Charcot-Marie-Tooth Disease: A Case Study

Abstract

This is a fictional case presentation based on a university aged varsity male soccer player who incurred a recent diagnosis of Charcot-Marie-Tooth Disease (CMT). The case study documents from the initial physiotherapy assessment and diagnosis through to follow up treatments throughout the patient’s lifespan. It highlights the primary challenges experienced by the patient, the patient-centered goals, the intervention methods and rehabilitation program, and the outcomes. The patient complained primarily of difficulties walking to and from class, increases in tripping while walking/running, a significant decrease in ability to play an entire game of soccer, and problems with cutting and shooting accuracy during soccer practices/games due to foot drop, calf pain, and lower extremity muscle weakness and fatigue. The initial assessment and use of specific outcome measures indicated bilateral antero-lateral muscle atrophy and increased tone of lower extremities, decreased DTR's, loss of ROM dorsiflexion on R side, reduced muscular strength bilaterally, fatigue, abnormal gait, and slight balance impairments. Interventions focused predominantly on the maintenance of lower extremity strength to preserve the patient’s functional ability and independence. Aerobic exercise was another large component of treatment due to the high risk of reduced peak oxygen consumption in CMT patients. Patient education regarding overtraining and self management will be a vital component throughout the progression of the disease as well as frequent balance assessments to reduce risk of falls. The prescription of stretching exercises and daily mobility is crucial to maintaining status. The use of an AFO will aid with dorsiflexion, improve gait, and decrease risk of falls. Through the use of manual muscle testing and the Fatigue Severity Scale, it was confirmed that the patient was able to maintain muscle strength and fatigue. The stretching and mobility exercises were successful at maintaining ROM and preventing the development of contractures. The use of the Community Balance and Mobility Scale as well as the 10 Meter Walk Test will be continued throughout the patient’s life to assess for balance and gait deficits. Follow up with the patient will take place every 4 months to assess the progression of the disease and adjust the rehab program as needed. This case study is written in the hopes that it will inform health care practitioners about common signs and symptoms of CMT, progression of the disease, the use of CMT specific outcome measures, evidence based intervention methods, and predicted outcomes for patients with CMT.

Introduction

This case study presents an 18-year-old male recently diagnosed with CMT disease type 1.  CMT disease is the most common genetically inherited neuromuscular disorder affecting approximately 1 in every 2500 people [1]. There are two major subtypes of the disease, with type 1 characterized by slow nerve conduction as a result of demyelination, and type 2 associated with axonal degeneration [2]. Both subtypes primarily affect motor neurons with sensory nerves affected to a lesser extent [2]. The onset of CMT disease typically occurs in the first 20 years of life and often has a slow progression [3]. Although the progression of the disease varies, symptoms commonly first arise in the distal lower extremities, with muscle weakness, sensory loss, and reduced reflexes [3]. As CMT disease progresses, the proximal lower extremities, as well as upper extremities can also become affected [2].

The purpose of this case study is to provide an example of how an individual may present with CMT disease in the early stages. This information may assist physiotherapists or other healthcare providers in recognizing the symptoms of CMT disease and knowing when to refer their patient to a neurologist to make a diagnosis. As previously mentioned, the onset and progression of the disease can vary. Therefore, this case represents how a more conventional patient may present. It is possible for the disease to have a much earlier onset and present with a more rapid progression, as seen in a case study on a Paralympic swimmer with CMT disease [4]. Moreover, this case provides examples of outcome measures that can be used to measure the progression of CMT disease over time. Due to the degenerative nature of the condition, symptoms cannot be improved. However, various interventions are outlined in this case study that can be utilized to assist in slowing the progression of the disease.

Client Characteristics

The patient is an 18 year old male Queen's University student and varsity soccer player. He was referred to physiotherapy by a neurologist with a recent diagnosis of Charcot-Marie-Tooth Disease but was previously very fit with no significant medical history. He spends most of his time in class or at soccer practices/games. The patient complains of difficulties walking to and from class and around campus/town as well as significant decreases in ability to play a full game of soccer due to foot drop, calf pain, and bilateral lower extremity muscle fatigue and weakness. He also indicates tripping often while walking/running and problems with shooting accuracy and cutting during soccer practices/games. Finally, the patient reports a progressive decrease in his ability to sleep.  

