1. CONCEPTUAL PRESENTATION IN PATHOPHYSIOLOGY
I. DEFINITION (Introduction)
Myasthenia gravis is a chronic autoimmune neuromuscular disease characterized by
varying degrees of weakness of the skeletal (voluntary) muscles of the body. The name
myasthenia gravis, which is Latin and Greek in origin, literally means "grave muscle
weakness." With current therapies, however, most cases of myasthenia gravis are not
as "grave" as the name implies. In fact, for the majority of individuals with myasthenia
gravis, life expectancy is not lessened by the disorder.
The hallmark of myasthenia gravis is muscle weakness that increases during periods of
activity and improves after periods of rest. Certain muscles such as those that control
eye and eyelid movement, facial expression, chewing, talking, and swallowing are often,
but not always, involved in the disorder. The muscles that control breathing and neck
and limb movements may also be affected.
II. PREVALENCE AND POPULATION AT RISK
Myasthenia gravis affects approximately 2 out of every 100,000 people and can occur at any
age. It is most common in women between the ages of 18 and 25. In men, the condition usually
develops between 60 and 80 years of age.
III. RISK FACTORS: ENVIRONMENTAL, PERSONAL AND DEVELOPMENTAL FACTORS
Myasthenia Gravis is an autoimmune disease. For reasons that are not
understood, the body's immune system, which normally fights infections
or cancers, attacks the nerve-muscle communication point. In about one
in ten Myasthenia Gravis patients, the disease is caused by a tumor called
a thymoma that stimulates the immune system to attack the nerve-
muscle junction. It is thought that what causes the disease in other
patients is a combination of genetic factors and one or more
environmental problems. The best guesses of environmental causes are
viruses or bacteria (germs) that stimulate the immune system at the
"wrong" time in a patient with genetic background that puts them at risk
for this autoimmune disease. An example might be that some types of
thyroid disease are caused by problems with the immune system and a
similar autoimmune condition can cause MG.
IV. MECHANISMS (Pathophysioloy/disease process)

2. V. PATHOLOGICAL CONSEQUENCES (Complications)
omplications in MG arise late in the disease when larger muscle groups become involved.
Dysphagia and dyspnea should raise red flags as these two symptoms may lead to respiratory
compromise and ultimately death.
Myasthenic crises are exacerbation of symptoms cause be an aggravating factor. Myasthenic
crises can be life-threatening. Aggravating factors include pregnancy, emotional stress,
infections, excessive alcohol, UV light, extreme temperatures, thyroid disease and certain
medications. Medications such as chloroquine, quinidine, procainamide, prednisone, lithium,
phenytoin, cisplatin, magnesium, statins, beta-blocker, calcium channel blockers, Botox,
polymyxin, and aminoglycosides have been known to precipitate dormant MG and to trigger
myasthenic crises.
VI. DIFFERENTIAL DIAGNOSIS (Diagnostic evaluation)
the differential diagnosis for MG is vast. Due to its variability in presenting symptoms, MG can
mimick many diseases. It is important to remember that the presence of pupillary abnormalites
excludes the diagnosis of MG.
Lambert-Eaton Myasthenic Syndrome (LEMS) can be thought of as the opposite of MG.
The clinical features in LEMS include proximal muscle weakness and hyporeflexia with
improvement of symptoms with repeated muscle stimulation. LEMS is caused by antibodies
directed against presynaptic calcium channels. It is associated with small cell lung carcinoma.
Since ptosis is the most common presenting symptom in MG, it is important to go through its
differential diagnosis. Ptosis is defined as margin to reflex diameter 1 (MRD 1) of less than 2mm
or an asymmetry of more than 2mm between eyes. Normal palpebral fissure (PF) vertical
length is about 9mm, a ptotic lid has a PF < 9mm. Myasthenia gravis with ptosis has an
extensive differential diagnosis. This includes: an intracranial lesion, tumor, pituitary adenoma,
aneurysm, fascicular lesion of CN 3, evolving CN 3 palsy, post-viral neuropathy, thyroid
disorders*, migraines, meningitis, Horner's syndrome, levator aponeurosis, chronic progressive
external ophthalmoplegia (CPEO), and developmental myopathy of the levator palpebrae
superioris muscle.
Diplopia is another common symptom. A variable pattern of diplopia without pupillary
involvement should bring MG to the top of your differential list.

