Fistulous withers causing spinal epidural abscess in a Thoroughbred mare.
Authors: Ceriotti Serena, Clark-Price Stuart, Cole Robert, Kramer Alana, Sandey Maninder, Mora Mariano
Journal: Journal of equine veterinary science
Summary
Fistulous withers represents a well-known chronic infection in horses, yet this case report documents the first recorded progression to spinal epidural abscess (SEA)—a catastrophic complication in a 15-year-old Thoroughbred mare initially managed with antibiotics and anti-inflammatories. Despite advanced diagnostic imaging and aggressive multimodal therapy incorporating antimicrobials, corticosteroids, and neuroprotective agents, the mare developed acute hindlimb ataxia and spastic paresis indicative of severe spinal cord compression at T3-L3; post-mortem examination revealed an extensive paraspinal abscess that had eroded into the epidural space. E. coli was isolated as the causative organism, consistent with typical fistulous withers microbiology, though the mechanism of vertebral seeding and abscess formation in this case remained incompletely characterised. For equine practitioners, this report highlights the critical importance of maintaining SEA as a differential diagnosis when chronic paraspinal infections deteriorate acutely, as the narrow therapeutic window and poor prognosis likely depend upon early aggressive surgical debridement coupled with targeted antimicrobial therapy—interventions that conventional imaging may fail to adequately define preoperatively. Recognising and acting upon warning signs of spinal involvement in fistulous withers cases could substantially alter outcomes, though the guarded prognosis reflects significant limitations in equine diagnostic and surgical capabilities for managing deep spinal infections.
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Practical Takeaways
- •Consider spinal epidural abscess as a diagnostic differential in horses with chronic fistulous withers that develop acute neurological signs; early imaging and surgical evaluation are critical.
- •Fistulous withers require vigilant monitoring and aggressive early treatment, as progression to vertebral osteomyelitis and epidural abscess can occur even with medical management.
- •Early surgical intervention combined with targeted antimicrobial therapy offers the best chance for favorable outcomes in cases of paraspinal infection extending toward the spinal canal.
Key Findings
- •Fistulous withers progressed to vertebral osteomyelitis and spinal epidural abscess in a 15-year-old Thoroughbred mare, a previously unreported complication.
- •The mare developed acute hindlimb ataxia and spastic paresis indicating spinal cord compression at T3-L3 despite initial antibiotic and anti-inflammatory therapy.
- •Post-mortem examination confirmed extensive paraspinal abscess with epidural extension causing severe spinal cord compression, with Escherichia coli isolated as the pathogen.
- •Despite aggressive medical therapy including antimicrobials, corticosteroids, and neuroprotective agents, neurological deterioration led to euthanasia, indicating guarded prognosis without early surgical intervention.