Jardins Myasthenia Flashcards
__________ is the most common chronic disorder of the neuromuscular junction.
Myasthenia gravis
The disorder interferes with the chemical transmission of _________ between the axonal terminal and the receptor sites of voluntary muscles
acetylcholine (ACh)
The hallmark clinical feature of myas- thenia gravis is ___________ , often with true muscle fatigue.
fluctuating skeletal muscle weakness
The fatigue and weakness usually improves following ____
rest
There are two clinical types of myas- thenia gravis:
ocular and generalized
In ________, the muscle weakness is limited to the eyelids and extraocular muscles.
ocular myasthenia gravis
In ___________ , the muscle weakness involves a variable combination of (1) muscles of the mouth and throat responsible for speech and swallowing (called bulbar muscles), (2) limbs, and (3) respira- tory muscles.
generalized myasthenia gravis
Neck extensor and flexor muscles are com- monly affected, producing what is called a “___________”
dropped head syndrome
The facial muscles are often involved, causing the patient to appear _______.
expressionless
Generalized myasthenia gravis may, or may not, involve the ________. Because the disorder affects only the ______ (motor) junction, sensory function is not lost.
ocular muscle / myoneural
The abnormal weakness may be confined to an isolated group of muscles (e.g., the drooping of one or both eyelids), or it may manifest as a generalized weakness that in severe cases includes the _______.
diaphragm
When the diaphragm is involved, ventilatory failure can develop—producing what is called a “ _________”
myasthenic crisis
myasthenic crisis.” In these cases, mechanical ventilation is required. If the patient is not properly managed (e.g., via the Bronchopulmonary Hygiene Therapy Protocol, and Mechanical Ventilation Protocols, may develop
• Mucous accumulation
• Airway obstruction
• Alveolar consolidation
• Atelectasis
The cause of __________ appears to be related to ACh receptor (AChR) antibodies (IgG antibodies) that block the nerve impulse transmissions at the neuromuscular junction.
myasthenia gravis
It is believed that the _________ disrupt the chemical transmission of ACh at the neuromuscular junction by (1) blocking the ACh from the receptor sites of the muscular cell, (2) accelerating the breakdown of ACh, and (3) destroy- ing the receptor sites
IgG antibodies
The disease usually has a peak age of onset in females of _______,
15 to 35 years
compared with ______ years in males.
40 to 70
The clinical manifestations associated with ________ are often provoked by emotional upset, physical stress, exposure to extreme temperature changes, febrile illness, and pregnancy.
myasthenia gravis
Screening methods and tests used to diagnose myasthenia gravis include
(1) clinical presentation and history, (2) bedside tests, (3) immunologic studies, (4) electrodiagnostic studies, and (5) evaluation of conditions associated with myasthenia gravis.
The hallmark of myasthenia gravis is chronic _______
muscle fatigue
Signs and symptoms include
facial muscle weakness; ptosis (drooping of one or both eyelids); diplopia; ophthalmoplegia, difficulty in breathing, speaking, chewing, and swallowing; unstable gait; and weakness in arms, hands, fingers, legs, and neck brought on by repetitive motions.
(drooping of one or both eyelids);
ptosis
(double vision);
diplopia
_________ (paralysis or weakness of one or more of the muscles that control eye movement);
ophthalmoplegia
The muscles that control the ______ are especially susceptible and are usually affected first.
eyes, eyelids, face, and throat
The signs and symptoms of myasthenia gravis during the early stages are often _____
elusive
In most cases, the first noticeable symptom is weakness of the eye muscles (________) and a change in the patient’s _______
droopy eyelids/ facial expressions.
As the disorder becomes more generalized, weakness develops in the ___ and ____
arms and legs.
The muscle weak- ness is usually more pronounced in the _____ parts of the extremities.
proximal
Bedside Diagnostic Tests
Ice Pack Test
Edrophonium (Tensilon) Test
The _______ is a very simple, safe, and reliable procedure for diagnosing myasthenia gravis in patients who have ptosis (droopy eye).
ice pack test
The test consists of the application of an ice pack to the patient’s symptomatic eye for _____
3 to 5 minutes
The test is considered positive for myasthenia gravis when there is improvement of the ptosis (an increase of at least ____ in the palpebral fissure from before to after the test).
2 mm
The ______\ test is used in patients with obvious ptosis or ophthalmoparesis.
edrophonium (Tensilon)
_____ , a short- acting drug, blocks cholinesterase from breaking down ACh after it has been released from the terminal axon.
Edrophonium
A disadvantage of the _______ test is that it can be complicated by cholinergic side effects that include cardiac arrhythmias and cardiopulmonary arrest.
edrophonium
Serologic tests to detect the presence of circulating acetyl- choline receptor antibodies (AChR-Abs) is the first step in the laboratory confirmation of myasthenia.
Immunologic Studies
The repetitive nerve stimulation (RNS) and single-fiber electromyography (SFEMG) tests are important diagnostic supplements to the immunologic studies.
Electrodiagnostic Studies
Thymic abnor- malities are often seen in patients with ______
myasthenia gravis
_______ scans may be used to identify an abnormal thymus gland or the presence of a thymoma
Computed tomography (CT) or magnetic resonance imaging (MRI)
_____ (a usually benign tumor of the thymus gland that may be associated with myasthenia gravis).
thymoma
A______ has been shown to reduce symptoms of myasthenia gravis. In fact, a _______ may be recommended even when there is no tumor.
thymectomy
The removal of the _____ seems to improve the condition in many patients.
thymus
May be performed to help evaluate the patient’s ventilatory status and the possibility of ventilatory failure—that is, a myasthenic crisis.
Pulmonary Function Testing
Chest Assessment Findings
• Diminished breath sounds
• Crackles
Cyanosis
(in Severe Cases)
Respiratory Rate
• Varies with the degree of respiratory muscle paralysis
• Apnea (in severe cases)
Chest Radiograph
• Normal, or
• Increased opacity (when atelectasis or consolidation are
present)
_______ inhibitors are recommended as the first line of treatment for symptomatic myasthenia gravis. Pyridostigmine (Mestinon) is usually the first choice
Acetylcholinesterase
Most patients with myasthenia gravis need some form of ________ ; in addition to an acetylcholinesterase inhibitor
immunotherapy
It is recommended that _______ be administered to patients who (1) are significantly symptom- atic while on an acetylcholinesterase inhibitor, or (2) who become symptomatic after a temporary response to an acetylcholinesterase inhibitor.
immunotherapy
Immunotherapy (Widely used agents include _____)
azathioprine, mycophenolate mofetil, and cyclosporine.
________ modalities are used most often for (1) myasthenic crisis, (2) preoperatively before thymectomy or other surgery, (3) as a bridge to slower acting immuno- therapies, and (4) to help maintain remission in hard-to- control patients. ______ modalities include plasmapheresis and IVIG therapy.
Rapid immunotherapy
________ (plasma exchange) directly removes the AChR antibodies from the patient’s blood.
Plasmapheresis
________ entails the administration of pooled immunoglobulins (IgG) from multiple donors.
Intravenous immune globulin (IVIG)
Although controversial, a _______ may be recommended for some patients with generalized myasthenia gravis, who are less than 60 years of age and without thymoma.
thymectomy
The ______ is the source of the anti-ACh receptor antibodies.
thymus
Because of the excessive mucous production and accumula- tion associated with myasthenia gravis, a number of bronchial hygiene treatment modalities may be used to enhance the mobilization of bronchial secretions
Bronchopulmonary Hygiene Therapy Protocol
