High-yield overview
Gout | Pseudogout (CPPD) | Tophi | Crystal Deposition
UrateGout crystals (negative birefringence)
CPPDPseudogout crystals (positive birefringence)
WristMost common hand site (CPPD)
AllopurinolChronic gout prophylaxis
Crystalline Arthropathy Types
Gout (MSU)
PatternMonosodium urate crystals, negatively birefringent needles, hyperuricemia
TreatmentNSAIDs, colchicine, allopurinol
Pseudogout (CPPD)
PatternCalcium pyrophosphate crystals, positively birefringent rhomboids, wrist common
TreatmentNSAIDs, colchicine, aspiration
Tophaceous Gout
PatternChronic: chalky tophi in joints/tendons, erosions, deformity
TreatmentTophus excision, urate-lowering therapy
CPPD Arthropathy
PatternChronic: degenerative arthritis pattern, TFCC/wrist chondrocalcinosis
TreatmentUsually non-operative, arthroplasty if severe
Critical Must-Knows
- Gout Crystals: Monosodium urate, negatively birefringent needles (yellow when parallel to polarizer).
- CPPD Crystals: Calcium pyrophosphate, positively birefringent rhomboids (blue when parallel).
- Tophaceous Gout: Chronic deposits in tendons/joints → nerve compression, erosions, skin breakdown.
- CPPD Wrist: Triangular fibrocartilage (TFCC) calcification classic finding on x-ray.
- Surgery Indications: Nerve compression (CTS), tendon rupture, skin ulceration, refractory pain.
Clinical Pearls
- "Negative birefringence = gout (urate needles)
- "Positive birefringence = CPPD (rhomboids)
- "Tophaceous gout: carpal tunnel syndrome common
- "CPPD: wrist TFCC calcification on x-ray
Clinical Imaging
Imaging Gallery
Critical Crystalline Arthropathy Exam Points
Crystal Identification
Joint aspiration with polarized light microscopy is diagnostic. Gout: negatively birefringent needle-shaped urate crystals (yellow when parallel). CPPD: positively birefringent rhomboid calcium pyrophosphate crystals (blue when parallel).
Tophaceous Gout Complications
Chronic tophi cause nerve compression, tendon rupture, skin ulceration, joint destruction. Carpal tunnel syndrome very common. Surgery indicated for nerve compression, tendon involvement, skin breakdown.
CPPD Wrist Involvement
Wrist is the most common hand site for CPPD. Triangular fibrocartilage (TFCC) calcification is classic x-ray finding (chondrocalcinosis). Can mimic other wrist arthropathies.
Medical Management First-Line
Optimize medical therapy before surgery. Acute attacks: NSAIDs, colchicine, steroids. Chronic gout: allopurinol/febuxostat to lower uric acid (target less than 6 mg/dL). Perioperative urate-lowering therapy essential.
Gout vs Pseudogout (CPPD)
| Feature | Gout (MSU) | Pseudogout (CPPD) | Key Difference |
|---|---|---|---|
| Crystal type | Monosodium urate (MSU) | Calcium pyrophosphate (CPP) | Chemical composition |
| Birefringence | Negative (yellow parallel) | Positive (blue parallel) | Polarized microscopy pattern |
| Crystal shape | Needle-shaped | Rhomboid/rectangular | Morphology under microscope |
| Classic joint (hand) | First MTP, MCP, wrist | Wrist (TFCC calcification) | Distribution pattern |
Mnemonic
NYPDGout vs CPPD Crystal Identification
| N | Negatively birefringent Gout (monosodium urate crystals) |
| Y | Yellow when parallel Gout crystals appear yellow when parallel to polarizer |
| P | Positively birefringent Pseudogout (calcium pyrophosphate crystals) |
| D | bLue when parallel (D for CPPD) CPPD crystals appear blue when parallel to polarizer |
| N | Negatively birefringent Gout (monosodium urate crystals) | P | Positively birefringent Pseudogout (calcium pyrophosphate crystals) |
| Y | Yellow when parallel Gout crystals appear yellow when parallel to polarizer | D | bLue when parallel (D for CPPD) CPPD crystals appear blue when parallel to polarizer |
Hook:NYPD = Negative Yellow (gout), Positive bLue/D (CPPD) - remember crystal birefringence!
