Paraspinous muscle weakness

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Paraspinous Muscle Weakness ⁴

Nosology: Camptocormia
- Etymology: Greek; "kamptos" = Bent forward + "kormos" = Torso
Paraspinous muscles: Erector spinae
- Spinalis capitis
- Spinalis cervicalis
- Iliocostalis
- Longissimus
- Spinalis thoracis
Camptocormia: Definition
- Forward spinal flexion: ≥45°
- Resolves in supine position
Clinical features
- Onset age: 90% > 40 years
- Males: 50% to 73%
- Weakness of trunk extension
- Stooped posture
Laboratory
- Serum CK: High in 40%
- EMG: May be myopathic
- MRI: Paraspinal muscle atrophy & fat replacement
  - Distribution: Along length of spine
  - Differential Dx: Interapophyseal osteoarthritis
    - Muscle atrophy
      - Focal
      - Centrifugal around posterior vertebral arches
Neuromuscular disorders
- General
  - Onset age
    - Mean 50 years
    - Younger than other causes of camptocormia
  - Deformity: Not initially fixed
  - Weakness
    - Often also in other muscles
    - Respiratory common
  - Spine MRI: Paraspinal muscle atrophy & fatty infiltration
- Amyotrophic lateral sclerosis
- Paraspinous (Axial) myopathies
  - Types
    - "Bent spine" syndrome (Camptocormia)
    - Cervical paraspinous myopathy: Head ptosis
  - Often idiopathic
  - EMG: Myopathic
- Myasthenia Gravis
- Myopathies
  - Hereditary
    - Limb girdle: 2A; 2B
    - Collagen VI
    - FSH: DUX4
    - Myotonia: DM1; DM2
    - Scapuloperoneal 1: FHL1
    - HSPB8
    - Multisystem Selenoprotein Deficiency: (SECISBP2
    - POLG
    - SEPN1
    - Myopathies with mutations in RYR receptor
    - MPD2: MATR3
    - Dystrophin: Mutation carriers
    - McLeod
    - Idiopathic congenital scoliosis: LBX1
  - Metabolic myopathy
  - Inflammatory
    - Inflammatory myopathies
    - Inclusion body myositis
  - Other
    - Nemaline myopathy: Sporadic, Late-onset (SLONM)
    - Also see: Neck weakness, posterior
- Motor neuron disorders
  - Spinal muscular atrophy
  - Benign focal amyotrophy of paraspinous muscles ¹
- Valproate toxicity (Reversible)
Spine & Spinal cord disorders:
- Fixed deformity
  - Ankylosing spondylitis
  - Vertebral fracture: May be associated with osteoporosis
- Syringomyelia
- Degenerative joint disease
Movement & CNS disorders
- General
  - Paraspinous involvement after onset of extrapyramidal syndrome
- Disorders
  - Gait disorders of aging
  - Parkinsonism
  - Multiple system atrophy (MSA)
  - Dystonias, Truncal ⁶
  - Psychiatric disorders
  - Cerebro-Renal syndrome
Also see

Vesalius

MRI: Paraspinous Muscle Atrophy

"Bent Spine" Syndrome ²

Luke 13:11
And behold, there was a woman who had a spirit of infirmity eighteen years,
and was bent over and could in no way raise herself up
Etiology: Family history positive in up to 50%
Epidemiology: Females > Males
Clinical
- Onset age: 4th to 7th decade; Idiopathic disorders usually > 50 years
- Paraspinous muscles
  - Reduced strength
  - Stooped posture when erect
  - Posterior neck muscles may be involved
- Limb muscles
  - Normal strength
  - Fatigue with repetitive movements
- Course: Slowly progressive
- Spinal: Upper thoracic kyphosis
Laboratory
- Muscle CT & MRI
  - Paraspinous muscles: Hypodensity; Fat infiltration
- EMG
  - Paraspinous: Myopathic 75%
  - Limb: Myopathic 50%
- Serum CK
  - Normal (75%)
  - Mildly high in minority: Up to 5x elevated
- Muscle biopsy
  - Paraspinous muscles
    - Variable muscle fiber size
    - Endomysial fibrosis
    - Little necrosis or regeneration
    - Internal architecture: Disorganized
  - Limb muscles: Minor or Non-diagnostic changes
Differential diagnosis: Other causes of paraspinous muscle weakness

