Disorders of the Neurological Junction (MG) Flashcards
Precautions during MG rehab:
- No exercise during exarcebations
- Stop exercise if symptoms worsen or SOB
- Fatigie should not last for more than 2 h post exercise
- Resudual muscle soreness should not be severe and resolve within a few days
Lambert-Eaton Syndrome AKA:
Lambert-Eaton Myasthenic Syndrome (LEMS)
acute care rehabilitation considerations of MG:
-
Acute care: supportive care
- PT stablishes accurate neurologic and respiratory baselines
- Be aware of myesthenic crisis:
- Increased wekaness
- respiratory distress
- dificulty talking, chewing, swallowing
Treatment of Botulism:
- Immediate
- Antitoxin injection
- Removal of unabsorbed toxin from GI
- ICU: intubation and mechanical ventalitaion may be needed
- Supportive care
In MG, an autoimmune response mediated by specific anti-ACh receptor antibodies that may:
- Block the site that normally binds ACh
- Damage postsynaptic muscle membrane
- Result in degeneration of the ACh receptors
Recently discovered types of Myesthenia Gravis:
Antibodies against MuSK protein
Prognosis of MG:
- Normal life with tretament
- Variable course: remission and exarcerbations
- Slowly progressive course
4 Older categories of MG:
- Ocular
- Mild generalized
- Acute fulminating
- Late severe
Rehabilitation Considerations of botulism:
Post-acute care:
- Graded, progressive rehab program to address:
- Muscle wasting
- Deconditioning
- Orthostatic hypotension
Generalized weakness in MG:
- Occurs in 85% of persons with MG-Affects limb musculature
- Usually more mild involvement
- Proximal muscles more affected than distal
- May see unstable, waddling gait-In more severe forms, can have respiratory muscle weakness
- No sensory loss
- Normal reflexes: because is a short contraction
Peak incidence of MG in females ages:
20’s – 30’s
Diagnosis of Lambert Eaton Syndrome:
- Decreased DTR
- Muscle atrophy
- Weakness that improves with activity
- Detection of voltage gated calcium channel
antibodies in serum - Positive Tensilon test
Treatment of Lambert Eaton Syndrome:
- Symptomatic: lung cancer treatment
- Other treatment similar to MG
Clinical features of Lambert-Eaton Syndrome:
- Weakness and fatigue of muscles
- Muscle Atrophy
- Little involvement of ocular muscles
- Depressed reflexes
- ¾ have autonomic involvement:
- Dry mouth
- Constipation
- Blurred vision
- Impaired sweating
- Orthostatic hypotension
True or false: reumatoid arthritis and lupus are risk factors of MG
True
Signs & symptoms of LEMS often precede what other serius condition?
Dx of cancer by 2 to 4 years
Cardinal feautures of MG:
- Skeletal muscle fluctuating weakness
- Skeletal Muscle fatigability
- Extraocular muscles 1st to be affected
Autoimmune disorder associated mainly with carcinoma of lung and may also be associated wuth DM I, Vitiligo, hypothyroidism?
Lambert-Eaton Syndrome
Transient Neonatal Myasthenia Gravis
- AChE antibodies can cross placenta
- Occurs in 10% of infants born to mothers
with MG
Most common autoummune disorder of the neuromuscular junction characterized by fluctuating weakness and fatigability of skeletal muscle:
Myasthenia Gravis
What are the neuromuscular symptoms of botulism?
- Flaccid paralysis of extremities
- Symetrical
- Proximal to distal
- Cranial nerve palsies:
- Blurred vision, diplopia, dysphagia, dysarthria
- Respiratory muscle paralysis
- Progression of symptoms depends on how much toxin
- No sensory deficits
- Normal mentation
Categories of Botulism:
- Food – borne (15%): classic form. Canned foods-
- Wound (20%): chronic drug abusers, after cesarean section-
- Infant (65%): most common from honey
- Adult intestinal toxemia (rare)
- Iatrogenic (don’t know the cause) botulism (rare)
Clostridium botulinum is an anaerobic bacterium that produces a potent neurotoxin and is found mainly where?
