CPPD vs Gout
== CPPD ==
Think About CPPD When:
• Self-limited synovitis after surgery/trauma (> 65 years old)
• Unilateral swelling in weird joints (shoulders, wrists, elbows)
• Underlying disease states
Pathophysiology:
• Pyrophosphate produced by chondrocytes likely precipitates with calcium to form CPP crystals, which then deposit and can activate inflammatory pathways, resulting in an acute arthritic flare.
1. Asymptomatic CPPD:
Cartilage calcification appears as a linear opacity below the surface of articular cartilage
2. Acute CPP Crystal Arthritis:
Monarticular inflammatory arthritis, characterized by sudden onset of swelling, pain, loss of function, tenderness, and warmth
3. Chronic CPP Crystal Inflammatory Arthritis:
Resembles RA
4. Osteoarthritis with CPPD:
OA in atypical locations: Wrist, MCP, or shoulder joints
Think of the "H's" Especially if < 50 Years Age:
• Hemochromatosis
• Hyperparathyroidism
• Hypothyroidism
• Hypomagnesemia
Synovial Fluid:
• WBCs >2000-100,000/µL; neutrophil predominance
• CPP crystals
• Rhomboid shaped
• Weakly positively birefringent or not birefringent
• Gram stain, culture used to diagnose concomitant infection
• Imaging may show chondrocalcinosis
== Gout ==
3 Conditions for Gout to Manifest:
1. Hyperuricemia
2. Monosodium urate deposition in joints and/or soft tissues
3. A reaction to phagocytosed crystals that leads to an acute inflammatory response
Risk Factors:
• Advanced age
• Male sex
• Metabolic syndrome
• Medications (diuretics)
Epidemiology:
• Men in 4th to 5th decade
• Postmenopausal women
Presentation:
1. Acute Intermittent Gout:
• Great toe (podagra): 50% of initial attacks
• Other joints include forefoot, ankles, knees, fingers, wrist, elbow
• Nocturnal onset --> Peak 12-24 Hours
• Fever, erythema, swelling, significant pain
2. Intercritical Gout: Asymptomatic period between attacks
Gout: Synovial Fluid Testing:
• WBCs >2000-100,000/µL; neutrophil predominance
• Urate crystal - Needle-shaped, negatively birefringent
• Acute gout - Intracellular (leukocyte) crystals
• Intercritical gout - Extracellular crystals
• Gram stain and culture- Diagnose concomitant infection
Serum Urate Levels:
• Not helpful in acute gout
• ↑ C-reactive protein, ESR, leukocytosis
• Nonspecific findings
#CPPD #Gout #Comparison #rheumatology #Diagnosis
