I think a lot of times these patients are not treated appropriately. We really should be timing their treatment and meals with their medication dosages, and providing fewer or shorter sessions including co-treats if necessary so that we don't over-fatigue them and hinder their progress instead of helping. And we also need to be careful not to eat up their outpatient benefits of they are not ready yet, are still in a myasthenic crisis.
Let me know in the comments if you find this helpful or have anything to add.
Good job Julie! Thanks for letting me share this on the blog!
~Kristin
Background, Causes, and Symptoms
MG -
grave muscle weakness
Myasthenia gravis
(MG) is a chronic autoimmune neuromuscular disease characterized by varying
degrees of weakness of the skeletal (voluntary) muscles of the body without any
other signs of neurological deficit. MG may affect any voluntary muscle,
including those used to speak, breathe, and swallow, as well as limb, trunk,
and eye muscles.
Muscle weakness usually occurs
during periods of activity and improves after periods of rest. This waxing-and-waning weakness of muscles, worsening
with use and improving with rest, is a hallmark of this particular disease.
There typically are periods when you may notice more symptoms (exacerbation),
interspersed with periods when symptoms decrease or disappear (remission).
Aside
from generalized muscle weakness, common symptoms include double vision,
dysphagia (oral, pharyngeal, and possibly esophageal), dysarthria, trouble with
balance, and shortness of breath. A myasthenic crisis occurs when weakness
affects the muscles that control breathing, creating a medical emergency.
Deterioration can be abrupt and may require the patient to be put on a respirator.
This can be triggered by infection, fever, medication side-effects, and
emotional stress.
The
general cause of MG is a disruption to the communication between nerves and
muscles at the point of the neuromuscular junction. The specific
neurotransmitter involved is acetylcholine. Though the exact cause of MG is
unknown, it is thought to be related to a thymus gland abnormality, which is a
gland located under the breastbone that is important in developing the immune
system in early life. MG can occur at any age, but is most common in women
under the age of 40 and men over the age of 60. MG is not contagious or fatal,
and does not affect life expectancy. It tends to progress slowly and treatment
is often highly successful. MG typically reaches maximum severity within the
first 5 years after onset, with males having more rapid symptom progression.
Most patients with MG improve to live healthy lives with close to normal
activity levels.
General Treatment: Medical
Factors that determine medical intervention
include severity of weakness, which muscles are affected, patient's age, and
co-morbid medical conditions. Medical interventions are as follows:
- Immunosuppressant Treatments
- Anticholinesterates: drugs that increase muscle strength and contraction; symptom relief can occur in as little as 15-30 minutes, and last as long as 3 to 4 hours; can be administered 3 to 4 times per day, depending on dose size (mg); side effects can actually cause additional weakness and symptoms similar to those of MG.
- Azathioprine: long-term immunosuppressive treatment (around 3-12 month activation period) that gradually improves muscle strength and decreases severity of symptoms.
- Corticosteroid Therapy: improves muscle strength, but also may cause transient deterioration upon initiation of treatment
o High-dose
intravenous immune globulin (IVIG): Can be effective to temporarily modify the
immune system and provide the body with normal antibodies from donated blood.
- Thymectomy
- Surgical removal of the thymus gland. This procedure takes years to have an effect and is used for long-term control of MG, possibly resulting in complete remission.
- Effective for symptom relief in patients under 60 years of age who have a tumor or abnormality of the thymus gland.
- Plasmapharesis
- Plasma exchange therapy typically involving 3 to 5 exchanges of 1 or 1.5 volumes (based on patient's height and weight) per week until the patient shows satisfactory improvement. Usually combined with immunosuppressive treatment.
- Helps to remove antibodies from the body.
- C-PAP or Bi-PAP
- Used with patients whose respiratory muscles are too weak to properly function on their own.
- May be used throughout the day or during sleep as needed, as well as during a myasthenic crisis.
Treatment: Speech-Language Pathology
Voice and Speech:
Voice problems correlated
with myasthenia gravis include vocal fatigue, difficulty controlling pitch, and
a monotone voice. The voice problem can stem from poor breath support, or from
weakness causing disordered vocal fold movement. Speech disturbances include hypernasality
(caused by weak palatal muscles) and dysarthria (particularly slurred speech,
caused by articulatory imprecision). Dysarthria is more frequently seen in
younger patients diagnosed with MG, whereas dysphonia is more often seen in
elderly men with MG. Typically, the symptoms appear and/or worsen with
continuing or extended speech.
The
treatment of speech and voice disorders in MG should occur on an individualized
basis, and should take into consideration the underlying cause and severity of
the problem. Speech and voice treatment should occur in conjunction with
medical treatment, with the SLP planning treatment during peak medication times.
The focus of speech and voice treatment in individuals with MG should be in providing
compensatory strategies and environmental modifications to help increase
intelligibility. Additionally, the patient should be educated on vocal hygiene,
with specific emphasis on vocal rest.
