IVDD in Dogs: When to Refer to a Neurologist
Intervertebral disc disease (IVDD) is one of the most common neurological emergencies in general practice. A Dachshund presents unable to walk. A French Bulldog yelps when picked up. The question every GP vet faces: can I manage this case, or does it need a neurologist now?
The 2022 ACVIM consensus statement on thoracolumbar intervertebral disc extrusion provides the clearest evidence-based framework to date for answering that question.^1 Here are the data and decision points that matter most.
The Numbers That Drive the Decision
The single most important assessment is whether the patient has voluntary motor function. Get them off the exam table and onto the floor. Can they advance their limbs, even poorly?
The ACVIM consensus data tells a clear story:^1
Ambulatory paraparetic dogs (can cross the room unassisted): 80% improve with medical management alone. With surgery, that number climbs to 98.5%. Medical management is a reasonable first step here.
Non-ambulatory paraparetic dogs (some limb movement but cannot walk unassisted): 81% improve medically, versus 93% with surgery. The gap is narrowing, but these patients warrant strong consideration for referral.
Paraplegic dogs with intact pain sensation: Only 60% recover with medical management, compared to 93% with surgery. This is the inflection point. Once a patient becomes non-ambulatory, referral should be strongly encouraged.
Paraplegic dogs without pain sensation: Just 21% recover medically, while 61% recover with surgery. These patients are neurological emergencies.
Pain Sensation: The Test You Must Get Right
For paralyzed patients, evaluating deep pain perception is the most consequential part of the neurological exam. A common and critical error: confusing the withdrawal reflex with pain sensation.
When you pinch a paraplegic dog’s toe and the limb pulls away, that is a spinal reflex. It does not confirm the patient can feel pain. The withdrawal reflex is mediated locally in the L6 to S1 spinal cord segments and does not require input from the brain.
To confirm pain sensation, you must observe a conscious response: the patient vocalizes, tries to bite, or attempts to escape. As Dr. Arnold puts it, borrowing a slogan from the University of Georgia: “If it squeals, it feels.”
If the patient withdraws the limb but shows no behavioral response, that patient has lost deep pain perception, and the clock is ticking.
When to Send Them Out
The recommendation is direct: if the dog cannot feel its feet, it leaves your clinic immediately. Do not hospitalize overnight. Do not wait until morning. Transfer the patient and let the attending neurologist or surgeon decide timing.
There are limited data supporting a 24-hour window for sensation-negative dogs. One study found that no dogs lacking pain sensation for over 24 hours recovered ambulation, even with surgery. Subsequent studies have shown that some dogs with prolonged loss can still recover, meaning surgery should never be denied simply because of elapsed time. But it also means you should not wait.
Put simply: the referring veterinarian’s job is to get the patient to someone who can intervene. The neurologist will determine whether surgery happens that night or the next morning.
Medical Management: What the Evidence Supports
For patients where medical management is appropriate, the ACVIM consensus recommends:^1
- Strict cage rest for at least four weeks to prevent further disc extrusion
- NSAIDs for at least 5 to 7 days, preferred over corticosteroids for acute management
- Gabapentin or pregabalin as additional analgesics for neuropathic pain
- Bladder management for any patient unable to void voluntarily (manual expression, intermittent catheterization, or pharmacologic support with prazosin or diazepam)
The consensus statement specifically notes that corticosteroids are not recommended for routine use in the acute phase.^1
The Complication You Must Warn About
Progressive myelomalacia (PMM) is a fatal complication that occurs almost exclusively in paraplegic, sensation-negative IVDD patients. Published prevalence rates reach up to 30% in this population. French Bulldogs appear especially prone.
PMM is progressive necrosis of the spinal cord. It cannot be prevented, stopped, or treated. Clinical signs include loss of the cutaneous trunci reflex, flaccidity in the pelvic limbs, and eventual respiratory failure. Prompt surgery may reduce the risk, but if PMM develops, the outcome is fatal.
Every owner of a paraplegic, sensation-negative dog should be warned about this possibility before discharge or transfer.
The Bottom Line
The decision framework is straightforward: if the patient can walk, medical management is reasonable. If the patient cannot walk, referral is strongly recommended. If the patient cannot feel its feet, referral is urgent.
Get them off the table. Watch what they can do. And if they cannot feel their toes, send them.
References
- Olby NJ, et al. ACVIM consensus statement on diagnosis and management of acute canine thoracolumbar intervertebral disc extrusion. J Vet Intern Med. 2022;36(5):1570-1596. PMID: 35880267.