DOI: 10.1148/radiol.2303021089
(Radiology 2004;230:692-696.)
© RSNA,
Case 68: Hirayama Disease1
Dheeraj Gandhi, MD,
Mayank Goyal, MD,
Pierre R. Bourque, MD, FRCP(C) and
Rajan Jain, MD
1 From the Departments of Diagnostic Imaging (D.G., M.G.) and Neurology (P.R.B.), Ottawa Hospital, Civic Campus, 1053 Carling Ave, Ottawa, ON, Canada K1Y 4E9; and Division of Neuroradiology, Department of Radiology, University of Michigan Hospitals, Ann Arbor (R.J.). Received August 30, 2002; revision requested October 31; revision received November 19; accepted January 15, 2003. Address correspondence to M.G. (e-mail: mgoyal@ottawahospital.on.ca).
Index terms: Diagnosis Please • Dura • Spinal cord, compression, 341.149 • Spinal cord, developmental defect, 341.149
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HISTORY
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A previously healthy 19-year-old man presented with insidious onset of weakness in the right hand for the past 2 years. He had also noticed fasciculations in his forearm and hand, along with a cramping sensation. He denied having trouble in any other limb. There was neither history of trauma nor family history of neuromuscular disease.
Findings of a physical examination included mild atrophy and weakness of the right volaris compartment and moderate atrophy of the right interossei dorsalis manus muscles. Spontaneous fasciculations were seen in the right flexor carpi ulnaris muscle. Monopolar needle electromyography showed acute denervation of the right interossei dorsalis manus muscles and chronic reinnervative changes in the right abductor pollicis brevis, flexor pollicis longus, and flexor digitorum profundus. Nervus ulnaris and nervus medianus conduction velocities were within normal limits. Midline sagittal T1- and T2-weighted images from the initial magnetic resonance (MR) examination of the cervical spine performed at the time of presentation are presented in Figure 1. MR imaging and computed tomographic (CT) myelography were subsequently performed 1 week after the initial MR imaging examination, with extension and flexion of the cervical spine. MR imaging included contrast material–enhanced T1-weighted sequences after intravenous administration of 0.2 mL of gadopentate dimeglumine per kilogram of body weight. Representative MR images and CT scans are shown in Figures 2 and 3, respectively.
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Figure 1a. (a) Midline sagittal T1-weighted (repetition time msec/echo time msec, 500/15) MR image of the cervical spine in neutral position reveals focal spinal cord atrophy (arrow) at C5 through C6. (b) Midline sagittal T2-weighted (2,800/90) MR image of the cervical spine in neutral position shows a small area of high signal intensity (arrow), which is possibly indicative of gliosis, in the atrophied segment of the spinal cord.
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Figure 1b. (a) Midline sagittal T1-weighted (repetition time msec/echo time msec, 500/15) MR image of the cervical spine in neutral position reveals focal spinal cord atrophy (arrow) at C5 through C6. (b) Midline sagittal T2-weighted (2,800/90) MR image of the cervical spine in neutral position shows a small area of high signal intensity (arrow), which is possibly indicative of gliosis, in the atrophied segment of the spinal cord.
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Figure 2a. T1-weighted (500/15) sagittal MR images of the cervical spine in (a) extension and (b) flexion. Note the spacious cervical dural canal and presence of wide subarachnoid space ventral to the spinal cord at C5-6 (arrow in a). The posterior dura (arrowhead) has shifted ventrally with flexion of the cervical spine. The epidural plexus is larger and contains multiple flow voids (arrow in b). (c) Contrast-enhanced T1-weighted (500/15) MR image of the cervical spine in flexion shows enhancement of the large posterior epidural plexus (arrows).
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Figure 2b. T1-weighted (500/15) sagittal MR images of the cervical spine in (a) extension and (b) flexion. Note the spacious cervical dural canal and presence of wide subarachnoid space ventral to the spinal cord at C5-6 (arrow in a). The posterior dura (arrowhead) has shifted ventrally with flexion of the cervical spine. The epidural plexus is larger and contains multiple flow voids (arrow in b). (c) Contrast-enhanced T1-weighted (500/15) MR image of the cervical spine in flexion shows enhancement of the large posterior epidural plexus (arrows).
