Overview
Crystal arthropathies are a diverse group of disorders characterized by deposition of various minerals in joints and soft tissues leading to inflammation. Two main types of crystal arthropathies:
- Gout – The most common of all the crystal arthropathies, caused by monosodium urate crystal precipitation, and its prevalence appears to be increasing.
- Pseudogout – caused by calcium pyrophosphate dihydrate
Clinical Manifestation
- Typically monoarthritis
Diagnosis
- Septic arthritis (Emergency)
- Joint trauma
Diagnosis
- Synovial fluid analysis – identification of specific crystal types in synovial fluid
| Synovial fluid analysis | |||
| Aetiology | Colour and Clarity | WBC (mm³) | |
| Normal | Normal | Clear and transparent | <200 |
| Non-Inflammatory | Osteoarthritis | Yellow and transparent | 0 to 2000 |
| Inflammatory | Gout | Yellow and traslucent-opaque | 2000-100,000 |
| Septic | Bacteria | Yellow/green and opaque | >25,000 – >100,000 |
| Haemorrhage | Trauma | Red and Bloody | 200-2000 |
| DIFFERENCE BETWEEN GOUT AND PSEUDOGOUT | ||
| Gout | Pseudogout | |
| Aetiology | Build up of uric acid crystal in joints | Build up of calcium pyropohosphate crystals in joints |
| Diagnosis | Synovial fluid examined under microscopy reveals the presence of uric acid crystals | Synovial fluid examined under microscopy reveals the presence of calcium pyrophosphate crystals |
| Morphology | Needle shaped | Rhomboidal |
| Birefringence | Strongly negative | Weakly positive |
| Treatment | Allopurinol, Colchicine | Colchicine, corticosteroid injection |
