Primary Lateral Sclerosis (PLS): A Case Study

ABSTRACT

This fictional case study

INTRODUCTION

Primary Lateral Sclerosis (PLS) is a rare, idiopathic progressive neurodegenerative disease that affects the upper motor neurons (UMN) (1,2). Further, degeneration of the motor cortex and corticospinal tracts will ensue with no loss of lower motor neurons (LMN) or disruption to the anterior horn cells (3,4,5,6). While the clinical presentation of PLS is very similar to that of ALS, PLS affects only the UMNs while ALS affects both the UMNs and LMNs (1,2,6). As a result, this often leads to PLS being misdiagnosed as ALS (3,4,5,6,7). In comparison to ALS, the prognosis of PLS is considered to cause less harm as it is not fatal in most cases (2,6). A confirmed diagnosis of PLS can only occur many years later when it is confirmed that there is no LMN disruption (3,4,5,6,7). There is currently not a lot of succinct research surrounding PLS as it is not only similar to ALS but a lot of other neurological conditions as well (2).

Previous case studies found that the clinical signs and symptoms of PLS had to be present, on average, for a minimum of three to five years to conclude a definite diagnosis (3,4,5,6,7). Additionally, those with PLS rarely have a family history of it (1,2,7). PLS is a slowly progressive disease that presents more commonly in males than females (1,2,3,4,5,6,7). The onset of the disease usually occurs between 40 to 60 years of age, with 50 to 55 years of age being the average age in most samples studied (1,3,4,5,6,7).

PLS is characterized by progressive weakness and stiffness involuntary muscles that typically emerge first in the lower extremity. The disease may then progress to the trunk, followed by the upper extremity, and lastly to the corticobulbar tract and can typically cause a pseudobulbar affect (emotional lability) (1,2,3,4,5,6,7). In addition, patients may also experience dysarthria (difficulty speaking) and dysphagia (difficulty swallowing) (1,2,3,4,5,6,7). In a case study by Wais et al. (2016), they found that very few patients displayed symmetrical distribution of symptoms (7). Some patients may undergo latent periods where symptoms seem to subside slightly to allow for more normal functioning (3,4,6). Typical signs and symptoms that patients reported included: weakness, clumsiness, hyperreflexia, increased muscle tone (spasticity), and increased urinary urgency. However, the first sign that patients typically described as a disruption in the smoothness of their gait cycle (1,2,3,4,5,6,7). Patients with comorbidities may present with some signs and symptoms that are not of the typical clinical presentation of PLS, including: sensory symptoms and LMN degeneration such as muscle atrophy, fasciculations, decreased reflexes, or tone (2,3). Most patients will experience a slow spread of symptoms over many years before plateauing indicating a better prognosis and more independent life than ALS (1,2). Death is typically as a result of bulbar dysfunction, malnutrition, or breathing decline (4,6).

https://www.youtube.com/watch?v=dcyAMDAPEeI

With respect to the fictional case study of Mr. Parker, the main challenge experienced during the physiotherapy sessions was managing his sporadic emotional outbursts. This presentation aligns with the emotional lability characteristic of PLS. While these outbursts do not happen often, it does take some time to refocus the session back to the activities that were being performed prior.

The purpose of this fictional case study is to provide a brief overview of what physiotherapy care may involve in an out-patient setting with respect to the assessment and management of an individual in the early stages of PLS. Further, we will discuss the role of physiotherapy in the management and maintenance or adaptation of function associated with PLS. There is currently limited research on such a topic, which is why this fictional case study aims to provide some framework for just that.

CLIENT CHARACTERISTICS

Mr. Parker is a retired 56-year-old male, right-hand dominant, who presents with early-stage PLS. Until about three years ago (2019), he was an avid Crossfitter, participated in leisure activities with his two granddaughters, and worked part-time at his family-owned construction company. Previously, he would train at the gym 2-3 times per week and would go on 3-5 km runs twice a week. Mr. Parker first presented to his family physician three years ago with reports of weakness in his legs that had progressed over time to cause clumsiness and stiffness during his runs. He reported that he “had to stop running because of a fear of falling”. He was then diagnosed with ALS in 2019 through subjective history, physical examination, and diagnostic tools (MRI and EMG). However, upon a recent reassessment in 2022, the neurologist concluded that Mr. Parker has PLS as his symptoms did not progress to the LMNs - as concluded by a secondary physical examination and diagnostic tools. Mr. Parker’s neurologist initially referred him to physiotherapy in 2019 following his ALS diagnosis. However, he still recommends that Mr. Parker continues with his rehabilitation following his PLS diagnosis for maintenance purposes.

Since the initial diagnosis of ALS, Mr. Parker's health status has slowly deteriorated. Mr. Parker was prescribed a single-point cane with a 2-point step-through pattern by his previous physiotherapist in 2019, which he uses on occasion.

In 2020, he was forced into an earlier retirement than planned as he was unable to keep up with the part-time hours and work duties at the construction company. Furthermore, he is now unable to participate in any recreational running or CrossFit training due to the severity and worsening of his symptoms. He has now adjusted his fitness regime and uses resistance bands to work out from time to time at home and tries to go for daily walks with his wife totaling 10-30 minutes. His home activities have also been reduced due to decreased activity tolerance, decreased endurance, and fatigue. Therefore, his wife has taken on more responsibilities at home.

