Diskospondylitis

# Diskospondylitis in Dogs and Cats

Overview

Diskospondylitis is a serious infectious condition that affects the intervertebral discs and adjacent vertebrae in the spine of dogs and cats. This painful condition occurs when bacteria or fungi invade the disc space between vertebrae, causing inflammation and infection that can spread to the surrounding bone tissue. The infection typically affects the disc space itself along with the endplates of the adjacent vertebral bodies.

While diskospondylitis can occur in any part of the spine, it most commonly affects the lumbar (lower back) and thoracic (mid-back) regions. The condition is more frequently diagnosed in dogs than cats, with large breed dogs being particularly susceptible. Male dogs appear to be affected more often than females, and the condition can occur at any age, though it's most common in middle-aged to older pets.

The severity of diskospondylitis varies depending on the causative organism, the location of the infection, and how quickly treatment begins. Without proper treatment, the infection can lead to serious complications including spinal cord compression, neurological deficits, and in severe cases, paralysis.

Causes

Diskospondylitis develops when infectious organisms reach the intervertebral disc space through various pathways. The most common cause is bacterial infection, with Staphylococcus species being the most frequently identified pathogens. Other bacterial causes include Streptococcus, E. coli, Brucella canis, and various gram-negative bacteria.

Fungal infections can also cause diskospondylitis, though they are less common. Aspergillus, Paecilomyces, and other opportunistic fungi may be responsible, particularly in immunocompromised animals or those living in areas where these organisms are endemic.

The infection typically reaches the disc space through hematogenous spread, meaning bacteria or fungi travel through the bloodstream from another infected site in the body. Common primary infection sources include urinary tract infections, dental disease, skin wounds, respiratory infections, or post-surgical complications.

Direct inoculation can occur through penetrating wounds, surgical procedures involving the spine, or from adjacent infected tissues. In some cases, the infection may spread from nearby structures such as infected vertebrae or soft tissues surrounding the spine.

Certain factors can predispose pets to developing diskospondylitis, including immunosuppression, diabetes mellitus, chronic kidney disease, or the use of immunosuppressive medications. Previous spinal surgery or trauma may also increase the risk of infection.

Symptoms & Signs

The clinical signs of diskospondylitis can vary significantly depending on the location and severity of the infection. Early recognition of symptoms is crucial for successful treatment and prevention of complications.

Early Symptoms

• Reluctance to move or exercise
• Stiffness when getting up or lying down
• Mild to moderate back pain
• Decreased appetite
• Lethargy or reduced activity levels
• Subtle changes in gait or posture

Advanced Symptoms

• Severe back pain and spinal sensitivity
• Hunched or arched back posture
• Difficulty walking or abnormal gait
• Weakness in the hind limbs
• Fever and general illness
• Weight loss due to chronic pain and decreased appetite
• Vocalization when touched or moved

Emergency Signs

• Sudden onset of paralysis or severe weakness
• Loss of bladder or bowel control
• Complete inability to walk or stand
• Severe neurological deficits
• Signs of systemic sepsis including high fever, vomiting, and collapse

The progression of symptoms can be gradual over weeks to months, or in some cases, acute with rapid deterioration. Pet owners may initially notice subtle changes in their pet's behavior or movement that gradually worsen over time.

Diagnosis

Diagnosing diskospondylitis requires a combination of clinical examination, imaging studies, and laboratory tests. The diagnostic process begins with a thorough physical and neurological examination to assess pain levels, mobility, and neurological function.

Radiographs (X-rays) of the spine are typically the first imaging study performed. Classic radiographic changes include narrowing of the disc space, destruction of the vertebral endplates, and new bone formation around the affected area. However, these changes may not be visible in the early stages of infection, as radiographic abnormalities typically take 2-8 weeks to develop.

Advanced imaging techniques provide more detailed information about the extent of infection. Magnetic resonance imaging (MRI) is considered the gold standard for diagnosing diskospondylitis, as it can detect early changes in the disc and surrounding tissues before they become visible on radiographs. Computed tomography (CT) scans can also be useful, particularly for evaluating bony changes and planning surgical interventions.

Laboratory tests play a crucial role in diagnosis and treatment planning. Complete blood count and chemistry panels may reveal signs of infection or inflammation. Blood cultures should be performed to identify the causative organism and determine antibiotic sensitivity, though they are positive in only about 45-75% of cases.

In some cases, fine needle aspiration or biopsy of the affected disc space may be necessary to obtain samples for culture and sensitivity testing. This procedure is typically performed under fluoroscopic or CT guidance to ensure accurate sampling.

Additional diagnostic tests may include urinalysis and urine culture to identify potential sources of infection, as well as testing for specific pathogens like Brucella canis in appropriate cases.

