Myasthenia Gravis Case Study

Original Editor - Alisha Oliver Top Contributors - Alisha Oliver, Kim Jackson, Emmy Arsenault and Lydia Straznicky

Abstract

The purpose of this fictional case study is to explore the physiotherapy assessment and treatment progression of a 35 year old woman diagnosed with myasthenia gravis (MG), class IIa. The patient discussed in this case study presents with fatigable weakness affecting mainly her upper limbs as well as diplopia. Due to an increased workload, the patient developed right shoulder pain, leading her to seek physiotherapy care. The physiotherapist developed an individualized treatment plan based on the patient’s short and long term goals which involved education, self management strategies, resistance and aerobic exercises, and manual therapy. Outcome measures (QuickDASH and MG QoL 15) were completed upon initial assessment and discharge to assess her progression throughout the 6 week treatment period. By the end of the treatment period, the patient had met all her treatment goals and continued to work on self-management of her MG.

Introduction

Myasthenia Gravis (MG) is a neurological condition involving dysfunction at the neuromuscular junction . It is a rare, but chronic, auto-immune disease that is said to affect approximately 1 in 5000 Americans of varying races, ages and genders .

MG is caused when there is an interruption in the communication between the nerve impulse and the muscle at the neuromuscular junction. Antibodies can be formed by a dysregulated immune system and they block or destroy the acetylcholine receptors that would normally be responsible for muscle activation . Because of this, the disease presents mainly with generalized weakness and fatigue in any or all of the muscles of the limbs, eyes, face, respiratory system or trunk .

Due to the nature of the condition, MG (also coined “the snowflake disease” because it affects each individual differently) can pose some challenges when forming treatment plans . Sometimes, a patient's condition may decline with too much activity, but they may also lose muscle mass to disuse. It is important to work with the patient to find an optimal balance to allow them to achieve their goals and daily activities.

The purpose of this case study is to examine the physical therapy assessment and treatment intervention for a 35 year old woman diagnosed with MG experiencing mild-moderate symptoms.

Working as a librarian at a high school, in December 2017 the patient noticed her eyelids were drooping while she was taking off her makeup before bed. Over the Christmas break she began to notice double vision and arm weakness while reading which became progressively worse. She visited her Primary Care Physician in early January 2018 who referred her to a local neurologist after having concerns. During her appointment with the neurologist, he ran a blood test and found high levels of acetylcholine receptor antibodies. After her blood test results and a physical exam, he diagnosed her with Myasthenia Gravis (MG), class IIa. She was prescribed a cholinesterase inhibitor medication and took time off work to help with her symptoms. Over the summer break, the patient continued to take her medication and took time to rest and relax. She noticed improvements in her condition and was eager to return to work in late August to prepare for the upcoming school year. During the second week back to work, she began to notice pain in her right shoulder and found herself exhausted by the end of the day. Unable to keep up with her workload and increasing pain in her shoulder, she decided to go to a physiotherapist recommended to her by one of the teachers at her school. Additionally, the patient has a history of hyperthyroidism from the age of 20 and has been treating it with an anti-thyroid medication successfully. 

Client Characteristics

The patient is a 35 year old woman from Peterborough, Ontario who works as a librarian in a high school. She lives with her husband and dog in a two-story house in the suburbs near the high school. The patient decided to try an outpatient physiotherapy clinic for her increasing shoulder pain over the past 3 weeks. She also hopes to get some help with her generalized muscle weakness and fatigue that is preventing her from completing her daily activities and work.

Examination Findings

The patient came in for a physiotherapy assessment on Monday, September 10, 2018 at 4:00 pm.

Subjective

Patient reported an aching pain in her right shoulder with occasional shooting pain when reaching too high overhead on bookshelves. She reports having little to no pain at the beginning of the day but it progressively gets worse and by her lunch break she is unable to unload a full cart of books. After taking a 30 minute lunch break, her fatigue and pain improves and she prefers finishing the rest of her day with computer work. By the end of the day, she notices her vision becomes slightly blurred and finds it worsens when driving home. Patient reports feeling frustrated with her exhaustion at the end of the day and is unable to do her normal activities with her husband including cooking and walking the dog because of arm weakness. Patient reports having a nap when she gets home from work and sleeping well through the night. No red flags were detected.

