Intradural Dirofilariasis in a Dog with Chronic Cervical Pain

Abstract

A 7 yr old female spayed Yorkshire terrier was referred to the author's institute for a 5 mo history of recurrent cervical spinal pain. Neurologic examination did not reveal any deficits. Hematologic and serum analyses were within normal limits. Thoracic radiographs that incorporated the cervical spine did not show structural abnormalities. Magnetic resonance imaging of the cervical spine demonstrated a contrast enhancing, intradural extramedullary lesion at the level of the C2 vertebra. Hemilaminectomy was performed, during which a long, narrow nematode was visualized upon opening of the dura mater. The parasite was alive when removed during surgery, and the dog recovered with complete resolution of symptoms. The parasite was submitted and confirmed as a male adult Dirofilaria immitis. This is a novel case of an intradural D. immitis infection in the dog with a magnetic resonance imaging description of spinal D. immitis.

Extensive Epidural Steatitis and Epaxial Myositis Associated with Intramuscular Injection of Melarsomine Dihydrochloride in Two Dogs

“…Previous reports have documented focal epidural steatitis in proximity to the injection site, thought to be a result of drug extension along spinal nerves, direct injection into the vertebral canal or aberrant heartworm larval migration. [4][5][6] In contrast, the dogs herein had extensive epidural steatitis and a consequent compressive myelopathy. Transverse myelitis is a rarely reported complication described in people receiving intramuscular injections of steroids or antibiotic medications with aberrant injection into nerve roots.…”

Verminous myelopathy secondary to aberrant Dirofilaria immitis migrans was detected in the cervical subarachnoid space of four dogs using MRI and CT

“…An L3 larvae could migrate to the subarachnoid space and mature there. 2,5,7,11 This would be unexpected as it has historically been hypothesized that venous blood is the support medium for maturation. 13,15, However, the presence of adults in the cervical subarachnoid space of the patients herein brings into question whether aberrant subarachnoid larval migration and subsequent maturity in the CSF are possible.…”

“…Scans were interpreted using an image analy- and the unfortunate happenstance that verminous migrans was not included on the list of differentials (as this case was the first presenting case seen by the authors at institution 1, and imaging characteristics for this disease process had not yet been published or widely recognized). 7 Necropsy examination revealed a 24-cm long, female heartworm from C2-3 within the dorsal subarachnoid space.…”

“…subarachnoid and epidural space of the vertebral column. [2][3][4][5][6][7] Clinical signs specific to verminous myelopathy vary and may be associated with mechanical compression of the neuropil, local inflammation, and vascular damage. [2][3][4][5][6][7] In people, MRI is integral in the diagnosis of CNS parasitic migrans.…”

“…A postmortem report, along with a more recent case report featuring MRI characteristics exist. 3,7 The purposes of this study were to describe the clinical and imaging features of spinal subarachnoid D. immitis migration in naturally infected dogs and to describe their response to treatment.…”