Mnemonic
NSAIDGout Acute Attack Management
| N | NSAIDs First-line: indomethacin, naproxen (if no renal/GI contraindication) |
| S | Steroids Oral prednisone or intra-articular if NSAIDs contraindicated |
| A | Aspiration Joint aspiration relieves pain and confirms diagnosis |
| I | Ice and rest Symptomatic relief during acute attack |
| D | Do NOT start allopurinol Don't start urate-lowering during acute attack (worsens flare) |
| N | NSAIDs First-line: indomethacin, naproxen (if no renal/GI contraindication) | I | Ice and rest Symptomatic relief during acute attack |
| S | Steroids Oral prednisone or intra-articular if NSAIDs contraindicated | D | Do NOT start allopurinol Don't start urate-lowering during acute attack (worsens flare) |
| A | Aspiration Joint aspiration relieves pain and confirms diagnosis |
Hook:NSAID = management of acute gout attack - but don't start allopurinol during flare!
Mnemonic
TENTSTophaceous Gout Surgical Indications
| T | Tendon rupture Tophus weakens tendons (extensor/flexor) → rupture |
| E | Erosive arthropathy Joint destruction, severe arthritis |
| N | Nerve compression Carpal tunnel syndrome, ulnar nerve compression |
| T | Tophus ulceration Skin breakdown, infection risk |
| S | Severe pain refractory Failed medical management, intractable pain |
| T | Tendon rupture Tophus weakens tendons (extensor/flexor) → rupture | T | Tophus ulceration Skin breakdown, infection risk |
| E | Erosive arthropathy Joint destruction, severe arthritis | S | Severe pain refractory Failed medical management, intractable pain |
| N | Nerve compression Carpal tunnel syndrome, ulnar nerve compression |
Hook:TENTS = indications for surgical tophus excision in chronic gout!
Overview and Epidemiology
Crystalline Arthropathy is joint inflammation from crystal deposition: monosodium urate (gout) or calcium pyrophosphate (CPPD/pseudogout).
Gout Epidemiology
Prevalence:
- 4% general population (increasing)
- Male greater than female (3:1)
- Peak onset: 40-60 years (men), post-menopausal (women)
Risk Factors:
- Hyperuricemia (uric acid greater than 7 mg/dL)
- Obesity, metabolic syndrome
- Alcohol (beer), purine-rich diet (red meat, seafood)
- Diuretics, chronic kidney disease
- Family history
Classic site: First MTP (podagra).
CPPD Epidemiology
Prevalence:
- 5-10% in elderly (over 65 years)
- Equal male:female
- Age-related: prevalence increases with age
Risk Factors:
- Advanced age (over 60 years)
- Osteoarthritis
- Hyperparathyroidism, hemochromatosis
- Hypomagnesemia, hypophosphatasia
- Prior joint trauma
Wrist is most common hand site.
Hand Involvement:
- Gout: 10-15% present with hand involvement (wrist, MCP, PIP, DIP)
- CPPD: Wrist most common hand site (TFCC calcification)
Pathophysiology
Crystal-Induced Inflammation
Both gout and CPPD cause acute inflammatory arthritis from crystal deposition. Crystals are phagocytosed by neutrophils → inflammatory cascade → intense pain, swelling, erythema (mimics septic arthritis). Joint aspiration with crystal identification is diagnostic.
