Calcium Pyrophosphate Dihydrate Crystal Deposition

1. Epidemiology
   1. Autosomal dominant inheritance and sporadic cases
2. Associated Conditions
   1. Hyperparathyroidism
   2. Hemochromatosis
   3. Hypothyroidism
   4. Amyloidosis
   5. Hypomagnesemia
   6. Hypophosphatasia
3. Signs: Pseudogout (25% of CPPD Deposition Disease)
   1. Acute self-limited joint inflammation
   2. Duration of Pseudogout attack: days to weeks
   3. Asymptomatic between episodes
   4. Distribution (may involve any joint)
      1. Knees (50%)
      2. First metatarsophalangeal Joint (similar to gout)
   5. Pseudogout precipitating factors
      1. Spontaneous attacks
      2. Trauma
      3. Surgery
      4. Cerebrovascular Accident (CVA)
      5. Myocardial Infarction
   6. Systemic signs
      1. Fever up to 103 F
4. Signs: Pseudo-Rheumatoid (5% of CPPD Deposition Disease)
   1. Symmetric Polyarthritis with low grade inflammation
      1. Synovial thickening
      2. Flexion contractures
   2. Morning Stiffness
   3. Fatigue
5. Signs: Pseudo-Osteoarthritis (50% of CPPD)
   1. Progressive joint degeneration
   2. Symmetric Distribution
      1. Knees (most commonly affected)
      2. Wrists
      3. Metacarpophalangeal joints
      4. Hips
      5. Shoulders
      6. Elbows
      7. Ankles
   3. Differs from Osteoarthritis
      1. No predilection for PIP, DIP, or MCP joints
   4. Flexion Contractures
   5. Valgus Knee deformity
6. Labs
   1. Arthrocentesis for Synovial Fluid exam
      1. CPPD crystals on Polarized Microscopy
   2. General studies for CPPD Deposition Disease
      1. Serum Calcium
      2. Serum Magnesium
      3. Serum Phosphorus
      4. Alkaline Phosphatase
      5. Thyroid Stimulating Hormone (TSH)
      6. Serum Ferritin
   3. Pseudogout attack
      1. Complete Blood Count
         1. Leukocytosis up to 15,000 per mm3
      2. Erythrocyte Sedimentation Rate (ESR) increased
   4. Pseudo-Rheumatoid
      1. Erythrocyte Sedimentation Rate (ESR) elevated
      2. Rheumatoid Factor may be positive at low titer
7. Radiology: Joint XRay
   1. Screening XRays for CPPD Deposition
      1. Bilateral AP Knee XRay
      2. AP Pelvis XRay
         1. Symphysis Pubis
         2. Hips
      3. Bilateral PA Hand and Wrist XRay
   2. Articular hyaline cartilage changes
      1. Punctate densities
      2. Linear densities
8. Management
   1. Large joint acute attack
      1. Joint aspiration (Arthrocentesis)
      2. Joint aspiration and joint Corticosteroid Injection
   2. Analgesia
      1. NSAIDs
      2. Colchicine (Intravenous is more effective than oral)
9. References
   1. Klippel (1997) Primer Rheumatic Diseases, p.226-9