X-rays Help Define Gout
In this article the clinical presentation, natural history, and diagnosis of gout are reviewed. Gout is a disorder of uric acid metabolism. Urate crystals are produced and deposited in the joints. The joints respond with an inflammatory reaction. The size of the deposits can increase until they burst through the skin.
Early diagnosis and treatment have helped reduce the painful joints often associated with gout in the past. Blood test for urate levels and X-rays are the most helpful diagnostic tools. Not everyone with high uric acid levels have signs and symptoms of gout. Treatment is not applied until uric acid is more than nine mg/dL.
There are four stages of gout. Each one is reviewed with X-rays to demonstrate changes seen. The exception is asymptomatic hyperuricemia, which does not show any differences on X-ray.
Acute gouty arthritis is the most common stage. The patient has one or more painful, hot, red joint(s). X-rays show soft-tissue swelling and places where the bone has been eroded. Thinning of the bone can occur. Bits of bone can form inside tendons, a process called calcification.
Some patients have quiet periods called intercritical gout when they don't have any symptoms. Others enter a phase of chronic gout affecting more than one joint. Bone changes in this phase are very clear on X-ray.
Deposits of urate crystals in the soft tissue called tophi are seen on the X-rays. Overhanging edges of bone from bone erosion are clearly seen. Areas of bone erosion often look like holes punched out of the bone.
The authors provide more than a dozen X-rays with descriptions to help physicians make the diagnosis. They describe how gout looks different on X-ray from other conditions such as osteopenia, osteoporosis, and rheumatoid arthritis.
X-rays aren't always specific enough during an acute attack. In those cases, the physician relies upon lab values and the patient's response to treatment.
Justin Spackey, MD, et al. Diagnosis: Gout. In Orthopedics. May 2007. Vol. 30. No. 5. Pp. 405-408.