Intervertebral disc disease (IVDD) is an uncommon but clinically significant neurological condition in cats, affecting the cushioning discs between vertebrae.
Overview and Clinical Importance
Intervertebral disc disease (IVDD) is an uncommon but clinically significant neurological condition in cats, affecting the cushioning discs between vertebrae. While considerably rarer than in dogs (prevalence of 0.02-0.26% in cats versus 2-3.5% in dogs), feline IVDD represents an important differential diagnosis for cats presenting with spinal pain, ataxia, or hindlimb paresis.
| Component |
Composition |
Function |
| Nucleus Pulposus |
Gelatinous matrix, high water content (70-90%), proteoglycans, Type II collagen |
Shock absorption, weight distribution, spinal flexibility |
| Annulus Fibrosus |
Concentric lamellae of Type I and II collagen, fibroblasts |
Contains nucleus pulposus, tensile strength, resists torsion |
| Cartilaginous Endplate |
Hyaline cartilage layer (less than 1 mm thick) |
Anchors disc to vertebral bodies, nutrient diffusion |
Anatomy and Pathophysiology
Feline Spinal Anatomy
The feline vertebral column consists of 7 cervical, 13 thoracic, 7 lumbar, 3 sacral, and 18-23 caudal vertebrae. Intervertebral discs are fibrocartilaginous structures positioned between adjacent vertebral bodies. Each disc contains two main components: the central nucleus pulposus (gelatinous, water-rich core) and the outer annulus fibrosus (concentric rings of fibrocartilage).
High-YieldIn cats, the spinal cord extends more caudally than in dogs. The conus medullaris terminates at S1-S3 in 90% of adult cats (versus L6-L7 in dogs). This results in closer correlation between vertebrae and spinal cord segments in cats.
Intervertebral Disc Components
Hansen Classification of Disc Disease
High-YieldUnlike dogs (where Type I predominates in chondrodystrophic breeds), cats develop both Type I and Type II IVDD without a clear chondrodystrophic predisposition. Hansen Type I accounts for approximately 67% of clinically symptomatic cases in cats.
| Feature |
Hansen Type I (Extrusion) |
Hansen Type II (Protrusion) |
| Degeneration Type |
Chondroid metaplasia with calcification of nucleus pulposus |
Fibroid metaplasia with progressive bulging of annulus fibrosus |
| Onset |
Acute (hyperacute to acute) |
Chronic, progressive |
| Annulus Status |
Completely ruptured |
Intact but bulging |
| Prevalence in Cats |
67% of clinically affected cats |
33% of clinically affected cats |
| Age at Presentation |
Young to middle-aged (3-9 years) |
Older cats (8-10+ years) |
| Clinical Signs |
More severe neurological deficits |
Milder, insidious onset |
Epidemiology and Risk Factors
Prevalence and Demographics
Feline IVDD has a reported prevalence of 0.02% to 0.26% in the general feline population. The median age at presentation is 8 years (range: 1.5-17 years). IVDD accounts for approximately 4-5% of feline spinal cord diseases.
Breed Predispositions
Purebred cats are twice as likely to be affected as domestic shorthair/longhair cats.
Common Disc Locations
The thoracolumbar and lumbosacral regions account for 86-95% of clinically significant feline IVDD.
NAVLE TipOn NAVLE, remember that L6-L7 is the MOST COMMON site of IVDD in cats (34%). The majority of cats (57%) present with L4-S3 neuroanatomical localization. Cervical disc protrusions are common at necropsy but rarely cause clinical signs.
| Breed |
Relative Risk |
Notes |
| Persian |
Significantly overrepresented (1.83% prevalence) |
May relate to body conformation |
| British Shorthair |
Significantly overrepresented (1.29% prevalence) |
Cobby body type may contribute |
| Maine Coon |
Possible predisposition |
Longer spine may be a factor |
| Himalayan |
Possible predisposition |
Similar conformation to Persian |
Clinical Signs and Neurological Examination
Clinical Presentation
Clinical signs progress with severity of spinal cord compression. The most frequently reported presenting complaint is difficulty walking (54.2%). Spinal hyperesthesia (pain) is present in 92% of affected cats.