Gout (Monosodium Urate) Pathophysiology:
- Hyperuricemia: Uric acid greater than 7 mg/dL (overproduction or underexcretion)
- Crystal Formation: Urate crystals precipitate in synovial fluid/tissue (lower temperature in extremities)
- Acute Attack: Crystals trigger inflammatory response (neutrophil activation, IL-1β release)
- Chronic Tophaceous Phase: Persistent hyperuricemia → tophus formation (aggregates of urate crystals with granulomatous reaction)
- Joint/Tendon Damage: Tophi erode bone, weaken tendons, compress nerves, ulcerate skin
Tophus Composition: Chalky white monosodium urate deposits surrounded by foreign body giant cells
CPPD (Calcium Pyrophosphate Deposition) Pathophysiology:
- Pyrophosphate Accumulation: Abnormal cartilage metabolism (age-related, genetic, metabolic)
- Crystal Deposition: Calcium pyrophosphate crystals deposit in cartilage (chondrocalcinosis)
- Acute Pseudogout: Crystal shedding into joint → acute inflammatory attack
- Chronic CPPD Arthropathy: Progressive cartilage/bone damage (OA-like pattern)
TFCC calcification in wrist is classic for CPPD.
Hand Sites:
| Condition | Common Hand/Wrist Sites |
|---|---|
| Gout | Wrist, first MCP (thumb), finger MCPs, PIPs, DIPs |
| Tophaceous Gout | Finger pulps, extensor tendons, olecranon bursa, carpal tunnel |
| CPPD/Pseudogout | Wrist (TFCC, radiocarpal), MCPs (less common) |
Clinical Presentation
Acute Gouty Arthritis
Classic Presentation:
- Sudden onset severe joint pain (often overnight, wakes patient)
- Monoarticular initially (can be polyarticular in recurrent attacks)
- Red, hot, swollen joint (mimics septic arthritis)
- Exquisitely tender - cannot tolerate touch, sheets
- Self-limited: Resolves in 7-10 days without treatment
Hand Manifestations:
- Wrist, MCP, PIP, DIP involvement
- Swelling and erythema
- Reduced ROM from pain
Triggers:
- Alcohol binge (beer)
- Dehydration
- Acute illness, surgery
- Starting allopurinol (paradoxical flare)
Podagra (First MTP): Classic presentation (70% of first attacks), but hand joints also common.
Examination
Inspection:
- Erythema, edema over affected joint
- Shiny, tense skin
- May have visible tophi (chronic cases)
Palpation:
- Marked tenderness (patient withdraws)
- Warmth
- Joint effusion
ROM: Severely limited by pain
Differential: Septic arthritis - must rule out with joint aspiration!
Medical Management
Algorithm
Acute Gout/Pseudogout Management
Goals: Reduce inflammation and pain rapidly
First-Line Therapy:
1. NSAIDs:
- Indomethacin 50mg TID or naproxen 500mg BID
- Start immediately at diagnosis
- Continue until attack resolves (7-10 days)
- Contraindications: Renal impairment, GI bleeding history, anticoagulation
2. Colchicine:
- Low-dose regimen: 1.2mg loading dose, then 0.6mg 1 hour later, then 0.6mg daily
- Effective if started early (within 24-48 hours)
- Side effects: Diarrhea, GI upset (dose-dependent)
- Contraindications: Severe renal/hepatic impairment
3. Corticosteroids:
- Intra-articular: Triamcinolone 10-40mg (if monoarticular, septic arthritis ruled out)
- Oral prednisone: 30-40mg daily for 5 days, then taper
- IM/IV methylprednisolone: If unable to take oral (hospitalized patients)
- Use if NSAIDs/colchicine contraindicated
Supportive Care:
- Rest and elevate affected joint
- Ice application
- Avoid weight-bearing if lower extremity
DO NOT:
- Start allopurinol/febuxostat during acute attack (worsens flare)
- Start urate-lowering therapy until attack resolves (wait 2-4 weeks)
Surgical Management
Surgical Indications in Crystalline Arthropathy
Gout:
| Indication | Surgical Procedure |
|---|---|
| Carpal tunnel syndrome | Carpal tunnel release + tophus excision |
| Tendon rupture (extensor/flexor) | Tendon repair/reconstruction + tophus removal |
| Skin ulceration/draining tophus | Tophus excision, wound closure/skin graft |
| Nerve compression (ulnar, radial) | Nerve decompression + tophus excision |
| Severe erosive arthropathy | Arthroplasty or arthrodesis |
| Cosmetically unacceptable tophi | Tophus excision (elective) |
CPPD:
- Usually non-operative
- Severe wrist arthritis: Proximal row carpectomy, wrist fusion, or arthroplasty
Principle: Optimize medical management (ULT for gout) before elective surgery. Perioperative uric acid control reduces wound complications.
Complications and Outcomes
Complications of Tophaceous Gout Surgery
| Complication | Incidence | Prevention/Management |
|---|---|---|
| Wound dehiscence | 10-20% | Optimize uric acid control pre-op, meticulous closure, avoid tension |
| Infection | 5-10% | Sterile technique, antibiotics if signs of infection, continue ULT |
| Tendon rupture | 5% | Gentle dissection, preserve tendon, may need repair/reconstruction |
| Nerve injury | Less than 5% | Careful dissection if tophus adherent to nerve |
| Recurrence of tophus | 5-10% | Adequate ULT post-op (uric acid less than 6 mg/dL) |
Wound Dehiscence:
- Most common complication (10-20%)
- Mechanism: Gout impairs wound healing, skin often friable/atrophic from chronic tophus
- Prevention: Optimize uric acid control 3-6 months pre-op, avoid skin tension, delayed closure if needed
- Management: Local wound care, secondary intention healing, delayed closure/skin graft if large
Infection:
- Higher risk than standard hand surgery (5-10%)
- Draining tophi may be colonized
- Management: Antibiotics (cover Staph aureus), debridement if abscess, continue ULT
Outcomes:
- CTS with tophus excision: 80-90% symptom improvement
- Tophus excision for skin breakdown: Wound healing in 70-80% (delayed healing common)
- Recurrence: 5-10% if inadequate uric acid control post-op
Key to Success: Perioperative and long-term uric acid control with ULT (allopurinol/febuxostat). Target less than 6 mg/dL.
Evidence Base
Level I
Neogi et al (2015 ACR/EULAR Gout Classification Criteria)
Key Findings:
- Data-driven classification criteria; MSU crystals in symptomatic joint/bursa or tophus is a sufficient criterion (no further scoring needed)
- Clinical, laboratory and imaging (ultrasound double-contour sign, urate on dual-energy CT, radiographic erosion) domains
- Overall sensitivity 92% and specificity 89%
- Developed when MSU crystal identification was the diagnostic gold standard
Clinical Implication: Demonstrated crystal identification on aspiration remains the diagnostic reference standard; imaging supplements but does not replace it.
Source: Ann Rheum Dis 2015
Guideline
FitzGerald et al (2020 ACR Guideline for the Management of Gout)
Key Findings:
- Strong recommendation to start urate-lowering therapy for tophaceous gout, radiographic damage, or frequent flares
- Allopurinol preferred first-line ULT, including in moderate-to-severe CKD (stage 3 or higher)
- Treat-to-target strategy with serum urate target under 6 mg/dL (under 0.36 mmol/L)
- Anti-inflammatory flare prophylaxis for at least 3 to 6 months when starting ULT
Clinical Implication: Authoritative GRADE-based framework: low-dose start, allopurinol first-line, treat-to-target under 6 mg/dL with prophylaxis cover.
Source: Arthritis Care Res 2020
Level I
Mackenzie et al (FAST trial)
Key Findings:
- Multicentre randomised non-inferiority trial; 6128 gout patients aged 60+ with a CV risk factor
- Febuxostat non-inferior to allopurinol for the composite CV endpoint (adjusted HR 0.85, 95% CI 0.70 to 1.03)
- No increase in all-cause death or serious adverse events with febuxostat
- Tempered the cardiovascular signal previously raised by the CARES trial
Clinical Implication: Reassures use of febuxostat as second-line ULT in patients with cardiovascular risk when allopurinol is unsuitable.
Source: Lancet 2020
Level I
Gamala et al (DECT diagnostic performance, systematic review/meta-analysis)
Key Findings:
- Ten studies pooled; person-based sensitivity 0.81 and specificity 0.91 for diagnosing gout
- Joint-based sensitivity 0.83 and specificity 0.88
- Sensitivity falls to ~0.55 in recent-onset gout (6 weeks or less)
- DECT most useful in established disease, not early presentation
Clinical Implication: DECT confirms urate deposition non-invasively in established gout but a negative scan does not exclude early disease - aspirate when in doubt.