3. * Thyroid eye disease occurs in conjunction with MG in up to 5% of patients.
VII. MANIFESTATIONS AND SURVEILLANCE
VIII. CLINICAL MANAGEMENT
a. Nursing
Educational topics for outpatient self-care include medication management.
Understanding the actions of the medications and taking them on schedule is
emphasized, as are the consequences of delaying medication and signs and
symptoms of myasthenic and cholinergic crisis.
• Myasthenic Crisis causes: undermedication, stress, infection
• Signs and symptoms: negative seeing, swallowing, speaking, breathing
• Treatment: administration of cholinergic agents as ordered
• Cholinergic Crisis cause overmedication
• Signs and symptoms: PNS, increased salivation risked for aspiration
• Treatment: anticholinergic agents, atropine sulfate
• Health teachings for energy conservation. To do this, the nurse can suggest that
frequently used items (i.e. hygiene products, cleaning products, snacks) be kep on
each floor to minimize travel between floors.
• Prevention and management of complications such as aspiration. To minimize the
risk of aspiration, mealtimes should coincide with the peak effects of
anticholinesterase medication. Rest before meals is encouraged to reduce muscle
fatigue. Sit upright during meals, soft foods in gravy or sauces can be swallowed
more easily.
• Health education for strategies to help with ocular manifestations. To prevent
corneal damage when the eyelids do not close completely, the patient is instructed
to tape the eyes closed for short intervals and to regularly instill artificial tears.
b. Medical & Surgical
Management of myasthenia gravis is directed at improving function and reducing
and removing circulating antibodies. Therapeutic modalities include:
• Administration of anticholinesterase
• Medications and immunosuppressive therapy

4. • Plasmapheresis
• Thymectomy
IX. CONCEPTUAL MODELS/FRAMEWORK (Theories Applied)
OREM’S GENERAL THEORY OF NURSING
Orem’s general theory of nursing in three related parts:-
Theory of self care
Theory of self care deficit
Theory of nursing system
A. Theory of Self Care
This theory Includes:
Self care – practice of activities that individual initiates and perform on their own behalf in maintaining
life ,health and well being
Self care agency – is a human ability which is "the ability for engaging in self care" -conditioned by
age developmental state, life experience sociocultural orientation health and available resources
Therapeutic self care demand – "totality of self care actions to be performed for some duration in
order to meet self care requisites by using valid methods and related sets of operations and actions"
Self care requisites - action directed towards provision of self care. 3 categories of self care
requisites are-
o Universal self care requisites
o Developmental self care requisites
o Health deviation self care requisites
X. CASE STUDIES – Case Analysis
a. Case Title

5. Impending respiratoty failure Type 1 secodary to probable HAP impending
Myasthenia Gravis Crisis.
b. Brief Intro of the Case
Myasthenia gravis (MG) is an autoimmune disorder resulting from the production of antibodies
against acetylcholine receptors leading to the destruction of the postsynaptic membrane at the
neuromuscular junction. In the US there are about 18,000 people with MG. Myasthenia gravis
crisis (MGC) is defined as any MG exacerbation necessitating mechanical ventilation. Most
patients presenting with MGC have an identifiable risk factor. The diagnosis of MGC should be
suspected in all patients with respiratory failure, particularly those with unclear etiology. Acute
management of MGC requires supportive general and ventilatory therapy and institution of
measures to improve the neuromuscular blockade. The latter includes plasma exchange or i.v.
immunoglobulin, and removal of the offending trigger. The outcome of patients with MGC has
improved significantly and the current mortality rate is about 4 to 8%.
c. Patient’s Profile
Patient name Uy, E 59 y/o female from Caloocan City, single. Patient admitted last
aApril 25, 2012 andwascleard CV was pricate internist outside.Patient underwent
sternotomy with thymomectomy the next day 4/26/2012.
d. Patient’s History
Patient hadbaseline PFT’s prior to |Orwhich showed normal results.Cefuroxime
wasuse as prophylacticantibiotic. Patient was received on FM rebreather at 5-6 lpm
very comfortable no ptosis and stable vital signs. Patient wasplacedon DATon 24/7
and tolerated feeding.Post-op days- patient still has CBS andno DOB.IV neostigmin
and hydrocortisone shifted back tooral. Patient was well post-op until yesterday
patient noticedesay fatigability with occasional shortness ofbreath. On PE there was
a decreasedbreath sounds in the right lung field and CXR done which showedpoor
respiratory effort minimal pleural effusion night no infiltrates.CBC repeatedand
showed inc WBC 15-1 segmenters of 96-5 plt 425. Patient wasrefferedto Pulmo
andincentive spirometry was advised.Today day 4 postop patient still complained
ofsame shotness of breath and PE still decrease breath sounds patient was decked
to ICU for closemonitoring and observation.
e. Assessment – Patient- centered

6. patient was diagnose with MG last February 2012 presenting ptosis oLeft eyelid and
easy fatigability and weakness of upper extrimities right morethan left (
assymertic)upon continuos/ repetitive use( example writing) RNS done consistent
with MG conjuactional area). Mainly affectedor bicularis oculi and nasalis.
f. Diagnostic exam – Results Only
finding were enlarged thymus 4x larger than normal size thymus. Left thymus
attached to phrenic nerve.
g. Pathophysiology – Patient – centered
h. Nursing Management – diagnosis,interventions,rationale
i. Medical & Surgical Management
XI. SELECTED RESEARCH – Literature Matrix
XII. QUESTIONS FOR FUTURE STUDIES
What is the best treatment algorithm and safest long-term management of
myasthenia gravis? What patients are likely to benefit from thymectomy?
How long should myasthenia gravis patients be treated? Is it possible to discontinue
immunotherapy once remission has been achieved? What are the risks associated
with long-term immunosuppression? In this article, we review current therapeutic
strategies and these unresolved questions about myasthenia gravis treatment.