in improperly preserved or canned food
Botulism prognosis:
- Severe cases:
- Fatal if untreated
- Mortality rate 20%
- Mild to moderate cases
- Gradual recover of muscle strenght may take up to 12 months
Rare, often fatal condition caused by a potent neurotoxin produced by Clostridium botulinum causing failure of the neuromuscular transmission:
Botulism
Diagnosis of botulism:
- History
- Serum or stool analysis
- Clinical signs: sudden paralysis
- EMG
Peak incidence of MG in males ages:
50’s – 60’s
Treatment of MG:
- Symptomatic Tx
- AChE inhibitor medication
- Thymectomy: long term
- Immunosuppresants drugs: corticosteroids; SEs
- Plasmapheresis
- IVIg: short term benefits
Risk Factors of Myasthenia Gravis:
- Thymic disorders: enlarged TG
- Thyroid related disorders: hyperthyroidism
- Diabetes
- Immune diseases: RA, lupus
- Exacerbation with: emotional stress, surgery, shortly after pregnancy, exposure to bright sunlight
- Familial association: 5% to 7%
More recent research identified other
forms of MG:
- Antibodies against MuSK protein (muscle specific kinase)
- Lack of this protein results in improper formation
of NM junction - Found in 30% - 40% of persons with Myasthenia
gravis
Circulating ingested neurotoxin from Clostridium botulinum binds to what structure in the body?
presynaptic nerve terminals inhibiting the release of ACh at motor end plate
Rehab considerations once MG is stable:
- Plan therapy with periods of max energy
- Use maximal isometric contractions
- Teach energy conservation principles:
- Frequent rest
- Home modifications
- Avoid streneous exercise andexposure to sun
- Minimal to moderate exer. intesities
- Aerobic: walking, stat bike, UBE
- Breathing Exercises
- Cooling vetsm cold packs, cold showers may decrease muscle fatigue
Causes of wound botulism:
- Occurs with contamination ofwounds by soil
- Chronic drug abusers
- After cesarean section
- Traumatic wounds
Rehabilitation considerations of LEMS?
- Exercise
- Similar precautions as MG
- Avoid high temperatures
What is the incidence in children and adults of botulism?
- 10 adult cases in US each year
- 100 infants
Which is the most common category of botulism? Why?
- Infant botulism
- Ingestion of honey
Incidence of Myasthenia Gravis :
- 1 : 200,000
- >100,000 cases in US
- Ratio female to male is 3:2
true or false:
Absence of anti-ACh receptor antibodies in the serum rules out MG:
false
Myasthenic Crisis:
- Medical emergency
- Often cause by infection
- weakning of respiratory muscles
- mechanical ventilation
Which muscles are the first to be affected in MG?
Cranial muscles, especially extraocular mm
General clinical picture of MG:
ALL bilateral:
- Ocular muscle involvement: diplopia, ptosis (dropping eyelids)
- Facial weakness: loss of facial expression, lips cannot close
- Oropharyngeal weakness: Impaired chewing, swallowing and speech
How do patients with Lambert Eaton Syndrome differ from myastethenia gravis?
LEMS patients may gain strenght with repeated muscle activity.
ACh can build up in large enough amounts in
neuromuscular junction for strength to improve
What are the initial symptoms of botulism?
When do they appear?
Initial symptoms of food poisoning
- Malaise
- Nausea
- Vomiting
- Diarrhea
- Abdominal pain
- Dryness of mouth
Symptoms usually appear within 12 to 36
hours after ingestion of contaminated food
- Range: 6 hours – 10 days
Autoimmune disorder in which a defect of neuromuscular transmission associated with blocked voltage gated calcium channel resulting in decreased release of ACh from the presynaptic nerve terminal:
Lambert-Eaton Syndrome
Newer classification system of MGFA:
5 main classes of MG with several subclasses
Medical diagnosis of MG:
- History
- Clinical observation of symptoms:
- intact DTRs,
- weakness improves with rest
- No sensory loss
- Clinical test: Patient looks up for 2 – 3 minutes;
- Ice test: x 5min
-
Immunologic testing:
- Presence of anti-ACh receptor antibodies in the serum.
- Absence of antibodies does not rule out MG. Presence of anti-MuSK protein antibodies.
- Pharmacologic testing: tensilon.
- EMG test
Pathology of Myasthenia Gravis
- Autoimmune response: anti ACh recpetor antibodies block or damage receptors.
- Number of Ach receptors on the muscle cell is decreased
- The remaining receptors are flattened
- Without ACh, the nerve impulses fail to pass across the neuromuscular junction to stimulate muscle contraction
Infant signs of botulism:
- Constipation
- Lethargy
- Poor feeding
- Weak cry
- Failure to thrive
Generalized version of MG:
- Occurs in 85% of pt with MG
- Affects limbs
- Proximal muscles more affected than distal
- Unastable, waddling gait
- No sensory loss
- Normal reflexes