A
high- or low-tech augmentative and alternative communication (AAC) device may
be useful for patients to communicate their wants and needs while resting their
voice. Low-tech devices are particularly recommended during myasthenic crises
when it is expected that the patient will be weaned off the ventilator in under
2 weeks. During periods of exacerbation or crisis, patients should be taught to
communicate using function or content words, thereby decreasing the overall
length of their message and resulting fatigue. Treatment may include strengthening
exercises, but this is not indicated during a myasthenic crisis or exacerbation
(see below for more information). Improvement and prognosis of voice and speech
is often related to the treatment of overall MG disease.
Swallowing:
The impact of MG
on swallowing may occur gradually or suddenly. Swallowing muscles may become
fatigued during a meal in as little as 1-20 minutes. A FEES examination is recommended for assessment because it can be used
over an extended period of time to assess laryngeal fatigue and potential
progression of aspiration throughout a meal. This will help ensure that the
patient's fatigue does not overwhelm their swallowing safety, and will allow
for appropriate recommendations to be made. The SLP should always be sure to
take into account the timing of the patient's medication cycle when
interpreting assessment results. The SLP should carefully schedule the
examination to be at peak performance time (to see the patient's optimal
swallow), or at a less peak time (to observe a more realistic situation). Dysphagia symptoms in individuals with
myasthenia gravis include the following:
Oral
·
anterior
spillage
·
prolonged
and incomplete mastication
·
trouble
forming cohesive bolus
·
oral
residue
·
decreased
posterior lingual bolus propulsion
Pharyngeal
·
delayed
onset of laryngeal elevation and epiglottic inversion
·
vallecular residue due to decreased tongue base to pharyngeal
wall approximation and decreased pharyngeal contraction (with resulting
multiple swallows)
·
decreased overall pharyngeal peak pressure
·
delayed pharyngeal response, possibly causing aspiration
before and during the swallow
·
decreased VF closure, aryepiglottic closure/tightening,
aryteniod-epiglottic approximation, epiglottic retroversion
·
note:
prognosis tends to be poorer in individuals with pharyngeal phase dysphagia
Esophageal
·
the muscles which provide traction
force to open the PES may not produce sufficient force to pull the PES open
·
decreased hyoid elevation and excursion, resulting in
decreased PES opening
·
prolongation in mean duration of the peristaltic wave in the
upper esophagus
Treatment
for dysphagia should be individualized and based on the underlying cause and
severity of the swallowing problem. It should be noted that there is a moderate
risk of silent aspiration in this population, and decreased pulmonary function
can lead to a myasthenic crisis. Signs and symptoms of aspiration (coughing, throat
clearing) should be minimized at all costs to reduce the risk of fatigue in the
respiratory muscles. If these signs and symptoms are present during treatment, allow the patient time to rest and recover muscle function before proceeding.
o exercise
is generally not recommended due to patient fatigability and energy expenditure,
particularly during
a myasthenic crisis or exacerbation. However, an active strengthening program
may be implemented during periods of stability or remission, considering that
medical treatments are stable and well-managed.
o consistent
exercise will elevate the patient's baseline functional capacity, and thereby
decrease the effect of future MG exacerbations and likelihood of aspiration.
o low
intensity exercise (60% of max or less) is most beneficial to maintain and even
regain some muscle strength and function.
o
Recommended
exercises:
§
Masako: improve bilateral pharyngeal
contraction
§
Mendelsohn: improve laryngeal
elevation
o Precautions:
§
always closely monitor for immediate during- or post-exercise
fatigue, as evidenced by decreased swallowing or speaking function. If fatigue causes
functional impairment, reduce the exercise intensity.
§
do not prescribe or practice
exercises around meal times.
§
try to complete exercises at peak
medication time, near 1.5 to 2 hours post-dosage of anticholinesterase.
§
collaborate
and communicate with the patient's other therapists to make sure that he or she
is not overwhelmed by the sum of all of the individual areas of therapeutic
exercise.
Diet considerations:
o patient strategies can include:
§ Alternate liquid/(semi)solid swallows to wash thicker
material down.
§ Consider diet with softer textures, less chewing required.
§ Multiple swallows per bite to clear residue (use with
caution because series of repetitive swallows may be too fatiguing).
§ Eat several small meals throughout the day, rather than 3
large meals.
§ Eat
calorie-rich foods as much as possible to ensure adequate nutrition.
§ Crushing
or halving pills to reduce swallow effort and risk of aspiration.
o warm
liquids, like coffee, tea or soup, can relax swallowing muscles and further
exacerbate swallowing difficulties. Ice chips can be a great alternative.
o very
hot, spicy, and dry foods may trigger MG symptoms.
o introduce
potassium-rich foods if a deficiency is the source of muscle weakness.
o consider
patient quality of life when making diet recommendations. Limiting diet in
patients who already find eating to be a chore may lead to more negative
reactions toward food.
o if
the patient has moderate to severe dysphagia, an NG or PEG tube may be
indicated as primary or secondary means of nutrition and hydration.
