Luca, a 1 year old male neutered hound mix, presented to his family veterinarian for walking slower than usual and being slightly wobbly in his pelvic. He had been a previously healthy dog with no prior episodes of back pain or weakness. Blood work was performed and was unremarkable; he was started on an anti-inflammatory dose of prednisone, together with tramadol, methocarbamol, and strict exercise restrictions. He showed good improvement and returned to normal within 2 days. Almost 2 weeks later, now off of all medications, his clinical signs returned and he started to show evidence of back pain. The following day he was unable to walk. Radiographs were performed and were unremarkable.
He was referred to Bush Veterinary Neurology Service for further evaluation. On exam he was non-ambulatory with severe paraparesis; with support he had weak motor to both pelvic limbs. Postural reactions were absent in both pelvic limbs; reflexes and sensation were intact. He was clearly uncomfortable with palpation through the thoracolumbar junction. MRI of the thoracolumbar spine was performed and revealed diskospondylitis at T12-T13 with extension of the disease process into the spinal canal and surrounding paraspinal tissues, causing meningomyelitis, radiculitis and cellulitis but only very mild spinal cord compression.
CSF analysis was unremarkable. CSF culture, urine culture, fungal serology and a Brucella titer were all negative. C-Reactive Protein was elevated at 58.8 (normal < 7.6). The patient was admitted to hospital and treated with antibiotics (Enrofloxacin and cefpodoxime) and pain medicines (codeine and gabapentin). He quickly showed good improvement in his comfort levels however he remained markedly paretic. He was discharged from hospital with a guarded prognosis for recovery. At recheck exam 10 days later, Luca was bright and very comfortable off all pain medicines, but sadly was found to be paraplegic with absent deep pain sensation in both pelvic limbs. Antibiotics were continued, with the addition of Clindamycin. About 2 weeks later Luca started to regain motor function in both pelvic limbs. Over the following 10 days he showed continued improvement, becoming able to stand and walk unassisted. Recheck radiographs around this time revealed moderate collapse of the T12-T13 intervertebral disc space, central lysis with sclerotic endplate margins; there was mild, irregular new bone formation along the caudoventral margin of T12 and cranioventral margin of T13. These changes were consistent with delayed osseous remodelling.
Antibiotics were continued and Luca continued to show improvement in his gait. At recheck exam 2 months later (4 months after the initial diagnosis was made) Luca was ambulatory with only very mild paraparesis and proprioceptive ataxia; postural reactions were intact in all limbs. Radiographs at this time revealed that the endplate margins were smoother with new bone formation along the ventral and lateral margins, however focal lysis of the cranial endplate of L5 was now seen; this was also thought to be due to delayed osseous remodelling. Antibiotics were continued and Luca continues to do well, pending the next recheck exam and radiographs.
Diskospondylitis is an infection of the intervertebral disk with concurrent osteomyelitis of contiguous vertebrae. It is usually caused by hematogenous spread of bacteria or fungi, though the microbial agent often remains unidentified.
The most common cause of diskospondylitis is spread of the infectious organism through the blood supply. The infection may originate from many different sources, with urinary tract infections (UTIs) being the most common concurrent infection. Other potential primary sources of infection include heart, dental or oral cavity infections, and respiratory infections. The disease has also been seen with foreign body migration (e.g., grass awns), penetrating wounds and abscesses.
Early diagnosis and appropriate therapy are essential to a successful outcome. Diagnosis is often made based on clinical signs and radiographs, however, in humans, MRI is considered the most sensitive and specific imaging modality for inflammatory and infectious diseases of the spine. MRI was key to making a diagnosis in this case, which supports the increased sensitivity of MRI over radiographs in detecting this disease in dogs.
C-reactive protein (CRP) is an acute phase protein manufactured by the liver that may be elevated in certain inflammatory, autoimmune and neoplastic diseases. It has been shown to be elevated in dogs with meningitis and, while no relationship between CRP and diskospondylitis has been published, it has been our group experience that it is also consistently elevated in these cases. It may be a more sensitive marker for inflammation than traditional indicators and may therefore be useful in identifying dogs with diskospondylitis, monitoring the response to treatment and perhaps even determining an end-point for treatment.
Prognosis in diskospondylitis cases can be variable. The recovery of patients with uncomplicated and mild cases is usually quicker and more complete; conversely patients with more severe cases may take longer to improve and may not make a full recovery. Severe neurologic deficits, especially severe nonambulatory paresis or paralysis, are a negative prognostic indicator. Under-dosing or an inappropriately short duration of antibiotic treatment may predispose the patient to a relapse of the clinical signs or development of more resistant infections.
Treatment of diskospondylitis is often prolonged and is conventionally continued until resolution of both clinical and radiographic signs. Treatment in this case continues.
Dr. Daniel Cuff is a graduate of St. George’s University School of Veterinary Medicine. After a rotating internship in small animal medicine and surgery at the Center for Specialized Veterinary Care on Long Island, NY, he joined BVNS as the first Neurology Intern in the fall of 2009.
Upon completion of his internship with BVNS, Dr. Cuff also began a Neurology Residency. Dr. Cuff’s Neurology Residency was completed in July, 2013 and he remained with BVNS as a staff neurologist. Now Board-Certified in Neurology/Neurosurgery, Dr. Cuff works out of our Rockville office. From Great Britain, Dr. Cuff loves to travel and is a Certified PADI rescue diver.
Dr. Cuff is available for consultations and diagnostics at Hope Advanced Veterinary Center – Rockville.
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