Ultrasound Found to be Accurate in Diagnosing Gout, Pseudogout

Noninvasive diagnostic tool provides clearest information to direct accurate treatment

November 29, 2007

For hundreds of thousands of people each year who suffer from sudden, painful occurrences of gout and pseudogout – arthritic conditions caused by crystallization of uric acid and calcium in joint fluid – noninvasive ultrasounds have been found to be better than MRIs or X-rays in diagnosing the condition and tracking its response to treatment, according to a University of Rochester Medical Center researcher.

Ralf G. Thiele, M.D., FACR, assistant professor of Medicine/Division of Allergy/Immunology and Rheumatology at the University of Rochester Medical Center, released the findings during a poster presentation at the 2007 American College of Rheumatology Annual Scientific Meeting on Nov. 10 in Boston. URMC is the only site in North America studying the impact of ultrasound on the diagnosis and treatment of gout and pseudogout.

Pseudogout is caused by excess calcium deposits in the fluid surrounding joints. Its symptoms are similar to gout, or metabolic arthritis, which is a common form of arthritis caused by crystals that form in the joints, a result of too much uric acid. Intense pain, caused both by the crystals and by swelling around the joint caused by inflammation, can hinder walking and impact quality of life.

Patients require medications to reduce either the amount of uric acid in the case of gout, or the decrease the symptoms of inflammation in the case of pseudogout. The medications are different for each, Thiele said, thus correct diagnosis of the problem and prescribing the proper drug is imperative in order to reduce or eliminate the pain. As Thiele’s research shows, ultrasound is a very sensitive tool to identify the conditions, and it can be done quickly and noninvasively.

Gout and pseudogout are difficult to diagnose, Thiele said. Because blood levels don’t provide a diagnosis, the only indisputable way to identify the conditions is to aspirate fluid from the affected joint, a painful procedure that requires the specimen be examined at a lab by a specialized technician using a polarizing microscope. In lieu of that approach, X-rays and MRIs are commonly done and can show crystallization in the joints, although results are not as clear as when ultrasound is used. The latter also have some difficulty detecting the calcium crystallization associated with pseudogout.

“Ultrasound technology can provide patients with a noninvasive, quick and accurate diagnosis right in the doctor’s office,” Thiele said. “Appropriate medications can then be prescribed to address the pain.”

Ultrasound images provide clear detail for an initial diagnosis in the doctor’s office, allowing physicians to ascertain the type of crystals causing the pain and enabling them to prescribe proper medications. Thiele’s research also found that the clear ultrasound image assists in tracking the progress of the treatment, to ensure crystalization is decreasing as a result of treatment.

The conditions are widespread in men over 50 and post-menopausal women. In three-quarters of patients, gout attacks the big toe joint, while pseudogout impacts other joints, such as the wrists, shoulders and knees. The number of cases in the United States is on the upswing, an increase thought to be caused in part by Americans’ rich diet of red meet; shellfish, particularly shrimp; and alcohol.

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