Treatment Options

Treatment of diskospondylitis typically involves long-term antibiotic therapy, pain management, and supportive care. The specific treatment approach depends on the severity of the condition, the causative organism, and the presence of neurological complications.

Veterinary Treatment

Antibiotic therapy forms the cornerstone of treatment for bacterial diskospondylitis. The choice of antibiotic depends on culture and sensitivity results when available, or empirical selection based on the most likely pathogens. Commonly used antibiotics include fluoroquinolones, clindamycin, cephalexin, or amoxicillin-clavulanate.

Treatment duration is typically prolonged, ranging from 6-12 weeks or longer, depending on the response to therapy. The extended treatment period is necessary because of the poor blood supply to intervertebral discs, which makes it difficult for antibiotics to penetrate the infected tissue effectively.

Pain management is essential for patient comfort and recovery. Non-steroidal anti-inflammatory drugs (NSAIDs), opioids, or other analgesics may be prescribed depending on the severity of pain and the individual patient's needs.

For fungal diskospondylitis, antifungal medications such as itraconazole, fluconazole, or amphotericin B may be required. Fungal infections typically require even longer treatment periods than bacterial infections.

Surgical Treatment

Surgical intervention may be necessary in cases that don't respond to medical therapy or when there are significant neurological complications. Surgical options include debridement of infected tissue, spinal fusion, or decompression procedures to relieve pressure on the spinal cord.

The decision for surgery depends on factors such as the extent of bone destruction, presence of spinal instability, neurological deficits, and response to medical treatment. Post-surgical patients typically require extended antibiotic therapy and careful monitoring.

Home Care

Home care plays an important role in supporting recovery from diskospondylitis. Strict rest and activity restriction are essential during the acute phase of treatment. This means confining the pet to a small area and avoiding activities that could exacerbate spinal pain or instability.

Pain management at home involves administering prescribed medications exactly as directed and monitoring for side effects. Creating a comfortable environment with soft bedding and easy access to food and water can help reduce stress and promote healing.

Gentle physical therapy exercises may be recommended once the acute phase has resolved. These exercises should only be performed under veterinary guidance and may include controlled leash walks and range-of-motion exercises.

Monitoring for improvement or deterioration is crucial. Pet owners should watch for changes in appetite, mobility, pain levels, and neurological function, reporting any concerns to their veterinarian promptly.

Prevention

Preventing diskospondylitis involves addressing risk factors and maintaining overall health. Prompt treatment of infections elsewhere in the body can help prevent hematogenous spread to the spine. This includes treating urinary tract infections, dental disease, skin wounds, and respiratory infections quickly and completely.

Maintaining good dental hygiene through regular brushing and professional cleanings can reduce the risk of bacteremia from dental disease. Similarly, proper wound care and hygiene can prevent skin infections that might spread systemically.

For pets undergoing spinal surgery, following post-operative care instructions carefully and attending all follow-up appointments can help prevent surgical site infections.

Maintaining a healthy immune system through proper nutrition, regular exercise, and routine veterinary care can help pets resist infections. Managing underlying conditions such as diabetes or kidney disease is also important for preventing immunosuppression.

Prognosis & Recovery

The prognosis for diskospondylitis varies depending on several factors, including the causative organism, the extent of infection, the presence of neurological complications, and how quickly treatment begins. With appropriate treatment, many pets can make a full recovery, though the process is often lengthy.

Pets with bacterial diskospondylitis generally have a better prognosis than those with fungal infections. Cases diagnosed and treated early, before significant neurological complications develop, typically have the best outcomes.

The presence of neurological deficits at the time of diagnosis significantly affects the prognosis. Pets with mild neurological signs may recover completely, while those with severe deficits or paralysis may have permanent disabilities despite treatment.

Response to treatment is typically gradual, with improvement in pain and mobility occurring over weeks to months. Radiographic healing often lags behind clinical improvement and may take several months to become apparent.

Some pets may experience chronic pain or stiffness even after successful treatment of the infection. In these cases, long-term pain management strategies may be necessary to maintain quality of life.

When to See a Vet

Immediate veterinary attention is necessary if a pet shows signs of severe back pain, difficulty walking, or any neurological symptoms such as weakness or loss of coordination. These signs could indicate diskospondylitis or other serious spinal conditions requiring urgent treatment.

Pet owners should also seek veterinary care if their pet shows persistent signs of illness such as lethargy, decreased appetite, or fever, especially if accompanied by any signs of back pain or stiffness. Early diagnosis and treatment significantly improve the chances of a successful outcome.

Any pet that has undergone spinal surgery and develops signs of pain, swelling, or discharge at the surgical site should be evaluated immediately, as these could indicate post-operative infection.

Changes in urination or defecation habits, particularly if accompanied by back pain, warrant immediate veterinary evaluation as they may indicate spinal cord compression requiring emergency treatment.