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Figure 2c. T1-weighted (500/15) sagittal MR images of the cervical spine in (a) extension and (b) flexion. Note the spacious cervical dural canal and presence of wide subarachnoid space ventral to the spinal cord at C5-6 (arrow in a). The posterior dura (arrowhead) has shifted ventrally with flexion of the cervical spine. The epidural plexus is larger and contains multiple flow voids (arrow in b). (c) Contrast-enhanced T1-weighted (500/15) MR image of the cervical spine in flexion shows enhancement of the large posterior epidural plexus (arrows).
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Figure 3a. Transverse CT scans of the cervical spine obtained after myelography at C5-6 in (a) extension and (b) flexion. The spinal cord is atrophied with disproportionate involvement of the right hemicord (arrow in a). Anterior subarachnoid space is completely effaced, the spinal cord is compressed, and posterior dura is shifted ventrally (arrows in b).
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Figure 3b. Transverse CT scans of the cervical spine obtained after myelography at C5-6 in (a) extension and (b) flexion. The spinal cord is atrophied with disproportionate involvement of the right hemicord (arrow in a). Anterior subarachnoid space is completely effaced, the spinal cord is compressed, and posterior dura is shifted ventrally (arrows in b).
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IMAGING FINDINGS
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Initial MR imaging of the cervical spine revealed focal atrophy of the spinal cord (Fig 1) from C5 through C6 vertebral levels. There was a small area of high signal intensity within the spinal cord on T2-weighted MR images. MR imaging was subsequently repeated with extension and flexion of the cervical spine to assess the relationship of posterior dura mater with the spinal cord.
On a midline sagittal T1-weighted MR image that was obtained with the neck in extension, the spinal cord was seen along the dependent dorsal aspect of the subarachnoid space (Fig 2a). Abundant cerebrospinal fluid was present anterior to the spinal cord, and there was no spinal cord compression. During neck flexion (Fig 2b), the posterior dura showed anterior displacement. An associated anterior displacement and compression of the spinal cord were noted. The posterior epidural space became larger, and the flow voids in the posterior epidural space during neck flexion (Fig 2b) were exaggerated. On contrast-enhanced T1-weighted MR images (Fig 2c), the epidural plexus was seen to enhance.
Transverse MR imaging of the cervical spine was unsatisfactory in quality; therefore, we performed both conventional and CT myelography with flexion and extension of the cervical spine. Asymmetric thinning of the right half of the spinal cord was noted on transverse CT myelograms obtained after conventional myelography at the C5–6 level (Fig 3a). At the corresponding level, an anterior displacement of dura could be seen clearly during flexion (Fig 3b). A complete effacement of the contrast material column anterior to the spinal cord was noted during flexion. In addition, there was a reduction in the anteroposterior diameter of the spinal cord.
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DISCUSSION
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On the basis of the clinical findings, the differential diagnoses included a restricted form of motor neuron disease (monomelic muscular atrophy), a limited form of multifocal motor neuropathy, and chronic right-sided radiculopathy. Asymmetric atrophy of the cervical spinal cord, which was observed on the initial MR image (Fig 1), was again nonspecific. A previous traumatic or ischemic insult could produce focal spinal cord atrophy, but this was easily excluded, given the patient’s history.
In a young patient with clinical evidence of hand and/or forearm muscle atrophy and asymmetric thinning of the cervical spinal cord, a diagnosis of Hirayama disease (juvenile muscular atrophy of the distal upper extremity) should always be considered. Detection of focal spinal cord atrophy in such a patient should prompt the radiologist to perform dynamic evaluation of the cervical spine with flexion and extension. Forward migration of the posterior surface of the dura mater with compression of the spinal cord on CT myelograms and/or MR images obtained with flexion of the cervical spine is a characteristic of Hirayama disease (1).