Positioning
o a properly-fitted
removable cervical collar can help support the patient's neck and reduce muscle
fatigue.
o sitting fully
upright will reduce the risk of nasal regurgitation.
o when considering
compensatory swallowing maneuvers, always try strategies that require less
effort first before those that
require more effort (e.g., chin tuck before supraglottic swallow).
o effective
minimal-effort strategies
§
head turn: decreases pharyngeal pooling by narrowing pharyngeal area to compensate for lack of
muscle constriction.
§
have the patient turn to the weak side
(if unilateral weakness) to divert the bolus to contralateral stronger side .
§
head
tilt: toward stronger side (if unilateral weakness) to compensate for oral
and/or pharyngeal weakness.
§
chin
tuck: compensate for reduced bolus control with aspiration before or during the
swallow.
Timing
o be sure that the
patient has adequate rest time before meals or PO trials, and avoid
conversation during these times.
o time the patient's
meals around their medication cycles (especially those that are intended to
improve muscle function).
o due to the fact
that muscle weakness usually occurs during periods of activity and improves
after periods of rest, the patient should have a rest break between each
therapy session.
o patients
benefit from shorter treatment sessions with frequent rest breaks.
Neuromuscular Electrical Stimulation (NMES)
o aim
to strengthen muscles without causing fatigue.
o since
not all motor end plates are affected to the same degree in MG, some motor
units (ones that are less affected) may have greater capacity for improvement than
others.
o limited
research base for NMES in this population. The following are recommended guidelines:
§ Initiate a conservative exercise program at moderate
exercise intensities while closely monitoring for fatigue and functional
decline.
§ Add electrotherapy to facilitate the process if no
progress is made but only if no functional declines were observed.
§ If still no progress is made and/or functional
declines are observed, stop electrotherapy.
o
functional
decline with NMES will be noticeable during or immediately after the very first
session. If this is observed, NMES should not be considered as a therapeutic
option for that patient.
Dysphagia may persist when other
clinical symptoms have improved. It is important for patients to have their
swallowing function re-assessed every 3 months, even when in a long-term remission period. This helps to manage potential
aspiration before it adversely affects pulmonary function and creates a
possible exacerbation of MG symptoms. The patient should be extensively
educated on signs and symptoms of aspiration and beginning signs of pneumonia,
in order to ensure on-going self-monitoring skills. The SLP should also make it
a focus to reduce the patient's stress and anxiety as much as possible during
his or her stay in the hospital, due to the impact of increased stress
and emotionality on a myasthenic crisis. This can be achieved through
education, collaboration, and building rapport.
References:
Duhon, K. & Tompkins, S. Myasthenia Gravis: Treatment of Swallowing Disorders (Retrieved from http://www.ucs.louisiana.edu/~ncr3025/roussel/codi531/MG2.htm)
Grob, D., Arsura, E. L., Brunner, N. G., & Namba,
T. (1987). The course of myasthenia
gravis and therapies affecting outcome. Ann
N Y Acad Sci. 505:472–499. doi:
10.1111/j.1749-6632.1987.tb51317.x.
Howard,
J. F. Jr., Ed. (2008). Myasthenia Gravis: A manual for the health
care provider. Myasthenia Gravis Foundation of America. (Retrieved from: http://www.myasthenia.org/LinkClick.aspx?fileticket=S472fPAE1ow%3D&tabid=69)
Juan, H.-C., Tou,
I., Lo, S.-C., & Wu, I.-H. (2010). Efficacy
of postural techniques assessed by videofluoroscopy for myasthenia gravis with
dysphagia as the presenting symptom: a case report. Journal
of Medical Case Reports, 4, 370. doi:10.1186/1752-1947-4-370
(Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3009659/ )
Myasthenia
Gravis Foundation of America, Inc. (www.myasthenia.org)
Patient
Education Institute, Inc. (2012). Myasthenia
Gravis. National Library of Medicine. (Retrieved from http://www.nlm.nih.gov/medlineplus/tutorials/myastheniagravis/nr239106.pdf)
Schwartz, D.C., Waclawik, A.J., Ringwala, S.N., & Robbins,
J. (2005). Clinical utility of
videofluorography with concomitant Tensilon administration in the diagnosis of
bulbar myasthenia gravis. Dig
Dis Sci.;50:858–861. doi: 10.1007/s10620-005-2653-2.
Vital
Stim Therapy System (2009). Guidance from the literature: Myasthenia Gravis (Retrieved
from http://www.vitalstim.com/uploadedFiles/Health_Professionals/Certified_Provider_Resources/Disease_Specific_Information/MG_111309.pdf)
