{"id":2752,"date":"2018-01-17T17:17:51","date_gmt":"2018-01-17T22:17:51","guid":{"rendered":"http:\/\/phosdev.com\/todaysveterinarynurse\/?post_type=articles&p=2752"},"modified":"2022-08-10T18:24:49","modified_gmt":"2022-08-10T18:24:49","slug":"discospondylitis-dogs-cats","status":"publish","type":"post","link":"https:\/\/navc.sitepreview.app\/todaysveterinarynurse.com\/infectious-disease\/discospondylitis-dogs-cats\/","title":{"rendered":"Discospondylitis in Dogs and Cats: Signalment, Diagnosis, and Treatment"},"content":{"rendered":"
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Discospondylitis<\/span> is an infection<\/a> of the vertebral endplates and associated intervertebral disk. Discospondylitis in dogs and cats<\/span> typically starts in the vertebral end plate, then spreads to the adjacent intervertebral disc. The blood supply within the vertebral endplates consists of capillary beds with reduced blood flow velocity. Pores in the end plate that normally allow for distribution of nutrients also provide a route for organisms to enter the intervertebral disc. The minimal vascular supply of the intervertebral disc further enables infection within the disk.<\/span>1<\/span><\/sup><\/p>\n

Pathophysiology of Discospondylitis<\/h2>\n

Infectious organisms can gain access to the disc space in many ways. <\/span>Hematogenous<\/span> spread of bacteria or fungi from the urogenital tract, oral cavity, heart valves, and skin is believed to be the most common method. Foreign-body migration, such as a plant awn, may introduce bacteria as migration occurs throughout tissues. Less commonly, <\/span>discospondylitis<\/span> occurs as an iatrogenic infection following spinal surgery or paravertebral injections.<\/span>2<\/span><\/sup> In cats, abscesses from bite wounds can cause <\/span>discospondylitis<\/span> by direct inoculation of bacterial organisms.<\/span>1<\/span><\/sup><\/p>\n

The most common causes of <\/span>discospondylitis<\/span> are coagulase-positive <\/span>Staphylococcus <\/span>pseudintermedius<\/span><\/em> or <\/span>Staphylococcus aureus<\/span><\/em>. Less commonly, <\/span>Streptococcus<\/span><\/em> species, <\/span>Escherichia coli<\/span><\/em>, and fungal organisms (such as <\/span>Aspergillus<\/span><\/em> species) can be causes.<\/span>3<\/span><\/sup> <\/span>Brucella <\/span>canis<\/span><\/em> can also cause <\/span>discospondylitis<\/span> and is an important infectious agent to consider in all suspected cases because of its zoonotic potential. <\/span>B <\/span>canis<\/span><\/em> is transmitted by direct exposure to bodily fluids or <\/span>transplacental<\/span> transmission from mother to puppy. Precautions, such as routine hand washing, minimization of exposure to urine, and the wearing of gloves, should be taken until <\/span>Brucella<\/span><\/em> has been ruled out as a cause.<\/span>4<\/span><\/sup><\/p>\n

Signalment\/Presentation of Discospondylitis in Dogs and Cats<\/h2>\n

Discospondylitis<\/span> is most commonly seen in young to middle-aged medium- to large-breed dogs. Less commonly, it has been reported in small-breed dogs and cats. Predisposed breeds include Great Danes, boxers, Rottweilers, English bull dogs, German shepherd dogs, Doberman pinschers, and Rhodesian ridgebacks.<\/span>2,5<\/span><\/sup> Most dogs will display progressive clinical signs over several weeks, but vertebral pathologic fractures can cause acute deterioration.<\/span>2<\/span><\/sup> Clinical signs may be nonspecific and include systemic illness, such as depression, anorexia, pyrexia, and lethargy. <\/span><\/p>\n

Paraspinal<\/span> hyperesthesia is the most common finding on neurologic examination. Gait abnormalities, such as ataxia, paresis, or paralysis, may be present if secondary spinal cord or nerve root compression occurs.<\/span>2<\/span><\/sup> When neurologic signs are present, they correlate to the location of the <\/span>discospondylitis<\/span> lesion; cervical vertebral column lesions may cause <\/span>tetraparesis<\/span> and neck pain; thoracolumbar lesions may cause pelvic limb paresis, proprioceptive ataxia, and back pain; and lumbosacral lesions may cause a stiff, stilted pelvic limb gait.<\/span>1,2<\/span><\/sup> <\/span>Discospondylitis<\/span> can affect any area of the vertebral column, but the most commonly affected sites are L7 to S1, caudal cervical, mid-thoracic, and the thoracolumbar spine. Multifocal lesions occur in 30% to 40% of cases.<\/span>5<\/span><\/sup><\/p>\n