Source: Rheumatology (Oxford) 2019
Case Series
Doscher et al (en masse excision and curettage of hand tophi)
Key Findings:
- 12 patients, 24 periarticular tophi excised from MCP/IP joints (some wrist and elbow), all on urate-lowering therapy
- Restoration of tendon excursion and joint mobility in all patients
- No wound complications and no recurrence over follow-up up to 15 years
- Highlights that meticulous technique plus medical urate control optimises results
Clinical Implication: Planned tophus excision in patients with controlled urate can restore function and aesthetics with low complication and recurrence rates.
Source: Eplasty 2022
Level II
Tang et al (Global Burden of Disease, gout in older adults)
Key Findings:
- Age-standardised prevalence in adults 65+ was ~3111 per 100,000 in 2021
- Disease burden in older men nearly twice that of women
- Burden projected to rise further by 2050, driven by ageing and metabolic risk
- Greatest increases in high-SDI/high-income regions
Clinical Implication: Gout is a rising global burden, particularly in ageing high-income populations - relevant to projected hand surgical caseload.
Source: Front Public Health 2025
Controversies & Areas of Uncertainty
Timing of Surgery vs Medical Optimisation
The conventional teaching is to optimise serum urate (under 6 mg/dL) for 3-6 months before elective tophus excision. However, severe carpal tunnel syndrome with motor signs or an ulcerated/infected tophus mandates earlier surgery. There is no high-level evidence defining the exact urate threshold or duration that minimises wound complications - practice is extrapolated from case series.
Extent of Tophus Excision
Whether to aggressively debulk all tophus material (risking tendon/nerve injury and large soft-tissue defects) or to perform conservative decompression remains debated. Some series report excellent function with en masse excision and no recurrence; others favour limited removal relying on ULT to resolve residual deposits over time.
Febuxostat Cardiovascular Safety
The CARES trial signalled increased CV/all-cause mortality, but the larger FAST trial found non-inferiority to allopurinol. The discordance (open-label design, differing discontinuation rates, populations) leaves residual uncertainty, and febuxostat is still used cautiously in established CV disease.
Imaging vs Aspiration for Diagnosis
DECT and ultrasound (double-contour sign) are increasingly used, but sensitivity is low in early gout and a negative scan cannot exclude disease. Crystal identification on aspiration remains the reference standard; over-reliance on imaging risks missing both early gout and coexistent septic arthritis.
Unresolved questions:
- No disease-modifying therapy exists for CPPD - management remains symptomatic, and no agent reliably dissolves calcium pyrophosphate deposits.
- Optimal reconstruction after tophus-related tendon rupture (primary repair vs graft vs transfer) is not standardised.
- Whether to treat asymptomatic hyperuricaemia to prevent crystal arthropathy is not supported by current guidelines.
Exam Viva Scenarios
Use these scenarios to practise clinical reasoning and management decisions
CLINICAL SCENARIOStandard
Scenario 1: Acute Gout Attack
CLINICAL PROMPT
"A 55-year-old man presents with sudden onset severe pain and swelling in his right wrist. The wrist is red, hot, and exquisitely tender. He cannot move it. He has a history of gout affecting his great toe. What is your diagnosis and initial management?"