Progression of Clinical Signs
- Spinal pain/hyperesthesia - Hunched posture, vocalization when handled
- Ataxia - Incoordination, wobbly gait
- Ambulatory paresis - Weakness with preserved voluntary movement
- Non-ambulatory paresis - Unable to walk but can move limbs
- Paralysis/Plegia - Complete loss of voluntary motor function
- Loss of deep pain perception - Most severe; poorest prognosis
Modified Frankel Scale for Neurological Grading
High-YieldThe majority of cats with IVDD present with Grade II neurological signs (ambulatory paraparesis). Testing deep pain perception is CRITICAL for prognosis - pinch the toe and look for a CONSCIOUS response (turning head, vocalization), not just withdrawal reflex.
Neuroanatomical Localization
| Location |
Frequency |
Neuroanatomical Localization |
| L6-L7 |
34% (most common) |
L4-S3 spinal cord segments |
| L4-L5 |
Second most common |
T3-L3 or L4-S3 |
| L7-S1 |
Common |
L4-S3/Cauda equina |
| T13-L1 |
Common |
T3-L3 spinal cord segments |
| Cervical (C6-C7) |
Rare clinically |
C6-T2 spinal cord segments |
Diagnostic Approach
Diagnostic Imaging
High-YieldMRI is the GOLD STANDARD for diagnosing feline IVDD (used in 74% of surgical cases). It provides superior visualization of the spinal cord, identifies the type of herniation, shows cord edema or myelomalacia, and helps with surgical planning.
Differential Diagnosis
NAVLE TipFIP is the MOST COMMON cause of feline myelitis (~50% of inflammatory spinal disease). Lymphosarcoma is the MOST COMMON spinal tumor in cats. When a cat presents with acute, non-painful, asymmetric spinal cord dysfunction after exercise, think FCE first!
| Grade |
Description |
Clinical Presentation |
| Grade 0 |
Neurologically normal |
No neurological deficits detected |
| Grade I |
Spinal pain only |
Pain on palpation, hunched posture, reluctance to jump |
| Grade II |
Ambulatory paraparesis |
Can walk but with ataxia, CP deficits present |
| Grade III |
Non-ambulatory paraparesis |
Cannot walk, can move limbs voluntarily |
| Grade IV |
Paraplegia with nociception |
Paralysis, intact deep pain perception |
| Grade V |
Paraplegia without nociception |
Paralysis, absent deep pain - POOREST PROGNOSIS |
Treatment Options
Conservative (Medical) Management
Indications: Mild cases (Grade I-II), first episode, ambulatory patients. Conservative management achieves good to excellent outcomes in approximately 85% of appropriately selected cats.
Components of Conservative Management
- Strict cage rest: 4-6 weeks in a small confined space
- Pain management: Multimodal approach (see table)
- Bladder management: Manual expression or catheterization if needed
- Physical rehabilitation: Passive range of motion, massage
- Nursing care: Soft bedding, prevention of pressure sores
Pharmacological Treatment Options
High-YieldGabapentin is a first-line drug for neuropathic pain in cats with IVDD. It targets voltage-gated calcium channels. Remember: NEVER combine NSAIDs with corticosteroids due to high risk of GI ulceration!
Surgical Management
Indications: Non-ambulatory patients (Grade III-V), failure of conservative management, progressive deterioration. Surgical decompression achieves positive outcomes in 62.5% at discharge and 91.3% at 2-week recheck.
| Localization |
Expected Findings |
Spinal Reflexes |
| C1-C5 |
Tetraparesis/plegia, cervical pain, respiratory compromise possible |
UMN all four limbs: normal to increased reflexes |
| C6-T2 |
Tetraparesis, possible Horner syndrome |
LMN thoracic, UMN pelvic limbs |
| T3-L3 (most common) |
Paraparesis/plegia, normal thoracic limbs, Schiff-Sherrington possible |
UMN pelvic limbs: normal to increased patellar, withdrawal |
| L4-S3 |
Paraparesis, flaccid tail, bladder dysfunction |
LMN pelvic limbs: decreased patellar, withdrawal |
Prognosis and Outcomes
NAVLE TipIn cats, unlike dogs, there is NO significant association between neurological grade at presentation and surgical outcome. However, intact deep pain perception = better prognosis.
