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Crystal deposition disorders are numerous and complex, but we'll review the basics of this class of disorders as they are common in the feet.
The term 'crystal deposition disorders' refer to a group of pathologies where the unifying component is that various crystals are forming within tissues for one reason or another. These disorders can cause symptoms ranging from a mild discomfort to tremendous, excruciating pain.
While the symptoms of diseases in this class can be quite similar, the differences are the types of crystals that are associated with each particular case.
The classic example of a crystalline deposition disease is gout. We discuss this condition at more length on a separate web page that can be accessed by clicking on the word 'gout'. But suffice it to say that gout is a very painful inflammatory condition associated with the deposition of monosodium urate (uric acid) crystals in various tissues throughout cooler portions of the body. Symptoms may include red, hot, painful, stiff and swollen joints and soft tissues.
Uric acid is a breakdown product of protein synthesis, and this condition can be controlled by changes in diet and/or with medications to prevent a patient from producing too much uric acid or to help the patient excrete more of it. But even with control of the cause of the disease, we often have to control the pain and dysfunction of a joint or tissue that has been damaged by this disease through physical medicine, medication, accommodative orthopaedic appliances or surgery.
Another common crystalline deposition is known as pseudogout, as its symptoms mimic those of gout. This condition is caused by the deposition of a different type of crystal known as calcium pyrophosphate crystals.
The cause of this crystal formation is unknown. It may be associated with an abnormality in the cartilage cells, disease, trauma or illness.
Treatment of pseudogout is similar to that of gout, but varies in that we do not aim to lower uric acid.
Hydroxyapatite deposition disease is a third type of crystal deposition. Often less painful than gout or pseudogout, hydroxyapatite deposition disease involves the deposition of still another type of crystal.
Treatment is similar to that of pseudogout.
Repeated steroid injections into a tissue can also cause painful crystal formation to develop, as the steroid itself, is made up of a crystal. This is ironic because steroids are often injected into joints and tissues in the attempt to calm down painful joints, yet repeated injections of steroids can actually cause a form of disease similar to what they are meant to treat.
Prevention of this disease is easy--we need to be judicious in the number and sites of steroid injections.
Other crystals that may be found in joints less frequently are: