbs - outstretched supine
– Right & left hip flexion (proximal) at 45 - 50°
° at least 100 sec.
– Test ankle dorsiflexion (distal)
Physical Assessment:
Respiratory Function
•
Breathing
– Breath count: number reached counting out loud in one breath
(at a rate of 1 per second)
– Supine: test chest expansion; observe for abdominal breathing
– Short of breath (SOB) in supine position; note time of onset
•
Other Pulmonary Testing that may be required:
– Forced Vital Capacity
• > 80% - within normal limits
• 65 – 79% - mild impairment
• 50 – 65% - moderate impairment
• > 50% - severe impairment
– Pulmonary Function Studies
– Pulse Oximetry
– Arterial Blood Gases
Patient Problem List:
Consequences of MG
•
•
•
•
•
•
•
•
•
•
Activity Intolerance/Mobility Problems
Communication
Nutrition
Risk of Aspiration
Sensory Perception/Visual Disturbance
Risk of Injury
Respiratory Dysfunction
Body Image
Self Care
Knowledge
Potential Patient Problems,
Expected Outcomes,
and
Nursing Interventions
Activity intolerance related to muscle
fatigability and weakness
Outcomes:
1. Maintains muscle strength,
endurance and activity level.
2. Demonstrates energy conservation techniques.
3. Verbalizes a decrease in muscle fatigue.
Interventions:
1. Identify factors that increase activity
intolerance.
2. Rest periods prior to and following
activities.
3. Develop energy conservation strategies to
decrease fatigue and optimize activities.
4. Adjust medications to maximize effectiveness
Impaired verbal communication
related to weakness of the larynx, pharynx, lips,
mouth, and jaw muscles
Outcomes:
1. Decreased frustration with
communication.
2. Uses an alternative methods to
communicate.
Interventions:
1. Determine the most effective mode of
communication including the use of
alternative methods (e.g. gestures, written,
communication cards.
2. Encourage patient to speak slowly & louder.
3. Reduce environmental noise.
4. Observe for nonverbal clues.
Interventions:
5. Ask questions that require short answers.
6. Discuss frustration associated with
the inability to communicate.
7. Explain need for patience by family/friends.
8. Consult a speech pathologist.
Alteration in nutrition related to fatigue of
the muscles for chewing & impaired
swallowing
Outcomes:
1. Maintains weight within
normal limits.
2. Absence of dehydration
Interventions:
1. Rest prior to eating and drinking.
2. Provide foods easy to chew.
3. Provide highly viscous foods and thickened liquids.
4. Offer frequent, small meals including high-calorie and highprotein foods.
5. Instruct patient on principles of good dental hygiene.
6. Instruct patient to take rests while chewing and in between bites
to restore strength.
7. Serve meals at times of maximum strength (usually in the early
part of the day & ½ hour after cholinesterase inhibitor
medications).
Interventions:
8. Serve large meals in AM & small meals in PM.
9. Review food preparation techniques so food is easier to
consume. Use softer consistencies.
10. Review principles of nutrition and basic food groups so
patient can select food that provides a balanced diet.
11. Consult a dietitian to determine appropriate food choices.
12. Consult with a swallowing specialist to determine most
effective swallowing techniques.
High risk of aspiration due to inability to
swallow, manage own secretions, and impaired
cough and gag reflexes
Outcomes:
1. Absence of aspiration.
2. Breath Sounds within normal limits.
3. Chest X-ray within normal limits
Interventions:
1. Discuss the causes and prevention of aspiration.
2. Position upright with head slightly forward when eating
and drinking.
3. Encourage taking small bites, chewing well, and frequent
swallowing.
4. Encourage taking small sips of liquids.
5. Encourage eating slowly – make sure patient has
swallowed after each bite.
6. Provide meals at times of optimal strength. (after
medications, early in the day, after rest periods).
Interventions:
7. If swallowing lightly impaired, instruct patient to lean
forward, take a small breath through the nose and cough
forcefully to push the irritating substance out of throat
8. If choking occurs - use emergency principles as outlined by
the AHA to include the Heimlich maneuver.
9. If aspiration suspected - assess breath sounds and obtain a
chest X-ray
Disturbed sensory
perception related to
double vision and ptosis
Outcome:
1. Absence of physical
injury associated with
impaired vision
Interventions:
1. Reinforce the need for rest periods.
2. Discuss the risks associated with visual
impairment.
Risk for injury related to visual
disturbance, muscle fatigue
and weakness
Outcomes:
1. Uses safety measures to
decrease risk of injury.
2. Absence of falls.
Interventions:
1. Use eye patch to eliminate double vision.
2. Use safety measures to prevent injury, e.g. remove
or anchor throw rugs, use hand
grips in bathroom, and railings on stairs.
3. Moderate exercise to maintain muscle strength.
4. Use of an alert system/mechanism in case
of increased weakness or a fall.
Ineffective respiratory function related to
weakness of inter-costal muscles &
diaphragm.
Outcomes:
1.
2.
3.
4.
Absence of shortness of breath.
Adequate air exchange.
Effective spontaneous cough.
Pulmonary Function tests are within
normal limits
Interventions:
1. Assess and document respiratory status, rate,
rhythm and breath sounds.
2. Assess gag and cough reflexes.
3. Assess quality of voice – notify MD
of changes from baseline.
Interventions:
4. Obtain baseline Forced Vital Capacity (FVC)
(normal > 60 mg/kg) and Negative Inspiratory
Force (NIF) (>70cmH20) and continue to monitor
5. Notify MD for any respiratory abnormalities or
change in FVC and/or NIF from baseline value or
NIF < 30, FVC <1.5L. (Values of FVC < 1.0L <15mL/kg
body weight /NIF <20 cm H2O are indications for
mechanical ventilation.)
6. If facial weakness – obtain NIF/FVC per face mask.
Interventions:
7. Administer oxygen as needed.
8. Suction if patient unable to manage secretions.
9. Teach patient/caregiver how to perform oral
suctioning.
Disturbed body image related to inability
to maintain usual life style, role, and
responsibilities
Outcomes:
1. Demonstrates a positive selfesteem, body image and
personal identity
2. Demonstrates adjustment to changes
in role and responsibilities.
Interventions:
Encourage patient to verbalize the meaning of the
illness/loss (i.e., "How do you feel about what is
happening to you?")
2. Listen attentively and compassionately.
3. Since appearances may greatly alter and weakness may
leave patients unable to take care of grooming needs, help
them to look their best.
4. Be honest about realities of the illness; encourage patients
to seek help if denial becomes detrimental.
1.
Interventions:
5. Facilitate acceptance; help patients set
realistic, short-term goals so that success
may be achieved.
6. Encourage patients to do the things that
they are capable of doing.
7. Share hopeful aspects of the disease with patients
and family.
8. Recognize that the family too will be experiencing
grief for the loss of the way
the patient "used to be."
Interventions:
9. Determine what their usual coping mechanisms are, and
how they can best be used to cope with MG.
10. Assist patient in identifying factors in the
environment that have the potential to undermine
positive adaptation.
11. Involve patient in the planning and decisionmaking regarding care.
Interventions:
12. Give patient/family information regarding the
disease, medications, emergency measures, and
precautions for living with MG after discharge from
the acute care setting.
13. Explore patient role changes so that they will be
less threatening.
14. Supply information on local MG chapter.
Relationships can be formed with others
with the disease and be a great source of
strength to patients and family
Self care deficit related to muscle fatigue and
weakness, and
visual impairment
Outcomes:
1.
Able to perform activities of daily living within limits
of weakness and fatigability.
2. Demonstrates increased strength, endurance, and mobility
Interventions:
1. Assess ability to carry out ADL’s (feed, dress, groom, bathe,
toilet, transfer, and ambulate).
2. Assess specific cause – weakness, vision.
3. Assess need for assistive devices.
4. Encourage as much independence as possible.
5. Use consistent routines and allow sufficient time to perform
each activity.
Interventions:
6. Provide positive reinforcement.
7. Position in optimal position to perform activity.
8. Plan activities so patient is rested.
9. Ensure needed equipment is available.
10. Encourage use of clothing that is easy to put on and
remove.
11. Consult with Physiotherapist and/or
Occupational Therapist.
Knowledge deficit related to the disease
and its management.
Outcomes:
1. Verbalizes knowledge of
the disease, management,
potential side effects, and
fatigue management.
Interventions:
1. Assess any barriers to learning and
readiness to learn by patient and
family.
2. Education about the disease process,
the treatment options, their effects
and side effects.
3. Education regarding fatigue
management.
Fatigue Worsening in MG:
•
•
•
•
•
Activity level/overexertion
Stress – physical & emotional
Warm temperature
High humidity
Physical inactivity
Consequences of Physical
Inactivity in MG:
• De-conditioning
–
Increases muscle atrophy and weakness
– Decreased cardiovascular fitness
• Increases obesity
• Increases insulin resistance & diabetes risk
• Accelerates osteoporosis
– Aging process
– Prednisone administration
Other Factors Exacerbating MG:
•
•
•
•
•
•
•
•
•
•
•
Infections
Surgery
Anemia
Thyroid problems
Menses
Pregnancy and post-partum
Low testosterone
Vitamin deficiencies (B12 and D)
Loss of potassium – diuretic, vomiting
Sleep disorders
Medications
(Howard, 2008)
Drug Alert:
Classes of Drugs that may exacerbate MG
Use with caution & monitor
•
•
•
•
•
•
•
•
•
Antibiotics
Neuromuscular Blocking Agents
Beta Blockers
Calcium Channel Blockers
Anticonvulsants
Ophthomologics
Psychiatric Drugs
Hormones
Electrolyte related
(Pascuzzi, 2007)
Specific Drug Alerts:
Use with caution & monitor
•
•
•
•
•
•
•
•
•
•
•
•
Neuromuscular blocking agents: succinylcholine and vecuronim
Quinine, quinidine, procainamide
Antibiotics:
– aminoglycosides - (-mycins) Erythromycin
– Quinolones (-oxacin) - Cipro, Levaquin,
Beta-blockers: propranolol, timolol eyedrops
Calcium channel blockers: Norvasc, Procardia
Magnesium salts: laxatives, antacids
Iodine based contrast dye
Local anesthetics: lidocaine
Analgesics: narcotics (Demerol, morphine)
Anxiolytics
Sedatives
Hypnotics
(Pascuzzi, 2007)
Other Related Drugs/Factors
may worsen MG:
• Statins
• Hormones:
– Estrogen therapy
– Thyroid therapy/imbalance
• Electrolyte related:
– Magnesium (eclampsia, pre-term labor)
– Hypokalemia (Diuretics)
– Hypocalcemia (Plasma exchange)
• Over-the-Counter Drugs
• “Natural “ or herbal preparations
(Pascuzzi, 2007)
Drug Alert:
Medications that should
NOT be used in myasthenics
•
•
•
•
Alpha-interferon
d-Penicillamine
Botulinum toxin (Botox)
Telithromycin (Ketek)
(Howard, 2008)
► Myasthenic Crisis
versus
► Cholinergic Crisis
MG Crisis Situation:
Key Issues
• 12-16% of generalized MG patients experience crisis
• Respiratory and swallowing impairment are the hallmark
symptoms
• Priority - differentiate between cholinergic or myasthenic
crises
– Method: Edrophonium: Tensilon challenge test
Characteristics of Crisis
• Worsening dysphagia and dysarthria despite taking
medication
• Severe choking
• Weak breathing - breathing worsening 30 minutes after
taking pyridostigmine
• Fast shallow breathing when beginning to feel tired
• Weak voice
• Head drop
Crisis: Signs and Symptoms
•
•
•
•
•
Restlessness, apprehension
Generalized muscle weakness
Dyspnea
Increased bronchial secretions, sweating
Dysarthria, dysphagia
Complications of Crisis
• Respiratory failure
• Hypoxemia and respiratory acidosis may render
the patient somnolent,
and unresponsive
• Pneumonia may be a cause of death
• Chronic respiratory failure
Myasthenic Crisis
• Prodrome - infection
• Worsening MG
Cholinergic Crisis
• Cause - Over medication with anticholinesterase drugs
• Symptoms:
– Abdominal cramping/diarrhea/vomiting
(MUSCARINIC Effects-slow)
– Profound generalized weakness
– Diaphoresis
– Excessive bronchial & nasal secretions and impaired
respiratory function (NICOTINIC Effects-rapid)
– Bradycardia, A-V block
Emergency Management
• Both are medical emergencies
• Both may require tracheal intubation and assisted
ventilation
• Parameters: Negative Inspiratory Force (NIF) <
20cm H20
• FVC <15cc/kg body weight
• Humidified Air and Oxygen (if PO2 <70)
Cholinergic Crisis Management
• Stop Acetylcholinesterase Inhibitors
• Bronchospasm associated with cholinergic crisis may
respond to bronchodilator
• Intubate and Ventilate
• Treat underlying cause:
– Infection, electrolyte disturbance (hypokalemia,
hypocalcemia, hypermagnesium)
• Resume ChE at lower dose and increase slowly
MG Crisis Management
• Intravenous immunoglobulin ( IVIg)
– Blood product – safe
– Modulates the immune system
– Benefits seen in 70%of patients within 2
weeks
– Common side effects – mild
• IVIg and TPE equal in terms of efficacy
MG Crisis Management
• Plasma Exchange (TPE)
– Removes the antibodies which cause weakness
– Benefits in 70% of patients within
2 weeks
• More difficult to arrange on short notice unless a
major medical center
Impact of MG on the myasthenic
and the family members
• Life Style
• Role Changes
• Energy Conservation
– Home
– Community
– Work
• Challenges
– Vocational
– Financial
• Caregiver Issues
Life Style Changes
• Modify home and work environment to reduce
fatigue and frustration associated with the
limitations related to the disease process.
• Alter life style to decrease physical and mental
stress
• Encourage patient to discuss concerns with health
professionals and family
Role Changes
• Promote positive body image, self esteem and
avoid social isolation.
• Assist patient to identify and utilize effective
coping mechanisms.
• Educate family and friends about the disease and
associated limitations.
• Connect with other MG patients and families.
Energy Conservation
• Modify daily routine to maximize optimum functional
level.
• Plan activities with rest periods.
• Balance strenuous activities with others that require less
exertion.
• Organize day according to medication timing
(mestinon).
• Use assistive devices to promote optimal and safe activity
level.
Energy Conservation: Home
Sit during chores
Delegate to family members
Keep objects at appropriate height
Schedule rest periods
Plan activities
– Break the activity to its parts
– Prepare everything ahead
• Use power tools/electrical appliances
•
•
•
•
•
Energy Conservation: Eating
•
•
•
•
•
Eat when muscle strength is good.
Take time to eat and rest between bites.
Frequent small meals.
Soft foods and not sticky.
Foods that do not require a lot of chewing.
Energy Conservation: Grooming
•
•
•
•
•
Sit on stool to shave or brush teeth
Elbow prop
Electric tooth brushes
Take rest breaks
Shorter shower/bath with warm water
• Sit to dress
Energy Conservation: Community
•
•
•
•
•
•
•
•
Park close (drop off or handicap tag)
Avoid peak shopping times
Wear supportive walking shoes
Stay balanced (walker, cane, etc.)
Use cart for merchandise
Plan according to medications
Unload perishables
Shop by mail order
• Small size weighs less
Energy Conservation at Work
• Proper neck and back support
• Sit rather than stand
• Avoid eye strain
• Take breaks
• Proper air conditioning
• Family medical leave act
Major Challenges
•
•
•
•
•
Vocational impact
Employment issues
Disability issues
Insurance coverage
Financial impact
Caregiver Issues
• Recognize limitations as a caregiver.
• Care for self as well as the person with MG.
• Recognize when it is time to nurture and care for
self.
• Seek assistance from another caretaker as
necessary.
• Utilize community resources to assist in providing
care.
GOALS:
Maximize function
Promote quality of life
Prevent life threatening events
References
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•
•
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•
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Angelini, C. (2011). Diagnosis and management of autoimmune myasthenia gravis. Clinical
Drug Investigation, 3(1), 1-14. DOI : 10.2165/1158/4740.
Benetar, M. (2006). A systematic review of diagnostic studies in myasthenia gravis.
Neuromuscular Disorders, 16(7), 459-467.
Chan KH, Lachance DH, Harper CM, Lennon VA. Frequency of seronegativity in adultacquired generalized myasthenia gravis. Muscle Nerve 2007; 36:651.
Golnik KC, Pena R, Lee AG, Eggenberger ER. An ice test for the diagnosis of myasthenia
gravis. Ophthalmology 1999; 106:1282.
Grob, D., Brunner, N., Namba, T., & Pagala, M. ( 2008). Lifetime course of myasthenia
gravis. Muscle & Nerve, 37(2), 141-149.
Howard, J. F. (2008). (ed.) Myasthenia Gravis: A Manual for the Health Care Provider. (1st
ed.). St. Paul, MN. Myasthenia Gravis Foundation of America.
Jaretzki A et al.Myasthenia gravis. Recommendations for clinical research standards. Task
Force of the Medical Scientific Advisory Board of the Myasthenia Gravis Foundation of
America Neurology , v.55 , p.16 , 2000 ,
Keesey JC. Clinical evaluation and management of myasthenia gravis. Muscle Nerve
2004; 29:484.
Mantegazza R, Beghi E, Pareyson D, Antozzi C, Peluchetti D, Sghirlanzoni A, Cosi V,
Lombardi M, Piccolo G, Tonali P, et al. A multicentre follow-up study of 1152 patients with
myasthenia gravis in Italy.J Neurol. 1990 Oct;237(6):339-44.
References
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Mays, J., Butts, C.L. (2011). Intercommunication between the Neuroendocrine and Immune
Systems: Focus on Myasthenia Gravis, Neuroimmunomodulation, 18, 320-327.
Meriggioli, M. Sanders, DB (2009). Autoimmune myasthenia gravis: emerging clinical and
biological heterogenicity. Neurology, 8, 475-486.
Muscular Dystrophy Association (MDA). (2009). Facts about Myasthenia Gravis, LambertEaton Myasthenic Syndrome and Congenital Myasthenic Syndrome. Muscular Dystrophy
Association, Inc., Tucson, AZ.
Oh SJ, Kim DE, Kuruoglu R, et al. Diagnostic sensitivity of the laboratory tests in myasthenia
gravis. Muscle Nerve 1992; 15:720.
Pascuzzi, R.M (2003). The edrophonium test. Semin Neurol 23(1):83-8.
Pascuzzi, R. (2007). Medications and Myasthenia Gravis: A Reference for Health Care
Professionals. Myasthenia Gravis Foundation of America, New York, N.Y.
Phillips, L. H. 2nd .( 2003). The epidemiology of myasthenia gravis. Annals of the New York
Academy of Science, 998, 407-412.
Smeltzer, S.C. Bare, B.G. (ed) (2007). 10th Brunner & Suddath's Textbook of Medical
Surgical Nursing,1520-1530.
Post Test Instructions
• Read the complete program: “Myasthenia Gravis: A Nursing
Perspective”.
• Take the test, recording your answers in the test answer section. Each
question has only one correct answer.
• Complete the registration information and course evaluation.
• Email the registration information, completed test answers and the
Evaluation Form to: kday@kellencompany.com
• Within 4 – 6 weeks you will be notified of your test results.
• If you pass with a 70% score (20 correct answers) you will receive a
certificate of earned contact hours and the answer key. If you fail, you
have the option of taking the test again.