Fibrocartilaginous Embolism of the Spinal Cord in Dogs: Review of 36 Histologically Confirmed Cases and Retrospective Study of 26 Suspected Cases

Abstract

Clinical features of 36 dogs with histologically confirmed fibrocartilaginous embolism (FCE) were contrasted with those of 26 dogs in which FCE was suspected based on characteristic clinical findings and the absence of compressive spinal cord disease on myelography. Dogs with confirmed and suspected FCE were of similar signalment, and had acute, nonprogressive dysfunction, often associated with trauma or exercise. The "suspected group included ibrocartilaginous embolism (FCE) is a syndrome of F acute spinal cord infarction caused by embolization of fibrocartilage, histochemically identical to the nucleus pulposus of intervertebral disks. Histopathologic evaluation is necessary to establish a definitive diagnosis. Based on published data from histologically confirmed cases, FCE appears to have a high prevalence in large and giant-breed dogs, and a predilection for the spinal intumescence^.'-'^ However, considering that large dogs with intumescence involvement could be at increased risk for euthanasia, we were concerned that data from necropsy cases could be skewed. To more critically evaluate this point, clinical findings of histologically confirmed cases were contrasted with those from dogs in which FCE was suspected, but not confirmed at necropsy. Materials and MethodsWe analyzed the historical, clinical, and necropsy features of 36 dogs with histologically confirmed FCE. Thirty-one of these dogs have been reported previo~sly'~'~; the other 5 were evaluated at the North Carolina State University College of Veterinary Medicine (NCSU-CVM). Data from one large retrospective series that did not clearly distinguish between confirmed and suspected cases were not in~1uded.l~ Case signalment; acuity of onset and progression of signs, and their association with trauma or exercise; history of pain; spinal cord segment involvement; symmetry; hyperesthesia; presence of deep nociception; cerebrospinal fluid evaluation results (site of collection was not consistently identified); spinal radiographic and myelographic findings; and gross and microscopic necropsy findings were recorded when found in case material from the published cases. These features were,,also characterized in 26 dogs with suspected FCE evaluated at the NCSU-CVM between 1985 and 1992. Criteria for inclusion in our study included peracute/acute, nonprogressive paresis or paralysis that was not associated with myelographic spinal cord compression, as detailed in the radiographic report found in the medical record. Dogs with suspected lesions were subsequently discharged. Follow-up information beyond the day of discharge was not consistently obtained. ResultsData to address certain features were not available on all dogs. The actual numbers of dogs from which data could be collected are included for each feature. Data from "confirmed" and "suspected" cases are given in Tables 1 and 2, respectively. Differences between the 2 groups are contrasted in Table 3. SignalmentNone of the dogs with confirmed or suspected FCE was a chondrodystrophoid breed. Sixteen of t...

Comparison of clinical signs and outcomes between dogs with presumptive ischemic myelopathy and dogs with acute noncompressive nucleus pulposus extrusion

“…schemic myelopathy and ANNPE are common neurologic emergencies in dogs that have similar clinical signs [1][2][3][4][5][6][7][8][9][10] such as the hyperacute onset of nonprogressive, often markedly asymmetric spinal cord dysfunction without obvious signs of pain. 1,3,5,10 In dogs, ischemic myelopathy is most commonly associated with embolization of fibrocartilaginous material within the spinal cord vasculature that is histologically indistinguishable from nucleus pulposus (ie, fibrocartilaginous embolism) 5,6,[11][12][13] and causes sudden onset of regional ischemia resulting in necrosis of the spinal cord parenchyma.…”

“…1,3,5,10 In dogs, ischemic myelopathy is most commonly associated with embolization of fibrocartilaginous material within the spinal cord vasculature that is histologically indistinguishable from nucleus pulposus (ie, fibrocartilaginous embolism) 5,6,[11][12][13] and causes sudden onset of regional ischemia resulting in necrosis of the spinal cord parenchyma. [4][5][6][11][12][13] In contrast,…”

Fibrocartilaginous Embolic Myelopathy in a Calf

“…Clinically, acute to subacute, nonprogressive, focal spinal cord dysfunction in the absence of hyperpathia is suggestive of fibrocartilaginous embolic myelopathy. 4,7,8 The following is a case report of fibrocartilaginous embolic myelopathy in a bovine.A 5-month-old Angus heifer calf was presented to the ambulatory service of the Virginia-Maryland Regional College of Veterinary Medicine Veterinary Medical Teaching Hospital (VMTH), Blacksburg, Virginia, with a history of being acutely down. The calf was found in lateral recumbency and was unable to rise with assistance.…”

“…Clinically, acute to subacute, nonprogressive, focal spinal cord dysfunction in the absence of hyperpathia is suggestive of fibrocartilaginous embolic myelopathy. 4,7,8 The following is a case report of fibrocartilaginous embolic myelopathy in a bovine.…”

“…[3][4][5]12 Several possible mechanisms have been proposed to explain both arterial and venous embolism in the various affected species. One suggested route of passage is dissection of the semifluid nucleus pulposus through a degenerating dorsal annulus fibrosis to exposed neovasculature.…”