Hirayama disease is also known as juvenile muscular atrophy of the distal upper extremity, monomelic amyotrophy, benign focal amyotrophy (2), juvenile muscular atrophy of a unilateral upper extremity (3), and juvenile asymmetric segmental spinal muscular atrophy (4). Hirayama et al (5) described this disease in 1959. Since then, several cases have been reported (1). This disease affects predominantly males in either their 2nd or their early 3rd decade of life (6). Typical clinical features are muscular weakness and atrophy in the hand and forearm. Since the brachioradialis muscle is spared, the pattern of forearm involvement is also referred to as an oblique amyotrophy. There is unilateral involvement in the majority of patients, but asymmetric and symmetric bilateral involvement are also observed (1). The onset of this disease is insidious, and the clinical course is steadily progressive. After a period of initial deterioration, a stable stage is reached (6).
The pathogenesis of this entity is debated. In a report of 73 patients, Hirayama and Tokumaru (1) concluded that dynamic spinal cord compression at neck flexion with forward displacement of the posterior dura is an unequivocal finding in the progressive stage of this disease. Furthermore, this finding is absent in elderly patients who have reached a stable stage in the progress of this disease. This observation suggests that dynamic compression of the spinal cord may be an important finding in the diagnosis of this disease.
Kikuchi et al (7) believe that a "tight" dural canal during flexion of the neck is due to a disproportional length between the vertebral column and the dural canal. During neck extension, the normal cervical dura mater is slack and consists of transverse folds (8). During neck flexion, the length of the cervical canal increases (8). In healthy subjects, the dural slack compensates for the increased length in flexion and stays in apposition with the bony canal. Patients with Hirayama disease, however, may have an imbalance in growth of the vertebrae and the dura mater (6). A short length of the dural canal cannot compensate for increased length of the vertebral canal, and the dural canal becomes tight when the neck is in the flexed position. This results in an anterior shift of the posterior dural wall, thereby causing spinal cord compression (6). In a series of five patients treated with duraplasty and surgical fusion, Konno et al (10) found histologically abnormal dura containing few elastic fibers without a normal wavy structure.
The mechanism of myelopathy may involve ischemic changes or chronic trauma inflicted by repeated neck flexion (1). In an autopsy study of a patient with this disease, ischemic changes were demonstrated in the anterior horn cells, along with asymmetric spinal cord thinning (9).
A number of radiologic findings have been reported. On radiographs of the cervical spine, there may be malalignment of the posterior surfaces of the vertebral bodies both in flexed and in neutral positions, a finding that resolves with extension (3). On myelograms and flexion-extension MR images, forward migration of the posterior wall of the dura mater is observed (1,3,4,6). The posterior epidural space becomes enlarged with flexion and is seen as a crescent of high signal intensity on T1- and T2-weighted MR images, with or without epidural flow voids (1). Uniform enhancement of this epidural space occurs with administration of contrast material (6). Compressive flattening of the spinal cord accompanies the forward shifting of the posterior dura (1,3,6). The changes are often greatest at the C6 vertebral level (1). In the majority of cases, spinal cord flattening is asymmetric (1). In later stages of the disease, spinal cord atrophy ensues and is generally limited to the anterior horn cells region. Morphologic changes on MR images correlate with clinical and electromyographic data (2).
Early recognition of this condition is necessary, because avoidance of neck flexion can stop the progression of this disease (6,11). Since the progressive stage is expected to cease in a few years, application of a cervical collar for 3–4 years generally has been advocated (11). In selected patients, encouraging results have also been obtained with surgical intervention, which involves mainly cervical decompression and/or fusion with or without duraplasty (12).
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FOOTNOTES
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Part 1 of this case appeared 4 months previously and may contain larger images.
