Hypertrophic spinal pachymeningitis (HSP) is an uncommon cause of spinal cord compression. Spinal cord compression is due to dural thickening. A number of etiologies have been attributed to its development including infection (tuberculosis, fungi, syphilis); however, in most cases the cause of spinal pachymeningitis is vague or idiopathic. In this report, we describe our experience with this entity and-review the world’s literature regarding this condition.
A 28 year old female presented with weakness of all extremities. She noted the onset of symptoms after a MI, one month prior to presentation at our institution. She hyperextended her neck during the fall. Immediately following the fall she was unable to move due to .paralysis. She gradually improved and was subsequently transferred to our institution. The patient was treated with intravennous steroids prior to transfer.
Initial physical examination upon transfer revealed 4/5 strength in all extremities. A patchy hyperesthesia to pinprick was noted diffusely without evidence of a sensory level, the patient was diffusely hyperreflexic with bilateral Babinski signs. Bilateral Hoffmann signs of the upper extremities were present. The patient also exhibited a positive L’hermitte’s sign. The patient was afebrile.
Plain radiographs of the cervical spine were normal including flexion-extension views. Magnetic resonance imaging (MRI) of the cranial cervical region was obtained, which demonstrated compression of the spinal cord at CI-C2 due to a dural based process. (See Fig. 1)
There was no enhancement of the dura after gadolmium injection. A brain MRI was also performed and was normal. Computerized tomogaphy (CT) obtained after intrathecal contrast injection demonstrated circumferential compression of the spinal cord. (See fig.2) CT with sagittal reconstruction at the cranial cervical junction was normal. (See Fig. 3) Cerebrospinal fluid analysis was normal (WBC - 5mm3, RBC - 10mm3, CSF glucose 64 mg/dl, serum glucose 103 mg/dl), except for an elevated CSF proteins (104 mg/dl). Cerebral spinal fluid cultures were negative for bacteria or parasites.
Peripheral white blood cell count and erythrocyte sedimentation rate were normal. Serum testing for syphilis, HIV, plus lupus and rheumatoid factor were normal. Skin testing for tuberculosis (PPD) was normal. The diagnosis of(IHSP) was made based on radiographic studies and the absence of known risk factors for development of pachymeningitis.
The patient was taken to surgery where a foramen magnum Cl and C2 posterior decompression was performed. A midline incision in the dura was performed. The dura was found to be thickened (approximately I cm). The thickened dura was partially excised and the specimen was sent for culture and pathology. A dural patch was used to repair the dural defect and to allow for a patulous closure. Fascia lata was used for dural repair. The patient’s postoperative recovery was uneventful. Followup at one year revealed normal strength. The patchy sensory hypestesia had improved. She no longer exhibited a positive L’hermitte’s sign. Pathologic examination of the dura revealed dense collagen bundles with lymphocyte and histiocyte infiltration. There was no evidence of tumor, granuloma, acid fast organisms or fungi. (See fig. 4) Cultures of the excised dura were negative.
Hypertrophic spinal pachymeningitis (HSP) was first described by Joffroy and Charcot in 1869. (6, 17) It is characterized by an inflammatory hypertrophy of the ineninges. We were able to identify 74 cases of idiopathic hypertrophic spinal pachymeningitis in the world’s literature. (2,3,5,8,2,13,16,24,25) Charcot and Joffroy described three stages of the disease. The first stage is characterized by pain (either local or radicular). The second stage is characterized by clinical signs of nerve root compression. The third stage is characterized by spinal cord compression. (6).
Pachymeningitis most commonly involves the cervical and thoracic regions. (10). However, it has been described intracranially.(15). In most case, the cause in unknown; however, it has been associated with trauma, metabolic diseases, intrathecal injections (steroids), rheumatoid arthritis, thrombophlebitis. (4,7,11,14,18,20) Infectious etiologies have also been associated with it, including syphilis, tuberculosis and fungi. Tuberclosis and syphilis are the most common identifiable causes of HSP. (1,9,22,23,27)
Surgical decompression involving both laminectomy and excision of the dura is advised in most cases since the condition can be progressive. (19,21,26) When patients present with frank clinical evidence of cord compression, the indications for surgery are more compelling. Whether or not the excised dura should be repaired with a graft’ or left open is a subject of debate. Review of the literature shows that success has been achieved with both methods. (6) Kanamori utilized a laminoplasty technique in addition to dural excision. (12) Some cases have been successfully treated with the use of prolonged steroids, immunosupression (cyclophosphamide) and radiation therapy, but the role of these modalities is controversial. (6) Thickening of the dura is the most salient feature on pathologic examination. Dural thickening can range, from 5 to 15 mm.
Histologic examination typically reveals a non-specific inflammatory response characterized by dense fibrous tissue with lymphocytic infiltration; however, plasma cells and foreign body giant cells have also been described. (21) When cord compression has been chronic and severe, softening of the spinal cord can occur with formation of the syringomyelia cavities.
IHSP does not exhibit a sexual predominance. Cases have been reported in all age groups, except young children. The youngest reported case in 15 and the oldest is 77. (12) Patients can present with both acute spinal cord dysfunction or a more prolonged clinical course taking years to come to a diagnosis.
Most patients improve after decompressive surgery; however, continued progression after surgical treatment has been reported. Moreover, some cases have resulted in death either due directly to pachymeningitis or from sequelae of spinal cord compression (e.g. pulmonary embolus). The presence of inflammatory signs (fever, leukocytosis, elevated sedimentation rate) may be associated with a poorer prognosis when compared to cases in which these signs are absent. (12).
The diagnosis of HSP should be considered in patients with clinical evidence of cord compression without bony changes on plain radiographs. Both MRI and CT are definitive in making the diagnosis; however, MRI with gadolinium injection is the diagnostic procedure of choice. Decompressive surgery with excision ofthe thickened dura is the treatment of choice in most cases.