Diskospondylitis, also known as spondylitis, intervertebral disk infection, or vertebral osteomyelitis, is a condition characterized by bacterial or fungal infections of the intervertebral disks, the soft tissue structures between the vertebrae in the spine. While it can occur at various sites along the spinal column, diskospondylitis is more common in dogs than in cats. However, cat owners should remain vigilant and watch out for signs and symptoms in order to keep their feline companions in tip-top shape.
Causes and Transmission of Diskospondylitis
The infection can reach the intervertebral disks through various means:
- Bloodstream: The most common method involves bacteria entering the bloodstream from chronic infections in other parts of the body, such as the skin, urinary tract, or prostate. These bacteria can then travel to the spinal disk area.
- Direct Contamination: Direct contamination can occur through puncture wounds or bite wounds near the spine or during surgical procedures in proximity to the spine.
- Migration of Foreign Bodies: Sometimes, foreign bodies can migrate through the area near the spine, introducing infection.
Signs and Symptoms
Signs of diskospondylitis typically have a gradual onset and progress over time. Initial symptoms may include spinal pain, stiffness, unsteady walking, and other neurological issues. Spinal pain is a consistent clinical sign, while impaired movement (paresis) is usually mild unless the infection affects the spinal canal. Without prompt treatment, symptoms can progress to paralysis, often due to fractures of the vertebrae. Muscles alongside the spine may atrophy (waste away), potentially due to local nerve damage or muscle inflammation (myositis).
Spinal cord compression can occur due to factors such as granulation tissue, bony changes, fractures, or dislocations resulting from the infection. Surgical stabilization may be necessary in cases of vertebral fractures or dislocations.
In some instances, the infection can lead to conditions like meningitis, meningomyelitis, or abscess formation within the spinal canal.
Diagnosis of Diskospondylitis
Diagnosing diskospondylitis requires a combination of diagnostic tools:
- Radiography (X-rays): Radiographs of the spine typically reveal damage to the vertebrae adjacent to the affected disks. Bone changes and spinal deformities may also be visible in chronic cases. It's important to note that radiographic changes may take 3-6 weeks to appear after the onset of clinical signs.
- Advanced Imaging: Techniques like bone scintigraphy, computed tomography (CT), and magnetic resonance imaging (MRI) are more sensitive than plain radiographs, especially for detecting early lesions. These imaging methods are crucial if neurological problems are present or if spinal surgery is planned.
- Urinalysis: Examination of urine may reveal the presence of pus and/or bacteria.
- Bacterial Cultures: Cultures of urine, blood, spinal fluid, or other infected tissues can help identify the specific organism responsible for the infection. Culturing the infected disk space yields the most accurate results.
- Serology: Testing for brucellosis in the blood should be performed, as it is a potential cause of diskospondylitis and can be transmitted to humans.
- Cerebrospinal Fluid (CSF) Analysis: In cases with neurological signs, CSF analysis is conducted, including culturing the CSF, routine cytology, cell count, and protein determination.
Treatment and Management
The treatment approach for diskospondylitis involves a prolonged course of antibiotics tailored to combat the specific infective organism. Ideally, antibiotic selection is based on culture and sensitivity results from the infected disk. In cases where disk culture isn't feasible, antibiotic selection relies on culture results from other infected areas like urine or blood.
Antibiotic therapy may extend for several months, and discontinuing treatment prematurely, using ineffective antibiotics, or introducing corticosteroids or other immunosuppressive drugs can lead to disease recurrence or persistent symptoms. If clinical signs do not improve with antibiotics, your veterinarian may recommend repeating the disk culture.
In the case of brucella infections, it's essential to understand that a complete cure is unlikely. Long-term antimicrobials will be necessary, and reinfection is common.
Antifungal therapy, particularly with drugs like itraconazole, may be effective against fungal diskospondylitis.
Surgical exploration may be advised if a lesion doesn't respond to treatment or if draining tracts suggest foreign body migration. Decompressive surgery and/or stabilization may be considered if spinal cord compression is identified through imaging or if severe neurological problems persist.
Supportive Therapy and Monitoring
Pain medications may be necessary for a short period if antibiotics are effective.
Monitoring involves periodic radiographs to assess lesion improvement, with clinical signs often improving before radiographic changes are observed. The prognosis for recovery is guarded, influenced partly by the underlying cause of diskospondylitis.
Prevention
Preventing diskospondylitis involves early detection through thorough veterinary evaluation and the timely administration of appropriate antibiotics. In cases of breed-related risk factors or recurrent infections, selective breeding strategies can help minimize the risk of disease transmission.
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