| Modality |
Advantages |
Limitations |
Usage in Cats |
| Survey Radiographs |
Widely available, may show disc calcification, rules out fractures |
Cannot visualize spinal cord compression |
Initial screening only |
| MRI (Gold Standard) |
Best soft tissue detail, visualizes spinal cord, identifies compression |
Cost, availability, longer anesthesia |
74% of surgical cases |
| CT |
Excellent for mineralized disc, bone detail, faster than MRI |
Limited soft tissue contrast without myelography |
14% of surgical cases |
| Myelography |
Can localize compression, combines with CT |
Invasive, contrast reactions, seizures possible |
11% of surgical cases |
Memory Aids and Board Tips
FELINE IVDD: Key Numbers to Remember
0.2% - Prevalence of IVDD in cats (vs 2-3% in dogs)
67% - Hansen Type I (extrusion) in clinically affected cats
34% - L6-L7 as most common disc location
8 years - Median age at presentation
2x - Purebreds have twice the risk
85% - Success rate with conservative management
91% - Positive outcome at 2-week surgical recheck
D - Difficulty walking (most common sign, 54%)
I - Imaging with MRI is gold standard (74%)
S - Spinal pain present in 92% of cats
C - Conservative care works in 85% of mild cases
| Category |
Conditions |
Key Differentiating Features |
| Infectious/Inflammatory |
FIP (most common feline myelitis ~50%), Toxoplasmosis |
CSF pleocytosis, systemic signs, young cats for FIP |
| Neoplastic |
Lymphosarcoma (most common spinal tumor), Meningioma |
Progressive, lymphoma: younger cats (median 4 years) |
| Vascular |
Fibrocartilaginous embolism (FCE), Aortic thromboembolism |
FCE: peracute, non-painful, asymmetric; ATE: absent femoral pulses |
| Traumatic |
Vertebral fracture/luxation, High-rise syndrome |
History of trauma, radiographic evidence |
| Drug Class |
Examples |
Feline Dose |
Notes |
| NSAIDs |
Meloxicam, Robenacoxib |
Meloxicam: 0.1 mg/kg Day 1, then 0.05 mg/kg q24h |
Monitor renal function; FDA cautions long-term meloxicam |
| Gabapentinoids |
Gabapentin, Pregabalin |
Gabapentin: 5-10 mg/kg PO q8-12h |
First-line for neuropathic pain; sedation common |
| Opioids |
Buprenorphine, Tramadol |
Buprenorphine: 0.01-0.03 mg/kg TM q6-8h |
Buprenorphine excellent OTM absorption in cats |
| Corticosteroids |
Prednisolone |
0.5-1 mg/kg PO q12-24h; taper over 2-3 weeks |
DO NOT combine with NSAIDs; use prednisolone in cats |
| Muscle Relaxants |
Methocarbamol |
20-44 mg/kg PO q8-12h |
For muscle spasms; sedation possible |
| Surgical Procedure |
Description |
Indications |
| Hemilaminectomy |
Unilateral removal of lamina to access ventrolateral disc material |
Lateralized disc extrusions (most common) |
| Dorsal Laminectomy |
Bilateral removal of dorsal lamina for dorsal compression |
Disc protrusions, dorsal compression |
| Ventral Slot |
Ventral approach through vertebral bodies |
Cervical disc disease |
| Neurological Status |
Conservative Management |
Surgical Management |
| Grade I-II (Ambulatory) |
Good (85% success); 30-40% recurrence risk |
Excellent (greater than 90%); faster recovery |
| Grade III-IV (Non-ambulatory with DPP) |
Variable; slower recovery |
Good to excellent (67-91%); surgery recommended |
| Grade V (No DPP) |
Poor |
Guarded (~50-70%); best if surgery within 48 hours |