PRACTICAL APPROACH
This is likely an acute gout attack affecting the wrist, given his history of podagra (great toe gout). However, the presentation mimics septic arthritis - red, hot, swollen joint with severe pain - so I must rule out infection. My immediate management is joint aspiration of the wrist under sterile conditions. I would send the fluid for cell count and differential, Gram stain and culture, and crucially, polarized light microscopy for crystal analysis. If I see negatively birefringent needle-shaped monosodium urate crystals, this confirms gout. The cell count in gout is typically 2,000-100,000 WBC/μL with neutrophil predominance (inflammatory but lower than septic arthritis which is usually greater than 50,000). Gram stain and culture should be negative. For acute management, I would start NSAIDs - indomethacin 50mg three times daily or naproxen 500mg twice daily - immediately to reduce inflammation. Alternatively, if he has contraindications to NSAIDs (renal impairment, GI bleeding history), I would use colchicine (1.2mg loading then 0.6mg one hour later) or corticosteroids (oral prednisone 30-40mg daily or intra-articular injection if monoarticular and infection ruled out). Supportive care includes rest, ice, and elevation. Importantly, I would NOT start allopurinol during the acute attack as this can worsen the flare - wait until the attack resolves in 2-4 weeks.
KEY CLINICAL POINTS
Joint aspiration essential to rule out septic arthritis
Gout crystals: negatively birefringent needles (yellow when parallel)
Acute treatment: NSAIDs, colchicine, or steroids
Do NOT start allopurinol during acute attack
COMMON PITFALLS
Starting allopurinol during acute flare (worsens attack)
Not aspirating joint (missing septic arthritis)
Confusing birefringence patterns (negative = gout, positive = CPPD)
FURTHER QUESTIONS
"What are the crystal characteristics in gout vs CPPD?"
"When would you start urate-lowering therapy?"
"What is the target uric acid level?"
CLINICAL SCENARIOChallenging
Scenario 2: Carpal Tunnel Syndrome in Tophaceous Gout
CLINICAL PROMPT
"A 60-year-old man with long-standing gout presents with progressive numbness in his thumb, index, and middle fingers. He has visible chalk-like deposits on his fingers and wrist. EMG shows severe carpal tunnel syndrome. His uric acid is 9 mg/dL despite allopurinol. What is your management?"
PRACTICAL APPROACH
This patient has carpal tunnel syndrome secondary to tophaceous gout - the tophi in the carpal tunnel are compressing the median nerve. This is indicated by his classic CTS symptoms, visible tophi, and EMG confirmation. His elevated uric acid (9 mg/dL) despite allopurinol suggests suboptimal medical management. My approach has two components: optimizing medical therapy and surgical decompression. First, I would work with his rheumatologist or internist to optimize urate-lowering therapy. The target is uric acid less than 6 mg/dL (ideally less than 5 for tophaceous gout). Options include increasing allopurinol dose (can go up to 800mg), switching to febuxostat, or adding a uricosuric like probenecid. For severe refractory cases, pegloticase (IV uricase) may be needed. However, given he has severe CTS on EMG with motor involvement (likely thenar atrophy), I would not delay surgery significantly. My surgical plan is open carpal tunnel release with tophus excision. The technique involves a standard CTR incision, dividing the transverse carpal ligament, then meticulously excising the chalky white tophus deposits from around the median nerve and flexor tendons. The median nerve may be encased in tophus, requiring very careful dissection. I would debulk extensively, irrigate thoroughly, and send tissue for pathology to confirm urate crystals. I would NOT close the TCL. Post-operatively, immediate finger ROM, continue his ULT, and monitor for wound dehiscence which occurs in 10-20% due to impaired healing in gout. Expected outcome is 80-90% symptom improvement, but recurrence risk is 5-10% if uric acid control is inadequate.
KEY CLINICAL POINTS
CTS from tophus in carpal tunnel
Optimize uric acid control (target less than 6 mg/dL)
Open CTR + meticulous tophus excision
Wound dehiscence risk 10-20%
COMMON PITFALLS
Delaying surgery in severe CTS (thenar atrophy indicates nerve damage)
Not optimizing ULT perioperatively (increases recurrence)
Aggressive dissection causing median nerve injury
FURTHER QUESTIONS
"What is pegloticase and when is it used?"
"What are complications of tophus excision?"
"How do you manage wound dehiscence?"
CLINICAL SCENARIOStandard
Scenario 3: CPPD vs Gout Differentiation
CLINICAL PROMPT
"A 70-year-old woman presents with acute wrist pain and swelling. X-ray shows calcification in the triangular fibrocartilage. You aspirate the joint and see rhomboid-shaped crystals under polarized microscopy. They appear blue when parallel to the polarizer. What is your diagnosis and management?"