Bent Spine syndrome
MRI: T2 images

Wasting & Fibrosis (T-spine): Symmetric, Severe (Arrows)

Wasting & Fibrosis (L-spine): Asymmetric (Arrow)

Scoliosis: Adolescent Idiopathic

Definition
- Lateral spinal curvature: Cobb angle ≥ 10° that
- Otherwise healthy children: Age of 10 years to end of pubertal growth spurt
Epidemiology
- 2%–3% of adolescents worldwide
- Female > Male: Especially with larger degres of scoliosis
Genetics & Linkages
- Heritability: 87.5%
- Chromosome linkages
  - 10q24.31
  - 6q24.1
  - 19p13.3: IS1
- PAX1 association: Females
- Basonuclin 2 (BNC2) ⁵
  - Epidemiology: Japanese & Han-Chinese populations
  - Genetics: SNP association; Intron 3 variant (rs10738445)
  - Mechanism: BNC2 over-expression
- Soliosis: Other hereditary disorders
  - Marfan syndrome
  - Dysautonomia (HSAN3)
  - Neurofibromatosis
  - Friedreich ataxia
  - General: Weakness causing loss of ambulation before puberty or growth finished

Scoliosis & Axial Myopathy ³

● Lady bird late, drosophila, homolog of, 1 (LBX1)

; Chromosome 10q24.31; Dominant

Epidemiology: 1 Spanish family, 2 patients
Genetics
- Mutation
  - Microduplication (chr10:102927883-103053612, hg19): 2 patients & 1 asymptomatic carrier
- Allelic disorders
  - Congenital Central Hypoventilation Syndrome-3 (CCHS3)
  - Polymorphisms: Associated with adolescent idiopathic scoliosis
LBX1 protein
- Homeobox gene
- Function: Migration of hypaxial muscle precursor cells
- Regulates properties specific for the migratory lineage of muscle precursors
- Present in
  - Activated satellite cells
  - Subset of cardiac neural crest cardioblasts during heart formation
- Partner: PHOXB2
Clinical
- Onset age: Congenital
- Scoliosis: Non-progressive
- CNS: Attention problems, Dyspraxia
Laboratory
- MRI: Paravertebral muscles very small
LBX1 variant: Congenital Central Hypoventilation Syndrome-3 (CCHS3)
- Epidemiology: 1 family, 2 patients
- Genetics
  - Inheritance: Recessive
  - Mutation: Frameshift; 1-bp del, 697T
- Clinical
  - Onset: Neonatal
  - Alveolar hypoventilation & Apnea
    - Need ventilatory support
    - No response to low O₂ saturation or hypercapnia
  - Paroxysmal attacks: Hypertension; Pallor; Sweating
  - GI: Feeding problems; Vomiting, Diarrhea & Constipation
  - Heat intolerance during infection

Return to Neuromuscular home page

References
1. J Neurol Sci 2000;176:70-74
2. Muscle Nerve 2002;25:189-193, J Neurol 2002;249:730-734, J Neurol Neurosurg Psychiatry 2002;73:1-7
3. Am J Med Genet A 2014;164A:2074-2078
4. Muscle Nerve 2015 Apr 21, Brain 2015 Dec 14, Neurol Clin Pract 2018;8:240-248
5. Am J Human Genet 2015; Online July
6. Rev Neurol (Paris) 2022;178:398-399

6/24/2022

Paraspinous Muscle Weakness 4

"Bent Spine" Syndrome 2

Scoliosis: Adolescent Idiopathic

Scoliosis & Axial Myopathy 3

Paraspinous Muscle Weakness ⁴

"Bent Spine" Syndrome ²

Scoliosis & Axial Myopathy ³