Case 4: Diagnosis and Conclusions

Case Summary:

Our patient is a young woman with symmetric inflammatory polyarthritis of both hands lasting for 3 months. Her exam confirms polyarticular swelling and tenderness in multiple small joints of hands. Basic labs demonstrate acute inflammation: anemia, thrombocytosis, elevated inflammation markers. Serologic studies confirm high tiers of RF and CCP. X-rays are so far unaffected by inflammatory changes, which correlates with the recent onset of her disease. This establishes the diagnosis of rheumatoid arthritis (RA). The fact that she has recently delivered a baby may also be important. Studies show an increased incidence of RA in the first 6 months post-partum. If you’d like to learn more about why this happens, check out this review article (1).

RA is a type of chronic inflammatory arthritis. It is more common in women with average age of onset in 5th or 6th decade. Typical joints affected include small joints of hands – MCPs, PIPs, carpal bones, wrist. Larger joints such as shoulders, elbows, knees, ankles can also be affected but usually after small joints. Although, patients do not read books, so absence of small joint involvement does not necessarily exclude this Dx. We expect swelling in affected joints and AM stiffness > 30 min and usually > 1 hour. In contrast, osteoarthritis usually presents with bony enlargement in PIP and DIP joints, has stiffness < 30 min in duration. OA tends to affect weight bearing joints: knees, MTPs (note that ankle is a hinge-joint, not a weight bearing joint) and overused joints (e.g., shoulders in baseball players). Lumbar and thoracic spine are usually not affected in RA. Check out our arthritis schema and inflammatory arthritis schema (coming soon!) for more information on DDx.

There are several genetic factors associated with development of RA. Environmental triggers, such as bacteria and viruses, have been implicated as well. An important modifiable risk factor to remember is smoking. The risk of RA is increased two-fold in men who smoke and 1.3-fold in female smokers compared with non-smokers (3).