CASE 113
By: Dr. Nizar Al-Nakshabandi MD, FRCPC
HISTORY: 42-year-old complaining of hip pain.
What are your findings?
What is the differential diagnosis?
What are the causes?
FINDINGS:
The AP radiograph of the pelvis [A] demonstrates concentric narrowing of the joint space bilaterally. The frog leg view of both hips [B] demonstrate congruent hips. Sacroiliac joints appear unremarkable. There are subchondral cysts present. Furthermore, there is para-articular osteoporosis seen. In addition, protrusio acetabuli is seen.
Axial and coronal T1 weighted fat saturated images with gadolinium enhancement [C and D] demonstrate evidence of subchondral subcortical cystic changes in the acetabulum and femoral heads. There is evidence of enhancement of the synovium from synovitis. Furthermore, concentric narrowing is better appreciated. Erosions of the femoral heads are probably seen.
DIFFERENTIAL DIAGNOSIS:
· Inflammatory arthropathy e.g. Rheumatoid arthritis.
· Degenerative Osteoarthritis.
· Erosive osteoarthritis.
· Psoriatic arthritis.
· Reactive arthritis.
· CPPD.
DIAGNOSIS:
Rheumatoid arthritis of the hips.
PEARLS AND DISCUSSION:
The hallmarks of RA are bilateral symmetric arthritis of more than three joints (polyarthritis). Over 60% of patients initially present with symmetric arthritis of multiple small hand joints. Typically, the second and third metacarpophalangeal and the third proximal interphalangeal joints are involved early during the disease.
The hips and sacroiliac joints are normally not affected. If the sacroiliac joints are involved in RA, an asymmetric and unilateral distribution is most likely, in contrast to the bilateral and symmetric arthritis in most seronegative spondylarthropathies. Furthermore, erosions are shallower, sclerosis is milder, and ankylosis is rarer in RA.
The Larson system for grading rheumatoid arthritis and related conditions by using standard differences in film radiographs.
Table 1.
| Grade | Definition | Findings |
|---|---|---|
| 0 | No radiographic changes | Abnormalities not related to arthritis may be present. |
| 1 | Slight abnormality | Periarticular swelling, paraarticular demineralization, slight joint space narrowing |
| 2 | Definite early abnormality | Definite presence of erosions except in weight-bearing joints, joint space narrowing |
| 3 | Medium destructive abnormality | Definite presence of erosions in all types of joints, joint space narrowing |
| 4 | Severe destructive abnormality | Erosions, joint space narrowing, bone deformation in weight-bearing joints |
| 5 | Mutilating abnormality | Disappearance of the original articular forces, gross bone deformities in weight-bearing joints. |
FURTHER READING:
1. Oliver J. Sommer, MD, Andrea Kladosek, MD, Volkmar Weile Rheumatoid Arthritis: A Practical Guide to State-of-the-Art Imaging, Image Interpretation, and Clinical Implications. RadioGraphics 2005; 25:381–398.
2. Weissleder R, Wittenberg J, Harisinghani MG. Primer of diagnostic imaging. Mosby Inc. (2003) ISBN:0323023282.
3. Brant WE, Helms CA. Fundamentals of diagnostic radiology. Lippincott Williams & Wilkin
