Spinal dural ossification causing neurological signs in a cat

Abstract

A six-year-old Ragdoll cat underwent examination due to a six-month history of slowly progressive gait abnormalities. The cat presented with an ambulatory tetraparesis with a neurological examination indicating a C1-T2 myelopathy. Radiographs of the spine showed a radiopaque irregular line ventrally in the vertebral canal dorsal to vertebral bodies C3-C5. In this area, magnetic resonance imaging revealed an intradural extramedullary/extradural lesion compressing the spinal cord. The spinal cord was surgically decompressed. The cause of the spinal cord compression was dural ossification, a diagnosis confirmed by histopathological examination of the surgically dissected sample of dura mater. The cat gradually improved after the procedure and was ambulating better than prior to the surgery. The cat’s locomotion later worsened again due to ossified plaques in the dura causing spinal cord compression on the same cervical area as before. Oral prednisolone treatment provided temporary remission. Ten months after surgery, the cat was euthanized due to severe worsening of gait abnormalities, non-ambulatory tetraparesis. Necropsy confirmed spinal cord compression and secondary degenerative changes in the spinal cord on cervical and lumbar areas caused by dural ossification. To our knowledge, this is the first report of spinal dural ossification in a cat. The reported cat showed neurological signs associated with these dural changes. Dural ossification should be considered in the differential diagnosis of compressive spinal cord disorders in cats.

Magnetic Resonance Imaging in 50 Captive Non-domestic Felids - Technique and Imaging Diagnoses

“…Extensive subdural ossification resulting in spinal cord compression was diagnosed in one serval, an uncommon condition with only few similar cases reported in the veterinary literature ( 61 , 62 ). The predominant MRI finding in this patient was extensive attenuation of the subarachnoid space on MR myelogram which is a nonspecific finding with a variety of possible causes including extradural compressive lesions, acute noncompressive spinal cord injury, spinal cord swelling, and/or infiltrative meningeal disease ( 63 , 64 ).…”

Pathology of the Aging Brain in Domestic and Laboratory Animals, and Animal Models of Human Neurodegenerative Diseases

“…101,105 In 1 report a 6-year-old Ragdoll cat with neurological signs had ventrally located dural plaques of osseous metaplasia on the C3-C5 segments and caudal lumbar areas. 3 The etiology of dural ossification remains unknown. It was suggested that mechanical factors such as rubbing of the dura matter against adjacent vertebral structures (eg, articular facets) or against other spinal disorders, such as disk protrusion may cause the lesion.…”

Transient bilateral blindness associated with presumptive idiopathic pachymeningitis in a 22‐year‐old Irish Sport Horse

“…The MRI and CSF findings in this case are consistent with idiopathic hypertrophic pachymeningitis which, to the authors' knowledge, has not been reported previously in a horse. Hypertrophic pachymeningitis is a rare condition described in human patients, dogs and a cat (Hess and Sellon 1997;Roynard et al 2012;Antila et al 2013;De Virgilio et al 2017). The thickening of the dura mater is secondary to inflammatory infiltrates and can affect the cerebral or the spinal dura mater or, less frequently, both (De Virgilio et al 2017).…”