Motor Neuron Disease Overview

Motor Neuron Disease (MND) is a fatal syndrome characterized by degeneration of upper motor neurons (UMN) and lower motor neurons (LMN).
It affects the cerebral cortex, brainstem, and spinal cord, leading to progressive weakness in various muscle groups.
MND is rare, with a prevalence of 1.0-2.5 cases per 100,000 people.
It is more common in males and typically affects individuals between the ages of 40 and 65.
MND can be sporadic or familial (5-10%)
There is no known cure for MND.
The average life expectancy is 2-3 years from diagnosis.

MND specifically targets Betz cells (UMN) and motor neurons in the ventral horn of the spinal cord and brainstem (LMN).
Motor neurons supplying extraocular muscles and those in the sacral spinal cord innervating pelvic floor muscles are typically spared.
Cellular mechanisms contributing to degeneration in MND include protein misfolding, RNA processing defects, and other cellular mechanisms.

Genetic factors are recognized as significant, with mutations in the SOD1 gene found in 46% of patients with familial MND.
Geographic factors may play a role, with documented areas of high incidence, such as Japan and Guam.
Environmental factors are less well understood but are being explored as possible contributors.

MND diagnosis is complex, as there's no single investigation specific to the disease.
Diagnosis relies on a combination of clinical examination, blood tests, electrodiagnostic tests, and neuro-imaging.
The Revised El Escorial Research Diagnostic Criteria for ALS are used to guide diagnosis effectively.
Early identification and prompt diagnosis are crucial for optimal management.
A multidisciplinary team approach is recommended from the beginning for comprehensive care.

Amyotrophic Lateral Sclerosis (ALS) encompasses both inherited and sporadic forms of the disease.
Progressive Muscular Atrophy (PMA) is a type of MND primarily affecting lower motor neurons.
Primary Lateral Sclerosis (PLS) involves the degeneration of upper motor neurons, resulting in spasticity and hyperreflexia.

Muscle weakness is the hallmark symptom of MND.
Hyperreflexia is a common finding.
Bulbar onset, affecting the muscles of the tongue, lips, and mouth, occurs in approximately 20% of patients.
Cervical and thoracic extensor muscle weakness can lead to difficulty holding the head up.
Muscle fasciculations (involuntary muscle twitches) are common.
Respiratory weakness is a serious complication that can develop over time.
Cognitive decline and frontotemporal dementia (FTD) have been observed in a small percentage (15%) of patients with MND.

It is crucial to rule out other conditions that may mimic MND.
MRI scans are typically normal in patients with MND, differentiating it from brain tumors.
Disc prolapse can be ruled out if there's no nerve root involvement corresponding to the symptoms.
Muscular dystrophy presents differently and can be differentiated through appropriate testing.

Assessment for MND is considered urgent and should be prioritized.
A comprehensive evaluation should include:
- Posture assessment
- Gait analysis
- Muscle strength testing
- Range of motion assessment
- Assessment of bulbar symptoms
- Respiratory assessment, which includes vital capacity, forced vital capacity, and maximum inspiratory pressure measurements.
- Other objective measures (e.g., grip strength, 6-minute walk test).
An MND passport can be used to streamline the patient’s care and provide consistent care across healthcare settings.

Maintaining Function: Physiotherapists play a vital role in helping patients maintain their functional independence.
Respiratory Management: Respiratory management is critical in MND, as respiratory muscle weakness can significantly impact quality of life and lifespan. - Non-invasive ventilation (NIV) - Assisted coughing techniques - Regular pulmonary assessments - Positioning for optimal lung function - Respiratory hygiene measures
Other interventions: - Exercise programs - Splinting or other assistive devices to support mobility - Pain management
- Adaptive equipment
- Education and counseling
Collaboration with the Multidisciplinary Team: Physiotherapists work collaboratively within a multidisciplinary team, including physicians, nurses, respiratory therapists, and other health professionals.
Maintaining Communication: Open communication and ongoing updates between physiotherapists and other healthcare professionals are essential.
Evidence-Based Practice: All interventions should align with current evidence-based guidelines for optimal care.