neuro myasthenia gravis

  1. mys=
    • muscle
    • weakness
  2. A chronic disorder of the neuromuscular junction that interferes with the chemical transmission of acetylcholine between the axonal terminal and the receptor sites located in the muscle cell membrane.
    myasthenia gravis
  3. cause of myasthenia gravis is
  4. Loss of function of acetylcholine receptors on muscle cell membrane (sarcolemma) results in muscle weakness and potentially
    paralysis in a descending pattern (think Mind to Ground)
  5. Myasthenic crisis refers to exacerbation of symptoms that result in
    respiratory impairment
  6. Symptoms improve with administration of what type of drugs
    anticholinesterase drugs
  7. clinical signs of myasthenia gravis is slow to abrupt onset- weakness of the
    facial muscles, particularly of the eyelids
  8. drooping of the eyelids
  9. double vision
  10. tongue and laryngeal muscles may also be affected- 2 types of impairs
    • speech
    • swallowing
  11. Progression of weakness moves from
    upper to lower extremeties
  12. Short-acting anticholinesterase drug
    10 mg is injected via IV while areas of major muscle weakness are observed
    Muscle weakness will resolve within 20-30 seconds and remain nearly normal for a few minutes if MG is the cause of the patient’s weakness
    tensolin test
  13. Confirm the diagnosis
    Identify the muscles involved
    Determine the degree of fatigability
  14. Presence of thymoma by:
    • Computed tomography (CT) scan
    • Magnetic resonance imaging (MRI) scan
  15. Pulmonary function testing
    • Decrease in volumes and expiratory flows
    • Obstructive AND Restrictive pattern
  16. Arterial blood gases
    • Respiratory acidosis (↓pH, ↑PCO2)
    • Acute ventilatory failure

  17. Inhibit the function of cholinesterase, increasing the concentration of acetylcholine to compete with the circulating anti-acetylcholine antibodies, which interfere with the ability of acetylcholine to stimulate the muscle receptors

    Tensilon (edrophonium chloride)
    Cholinesterase inhibitors
  18. Prostigmin (neostigmine)
    -Overuse may result in a cholinergic crisis, which is characterized by
    increasing muscle weakness and which, through involvement of the muscles of respiration, may result in death
  19. due to an increase in the severity of the disease, is also accompanied by extreme muscle weakness, and thus may be difficult to distinguish from cholinergic crisis on a symptomatic basis

    what type of chrisis
    Myasthenic crisis
  20. Corticosteroids
    Cyclophosphamide (Cytoxan, Neosar)
    Azathioprine (Imuran)

    are what type of drugs
  21. Administration of adrenocorticotropic hormone (ACTH)

    is what type of therapy
    Adrenocorticotropic Hormone Therapy
  22. removal of the thymus
  23. Replacing patient’s plasma with human processed plasma (human albumin)
  24. But what is our role? - Respiratory Therapy
    • Vital capacity (VC)
    • Normal is 60-80ml/kg
    • <10 ml/kg = impending ventilatory failure

    Negative inspiratory force (NIF) or maximal inspiratory pressure (MIP)

    Measurement greater than -20 to -30 cmH2O usually indicates severe weakness of the inspiratory muscles

    • Oxygen therapy
    • Bronchopulmonary hygiene therapy
    • Hyperinflation therapy
    • Mechanical ventilation if patient clinically demonstrates impending or acute ventilatory failure (↓pH, ↑PCO2)
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neuro myasthenia gravis
neuro myasthenia gravis