Diagnostic Imaging<\/span><\/h2>\n

Definitive diagnosis of <\/span>discospondylitis<\/span> is based on characteristic findings on spinal radiography in a patient with supportive clinical features. Typical radiographic findings include collapse of the affected disc space, lysis of the adjacent vertebral endplates, and bony proliferation of adjacent vertebral bodies (<\/span>FIGURES<\/span> 1 and 2<\/span><\/strong>). Because multiple lesions are common, radiography of the entire spine should be performed to properly assess the extent and severity of disease.<\/span>2<\/span><\/sup> The patient should be sedated for spinal radiography to ensure proper positioning and an accurate assessment of the area of interest. It is important that the veterinary technician use caution when transporting and positioning a sedated patient with potential spinal lesions. Care should be taken to avoid patient manipulation and to prevent further injury. The main limitation of standard radiography is that radiographic changes may lag behind the onset of clinical signs in the first 2 to 4 weeks of infection. Patients with suspected <\/span>discospondylitis<\/span> and normal radiographs may still have the disease; radiography should be repeated every 1 to 2 weeks or more advanced imaging should be considered.<\/span>2,6<\/span><\/sup> <\/span><\/p>\n

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FIGURE 1.<\/strong> Radiograph of the lumbar spine showing vertebral body endplates that are irregular with permeative lysis centered at the disc spaces (arrows<\/strong>). \u00a9The Ohio State University<\/em><\/p><\/div>\n<\/div>\n<\/div>\n

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\"FIGURE<\/a>

FIGURE 2.<\/strong> Radiograph of the lumbar spine showing lysis of the vertebral body and caudal endplate of L7 and the cranial endplate of S1 (arrow<\/strong>). \u00a9The Ohio State University<\/em><\/p><\/div>\n<\/div>\n<\/div>\n

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Magnetic resonance imaging (MRI) and computed tomography (CT) have an increased sensitivity for the diagnosis of <\/span>discospondylitis<\/span> and can be useful in revealing early lesions. MRI is superior for evaluating soft tissue structures, and its advantages over standard radiography include its visualization of the spinal cord and nerve roots, its high contrast resolution, and the ability to use contrast agents. The use of MRI in a patient with <\/span>discospondylitis<\/span> may reveal T2-weighted increased signal intensity and T1-weighted decreased signal intensity in the intervertebral disc, vertebral end plates, and vertebral bodies (<\/span>FIGURES <\/span>3<\/span> and <\/span>4<\/span><\/strong>). Contrast enhancement is often observed in the endplates of the affected vertebrae, and inflammation in the surrounding muscles may also be highlighted.<\/span>2,6<\/span><\/sup> Compressive lesions that can potentially be surgically corrected,<\/span> such as disc protrusion\/extrusion, vertebral subluxations, fractures, and concurrent epidural abscess, can be easily identified. CT is useful to aid in identifying subtle endplate erosion, vertebral fractures, and vertebral subluxations and can aid in obtaining fine-needle aspirates.<\/span><\/span>3,5<\/span><\/span><\/sup><\/p>\n

\"FIGURE<\/a>

FIGURE 3.<\/strong> Sagittal T1-weighted MRI image of the lumbar spine with hypointensity and lysis of the vertebral endplates of T13-L1 and L1-L2 (arrows<\/strong>). \u00a9The Ohio State University<\/em><\/p><\/div>\n

\"FIGURE<\/a>

FIGURE 4.<\/strong> Sagittal T1-weighted MRI image of the lumbar spine with hypointensity of the caudal endplate of L7 and the cranial endplate of S1 (arrow<\/strong>). \u00a9The Ohio State University<\/em><\/p><\/div>\n

Hematologic Evaluation and Microbiology<\/h2>\n

Veterinary technicians play a vital role in the collection of laboratory tests and interpretation of the results. Blood values are often unremarkable, but leukocytosis characterized by neutrophilia and <\/span>monocytosis<\/span> can occasionally be seen on complete blood count. Leukocytosis is more common in dogs with associated endocarditis.<\/span>1<\/span><\/sup> Mild hypoalbuminemia and mild to moderate hyperglobulinemia are the most common abnormalities noted on the serum biochemistry panel.<\/span>5<\/span><\/sup><\/p>\n

Procedure for Obtaining Blood Cultures<\/h3>\n