PRACTICAL APPROACH
This is pseudogout (CPPD - calcium pyrophosphate deposition disease) affecting the wrist. The key diagnostic features are: 1) Wrist is the most common hand site for CPPD, 2) TFCC calcification on x-ray (chondrocalcinosis) is classic for CPPD, and 3) Rhomboid crystals that are positively birefringent (blue when parallel to polarizer) confirm calcium pyrophosphate crystals. This differentiates it from gout, which has negatively birefringent needle-shaped monosodium urate crystals that appear yellow when parallel. Management of acute pseudogout is similar to acute gout: NSAIDs as first-line (indomethacin or naproxen), colchicine, or corticosteroids (intra-articular injection is effective for monoarticular wrist pseudogout, or oral prednisone). The joint aspiration itself is therapeutic by relieving pressure. However, unlike gout, there is NO disease-modifying therapy for CPPD - we cannot dissolve or prevent calcium pyrophosphate crystals the way allopurinol lowers uric acid in gout. For chronic CPPD, I would screen for metabolic causes: check serum calcium, phosphate, and magnesium to rule out hyperparathyroidism, hemochromatosis, or hypomagnesemia. For patients with recurrent pseudogout attacks, low-dose colchicine 0.6mg daily can reduce flare frequency. If she develops severe chronic wrist arthritis from CPPD, surgical options include proximal row carpectomy, wrist arthrodesis, or wrist arthroplasty, but most patients are managed non-operatively.
KEY CLINICAL POINTS
CPPD crystals: positively birefringent rhomboids (blue when parallel)
TFCC calcification on x-ray is classic for CPPD
Acute management: NSAIDs, colchicine, steroids (same as gout)
No disease-modifying therapy for CPPD (unlike gout)
COMMON PITFALLS
Confusing birefringence (positive = CPPD, negative = gout)
Starting allopurinol for CPPD (only works for gout)
Not screening for metabolic causes (hyperparathyroidism, etc.)
FURTHER QUESTIONS
"What metabolic disorders are associated with CPPD?"
"What surgical options exist for CPPD wrist arthritis?"
"Can gout and CPPD coexist in the same patient?"
Guidelines, Registries & Global Practice
Global Epidemiology:
- Gout is the most common inflammatory arthritis worldwide; prevalence is rising with ageing populations and metabolic syndrome
- Age-standardised prevalence in adults 65+ was ~3,100 per 100,000 (GBD 2021), with burden in older men nearly double that of women and projected to keep rising to 2050
- Marked ethnic variation: highest prevalence in Māori and Pacific Island populations of Oceania (genetic urate transporter variants); lower rates historically reported in parts of Africa and East Asia
- Hand/wrist involvement complicates roughly 10-15% of established gout; CPPD prevalence rises steeply with age
Side-by-Side Guidelines:
| Body | Diagnosis | First-line ULT | Serum urate target | Notable position |
|---|---|---|---|---|
| ACR (US, 2020) | MSU crystals; supports DECT/US when aspiration unavailable | Allopurinol (incl. CKD), low-dose start | under 6 mg/dL, treat-to-target | Strong: ULT for tophi/erosions/frequent flares; prophylaxis 3-6 months |
| EULAR (Europe) | Crystal confirmation preferred; imaging adjuncts | Allopurinol, titrate to target | under 6 mg/dL (under 5 for severe/tophaceous) | Endorses treat-to-target and patient education |
| BSR/BOA (UK) | Clinical plus crystal/imaging | Allopurinol first-line | under 6 mg/dL (under 5 for tophi) | Emphasises ULT offered to all after a diagnosis is confirmed |
| ACR/EULAR (2015 criteria) | Classification: clinical + lab + imaging | n/a (classification) | n/a | Sensitivity 92%, specificity 89% |
Registry & Evidence Notes:
