Armando Hasudungan
Biology and Medicine videos

Crystal Arthropathy


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 Presentation

  • Typically monoarthritis

Differential 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


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