Pain Assessment

---
name: pain-assessment
description: Glasgow Composite Pain Scale (dogs), FMPI/UNESP-Botucatu (cats), Colorado State pain scales, multimodal analgesia ladder, species-specific pain indicators, opioid/NSAID protocols with dosing.
---

# Pain Assessment

## Overview

Validated, species-specific pain assessment tools with interpretation guidance. Includes acute and chronic pain scales, multimodal analgesic protocols, and species-specific pain manifestations (especially feline pain hiding).

## When to Use

- User performs perioperative/acute pain assessment or pain management planning
- User needs pain scale interpretation or analgesic selection/dosing
- Keywords: pain, analgesia, Glasgow, UNESP, FMPI, pain scale, acute pain, chronic pain, multimodal, opioid, NSAID, gabapentin, meloxicam, tramadol

## Glasgow Composite Pain Scale (GCPS) - Dogs

**Scoring**: Observer-rated scale; 0-26 points (higher = more pain); sections for behavior, posture, consciousness, physiologic values

| Domain | 0 Points | 1 Point | 2 Points | 3+ Points |
|---|---|---|---|---|
| Vocalization | Silent | Crying/groaning | Howling | Constant vocalization |
| Body Tension | Relaxed | Slightly tense | Moderate tension | Rigid/severe tension |
| Posture | Normal | Slightly abnormal | Moderately abnormal | Severely abnormal (hunched, stretched) |
| Consciousness | Normal | Drowsy | Depressed | Unresponsive |
| Appetite | Eating normally | Reduced intake | Not eating | Vomiting/retching |
| Responsiveness | Normal behavior | Slightly subdued | Withdrawn | Unresponsive/hostile |

**Interpretation**: 0-4 = minimal pain; 5-13 = mild-moderate pain; 14-26 = severe pain
**Trending**: More important than absolute score; assess pre-treatment and post-analgesic to evaluate efficacy

## Feline Musculoskeletal Pain Index (FMPI) and UNESP-Botucatu

**FMPI** (6 items scored 0-3): Lameness, reluctance to move, pain on palpation, posture abnormalities, activity level, dynamic gait changes
- Interpretation: 0-3 = minimal, 4-9 = mild-moderate, 10-18 = severe pain
- **Critical**: Cats hide pain; absence of vocalization does NOT indicate absence of pain

**FMPI Behavioral Indicators of Pain**:
- Reduced activity, reluctance to jump
- Abnormal gait or position changes
- Reduced grooming/self-care
- Behavioral changes (aggression, withdrawal)
- Palpable muscle rigidity, guarding

**UNESP-Botucatu** (Alternative feline scale): Behavioral components (posture, activity, lameness) + physiologic (appetite, autonomic signs); used primarily in research settings

## Colorado State Pain Scale (Multi-Species)

**Acute Pain Categories**:
1. **Pain Behaviors**: Vocalization, posture abnormality, aggression, self-mutilation, attention to wound
2. **Physiologic Signs**: Tachycardia, tachypnea, hypertension, mydriasis, salivation/lacrimation
3. **Wound/Disease Assessment**: Swelling, discharge, redness, lameness severity

**Chronic Pain**: Similar assessment but includes behavioral/activity changes (depression, reduced movement, sleep disturbance)

## Multimodal Analgesia Ladder

### Tier 1: Non-Pharmacologic
- **Physical**: Rest, ice/heat application, physical therapy, passive range of motion
- **Environmental**: Quiet recovery space, soft bedding, frequent positioning

### Tier 2: Oral/Injectable Analgesics (Acute)
**NSAIDs** (first-line for inflammatory pain):
- **Dogs**: Meloxicam 0.1-0.2 mg/kg daily; carprofen 2-4 mg/kg BID; deracoxib 1-2 mg/kg daily; firocoxib 5 mg/kg daily
- **Cats**: Meloxicam 0.1 mg/kg daily (controversial—use lowest effective dose; monitor renal function); consider carprofen alternative
- **Dosing caveat**: NSAIDs contraindicated in dehydration, renal disease, hepatic disease, GI ulceration; monitor PCV/TP, creatinine, BUN

**Opioids** (acute severe pain):
- **Dogs/Cats (acute)**: Morphine 0.5-1 mg/kg IM/SC q4-6h; hydromorphone 0.05-0.1 mg/kg IM/SC q4-6h; buprenorphine 0.01-0.02 mg/kg IM/IV q6-12h
- **Dogs (chronic)**: Tramadol 5-10 mg/kg TID-QID; lower efficacy than traditional opioids; less abuse potential
- **Cats (chronic)**: Buprenorphine preferred (longer duration, less hyperthermia risk); 0.01-0.02 mg/kg q6-12h (transmucosal absorption)