Examination Findings

Subjective

Discomfort and Pain

Onset: April 16th, 2019 (3 wks ago)
Body Diagram.png
Site: bilateral antero-lateral lower leg

Characteristics: deep, dull ache or sharp and shooting

Radiation: antero-lateral leg to dorsum of the foot

Periodicity: intermittent, no discernable pattern

Duration: varies from 10-30+ minutes.

Aggravating factors: activities such as soccer or walking to class

Alleviating factors: rest

Intensity: McGill Pain Questionnaire [5]:Sensory: 8/33, Affective: 4/12, VAS: 4/10

Objective

Observation

Lower extremities: slightly more right side calf muscle atrophy when compared to left but present bilaterally predominantly in the antero-lateral portion of the shank. Pes planus foot presentation bilaterally.

Palpation: increased tone bilaterally in the antero-lateral portions of the shank, gastrocnemius, and soleus muscles. Hypertrophic nerve, predominantly the common and superficial peroneal nerve, is palpable but not visible.

Examination

Upper and Lower Neurological Scan
  • Physiological ROM: Cervical and lumbar: WNL
  • Non-physiological ROM: Cervical and lumbar: WNL
  • Dermatomes: normal.
  • Myotomes: decrease strength through L4- S1 bilaterally.
  • AROM: right dorsiflexion slightly diminished but all other movements for upper and lower extremity WNL.
  • Dural testing: negative Spurling's Test, Straight Leg Raise Test, and Slump Test.
  • Reflexes: negative Babinski and Hoffman’s, decreased deep tendon reflexes bilaterally (Achilles and patellar).
  • Vascularity: radial and tibial pulses found bilaterally.
Range of Motion
  • Composite functions of the hand: full
  • Upper extremity: All joints WNL.
  • Lower extremity: 14° of dorsiflexion on right side, all other joints WNL.
Muscle Strength Testing
  • Grip strength using dynamometer:
    • Dominant hand (R) 52.1 kg, non-dominant hand (L) 49.4 kg
  • Maximal Voluntary Isometric Contraction:
    • Reduced strength bilaterally with ankle dorsiflexion (R: 3+/5, L: 4/5), great toe extension (R: 3+/5, L: 4/5), eversion (R: 3+/5, L: 4/5), plantar flexion (R: 4/5, L 4/5), knee flexion (R: 4/5, L: 4+/5)
  • Repeated Body Weight Calf Raises to Fatigue:
    • R: 7 reps; L: 13 reps
Neurological Testing
  • Deep Tendon Reflexes:
    • Biceps, brachioradialis, and triceps: 2 (normal)
    • Achilles and patellar: 1 (depressed but present)
  • Sensation Testing:
    • Issues with differentiating between hot and cold stimuli throughout the L4-L1 distributions but not between 1st and 2nd toes.
    • Intact differentiating to soft touch, dull/ sharp, and crude pressure.
CMT Specific Outcome Measures
  • Fatigue Severity Scale (FSS) [6]: to measure fatigue, activities of daily living, life participation, and sleep.
    • Score= 49/63
  • CMT Neuropathy Score [7]: measure of disability
    • Score= 12 /36
  • Overall Neuropathy Limitations Scale (ONLS)[8]:
    • Upper Limb Score= 0/5 (arms not affected)
    • Lower Limb Score= 2/7(Walks independently but gait looks abnormal)
    • Total score= 2/12
  • 9-Hole Peg Test (9-HPT) [9]: for hand dexterity
    • Dominant= 18.3 seconds, non-dominant= 19.1 seconds
Balance Assessment
Gait Analysis
  • 10 Meter Walk Test (T10MW) [11]:
    • Score= 1.1 m/sec
  • Observation:
    • Step and stride length WNL, stride width WNL, no noticeable deviation from normal time spent in single and double support, stance phase slightly longer on the left side, and swing phase slightly longer on the right side. There is a lower walking speed of 1.1 m/sec as measured by the T10MW but data still within normal limits. Foot drop was detected as well as decreased dorsiflexion at the level of the right ankle. The pelvis shows slight hiking on the right and there is a marginal trunk lean to the left possibly to allow for clearance of the right lower extremity. Arm swing is normal and reciprocal.

Clinical Impressions

PT Diagnosis: 18 year old male recently diagnosed with Charcot-Marie-Tooth Disease presenting with decreased muscle strength and endurance, increased muscle fatiguability, balance and sensory deficits, gait abnormalities, and pain in lower extremities. Condition is affecting patient’s ability to participate in sport and get to and from classes.