- No dedicated arthroplasty registry stratum exists for crystalline hand arthropathy; surgical evidence is limited to case series, so consent must reflect this
- Pharmacovigilance data (FAST trial, EU regulator-mandated) reshaped febuxostat cardiovascular guidance globally
High- vs Limited-Resource Practice Variation:
- High-resource: ready access to polarised microscopy, DECT, biologic uricase (pegloticase) for refractory tophaceous disease, and elective hand surgery
- Limited-resource: diagnosis often clinical; allopurinol remains the affordable backbone; DECT and pegloticase frequently unavailable; patients may present later with advanced tophaceous deformity requiring surgery
- Universal priorities: confirm crystals where possible, rule out septic arthritis, and achieve sustained serum urate under 6 mg/dL before and after any surgery
Medicolegal / Consent Essentials:
- Document joint aspiration and crystal analysis before committing to a diagnosis
- Always exclude septic arthritis (Gram stain, culture) - a missed joint sepsis is a key litigation risk
- Consent for tophus excision must cover wound dehiscence (10-20%), infection (5-10%), possible skin graft, and recurrence if urate control fails
CRYSTALLINE ARTHROPATHY - HAND
Clinical summary
Crystal Types
- •Gout: Monosodium urate (MSU)
- •CPPD: Calcium pyrophosphate (CPP)
- •Birefringence distinguishes them
- •Joint aspiration is diagnostic
Crystal Identification
- •Gout: Negatively birefringent needles (yellow parallel)
- •CPPD: Positively birefringent rhomboids (blue parallel)
- •Polarized light microscopy essential
- •NYPD mnemonic: Negative Yellow, Positive bLue/D
Acute Gout Attack
- •Sudden severe pain, red/hot/swollen joint
- •Wrist, MCP, PIP involvement possible
- •Mimics septic arthritis (must rule out)
- •Self-limited 7-10 days
Acute Management
- •NSAIDs: Indomethacin, naproxen (first-line)
- •Colchicine: 1.2mg load, 0.6mg 1h later, 0.6mg daily
- •Steroids: Intra-articular or oral if NSAID contraindicated
- •Do NOT start allopurinol during attack
Chronic Gout (ULT)
- •Allopurinol 100-800mg daily (first-line)
- •Febuxostat 40-80mg (alternative)
- •Target: Uric acid less than 6 mg/dL (less than 5 for tophi)
- •Colchicine prophylaxis 3-6 months during ULT start
Tophaceous Gout
- •Chalky white deposits in joints/tendons
- •Complications: CTS, tendon rupture, skin ulceration
- •Punched-out erosions on x-ray (rat-bite)
- •Surgery for nerve compression, skin breakdown
Surgical Indications
- •Carpal tunnel syndrome (most common)
- •Tendon rupture (extensor/flexor)
- •Skin ulceration/draining tophus
- •Nerve compression (median, ulnar)
- •Severe erosive arthropathy
CTR in Tophaceous Gout
- •Standard CTR + tophus excision
- •Dissect tophi off median nerve carefully
- •Debulk extensively, irrigate
- •Wound dehiscence risk 10-20%
- •Continue ULT perioperatively
Tophus Excision Complications
- •Wound dehiscence: 10-20%
- •Infection: 5-10%
- •Tendon rupture: 5%
- •Nerve injury: Less than 5%
- •Recurrence: 5-10% if poor uric acid control
CPPD / Pseudogout
- •Wrist most common hand site
- •TFCC calcification (chondrocalcinosis) on x-ray
- •Acute: NSAIDs, colchicine, steroids
- •No disease-modifying therapy (no ULT equivalent)
Imaging
- •Gout: Punched-out erosions, overhanging edges
- •CPPD: Chondrocalcinosis (TFCC calcification)
- •Ultrasound: Double contour sign (gout)
- •X-ray normal in early gout
Exam Pearls
- •Rule out septic arthritis (joint aspiration mandatory)
- •Negative birefringence = gout (yellow parallel)
- •Positive birefringence = CPPD (blue parallel)
- •CTS in tophaceous gout: CTR + tophus excision
- •Target uric acid less than 6 mg/dL with ULT