What is the next step in managing Calcium Pyrophosphate Dihydrate (CPD) crystals associated with pseudogout?

Management of Calcium Pyrophosphate Dihydrate (CPD) Crystal Deposition Disease

The next step in managing CPD crystals associated with pseudogout is joint aspiration with intra-articular glucocorticoid injection for acute attacks, followed by oral NSAIDs with gastroprotection or low-dose colchicine (0.5-1.0 mg daily) for ongoing management. 1

Acute Attack Management Algorithm

1. First-line: Joint aspiration + intra-articular glucocorticoid injection

   • For monoarticular or oligoarticular attacks
   • Provides rapid symptom relief
   • High strength of recommendation (SOR: 95%) 1

2. If joint aspiration is not feasible, use:

   • NSAIDs (if no contraindications)
   • Colchicine (if NSAIDs contraindicated)
   • Systemic glucocorticoids (if both NSAIDs and colchicine contraindicated) 1

3. For severe attacks unresponsive to oral medications:

   • IV methylprednisolone (125 mg) - provides rapid relief with NNT of 3 compared to oral NSAIDs
   • Alternative: IM betamethasone (7 mg) 1

Chronic Management Algorithm

1. First-line options:

   • NSAIDs with gastroprotection (moderate evidence)
   • Low-dose colchicine (0.5-1.0 mg daily) (moderate evidence) 1
     • NNT of 2 at 4 months for >30% pain reduction
     • Dose adjustment required in renal impairment 2

2. Second-line option:

   • Low-dose oral corticosteroids (low evidence) 1

3. Third-line options:

   • Methotrexate (5-10 mg/week) (low evidence)
   • Hydroxychloroquine (NNT for clinical response: 2) 1

4. For refractory cases:

   • Consider IL-1 inhibitors when other anti-inflammatory therapies are ineffective 1

Special Considerations

Dose Adjustments for Colchicine

1. Renal impairment:

   • Mild to moderate impairment: No dose adjustment needed but monitor closely
   • Severe impairment (CrCl <30 mL/min): Start with 0.3 mg/day
   • Dialysis patients: 0.3 mg twice weekly 2

2. Hepatic impairment:

   • Mild to moderate impairment: No dose adjustment needed but monitor closely
   • Severe impairment: Consider dose reduction and limit treatment courses 2

3. Drug interactions:

   • With CYP3A4 inhibitors: Reduce colchicine dose
   • Patients with renal or hepatic impairment should not receive colchicine with CYP3A4 inhibitors 2

Underlying Conditions

• Screen for associated metabolic disorders:
  • Hyperparathyroidism (patients with CPPD are 3 times more likely to have this condition)
  • Hemochromatosis
  • Hypomagnesemia
  • Hypophosphatemia 1

Monitoring and Follow-up

• Assess treatment response
• Monitor for medication side effects
• Evaluate for progression of joint damage
• Reassess for underlying metabolic disorders 1

Common Pitfalls to Avoid

1. Failing to confirm diagnosis - Always confirm CPPD through synovial fluid analysis for weakly positive birefringent rhomboid-shaped crystals under compensated polarized light microscopy 1

2. Overlooking medication risks:

   • NSAIDs: GI bleeding, cardiovascular events, renal impairment
   • Colchicine: Diarrhea and GI side effects (avoid high-dose regimens)
   • Corticosteroids: Hypokalaemia, hyperglycaemia, fluid retention 1

3. Special caution in elderly patients who have higher risk of toxicity with NSAIDs and colchicine 1

4. Missing early-onset disease (before age 60) which requires thorough metabolic workup, particularly for hemochromatosis 1