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!
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.
- 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.
- 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.
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:
· anterior spillage
· prolonged and incomplete mastication
· trouble forming cohesive bolus
· oral residue
· decreased posterior lingual bolus propulsion
· 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
· 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.
§ Masako: improve bilateral pharyngeal contraction
§ Mendelsohn: improve laryngeal elevation
§ 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.
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.
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.
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.
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