### Tier 3: Adjuvant Agents
- **Gabapentin** (neuropathic/chronic pain): Dogs 10-20 mg/kg TID; Cats 100-200 mg TID; slower onset (days-weeks) but excellent for chronic neuropathic pain
- **Amantadine** (NMDA antagonist): 3-5 mg/kg daily-BID; useful for chronic pain and opioid tolerance
- **Alpha-2 agonists** (acute): Dexmedetomidine 5-10 mcg/kg IM/IV (profound sedation; reversal with atipamezole); not recommended for prolonged pain management
- **Corticosteroids** (inflammatory pain, limited duration): Prednisolone 0.5-1 mg/kg initial; taper after acute phase to avoid complications

### Tier 4: Regional/Interventional
- **Local anesthetic blocks**: Ring blocks (digit), maxillary/mandibular blocks, intra-articular injections
- **Epidural anesthesia**: Morphine 0.1 mg/kg + local anesthetic; prolonged postoperative analgesia
- **Joint injections**: Steroid (triamcinolone, dexamethasone) ± local anesthetic for chronic OA

## Species-Specific Pain Indicators

### Dogs
- Vocalization (whining, whimpering, howling)
- Posture changes (hunched, stretched, shifting weight)
- Appetite suppression
- Activity reduction
- Licking/biting at wound or affected area
- Reluctance to stand/move

### Cats
- **UNDERREPORT pain behaviors**; quiet cats often in significant pain
- Reduced grooming (hunched, unkempt appearance)
- Reluctance to move/jump
- Hidden behavior (seeking quiet, dark spaces)
- Subtle aggression, irritability
- Loss of appetite (early indicator)
- Altered sleep patterns (restlessness)

**Critical**: Absence of vocalization in cats does NOT = absence of pain; behavioral and gait assessment essential

### Small Mammals/Exotics
- **Rabbits**: Teeth grinding (bruxism), eye bulging (pain squeeze), immobility, reduced eating, hunched posture
- **Rodents**: Reduced activity, porphyrin around eyes (stress), piloerection, huddle posture
- **Birds**: Ruffled feathers, reluctance to move, wing drooping, lack of preening

## Perioperative Analgesic Protocol Example (Dog, Soft Tissue Surgery)

1. **Pre-emptive**: Meloxicam 0.2 mg/kg PO/IV (1 hour pre-op)
2. **Intra-operative**: Morphine 0.5 mg/kg IM (30 min pre-op); local anesthetic ring block or incision-line infiltration
3. **Immediate recovery**: Meloxicam q24h × 5-7 days; morphine IM/SC q4-6h PRN first 24-48 hours (assess GCPS)
4. **Home care**: Meloxicam daily × 7-10 days; oral gabapentin 15 mg/kg TID if high-anxiety patient or chronic pain risk

## Opioid/NSAID Considerations

**Concurrent Use**: NSAIDs + opioids acceptable (multimodal); reduces required opioid dose, lowers GI ulceration risk
**Corticosteroid Washout**: Avoid NSAIDs <1 week after systemic corticosteroid discontinuation (ulceration risk)
**Renal Monitoring**: Baseline + 7-14 days into NSAID therapy (assess creatinine, BUN, urine specific gravity); especially critical in geriatric patients, dehydrated animals, or those with pre-existing renal disease
**Hepatic Monitoring**: Baseline liver enzymes if prolonged NSAID use (>2 weeks) in at-risk patients

## Key Species Differences

- **Dogs**: Tolerate NSAIDs well; opioid tolerance develops over weeks; gabapentin effective for chronic neuropathic pain
- **Cats**: Meloxicam dosing controversial/contentious (use judiciously); excellent responders to gabapentin; buprenorphine preferred opioid (higher partial agonist ceiling effect); pain behaviors subtle
- **Rabbits/Rodents**: High metabolic rate; shorter analgesic intervals; tramadol less effective; opioids prone to GI stasis (combine with motility agents)
- **Exotics**: Species-specific pharmacokinetics vary widely; consult specialized resources before prescribing

## Limitations

- **Pain scales**: Observer-dependent subjective assessment; provide framework only, not absolute diagnosis
- **Feline pain assessment**: Cats significantly undertreat due to cryptic pain behaviors; provider awareness essential
- **NSAID safety**: Contraindications common (renal disease, GI ulceration, dehydration); not universal analgesic choice
- **Opioid tolerance**: Develops within days-weeks; rotation or adjuvant strategies needed for chronic pain
- **Regional anesthesia**: Requires technical skill; duration limited (4-24 hours depending on agent)
- **Chronic pain**: Long-term analgesic strategies less evidence-based than acute protocols; referral to pain specialist recommended for refractory cases