Upon reassessment in 2022, Mr. Parker reports that he is starting to experience swallowing difficulties and painful spastic posturing in his left arm. Overall, his condition continues to remain relatively the same since the initial onset but has since started to consistently take medication (Lexapro) for his concurrent depression. Additionally, his wife describes that he has been having intermittent, uncharacteristic behavioral outbursts as of two months ago.

EXAMINATION FINDINGS

Subjective

Patient Profile

Date of Birth (DOB): May 9, 1966 (56 years old)

Gender: Male

Hand Dominance: Right-hand dominant

Significant Presentation: PLS (misdiagnosed as ALS three years ago)

History of Present Illness

Insidious onset of bilateral leg weakness and stiffness which Mr. Parker noticed during his daily runs 3 years ago. Symptoms developed to include painful spastic posturing in the left arm, difficulty balancing/ clumsiness, intermittent dysphagia, and generalized fatigue. Had experienced several falls over the last few years due to poor balance control during ambulation. Developed a fear of falling that has greatly limited his participation in work, leisure activities, and general ambulation. He discussed his onset of symptoms with his family physician, who referred him to a neurologist in Toronto. He was initially diagnosed with ALS about 3 years ago (2019) by his neurologist, who then updated the diagnosis to PLS about 5 weeks ago after reassessment.

Pain: Describes intermittent, sharp pain isolated to the left arm, which refers down the shoulder to the elbow distally. The onset of pain occurs during elbow flexion ROM. Reports pain 6/10 with movement and 0/10 at rest. Takes 30 minutes for the pain to subside (moderate irritability).

Past interventions:

• Physiotherapy 2.5 years ago with no effect
  • Therapist only used passive treatment (i.e., stretching, PROM, and modalities like NMES to treat the lower extremity)

• Massage Therapy: Attended weekly for 3 months (2020) with no effect.
• Acupuncture: Attended weekly for 3 months (2020) with no effect.

Pharmacological Agents: Baclofen (prescribed by a neurologist to treat muscle spasticity) but stopped after a couple of months as it was not helpful and the side effects experienced outweighed the benefits associated with the medication.

Past Medical History

• Depression
• Otherwise functionally healthy

Medications

• Lexapro (10 mg OD, for 8 weeks) - to treat depression.
• Clonazepam (0.5 mg TID) - to treat muscle spasticity.

Health Habits

Smoking History: Non-smoker

Alcohol Consumption: Maximum of 4 alcoholic drinks per week

Recreational Drug Use: N/A

Family History

Mother: Diabetes and Hypertension.

Father: Colon Cancer.

No family history of PLS or other neurodegenerative diseases.

Psychosocial

Mr. Parker experiences feelings of depression often, such as hopelessness, frustration, and general sadness. He has developed a strong fear of falling due to his poor balance that has forced him to guide himself using walls, railings, and installed support bars throughout his home. This constant need for support has dampened his courage and motivation to ambulate or exercise. Mr. Parker’s previous highly active lifestyle has made it difficult to adjust to his current, more sedentary lifestyle. He constantly worries about burdening his wife with their household chores, especially because of her lower back pain. The growing conflict between his inability to perform his usual activities and desire to help his wife and family business has made him increasingly irritable and restless.

Social History

Mr. Parker lives in a bungalow with his wife and two small dogs. The house has three concrete steps leading up to the front door, and 10 stairs inside to get down to the basement. Has one bedroom on the main floor with a full bathroom, and a half bathroom closer to the living room. Hardwood flooring throughout the hallways, tile floor in the kitchen, and carpet in the bedroom. He enjoys spending time with his two granddaughters, taking them to the park by his house during the summer and skating with them during the winter. He used to work part-time at his family-owned construction company which he enjoyed greatly, but has had to retire early due to the progression of his disease.

Functional History

Mr. Parker reports being very active prior to disease onset as he participated in CrossFit, attended the gym 2-3x/week, and ran 3-5km twice a week. He used to drive up until about a year ago (2021) when needed but would walk or bike to his destination whenever possible. He was able to complete all activities of daily living, household chores, and property management (i.e. mowing the lawn and gardening) independently. He denies the use of mobility aids prior to being prescribed a single-point cane by his previous PT in 2019. Prior to his diagnosis, he ambulated freely with no balance issues or worries of falls.

Current Functional Status

He is currently able to ambulate for 10-30 minutes independently. He utilizes a single-point cane with a 2-point step-through pattern when feeling fatigued or when he needs a boost of confidence ambulating for longer distances. At home, he currently performs light upper extremity exercises using a resistance band. He is able to perform light household chores such as dusting, folding laundry, and washing dishes, but needs assistance from his wife for heavy chores like vacuuming, lifting anything heavier than 25 lbs., and shopping. He is currently able to perform self-care activities in full with no reports of difficulty. As mentioned above, Mr. Parker has refrained from driving since one year ago due to generalized weakness and fatigue. He is only able to ascend and descend the stairs outside and inside his house if he holds onto both railings or one railing and his cane. He reports feelings of being unbalanced often in a variety of situations like going up or down stairs, intermittently when standing, and walking for long periods of time.

PATIENT GOALS

Short-Term Goals (STG)

Body Structure/Function

Activity

Participation

Long-Term Goals (LTG)

Body Structure/Function

Activity

Participation