Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease, also known as chondrocalcinosis, pseudogout and pyrophosphate arthropathy is a rheumatologic disorder with varied symptoms and signs arising from the accumulation of crystals of calcium pyrophosphate dihydrate in the connective tissues. The alternative names emphasize particular aspects of the clinical or radiographic findings. The knee joint is the most commonly affected.
Symptoms of (CPPD)
This arthritis disorder is more common in order adults. It can be connected with osteoarthritis, or it can present as an acute or chronic provocative arthritis that causes pain in one or more joints. The white blood cell count is often raised.
The arthritis is usually polyarticular although it may begin as monoarticular. CPPD crystals tend to form within articular tissues. In theory, any joint may be affected, but statistics show that the knees are the most commonly affected joints, as well as wrists and hips. In rare cases, pseudogout may affect the spinal canal and cause damage to the spinal cord.
In many instances, patients may also have signs of carpal tunnel syndrome. This condition can also be associated with Milwaukee shoulder syndrome.
Two elements are considered: radiology and joint fluid analysis.
Radiology has a large role to play in the diagnosis of chondrocalcinosis, with radiographs, CT scans, MRIs, US, and nuclear medicine all having a part. CT scans and MRIs show calcific masses (usually within the ligamentum flavum or joint capsule), however radiography is more successful. At ultrasound, chondrocalcinosis may be depicted as echogenic foci with no acoustic shadow within the hyaline cartilage. As with most conditions, chondrocalcinosis can present with similarity to other diseases such as ankylosing spondylitis and gout.
Arthrocentesis, or removing synovial fluid from the affected joint, is performed to test the synovial fluid for the calcium pyrophosphate crystals that are present in CPPD. When stained with H&E stain, calcium pyrophosphate crystals appears deeply blue ("basophilic").However, CPP crystals are much better known for their rhomboid shape and weak positive birefringence on polarized light microscopy, and this method remains the most reliable method of identifying the crystals under the microscope However, even this method suffers from poor sensitivity, specificity, and inter-operator agreement.