Myelopathy secondary to an intramedullary arteriovenous malformation in a mature dog

Case report: Surgical treatment and long-term successful outcome of a spinal intramedullary vascular malformation in a dog

A 3.5-year-old male intact Staffordshire terrier crossbreed dog was presented with a one-week history of progressive paraparesis with fecal and urinary incontinence. Neurological examination was consistent with a T3-L3 myelopathy. A magnetic resonance imaging study revealed the presence of a well-circumscribed hemorrhagic space-occupying lesion at the level of T12, suspected to be a vascular malformation, such as cavernoma or arteriovenous fistula, primary hematoma or hamartoma; less likely considerations included hemorrhagic inflammation or hemorrhagic primary or secondary neoplasia. A dorsal laminectomy, durotomy, and midline dorsal myelotomy were performed with a surgical microscope, and the vascular lesion was identified and removed. Histological examination of surgical samples yielded fibrin, hemorrhage, hematoidin pigment, and some neural tissue. Although a lining wall was visualized during surgery consistent with a vascular malformation, there was no histological confirmation of such a structure, hampering definitive classification of the lesion. There was no gross or histopathological evidence that would support a diagnosis of a hamartoma or benign neoplasia. The dog was paraplegic with intact nociception the day following surgery. Ambulation was recovered within 2 weeks. Progressive and complete recovery of neurological function was seen over the next 12 weeks. No recurrence of neurological dysfunction was seen over a 12-month follow-up period. Surgical treatment should be considered in dogs with spinal intramedullary vascular lesions which can have a successful long-term outcome.

Case report: Intracranial and spinal subarachnoid hemorrhage in a dog with Angiostrongylosis

A 1-year-old male intact Staffordshire terrier, born and raised in the Netherlands, was presented with a 3-week history of progressive lethargy and spinal, predominantly cervical, hyperesthesia. Other than hyperthermia and cervical hyperesthesia, general and neurological examination did not reveal any abnormalities. Comprehensive hematological and biochemical tests were considered normal. Magnetic resonance imaging of the craniocervical region revealed heterogeneity of the subarachnoid space, characterized by pre-contrast T1W hyperintensity, corresponding to a T2* signal void. Extending from the caudal cranial fossa to the level of the third thoracic vertebra, there were uneven patchy extra-parenchymal lesions that caused mild spinal cord compression, most marked at the level of C2. At this level, the spinal cord showed an ill-defined hyperintense T2W intramedullary lesion. Mild intracranial and spinal meningeal contrast enhancement was evident on post-contrast T1W images. Subarachnoid hemorrhage was suspected, and further diagnostic tests including Baermann coprology resulted in a diagnosis of hemorrhagic diathesis caused by an Angiostrongylus vasorum infection. The dog rapidly responded to treatment with corticosteroids, analgesic medication, and antiparasitic treatment. Follow-up over 6 months yielded complete clinical remission and repeatedly negative Baermann tests. This case report details clinical and magnetic resonance imaging findings in a dog with subarachnoid hemorrhage associated with an Angiostrongylus vasorum infection.

Myelopathy secondary to an intramedullary arteriovenous malformation in a mature dog

A 2‐year‐old crossbreed dog was presented for evaluation of a 6‐week history of progressive paraparesis. Magnetic resonance imaging and computed tomography angiography of the thoracic and lumbar spinal cord disclosed multifocal, anomalous, small, vascular structures, distributed throughout the subarachnoid space of the included section of the spinal cord. An additional focal intramedullary lesion was identified extending from T9 to T10 to T12. Histopathological examination confirmed the presence of an intramedullary arteriovenous malformation affecting the thoracic spinal cord and leading to diffuse congestion and focal hemorrhages into the affected spinal cord.