Neuromuscular Disorders Flashcards
What are neuromuscular disorders and their key classifications?
- Neuromuscular disorders affect any part of the motor unit: anterior horn, peripheral nerve, neuromuscular junction, or muscle.
- They can be hereditary (genetic) or acquired.
- Key classifications include myopathies, dystrophies, and neuropathies, with further divisions like axonal or demyelinating neuropathies.
What are the main types of muscular dystrophies and their causes?
Muscular dystrophies are genetically determined disorders with progressive muscle degeneration. They include Duchenne Muscular Dystrophy (DMD), Limb-Girdle Muscular Dystrophy (LGMD), and Congenital Muscular Dystrophy. Causes typically involve mutations that interfere with protein production, leading to abnormal or missing proteins and muscle weakness.
Describe the genetics and epidemiology of Duchenne Muscular Dystrophy (DMD).
DMD is the most common childhood muscular dystrophy, affecting 1 in 3,500 males worldwide. It is an X-linked disorder caused by mutations on the Xp-21 gene, leading to absent or decreased dystrophin production. Only males are affected, with symptoms typically appearing between ages 2-5.
What are the stages of DMD progression, and what are common symptoms?
Stages: Presymptomatic (birth-5 yrs), Early Ambulatory (5-8 yrs), Late Ambulatory (8-12 yrs), Early Non-Ambulatory (12-15 yrs), and Late Non-Ambulatory (16+ yrs). Common symptoms include delayed walking, speech delays, muscle weakness, frequent falls, larger calves, and Gower’s sign.
What are primary and secondary impairments of DMD, and what complications arise?
Primary impairment is progressive muscle weakness. Secondary impairments include contractures, postural malalignment, decreased respiratory capacity, and possible obesity. Complications include intellectual and behavioral issues, and cardiopulmonary decline, often leading to death between ages 20-30.
Describe physical therapy goals and interventions for DMD patients.
PT goals include slowing contracture progression, maintaining ROM, and promoting independence. Interventions: submaximal exercise, avoiding high-resistance/eccentric exercises, 2-3 hours of standing/walking per day, and low-impact activities like cycling/swimming. Stretching splints and transfer training are also recommended.
What standardized tests are used for DMD, both ambulatory and non-ambulatory?
For all DMD patients: Brooke Scale for Upper Extremity, Vignos Scale for Lower Extremity, and Egan Klassification Scale. Ambulatory patients: Northstar Ambulatory Assessment, 6-minute walk test, timed floor to stand, and 10-meter walk test. Non-ambulatory patients: Performance of Upper Limb 2.0.
What medical management options are available for DMD?
Corticosteroids can delay muscle weakness progression and scoliosis. Cardiopulmonary interventions include ACE inhibitors and beta-blockers for heart health, cough assist for respiratory support, and surgical options like tendon releases for orthopedic issues. Recent gene therapies and exon-skipping drugs are also emerging.
Summarize the key physical characteristics and prognosis for Limb-Girdle Muscular Dystrophy (LGMD).
LGMD primarily affects proximal muscles, varies in presentation, and can emerge from childhood to adulthood. LGMD can lead to elevated serum CK and increased risk for cardiomyopathy. Prognosis depends on subtype, with sacroglycanopathies resembling Duchenne.
What are the main characteristics and management strategies for Congenital Muscular Dystrophy?
Congenital Muscular Dystrophy often involves CNS abnormalities (Fukuyama CMD, Walker-Walburg syndrome) and presents in early infancy with poor muscle tone, delayed milestones, and progressive weakness. PT management focuses on ROM maintenance and adaptive equipment for mobility and ADLs.
Describe Spinal Muscular Atrophy (SMA), its genetic basis, and how SMA types differ.
SMA is caused by SMN protein deficiency due to SMN1 gene mutations. SMA types vary by symptom onset and highest motor milestone achieved: Types 0-4 range from non-sitters to walkers. More SMN2 gene copies typically mean milder symptoms. Newborn screening and early treatment improve outcomes.
What are common symptoms and physical therapy interventions for SMA?
Symptoms include muscle weakness, low tone, joint tightness, respiratory issues, and spinal deformities. PT focuses on ROM, balance, respiratory support, endurance, and mobility with assistive devices like wheelchairs, standers, and transfer equipment to promote function and prevent complications.
List current drug therapies for SMA and their mechanisms.
Spinraza promotes SMN protein by modifying SMN2 splicing; Zolgensma replaces mutated SMN1 genes via virus injection; Evrysdi increases SMN protein levels body-wide. Spinraza is given via IT injection, Zolgensma is a single-dose IV for young children, and Evrysdi is a daily oral drug.
What standardized assessments and intervention strategies are used for SMA based on functional levels?
Non-sitters: HINE, CHOP-INTEND. Sitters: HFMSE, RULM. Walkers: Timed tests, 6MWT. Interventions: ROM, assistive tech, postural support, aquatic therapy, and fatigue management. Each intervention supports functional independence and quality of life across ability levels.
What are the causes and primary symptoms of Charcot-Marie-Tooth (CMT) Disease?
CMT is a hereditary motor and sensory neuropathy that affects peripheral nerves, leading to sensory loss, distal muscle wasting, and weakness. CMT has multiple types based on gene defect and myelin or axon abnormalities, with onset often in early adulthood.
