Synopsis
Recognise acute, chronic and asymptomatic calcium-pyrophosphate phenotypes, confirm crystals while excluding infection, identify important metabolic associations and treat inflammation without promising a crystal-dissolving therapy.
- CPPD is an umbrella for asymptomatic chondrocalcinosis, acute CPP crystal arthritis, chronic CPP inflammatory arthritis and osteoarthritis with CPP deposits; avoid the imprecise term pseudogout when a phenotype can be named.
- Acute CPP arthritis commonly affects an older adult's knee or wrist, can be intensely painful and febrile and may take longer than gout to settle.
- The reference confirmation is CPP crystals in symptomatic-joint fluid: usually rhomboid or rod-shaped and weakly positively birefringent under compensated polarised light.
- A negative crystal search does not fully exclude CPPD because crystals can be sparse and weakly birefringent; expert microscopy and prompt analysis improve yield.
- Always send synovial culture when infection is possible. Chondrocalcinosis and CPP crystals can coexist with septic arthritis.
- Plain radiography can show linear or punctate calcification in menisci, triangular fibrocartilage, symphysis or hyaline cartilage; absence of chondrocalcinosis does not exclude symptomatic disease.
- Ultrasound is useful for accessible cartilage and effusion, while CT is the preferred test for crowned dens syndrome around the odontoid.
Key red flags
Fever, shock, prosthesis, recent joint procedure, skin breach or bacteraemia requires immediate septic-arthritis assessment regardless of chondrocalcinosis.
Acute severe neck pain with rigidity, fever, headache, focal neurology or altered consciousness requires urgent exclusion of meningitis, haemorrhage, spinal infection and giant cell arteritis.
A painful swollen hip, shoulder or other deep joint needs urgent image-guided aspiration because examination cannot reliably separate crystal disease from infection.
Trauma, anticoagulation or inability to bear weight widens the differential to fracture, haemarthrosis and structural injury before anti-inflammatory treatment.
Acute kidney injury, ulcer bleeding, heart failure or anticoagulation can make NSAID treatment dangerous; pregnancy changes colchicine and imaging decisions.
CPPD beginning before age 60, widespread deposits or strong family history should prompt a metabolic and inherited-cause assessment rather than an age-only explanation.
Acute upper-neck pain, restricted rotation, fever and high inflammatory markers with peri-odontoid CT calcification defines this CPPD presentation.
Investigation priorities
Confirm CPP crystals in a symptomatic joint and distinguish gout.
Management branches
An acute effusion with severe warmth and restricted movement is present.
- Check sepsis, prosthesis, recent procedure, skin breach and bacteraemia and obtain observations and blood cultures when systemically unwell.
- Aspirate before antibiotics when safe, sending cell count, Gram stain, culture and expert polarised microscopy for CPP and urate crystals.
- Treat suspected infection immediately and remember that a positive CPP crystal result does not cancel microbiological risk.
One accessible joint is affected and infection has been reasonably excluded.
- Remove as much inflammatory fluid as practical, document the specimen and use strict asepsis for any subsequent injection.
- Give joint-size-appropriate intra-articular corticosteroid, local cool treatment and short relative rest with post-injection infection warnings.
- Restore range and progressive loading as pain settles and reassess promptly if fever, swelling or pain worsens.