Hirayama-Krankheit

Hirayama
disease a rare cause for distal upper limb weakness: case report with MRI findings. T1 post contrast saggital shows enhancing epidural soft tissue extending from lower cervical region into upper thoracic region.
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Location,
length, and enhancement: systematic approach to differentiating intramedullary spinal cord lesions. Hirayama disease. A 22-year-old male with upper extremity weakness and muscle atrophy. a There is focal T2 hyperintensity in the anterior horns (arrowheads). Subtle asymmetric focal cord atrophy at this level (C5–C6), slightly more conspicuous on the left (arrow). b Flexion view shows anterior displacement of the dura (arrows) with narrowing of the thecal sac (bracket), extending from C3 to T2, most pronounced at C5–C6. Note the long segment T2 hyperintensity within the anterior horns
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Hirayama
Disease-Atypical Presentation. GRE axial flexion image showing anteriorly displaced dura more prominent on the right side (arrow).
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Hirayama
Disease-Atypical Presentation. T2W sagittal flexion image showing anterior indentation of the posterior dura with flow voids (arrow) in the displaced extradural compartment.
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Hirayama
Disease-Atypical Presentation. T2W sagittal image showing degenerative discs at multiple levels with focal cord atrophy at C5-6 (arrow) and cord signal changes extending from C4 to C6 level.
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Hirayama
Disease-Atypical Presentation. Figure 1: T1W sagittal image showing focal cord atrophy at C5-6 level (arrow).
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Hirayama
disease a rare cause for distal upper limb weakness: case report with MRI findings. STIR image of cervical spine shows compression of spinal cord against vertebral body on flexion of neck.
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Hirayama
disease a rare cause for distal upper limb weakness: case report with MRI findings. T2W axial image of cervical region shows separation of dura from lamina with flattening of cord.
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Hirayama
disease a rare cause for distal upper limb weakness: case report with MRI findings. Image shows atrophy of hypothenar muscles of both hands.
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Hirayama
disease a rare cause for distal upper limb weakness: case report with MRI findings. T2W sagittal image of cervical spine shows atrophy of lower cervical cord.
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Hirayama
Disease-Atypical Presentation. Post contrast T1W FS sagittal flexion image showing enhancement of the engorged venous plexus posterior to the displaced dura (arrow).
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Radiopaedia • CC-by-nc-sa 3.0 • de

Hirayama disease, also termed non-progressive juvenile spinal muscular atrophy of the distal upper limbs, is a type of cervical myelopathy related to flexion movements of the neck. It is considered a benign motor neuron disorder with a stationary stage after a progressive course .

Epidemiology

It typically occurs mainly in young males between the ages of 15-25 years .

Clinical presentation

It is often of insidious onset presenting with a predominantly unilateral upper extremity weakness and atrophy, cold paresis, and no sensory or pyramidal tract involvement. It is also characterized by muscle weakness and atrophy in the hand and forearm with sparing of the brachioradialis, giving the characteristic appearance of oblique amyotrophy that affects the C7, C8 and T1 myotomes . The amyotrophy is unilateral in most patients, asymmetrically bilateral in some and rarely symmetric .

Pathology

Chronic microcirculatory changes in the territory of the anterior spinal artery induced by repeated or sustained flexion account for the necrosis of the anterior horns of the lower cervical cord, which is the hallmark of pathology .

Radiographic features

On myelograms and flexion-extension MR images, there can be a forward migration of the posterior wall of the dura mater. The posterior epidural space becomes enlarged with flexion and is seen as a crescent.

At the site of maximal forward shift of the posterior dural sac the spinal cord is dynamically compressed with a reduction in the AP diameter of the cord compared to neutral imaging .

MRI
  • neutral position: abnormal T2-weighted signal of the spinal cord at site of maximum forward shift without an obvious cause
  • flexion position: the posterior dural sac crescent appears as high signal intensity on T1- and T2-weighted sequences and enhances uniformly on T1 C+ (Gd), with or without epidural flow voids

History and etymology

It was initially described by Keizo Hirayama et al. in 1959 .​

Siehe auch:
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Assoziationen und Differentialdiagnosen zu Hirayama-Krankheit:
epidurale
intraspinale Raumforderung
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Arteria
spinalis anterior
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Myelopathie
 
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snake eye
appearance
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