Spinal Muscular Atrophy

Question 1

SMA - Categories and Etiology

Answer 1

Types

• Type 1 - Werndig Hoffman
  
  • most severe
• Type 2
• Type 3 - Kugelberg-Welander
  
  • least severe

Etiology

• Autosomal recessive disorder
• genetic defect - chromosome 5
• SMN protein location
• loss of alpha motor neurons = weakness. atrophy

Question 2

Characteristics

Answer 2

• weakness
• atrophy
• absent or decreased DTRs
• fasciculations
• sensation intact
• cognition intact

Clinical Exam findings

• parent report regarding develop
• proximal weakness UE/LE
• tongue fasciculation
• loss of DTRs
• sensation
• muscle enzyme test
• EMG testing
• muscle biopsy
• genetic testing

Question 3

SMA Type 1

Answer 3

Infantile SMA

• noted within first 8 months
• decreased fetal movement
• hypotoniea at birth - floppy
• oral motor weakness
• muscle atrophy
• absence of head control•
• recurrent respiratory issues
• limited life expectancy

Role of PT

• QOL
• adaptive equipment
• respiratory support
• ROM, contracture management

Question 4

SMA Type 2

Answer 4

• presents 6-18 months
• weakness and atrophy of trunk/extrem
• progressive weakness of swallowing, resipiratory muscles
• tongue fasciculations
• fine motor tremor
• peak in skills then decline fxn
• poor head control
• distal strength > prxmal strength
• kyphoscoliosis
• URIs

PT Role

adaptive equip, contracture manage, scoliosis, orthotic, fxnal skills, respiratory support, parents, monitor ortho needs and posture

Question 5

SMA Type 3

Answer 5

Onset after 18 mo

• weakness, atrophy, fasciculations
• proximal muscles involved first
• DTRs decreased
• contractures, scoliosis not common
• ambulatory

Role of PT

• maintenance of fxn
• maintenance of flexibility
• orthotic management

Question 6

Seating for Mobility

Answer 6

• adaptive equip for QOL
• symmetry in alignment to prevent scoliosis and enhance respiration
• functional play
• spinal alignment
• postural symmetry
• freedom of hands
• trunk strength

Question 7

Respiration

Answer 7

• mechanical ventilation in home:
  
  • BIPAP
  • Chest PT
  • Supplemental O2
• morbidity assoc with resp complications
• resp care is prophylactic to prevent URIs