Myasthenia Gravis - PowerPoint PPT Presentation

Loading...

PPT – Myasthenia Gravis PowerPoint presentation | free to download - id: 45b056-MWE5O



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Myasthenia Gravis

Description:

Myasthenia Gravis. The textbook and clinical perspectives. Amy Dossey BSN, RN, CNRN. Libby Cyran BSN, RN – PowerPoint PPT presentation

Number of Views:634
Avg rating:3.0/5.0
Slides: 17
Provided by: stvincent6
Learn more at: http://www.stvincent.org
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Myasthenia Gravis


1
Myasthenia Gravis
  • The textbook and clinical perspectives
  • Amy Dossey BSN, RN, CNRN
  • Libby Cyran BSN, RN

2
History
  • 1672-myasthenia gravis (MG) was first described
    by Sir Thomas Willis, English Physician.
  • Late 1800s-first description of MG published
    and disease named
  • 1959-Proposed to be an autoimmune disorder
  • 1970s-Prednisone and Azathioprine became
    established treatments and plasma exchange was
    introduced

3
Prevalence and Etiology
  • 20/100,000
  • Onset is usually after age 50
  • Etiology is usually acquired autoimmune process
  • 75 of MG patients have thymus abnormalities, 15
    being thymomas. In this case, the abnormalities
    may be responsible for causing an immune attack
    on the receptors

4
Pathophysiology
  • In either case, acetylcholine (AChR) at the
    muscle surface are reduced by autoantibodies,
    resulting in impaired neuromuscular transmission
    and subsequent muscle weakness

5
Types of MG
  • Related to the muscles involved, but also include
    the neonatal and non-immune types
  • Ocular
  • Bulbar
  • Generalized
  • Neonatal
  • Non-immune

6
Presentation
  • Onset is usually insidious
  • Muscle weakness/fatigue with sustained activity,
    improving with rest
  • Diplopia and ptosis (Ocular)-80 of cases
  • Slurred and/or nasal speech (Bulbar)
  • Dysphagia (Bulbar)
  • Shortness of breath (Generalized)

7
Diagnostics
  • Anti-AChR Antibody test-test run on blood serum
    to detect antibodies that bind to AChR
  • Electromyography (EMG)-repetitive nerve
    stimulation is used to observe for decremental
    response
  • Tensilon Test-Edrophonium Chloride (Tensilon), a
    short-acting anticholinesterase inhibitor, is
    administered IV.
  • CT Scan-scan of mediastinum used to rule out
    thymus abnormalities

8
Treatment
  • Medications
  • Anticholinesterase Inhibitors-improves symptoms
    in almost all MG patients ex.) Mestinon
  • Corticosteroids-produces improvement in most
    cases with the best response in recent onset of
    disease
  • Immunosuppressive Agents-reduces production of
    antibodies ex.) Azathioprine, Cellcept
  • Cyclosporine-inhibits T-cell response

9
Treatment
  • Plasmapheresisremoves circulating AChR
    antibodies
  • IVIG-mechanism of action is not well understood
  • Surgery-if thymoma is present, a thymectomy is
    always recommended, although the benefits are not
    well understood

10
Myasthenic Crisis
  • Rare, but potentially life threatening medical
    emergency
  • 15-20 of MG patients will experience crisis in
    their lifetime, typically within the first 2
    years following diagnosis
  • Characterized by respiratory failure requiring
    noninvasive or invasive mechanical ventilation
  • Treatment includes corticosteroids and IVIG or
    plasma exchange

11
Case Study-Background information
  • 66 year old female
  • Diagnosed with MG 3 years ago
  • Regimen of Mestinon and steroids effective
  • Recent stressful life events and self-described
    as high-strung
  • Symptoms bringing her to the ED included trouble
    breathing, severe ptosis and difficulty
    swallowing

12
Case Study-Treatment at OSH
  • IV Mestinon not immediately available but when
    administered saw improvement
  • Nurse to nurse report indicated the problems
    where primarily stress induced and possibly psych
    issues
  • Physician had received information in his report
    that made him suspicious for Myasthenia Crisis.
    Physician waited on unit for patient to arrive.

13
Case Study-Arrival Assessment
  • Severe SOB
  • Unintelligible speech, nasal and garbled
  • Severe bilateral ptosis, left gt right
  • Extraocular movements intact
  • Classic Myasthenia snarl
  • Minor weakness in upper extremities

14
Case study-Initial course of treatment
  • Admitted to Neuro unit but almost immediately
    sent to ICU for Myasthenia Crisis and potential
    for respiratory failure.
  • Vital capacity Q8
  • Continued to receive IV pyridostigmine q3 and
    steroids
  • By the next morning speech was much better and
    swallow study was ordered. SBFT was inserted.

15
Case Study-Patient Outcome
  • Nine day stay, 3 days in ICU
  • 5 day course of IVIG
  • Symptoms waxed and waned with gradual overall
    improvement
  • Released on Pyridostigmine and Prednisone

16
References
  • Alshekhlee, A., Miles, JD. et al (2009).
    Incidence and mortality rates of myasthenia
    gravis and myasthenic crisis in US hospitals.
    Neurology, 721548-1554.
  • Chadhuri, A. and Behan, PO. (2009). Myasthenic
    Crisis. Q J Med, 10297-107.
  • Conti-Fine, BM., Milani, M. et al (2006).
    Myasthenia gravis past, present and future. The
    J. Clin. Invest., 1162843-2854.
  • Polak,M., Richman, J. et al Neuromuscular
    Disorders of the Nervous System. Bader, MK,
    Littlejohns, LR, editors AANN Core Cirriculum
    for Neuroscience Nursing, 4th ed., St. Louis,
    2004, Saunders.
About PowerShow.com