Ann Rehabil Med.  2012 Aug;36(4):569-572. 10.5535/arm.2012.36.4.569.

Upper Thoracic Myelopathy Caused by Delayed Neck Extensor Weakness in Myotonic Dystrophy

• Son HK
• Cha YS
• Suh H
• Ki CS
• Shin YB

• KMID: 2266731
• DOI: http://doi.org/10.5535/arm.2012.36.4.569

Abstract

Myotonic dystrophy is the most common autosomal dominant myopathy in adults. Our patient, a 41 year-old female suffering from myotonic muscular dystrophy, developed upper thoracic myelopathy due to hypertrophy of the ligamentum flavum and the posterior longitudinal ligament. She had a typical hatchet face and ptosis with "head hanging forward" appearance caused by neck weakness. Motor weakness, sensory changes and severe pain below T4 level, along with urinary incontinence began 3 months ago. Genetic and electrodiagnostic studies revealed myotonic dystrophy type 1. Magnetic resonance imaging of the spine showed loss of cervical lordosis and spinal cord compression due to hypertrophied ligamentum flavum and posterior longitudinal ligament at T1 to T3 level. We concluded that her upper thoracic myelopathy was likely related to the thickness of the ligamentum flavum and posterior longitudinal ligament due to repetitive mechanical stress on her neck caused by neck muscle weakness with myotonic dystrophy.

Keyword

Myotonic dystrophy; Neck weakness; Thoracic myelopathy

MeSH Terms

Adult
Animals
Female
Humans
Hypertrophy
Ligamentum Flavum
Longitudinal Ligaments
Lordosis
Magnetic Resonance Imaging
Muscular Diseases
Muscular Dystrophies
Myotonic Dystrophy
Neck
Neck Muscles
Spinal Cord Compression
Spinal Cord Diseases
Spine
Stress, Mechanical
Stress, Psychological
Urinary Incontinence

Figure

• 

  Fig. 1 Southern blot analysis of the DMPK gene shows a normal 10 kb band (arrow) and an abnormal 13-15 kb band corresponding to 900-1666 CTG expansion (*). Negative control 1 and 2 have heterozygous 9 and 10 kb bands and a homozygous 9 kb band, respectively, while the positive control has a normal 9 kb band and an abnormal 12.5-13.5 kb band (**).

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  Fig. 2 Sagittal view of the spinal MRI showing spinal cord compression by thickness of posterior longitudinal ligament and ligamentum flavum at the level of T1 to T3.

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  Fig. 3 Axial view of the spinal MRI demonstrating thecal sac indentation and abnormal signal changes of the spinal cord by epidural fibromatosis derived from hypertrophied ligamentum flavum at the T2 level.

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