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An Urban Experience
primary or metastatic tumors most frequently reported
in large and giant-breed dogs. Commonly described tumors in dogs include: osteosarcoma; fibrosarcoma; chondrosarcoma; hemangiosarcoma; plasma cell tumor; carcinoma; lymphoma; and liposarcoma. Small-breed dogs have a higher rate of vertebral metastasis than large-breed dogs. In cats, the most commonly described vertebral body tumor is osteosarcoma. Primary vertebral body tumors will cause a secondary myelopathy by compression or direct spinal cord invasion. The diagnosis is often based on survey radiographic findings, such
as lysis, and pathological fractures secondary to tumor destruction of the bone. Other supportive diagnostic techniques, such as CT, MRI and myelography, are used to determine lesion extent. MRI and scintigraphy can be used to detect multiple metastases. Fluoroscopic-guided needle aspiration or surgical biopsy can be used to obtain a definitive diagnosis. Palliative treatment options include surgery, radiation therapy, chemotherapy or various combinations of the three. A vertebrectomy with a bone allograft fusion has been used for the treatment of a primary vertebral neoplasm in a dog. Decompression or stabilization techniques are used in patients that are rapidly deteriorating. The overall prognosis is considered guarded for dogs and cats with vertebral neoplasia. Survival is not impacted greatly by various treatments
but is often determined by the neurological deficits at the time of diagnosis.
Discospondylitis is due to infection of the intervertebral disc and adjacent vertebral endplates; if the infection is confined to the vertebral body, it is called vertebral osteomyelitis or spondylitis. The sites most commonly affected are L7-S1, caudal cervical, midthoracic,
and thoracolumbar spine. The infection is usually
slowly progressive but can result in acute signs due
to secondary pathological vertebral fractures and intervertebral disc disease. Its most common clinical sign is that of spinal pain but neurologic signs are seen and realte to the localization. An association with empyema has been documented in several dogs, which may represent an extension of the disease and should be considered when considering diagnostic tests and or when dealing with a refractory case. Coagulase positive Staphylococcus spp. (S. intermedius or S. aureus) is
the most common etiological agent associated with canine discospondylitis; other less commonly identified organisms include Streptococcus spp., Escherichia
coli, Actinomyces spp. and Brucella canis, as well as Aspergillus spp. Young German Shepherd bitches
seem to be predisposed to aspergillosis, whereas
young Basset Hounds contract discospondylitis due to systemic tuberculosis. Spinal pain is the most common initial clinical sign in this disease, which is most frequently seen in large intact male young to middle-aged dogs. With proliferation of inflammatory tissue, compression of
neural tissue can lead to ataxia, paresis and occasionally paralysis dependent on where the lesion is located. Although it can occur in any animal, the condition is less common in toy and chondrodystrophoid breeds of dog, and rare in cats. Purebred dogs seem more commonly affected than mixed-breeds.
Once imaging based radiographic evidence of discospondylitis is present, treatment for the common potential pathogen Staphylococcus spp.intermedius infection may be started. The initial treatment of discospondylitis consists of antibiotics (potentiated amoxicillin or cephalexin), cage rest and analgesics. Results of cultures may require alteration of this choice.
Intravenous antibiotics should be considered if severe neurological compromise or signs of sepsis are present; otherwise, oral antibiotics are acceptable. However quickly the patient improves, continuation of the antibiotics for 8-16 weeks is recommended. Resolution of clinical signs, such as pain and fever, should be expected within 5 days of initiating therapy; however, complete neurological resolution may take 2–3 months. Residual deficits may remain, but persistent pain indicates an active disease, and these patients should be treated with an additional antibiotic and considered for further diagnostics as they may have a potential fungal infection or surgical lesion. Discospondylitis associated with Aspergillus spp. has been treated with itraconazole (5 mg/kg of body weight, PO, q 24 h) although long term reports of success are lacking with the belief being that chronic recurrence and progression is likely.
The prognosis for this disease is generally very good unless the aetiology is fungal, there are multiple lesions, vertebral fracture or subluxation occurs or there is endocarditis; the potential for recurrence should be considered, especially if brucellosis has been diagnosed or an underlying immunosuppressive condition is present. Residual neurological deficits are possible, and in those cases that have severe neurological deficits associated with the infection the prognosis should initially be guarded.

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