Problem List

  1. Decreased muscle strength and endurance
  2. Increased muscle fatiguability
  3. Minimal balance deficits
  4. Gait abnormalities (decreased dorsiflexion, tripping, foot drop)
  5. Pain in lower extremities

Intervention

Short Term Goals

  • Decrease pain to a 3/10 on the VAS and McGill Pain Questionnaire using AFO and avoid contractures in the lower limbs through ROM exercises and stretches for the first 4 weeks of therapy.
  • Maintain strength at 3+/5 for dorsiflexion bilaterally and maintain endurance of the lower limbs using the Fatigue Severity Scale (49/63) and The Repeated Plantar Flexion to Fatigue Test (R: 7, L: 13) by using strength and aerobic training protocols for the first 2 weeks of therapy.
  • Educate the patient on the importance of exercising and energy conservation techniques during the first treatment session.
  • Develop plans to maximize energy efficiency and reduce fatigability (ex. planned walking routes on campus) during the initial treatment sessions.
  • Improve gait through the use of an AFO and gait retraining to maintain pain at 4/10 on VAS and McGill Pain Questionnaire and maintain score on 10-m Timed Walk at 1.1m/sec throughout the first 4 weeks of treatment.

Long Term Goals

  • Limit the speed of progression of the disease as well as limit any new symptom development through the provided exercise programs, patient education, self management techniques, energy conservation,  follow up treatment sessions, and the continuous use of the ONLS and CMT Neuropathy Score.
  • Be able to more comfortably and efficiently commute to classes with the use of planned walking routes designed in initial therapy sessions. Determine this through subjective history during follow up treatment sessions.
  • Maintain exercise and activity to remain physically fit with prescribed exercises.

One of the main focuses for our patient is the maintenance of strength in the lower limbs. Although a disease such as CMT is progressive and strength gains will likely not be made, maintaining strength is important in optimizing the patient's functional ability, independence, and safety. The strength program developed will be a progressive home-based program using ankle weights. Research indicated that lower body exercise using ankle weights 3 days per week increased led to improvement in knee tension and increased type 1 fibre diameter [12]. Exercises would consist of resisted ankle dorsiflexion, eversion, and inversion as well as hip strengthening exercises such as abductions, flexion, and extension.   It is also common for CMT patients to develop reduced peak oxygen consumption and exhibit a decreased functional aerobic capacity, therefore we would suggest and prescribe an aerobic exercise 3 days per week at roughly 70% of the patient's max heart rate [12][13]. Education would also be a vital component, specifically on the importance of not overtraining that may lead to overwork weakness [14]. Through our assessment, we also found some small balance deficits. Ultimately these are likely due to strength in the lower limbs and will be addressed by the strength program, however, continual balance assessments will be completed to assess falls risk and would be addressed if a further decrease in balance was found.

Due to weakness found in the patient's ankle dorsiflexors, this could lead to increased tone and tightening of the gastrocnemius and soleus muscles as well as fibrosis of the achilles tendon. These changes could all put the patient at high risk for developing ankle contractures [15]. In order to avoid these changes and maintain appropriate joint range of motion the patient was prescribed to do a minimum of 2 to 3 hours a day of standing or walking as well as some passive stretching exercises 2-3 times per day for the structures at risk for contractures[15]. Passive range of motion exercises have been shown to be effective in delaying the development of contractures in CMT [15].

With walking, because the patient has expressed tripping issues that can be attributed to drop foot and sensory deficits, a custom ankle-foot orthoses (AFO) has been recommended. There are many benefits in wearing an AFO for those with CMT, including improvement in walking economy by reducing the energy cost of walking compared to just wearing shoes [16]. AFO’s have also been shown to increase gait velocity, increase comfort, decrease pain, improve lower extremity control during walking, and very importantly increase dorsiflexion and therefore reducing foot drop in patients with CMT [7][17][18]. On top of this recommendation, the patient was also provided with gait training and education in order to allow for normal gait biomechanics in the hopes of decreasing compensatory muscle recruitment and improving energy efficiency [19].

