Transcript Clinical Simulations Due

Neuromuscular Disorders
Guillain-Barré Syndrome - Chapter 30
Myasthenia Gravis – Chapter 31
Neuromuscular Diseases
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Guillain-Barré Syndrome
Myasthenia Gravis
Amyotrophic Lateral Sclerosis (ALS)
Muscular Dystrophy
Multiple Sclerosis
Cerebral Palsy
Spinal cord injury
Guillain-Barré Syndrome
Definition
• An acute, usually rapidly progressive form of
inflammatory polyneuropathy characterized by
muscular weakness and mild distal sensory loss,
which in about 2/3 of cases, begins 5 days to 3
weeks after a banal infectious disorder, surgery,
or an immunization.
• Disorder of the peripheral nervous system.
• Also known as
• Landry's Ascending Paralysis
• Acute Inflammatory Demyelinating
Polyradiculoneuropathy
• Post-infectious polyneuritis
• Acute post-infection polyneuropathy
Etiology
• Cause is unknown.
• Autoimmune?
• Follows a febrile infection by 1-4 weeks:
• Upper Respiratory Tract
• GI illness
• Viruses and bacteria
• Infectious mononucleosis is associated with 25%
of cases.
• Followed the swine flu influenza vaccination in
1976.
• 500 cases of Guillain-Barré and 25 deaths.
Etiology
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Parainfluenza 2
Variola
Measles
Mumps
Hepatitis A and B
Mycoplasma Pneumoniae
Salmonella typhi
Etiology
• All age groups
• Greater incidence in age group > 45 years
age.
• Either sex
• Greater incidence in males.
• Greater incident in white population.
• No seasonal clustering.
Pathophysiology
• Most common acquired demyelinating
neuropathy.
• Inflammation and deterioration of
peripheral nervous system.
• Decreased ability of the neurons to transmit
impulses to the muscles.
• Paralysis.
Neurilemma
• The outer membrane of the Schwann cells
is called the neurilemma.
• Neurilemma is essential for
regeneration of cut and injured axons.
• Axons in the brain and spinal cord have no
neurilemma and therefore cannot
regenerate.
Clinical Manifestations
• Progressive ascending skeletal muscle paralysis.
• Ground to brain (G-B).
• Tingling sensation and numbness.
• Paresthesia
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Loss of deep tendon reflexes.
Sensory nerve impairment.
Peripheral facial weakness.
Decreased gag reflex.
Decreased ability to swallow.
• Dysphagia
Symptoms
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Fever
Malaise
Nausea prostration.
Tingling or numbness in extremities.
• Feet/legs affected first.
• Paralysis and loss of reflexes.
Ventilatory Failure
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Mucous Accumulation
Airway Obstruction
Alveolar Consolidation
Atelectasis
Progression of the Disease
• Paralysis peaks in less than 10 days.
• Progression of the paralysis may stop at
any point.
• As paralysis reaches its maximum, it
usually remains unchanged for a few days
to weeks.
Clinical Manifestations
• ABG
• Acute ventilatory failure with hypoxemia.
• Cyanosis
• PFT
• Restrictive lung disease.
• Decreased volumes.
• Breath Sounds decreased.
Diagnosis
• Neurological symptoms.
• Cerebral Spinal Fluid.
• Increased protein and normal cell count.
• Electro-diagnostic studies.
X-ray
• Normal.
• If atelectasis is present:
• Radiopaque or radiodense (white).
Autonomic Nervous System
Dysfunction
• Develops in 50% of cases
• Sympathetic
• Parasympathetic
• Loss of bowel and bladder sphincter control may
occur
Management
• Oxygen
• Frequent monitoring of pulmonary function
parameters.
• Vital capacity
• NIF or MIP & MEP
• Frequent monitoring of PO and ABG.
• Mechanical ventilation:
• Ventilatory Respiratory Failure.
• Tracheostomy
Management
• Hyperinflation Protocol.
• Bronchial Hygiene Protocol.
• Risk of thromboembolic events:
• Subcutaneous heparin.
• Elastic stockings.
• Passive range of motion exercises.
• Management of bedsores:
• Frequent turning.
• Monitor for Pneumonia (infection).
Management
• Urinary catheterization.
• Treat cardiac dysrhythmias.
• Plasmapheresis
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Withdraw blood.
Separate out the plasma & discard.
Re-infuse the cells with fresh frozen plasma.
Decreases the antibodies.
Total of five exchanges of 3 L each over 8-10
days.
• Steroid Therapy is controversial.
Pulmonary Function
Monitoring
• Mechanical Ventilation is indicated if:
• If VC decreases to 10 - 15 cc/kg or less.
• NIF (MIP) is –20 cm H20 or lower.
• f increases above 30/min.
Prognosis
• Spontaneous recovery is expected in 8595% of cases.
• Improvement may take weeks or months.
• 30% of adults have residual weakness at 3
years.
Myasthenia Gravis
Definition
• A disease characterized by episodic
muscle weakness caused by loss or
dysfunction of acetylcholine receptors.
• Chronic disorder.
• Axon and receptor site of the voluntary muscle.
• Periods of fatigue with improvement following
rest.
Etiology
• Circulating anti-ACh receptor antibodies
disrupt the chemical transmission of ACh.
