A 56-Year-Old Woman Presents with Progressively Worsening Pain

A 56-year-old white woman complains of wrist pain, primarily located in the right wrist but to a lesser degree in the left as well. She said the wrist pain has been intermittent for the last 2 or 3 years, but recently has gotten progressively worse. She also added that she has had mild pain in her feet, right greater than left, with a mild amount of pain in her left knee. 

History

Her past medical history is noncontributory.

Physical Examination

The patient is well-nourished and in no acute distress. Her vital signs are within normal limits.

Physical examination of her right wrist demonstrates mild diffuse swelling with a focal area of soft tissue swelling in the ulnar aspect of the carpus. This is not focally tender. There is mild pain with movement and mild loss of range of motion. 

Examination of the left wrist demonstrates a lesser degree of swelling and a lesser degree of pain. The examination of her feet and knees was unrevealing. 

Laboratory Tests

The radiographs of the right wrist demonstrate a focal lucency in the distal ulna, proximal to the ulnar styloid, and an adjacent area of soft tissue swelling. The focal lucency has well corticated margins. There is also lucency in the lunate with a lucency identified in the base of the first metacarpal, best appreciated on the lateral view (Figures 1-3). Close inspection demonstrates other small focal lucencies scattered throughout the carpus on the right. 

An arthridity was suspected.

How would you diagnose this patient? 

A.  Rheumatoid arthritis
B. Calcium pyrophosphate deposition disease
C. Gout
D. Infection
E. Metastatic disease

Answer: Gout

A nuclear medicine bone scan was performed to evaluate all the joints. Nuclear medicine in this setting can be very effective. The nuclear medicine scan gives an overview of all the joints in the body on 1 scan. The nuclear medicine scan is far more sensitive than conventional radiographs for detecting early erosive arthritis or other conditions that will affect joints or bones. The nuclear medicine bone scan can be supplemented with conventional radiographs and/or an MRI as needed to provide additional specificity.

In this case, the nuclear medicine scan demonstrates increased activity in the carpus on the right diffusely. There is mild increased activity within the carpus on the left, with moderate to severe increased activity within the second metacarpal phylangeal joint of the left hand (Figure 4). The feet and left knee were negative. The remainder of the patient’s joints demonstrated minimal areas of osteoarthritis.  

An MRI was ordered to evaluate the severity of the case. T1 weighted images (Figure 5) and T2 weighted images (Figure 6) demonstrate soft tissue deposits in the soft tissues eroding into bone. This is most clearly visible in the region of the distal ulna. This does involve the distal radioulnar joint and lunate on these images. Deposits are intermediate signal on T1 and high signal on T2 weighted images. The lesion in the base of the first metacarpal can be appreciated on the T2 weighted image (Figure 6).

Diagnosis

A presumptive diagnosis of gout was made due to the patient history. A blood uric acid level was drawn, which confirmed the suspicion. Aspiration of the lesion in the ulnar aspect of the carpus yielding uric acid crystals confirmed the diagnosis. 

Gout

Over 8 million people in United States are affected by gout and more than 2 million people are on medication to decrease serum uric acid levels. Gout has a male predominance—almost 3 times more common in men than women—and typically occurs between the age of 30 and 60, but can be seen in patients over 70. Gout is associated with a positive family history, hypertension, diabetes, male gender, obesity, alcohol abuse, and eating foods rich in purines. Certain medications (eg, diuretics or levodopa) can predispose patients to attacks. 

Gout is typically classified as arthritis. It occurs when uric acid blood levels are causing deposition of uric acid in soft tissues. This most commonly occurs in the region of the first metatarsophalangeal joint, at a location known as podagra. 

Acute gout attacks can be very painful and cause acute inflammation of the site. Over time, deposition of crystals can take place, which causes soft tissue masses in periarticular locations, as seen in this case.

Other joints that are frequently involved include the ankle, wrist, fingers, and knees. In the acute setting, the differential diagnosis is septic arthritis as the red hot swollen painful joints can mimic infection.

Complications of gout include severe arthritis, secondary infections, uric acid nephropathy, and renal stones. Nerve or spinal cord inpingement can be identified related to the position of uric acid depostion.

The diagnosis is often made when classic symptoms are identified and there is a high uric acid level. Joint aspiration with fluid analysis can be performed if the diagnosis is unclear from the patient’s symptoms and blood work.

Differential Diagnosis

Rheumatoid arthritis would be expected to be symmetrical. Rheumatoid arthritis would demonstrate erosive changes that are not appreciated on the conventional radiographs. The abnormalities in this case are periarticular and not intra-articular, making rheumatoid arthritis less likely. Additionally there is no ligamentous laxity or periarticular osteopenia.

Calcium pyrophosphate deposition disease typically demonstrates chondrocalcinosis. In the wrist, this is most commonly seen in the triangular fibrocartilage complex. It is not associated with soft tissue masses. It typically contributes to advanced osteoarthritic changes within the joints, not periarticular erosive changes. 

Infection is thought to be less likely. It would be unusual for infection to be polyarticular without the patient being septic and hence, more symptomatic. It would also be unusual for infections to present with this chronic intermittent history. It is difficult to definitively exclude infection, but given the history and the radiographic appearance infection is thought to be less likely. In the acute setting, infection causes more aggressive erosive changes with soft tissue swelling. In the more chronic setting, more sclerosis in the osseous structures would be expected in the setting of infection although the appearance in the chronic setting can be quite variable depending upon the type of infection and treatment regimens.

Metastatic disease would be extremely unlikely. It is very unusual for most malignancies to demonstrate metastatic disease outside of the axial skeleton unless the disease is extremely widespread. This patient has no known malignancy. 

Outcome of the Case

The patient was placed on appropriate medications and did well.  

William Yaakob, MD, is a board-certified radiologist working in Tallahassee, FL.