Objective

• General observation: slightly drooping eyelids, slight forward head posture, small anterior translation of the right head of the humerus, winging of the right scapula
• Palpation: increased tightness in right pectoralis major and upper fiber trapezius

• VAS: 1/10 at beginning of day, increases to 7/10 after increased workload
• Gait observation: slight decrease in arm swing, particularly on the right side
• AROM: right shoulder flexion 90° and abduction 100° (limited by pain and weakness), all other major upper and lower extremity joints within normal ranges
• Right Shoulder PROM: full range with normal end feel
• Upper Motor Neuron Tests: normal
• Reflexes: normal
• Skin sensation and dermatomes: normal and intact
• Myotomes: positive testing with fatigable weakness in shoulder elevation and abduction
• Strength: shoulder flexion and abduction ⅖ MMT, scapular protraction and retraction ⅗ MMT, wrist and elbow ⅘ MMT
• Myasthenia Gravis - Quality of Life 15 (MG - QoL 15): 12/30
• Quick Disability of Arm, Hand, and Shoulder (QuickDASH): 43.2%

Clinical Impression

Physiotherapy Diagnosis

Impaired motor function and fatigable weakness affecting upper extremities and face, with significant impairments affecting the functional mobility of the right dominant shoulder as the day progresses. Difficulties completing instrumental activities of daily living and occupational duties.

Problem List

1. Unable to complete IADLs and activities at work due to shoulder pain and fatigable weakness.
2. Unable to reach above head due to decreased ROM and strength in shoulder flexion and abduction.
3. Sub-optimal alignment in the right shoulder due to muscle imbalances.
4. Unable to work at her computer for long periods of time due to diplopia and eye fatigue.

Intervention

Short Term Goals

1. Be able to complete a full work day without having to stop from fatigue by the end of the first week.
2. Reduce shoulder pain to 0/10 at the beginning of the day and 4/10 after work by 2 weeks.
3. Increase shoulder active range to 110° flexion and 120° abduction by 2 weeks.

Long Term Goals

1. Improve QuickDASH score to 30% by 6 weeks.
2. Improve MG QoL 15 score to 8/30 by 6 weeks.
3. Increase shoulder flexion and abduction strength to 3+/5 MMT and scapular protraction/retraction to ⅘ MMT by 6 weeks.
4. Be able to work in the kitchen with her husband for an hour (cooking and cleaning) without fatigue or pain every second night by 4 weeks.

Management Program

Education/Self Management

1. Management at work:
   • A discussion about pacing activities appropriately throughout the day to minimize fatigue took place. With the patient, we came up with a work schedule that gives her ample breaks throughout the day. She will space out  30 minutes of stocking shelves/loading book carts with 30 minutes of restful computer work to help minimize fatigue. Additionally, it was suggested that she find a dark and quiet room during her lunch break and attempt to take a nap if possible. Research shows 5 minutes of napping or more during the day helps decrease neuromuscular fatigue . To improve blurriness and vision while looking at the computer screen, a glare screen and screen reading software can be installed .
2. Management at home:
   • Patient can use electronic devices/power tools to help decrease fatigue and reserve energy (i.e. electric toothbrush) and a bench can be installed in the shower to increase patient safety .
3. Patient can join the Canadian MG Facebook support group where patients and caregivers can offer practical ideas for coping and living with the condition as well as emotional support .

Resistance Exercise

Patient will perform right scapular punches in supine with a 1lb weight, assisted active right shoulder flexion and abduction with a broomstick, and middle trap prone T’s with bodyweight. All exercises will be done 2-3 times per week at 3 sets of 8 repetitions. It is very important that she takes adequate rest between sets such that her MG symptoms do not worsen. Resistance exercise is shown to increase proximal limb muscle function, increase muscle mass, and improve patient confidence in exercising in patients with mild MG . It is important to note that the patients in the study mentioned had a long disease duration of MG (4-40 years) while our patient has a disease duration of less than one year, so it is difficult to know if the outcomes of resistance training in this study can be generalized to our patient. We should carefully monitor her reaction to the exercise program. Adequate rest time between sets of resistance training is important to minimize worsening of MG bulbar symptoms in patients with mild to moderate MG who are participating in a resistance training program .

Aerobic Exercise

Patient will go on a 20 minute walk at a moderate pace every second day with one rest halfway. If the patient wants to bring her dog on the walk ensure the leash is tied around the waist to avoid holding it with her right arm. Aerobic training was shown to improve the patient’s score in the 6 minute walk test and 30 second sit to stand test in patients with mild MG . It should be noted that the participants in this study participated in an exercise program that involved both resistance and aerobic training, so it is difficult to determine whether these benefits were due to the resistance aspect, aerobic aspect, or both. Low impact aerobic exercise was shown to help decrease fatigue, increase strength, and improve functional mobility .

Manual Therapy

During treatment sessions, soft tissue release will be done to address the increased tightness in the pectoralis major and upper fiber trapezius. This aspect of treatment will also help provide some relaxation for the patient.