• Blocking the ACh from the receptor site.
• Accelerating the breakdown of ACh.
• Destroying the receptor sites.
• Thymus gland is abnormal:
• Antibodies thought to come from the thymus
gland.
Etiology
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Twice as common in women.
Peak age of onset for females is 15 to 35 years.
Peak age of onset for males is 40 to 70 yrs.
Signs/symptoms are provoked by:
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Emotional upset.
Physical stress.
Exposure to extreme temperature changes.
Febrile illness.
Pregnancy.
• Death is possible but incidence of deaths decline
after 10 years.
Anatomic Alterations
• Isolated groups of muscles (eyelids).
• Generalized muscle weakness:
• May include the diaphragm.
• Ventilatory Failure.
Clinical Findings
• Weakness of striated muscle
• Eye muscles (ptosis).
• Extraocular muscles (diplopia).
• Muscles of the lower portion of the face
(speech impairment).
• Chewing and swallowing muscles (dysphagia).
• Muscles of the arms and legs.
Clinical Findings
• Descending paralysis.
• Mind to Ground (MG)
• Gradual onset.
• First symptoms.
• Drooping of the eyelids.
• If only the eyes are involved than it is
referred to as Ocular Myasthenia.
Clinical Findings
• Generalized skeletal muscle disorder
• Muscles of neck and face.
• Unable to chew and swallow.
• Aspiration
• Unable to speak clearly.
• Weakness of neck muscles causes the
patients head to fall forward.
Clinical Findings
• Weakness of arms and legs results in
difficulty in:
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Climbing stairs.
Lifting objects.
Maintaining balance.
Walking.
Hand cannot lift to the mouth.
Clinical Findings
• Pain is rare.
• Tendon reflexes remain intact.
• Patient may demonstrate normal health for
weeks and months at a time.
• May only show signs of weakness late in
the day or at night (exhaustion).
• Develop a sudden and transient
generalized muscle weakness that includes
the diaphragm.
Clinical Findings
• If ventilatory failure is handled properly the
chest x-ray findings should be normal.
• If improperly managed:
• Alveolar consolidation
• Atelectasis
• Excessive secretions
ABG
• Acute ventilatory failure with hypoxemia
• Decreased pH
• Increased PaCO2,
• Decreased PaO2
• Hypoxemia secondary to hypoventilation
Clinical Findings
• Pulmonary Functions
• Decreased volumes.
• Cyanosis
• Diminished BS
• X-ray
• Normal or radiopaque (white) if atelectasis is
present.
Diagnosis
• Clinical history.
• Clinical response to an IV injection of
edrophonium chloride (Tensilon).
• Tensilon Test
• Tensilon is an anticholinesterase.
• Electrophysiological tests (EMG).
• Circulating antibody levels in the blood.
• Enlarged Thymus gland.
Thymus Gland
• Manufacture Tlymphocytes.
Management
• Patients may live a normal life span.
• Exacerbation:
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Oxygen
Frequent monitoring of VC and NIF.
Frequent monitoring of BP and SpO2.
Frequent monitoring of ABG.
Mechanical ventilation.
Management of MG
• Anticholinesterase Drugs
• Edrophonium Chloride (Tensilon)
• Neostigmine (Prostigmine)
• Pyridostigmine (Mestinon)
• Steroid Therapy
• Prednisone
• ACTH therapy
Management of MG
• Thymectomy
• Useful in young adult females
• Plasmapheresis
• Bronchial hygiene
• Hyperinflation protocol
• Atelectasis
Myasthenia Crisis vs.
Cholinergic Crisis
• Myasthenia Crisis
• Exacerbation of the disease.
• Muscle strength improves after Tensilon Test.
• Increase dosage of anticholinesterase agents.
• Cholinergic Crisis
• Too much anticholinesterase drugs.
• No muscle strength noted after Tensilon.
• Stop or decrease dosage of anticholinesterase
agents and give atropine.
• MEDICAL EMERGENCY
SPINAL CORD INJURY
Spinal Nerves
• 31 Pair
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8 Cervical
12 Thoracic
5 Lumbar
5 Sacrospinal
1 Coccygeal
Spinal Cord Injury
• High neck fractures (above C3).
• Apnea.
• All respiratory muscles are affected.
• Mechanical ventilation/Tracheostomy.
• Injury to C3-C8 is a quadriplegic but
retains some use of respiratory muscles.
• Night-time mechanical ventilation.
• Injury below C8.
• Cough weak and ineffective secretion
removal .
• Loss of function of abdominal muscles.
Amyotrophic Lateral Sclerosis
Lou Gehrig’s Disease
• Anterior Horn Cells.
• Weakness of hands and less often in the feet.
• The site of onset is random, and progression is
asymmetric.
• Dysarthria and dysphagia are due to involvement
of brain stem nuclei and pathways.
• Sensory systems, voluntary eye movements, and
urinary sphincters are spared.
• Rarely, a patient survives 30 years
• 50% die within 3 years of onset.
• 20% live 5 years.
• 10% live 10 years.
• ALS can strike anyone.
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Male or female
Any ethnic origin
At any age
Some have been diagnosed as teens
Usual onset is in middle age
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