As the patient presented with symptoms of muscle fatigue, and with overwork weakness being a common finding in CMT, it was decided that education on energy conservation techniques would be one of the focal points during treatment [7]. The education included advice on pacing himself with activities and ensuring adequate rest periods, planning out the most efficient walking routes while on campus, and making sure he wears his custom AFO once received in order to optimize his biomechanics and improve his walking efficiency. Unfortunately, it was also recommended that the patient discontinues playing competitive soccer in order to prioritize other activities of daily living from an energy cost standpoint. Lastly, because the patient reported difficulties with sleep, and because it is known that CMT may predispose patients to sleep conditions such as obstructive sleep apnoea and restless leg syndrome, it was decided that the patient be referred back to his family doctor with the recommendation of seeing a sleep specialist [20].

Outcome

Using the strength and aerobic protocols provided, our patient managed to maintain strength and fatigue. This was confirmed using manual muscle testing where it was found that the patient presented with 3+/5 for dorsiflexion bilaterally, and a score of 47/63 on the Fatigue Severity Scale. The ROM exercises combined with the 2-3 hours per day of standing or walking successfully prevented the patient from developing contractures in his gastrocnemius, soleus, and achilles tendon, and the patient reported no decreases in dorsiflexion ROM. This was confirmed through measurement as the patient maintained 14° of dorsiflexion. With this patient, there will be no formal discharge as CMT is a progressive disease and will require progressions and changes to treatment. The patient will be provided with the self-management techniques and training methods for at home use. Follow up approximately every 3 months to assess progression of the disease, re-test outcome measures, prescribe new exercises and self-management to ensure maximal retention of function. No issues were found with the upper extremities but would be monitored during follow up sessions using dynamometry, 9 hole peg test, CMT neuropathy score, ONLS to assess changes in function. The patient is, however, being referred out to both a clinic that specializes in custom orthotics in order to get him his custom AFO, as well as back to his family doctor with the recommendation of getting a referral to see a sleep specialist. These referrals are necessary in order to improve the patient's activity and participation impairments.

Discussion

A 18 year old male with a recent diagnosis of CMT 1 was referred to us for physical therapy treatments. An examination which brought to light the patients issues with tripping, playing soccer, intermittent pain, and fatigue in his daily life as well as visible muscle atrophy, decreased hot/cold sensation, diminished deep tendon reflexes, decreased dorsiflexion on the right side, decreased strength bilaterally, and gait abnormalities (hip hike, trunk lean, and foot drop) informed our interventions. All deficits were limited to the lower extremity, specifically the calf, ankle, and foot, and had not yet progressed to the upper extremity as shown by the normal performances on the 9-Hole Peg Test, the hand dynamometer, and the upper extremity portion of the ONLS. The FSS measured fatigue, activities of daily living, life participation, and sleep and found a relatively high score of 49/63 indicating fatigue issues. The patient scored a 12/36 on the CMT Neuropathy Score measuring disability which illustrates that the patient is able to walk independently however an AFO is required. This is supported by the fact that the patient scored a 2/7 on the lower limb score of the ONLS as they were able to walk independently but the gait was abnormal. Referrals to a sleep clinic and orthotics specialist were warranted as his lack of sleep was affecting his participation and activities of daily living and the AFO has been proven to decrease pain, increase gait speed, and improve overall function [16][17][18][19]. The focus of the physical therapy interventions were to maintain function and mobility and where possible increase these areas by decreasing pain and increasing the patient’s quality of life. Attention in the initial sessions was on maintaining aerobic capacity and muscle strength as balance, shown with the score of 81/96 on the CBMS, is only slightly impaired and may be a result of progressive weakness and can be addressed in subsequent sessions once strength is optimized. Treatments such as gait training, range of motion, and stretching exercises were also given to maintain the normal, yet slightly slower than average, gait speed of 1.1 m/sec on the T10MW. In cases of CMT, or other neuromuscular conditions such as Guillain Barre, Multiple Sclerosis, and Amyotrophic Lateral Sclerosis, interventions should be aimed at slowing the progression of the condition, optimizing function where possible, and educating the patient on proper self-management techniques to improve their participation and quality of life.

Review Questions

  1. Charcot-Marie Tooth disease is associated with:
  • A)    Nerve demyelination
  • B)    Damage to the neuromuscular junction
  • C)    Axonal degeneration
  • D)    Upper motor neuron lesion
  • E)    Both A and C

Answer: E

2. Which of the following would not be a relevant intervention for someone in the early stages of Charcot-Marie Tooth disease:

  • A)Gait training
  • B)Lower extremity strengthening exercises
  • C)Upper extremity strengthening exercises
  • D)Balance training

Answer: C

References

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