Gout, a form of inflammatory arthritis, is usually associated with the big toe. However, it can sometimes affect the spinal column, a rare condition known as spinal gout. It occurs when uric acid crystals, the cause of gout, build up in the spine’s joints and tissues. Because it is uncommon and its symptoms mimic other back problems, it can be difficult to diagnose.
Causes and Risk Factors
Spinal gout is caused by hyperuricemia, a condition of excessive uric acid in the blood. Uric acid is produced when the body breaks down purines, which are found in many foods. If the body produces too much uric acid or the kidneys fail to filter it out, it can form needle-like crystals. Over time, these crystals can form larger deposits called tophi, which can accumulate in various parts of the spinal column in cases of chronic or poorly managed gout.
A primary risk factor is a pre-existing diagnosis of chronic gout, especially if untreated for 10 to 20 years. Other contributing factors include older age, being male, and having underlying kidney disease that impairs uric acid excretion. Certain medications, such as diuretics or specific organ-rejection drugs, can also elevate uric acid levels.
Symptoms and Complications
The symptoms of spinal gout are often nonspecific and can mimic more common spinal conditions. The most frequent complaint is axial back or neck pain, which is localized discomfort and stiffness in the affected region. This pain results from the inflammatory response to crystal deposits in the spinal joints.
If these crystal masses, or tophi, grow large enough to press on nearby nerve roots, they can cause radicular symptoms. This involves pain that radiates from the spine into the limbs. It is often accompanied by sensations of tingling, numbness, or muscle weakness.
If left untreated, the condition can lead to significant complications. The pressure from large tophi can cause spinal cord compression, which may result in widespread neurological problems like loss of bladder or bowel control. The erosive nature of the crystal deposits can also weaken the vertebrae, potentially leading to fractures.
The Diagnostic Process
Physicians consider spinal gout when a patient with a known history of the condition presents with unexplained back pain and neurological symptoms. The diagnostic process begins with ruling out more common causes of back pain. A physical examination helps assess for nerve involvement.
Imaging studies are a primary diagnostic tool. Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) scans can reveal masses or erosions in the spine consistent with tophi. While these scans can identify a suspicious mass, they cannot definitively confirm it is composed of urate crystals.
A specialized imaging technique called Dual-Energy Computed Tomography (DECT) offers a more specific diagnosis. A DECT scan can differentiate materials in the body, allowing it to identify and color-code uric acid deposits along the spine. Blood tests are also used to measure uric acid levels, but elevated levels are not conclusive, as not everyone with hyperuricemia develops gout.
Treatment Approaches
Treatment for spinal gout focuses on managing the underlying cause with urate-lowering therapies. The primary long-term strategy is medication, such as allopurinol, to reduce the body’s production of uric acid. This approach helps dissolve existing urate crystals and prevent new ones from forming.
During an acute flare-up, the goal is to control pain and inflammation. This is achieved with medications like nonsteroidal anti-inflammatory drugs (NSAIDs) or colchicine. In some cases, corticosteroids may be used to reduce severe inflammation.
Surgical intervention is reserved for severe cases where conservative treatments fail or when neurological complications are present. Surgery may be necessary to decompress the spinal cord or nerve roots if a tophus causes progressive weakness or loss of sensation. Procedures involve removing a portion of the vertebra to relieve pressure.
Lifestyle and dietary modifications can complement medical treatment to help lower uric acid levels. These changes include:
- Losing weight
- Reducing the intake of alcohol
- Avoiding foods high in purines
- Engaging in regular exercise to help the body process and remove uric acid