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REFERENCES
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- Hirayama K, Tokumaru Y. Cervical dural sac and spinal cord in juvenile muscular atrophy of distal upper extremity. Neurology 2000; 54:1922-1926.[Abstract/Free Full Text]
- Biondi A, Dormont D, Weitzner I, Jr, et al. MR imaging of the cervical cord in juvenile amyotrophy of distal upper extremity. AJNR Am J Neuroradiol 1989; 10:263-268.[Abstract]
- Kohno M, Takahashi H, Yagishita A, Tanabe H. "Disproportion theory" of the cervical spine and spinal cord in patients with juvenile cervical flexion myelopathy: a study comparing cervical magnetic resonance images with those of normal controls. Surg Neurol 1998; 50:421-430.[CrossRef][Medline]
- Pradhan S, Gupta RK. Magnetic resonance imaging in juvenile asymmetric segmental spinal muscular atrophy. J Neurol Sci 1997; 146:133-138.[CrossRef][Medline]
- Hirayama K, Toyokura Y, Tsubaki T. Juvenile muscular atrophy of unilateral upper extremity: a new clinical entity. Psychiatr Neurol Jpn 1959; 61:2190-2197.
- Chen CJ, Chen CM, Wu CL, Ro LS, Chen ST, Lee TH. Hirayama disease: MR diagnosis. AJNR Am J Neuroradiol 1998; 19:365-368.[Abstract]
- Kikuchi S, Tashiro K, Kitagawa K, Iwasaki Y, Abe H. A mechanism of juvenile muscular atrophy localized in the hand and forearm (Hirayama’s disease): flexion myelopathy with tight dural canal in flexion. Clin Neurol (Tokyo) 1987; 27:412-419.
- Bland JH. Basic anatomy. In: Bland JH, eds. Disorders of the cervical spine: diagnosis and medical management. 2nd ed. Philadelphia, Pa: Saunders, 1994; 41-70.
- Araki K, Ueda Y, Michinaka C, Takamasu M, Takino T, Konishi H. An autopsy case of juvenile muscular atrophy of unilateral upper extremity (Hirayama’s disease). J Jpn Soc Intern Med 1989; 78:674-675.
- Konno S, Goto S, Murakami M, Mochizuki M, Motegi H, Moriya H. Juvenile amyotrophy of the distal upper extremity: pathologic findings of the dura mater and surgical management. Spine 1997; 22:486-492.[CrossRef][Medline]
- Tokumaru Y, Hirayama K. Cervical collar therapy for juvenile muscular atrophy of distal upper extremity (Hirayama disease): results from 38 cases (abstr). Rinsho Shinkeigaku 2001; 41:173-178. [Japanese].[Medline]
- Kohno M, Takahashi H, Ide K, Yamakawa K, Saitoh T, Inoue K. Surgical treatment for patients with cervical flexion myelopathy. J Neurosurg 1999; 91(suppl 1):33-42.[Medline]
Congratulations to the 81 individuals who submitted the most likely diagnosis (Hirayama Disease) for Diagnosis Please, Case 68. The names and locations of the individuals, as submitted, are as follows:
- Hisashi Abe, Osaka, Japan
- Gholamali Afshang, MD, Tinley Park, Ill
- Dr Prachi Pragya Agarwal, Ottawa, Ontario, Canada
- Dr Jorge Ahualli, Tucuman, Argentina
- Albert J. Alter, Madison, Wis
- Lazaro Amaral, São Paulo, Brazil
- Ken Baliga, Rockford, Ill
- Alvaro Belmar, MD, Santiago, Chile
- Mark A. Bisesi, MD, Bloomington, Ind
- Eric L. Bressler, MD, Minnetonka, Minn
- Michael P. Buetow, MD, Okemos, Mich
- Marcella Camicia, MD, Castellana Grotte, Italy
- María Jesús Díaz Candamio, La Coruña, Spain
- Oscar Luis Casado Verdugo, Alava, Spain
- Luisa Fernanda Cervantes, Miami, Fla
- Can Cevikol, MD, Antalya, Turkey
- Chi-Jen Chen, MD, Taipei, Taiwan
- Yao-Liang Chen, MD, Taoyuan, Taiwan
- Bharath Chinta, Rochester Hills, Mich
- Timothy Clark, Greenville, NC
- James W. Cole, MD, Cincinnati, Ohio
- Marc G. de Baets, MD, Lugano, Switzerland
- M. Kemal Demir, MD, Ataköy, Istanbul, Turkey
- Esther Dominguez-Franjo, Madrid, Spain
- Steven Falcone, MD, Miami, Fla
- Nelson Fortes Ferreira, São Paulo, Brazil
- Akira Fujikawa, Tokyo, Japan
- Hirokazu Fujiwara, MD, Tokyo, Japan
- Yasutaka Fushimi, Kyoto, Japan
- Mark Goldshein, MD, Andover, Mass
- Jean Pierre Gurret, Annecy, France
- Hiroto Hatabu, MD, PhD, Boston, Mass
- Satoru Iwasaki, Osaka, Japan
- Masako Kataoka, Cambridge, United Kingdom
- Koki Kato, Tochigi, Japan
- Alexander G. Khandji, MD, New York, NY
- Pat Kiely, Limerick, Ireland
- Takuji Kiryu, MD, Gifu, Japan
- Miyuki Konno, Yamagata, Japan
- Jacob Sam Koruth, MD, Worcester, Mass
- Hisnobu Koyama, Tenri-city, Japan
- Mario Laguna, West Allis, Wis
- John Lim, MD, Newport Coast, Calif
- N. B. S. Mani, MD, Nassau, Bahamas
- Luis Mendez-Uriburu, Tucuman, Argentina
- Manabu Minami, MD, Tokyo, Japan
- Dr Tibor Mitrovics, Würzburg, Germany
- Sankar Ranjan Mondal, MD, Nassau, Bahamas
- Eduardo Mondello, Buenos Aires, Argentina
- Tetsuro Nakahara, Shiga, Japan
- Tetsuo Nakayama, MD, Osaka, Japan
- Mizuki Nishino, MD, Boston, Mass
- Kenjirou Ohashi, MD, Iowa City, Iowa
- Laura Oleaga, Bilbao, Spain
- Mike O’Loughlin, MD, West Hartford, Conn
- Dennis N. Peters, Philadelphia, Pa
- Mario P. Pliego, MD, Bloomington, Minn
- Daniel Rappaport, MD, FRCPC, Toronto, Ontario, Canada
- Enrique Remartinez Escobar, MD, Melilla, Spain
- Ranji N. Samaraweera, MD, Okemos, Mich
- N. Saravanan, MD, Chandigarh, India
- Pierre J. Sauvage, MD, Mâcon, France
- Steven M. Schultz, MD, Fort Worth, Tex
- Matt Shapiro, MD, Staunton, Va
- Taro Shimono, MD, Osaka, Japan
- Dr Ashok Srinivasan, Ottawa, Ontario, Canada
- Kouichi Sugiyama, Hamamatsu, Japan
- Satoru Takahashi, MD, Osaka, Japan
- Luis Tata, MD, Amadora, Portugal
- Douglas L. Teich, MD, Brookline, Mass
- Kazuma Terauchi, MD, Osaka, Japan
- Eugene Tong, MD, Austin, Tex
- Meriç Tüzün, Ankara, Turkey
- Hiroyuki Ueda, Kyoto, Japan
- Dra Elida Vazquez, Barcelona, Spain
- Christopher Vittore, MD, Rockford, Ill
- Yukari Wakabayashi, Tokyo, Japan
- Hsu-Huei Weng, MD, MPH, Putz City, Chia-Yi County, Taiwan
- Jeff West, MD, Jacksonville, Fla
- Tatsuya Yamamoto, Obama, Japan
- Satoru Yoshida, MD, Muroran City, Japan
- Joe Yut, Olathe, Kan
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TOP
HISTORY
IMAGING FINDINGS
