As it turns out, the house officer was right. There were in fact some joints with synovitis (three metacarpophalangeal joints to be precise), and the tissues surrounding the joints were clearly thickened. When I pressed these joints bit harder, Mr. Jones said, “I can feel it,” which I interpreted as mild tenderness. Not surprisingly, the global assessment was low and, like some stoics and people who want to banish symptoms with positive thought, Mr. Jones rated it only a 10 on a 0 to 100 scale.
Given the physical findings, I expected a DAS in the 3 to 4 range and was prepared to recommend a boost in the methotrexate dose. The difficulty, however, was the erythrocyte sedimentation rate (ESR). The ESR was 1 and, even if the patient had synovitis in up to 10 joints (with a global of 10), an ESR that low produces a DAS in the remission range. I therefore had to ask myself which number was more informative: the joint count or the ESR rate?
T2T is here to stay, even if an occasional value … will stymie me as I decide whether to increase or decrease an agent or add another therapy. Rheumatologists have an increasingly large armamentarium of effective agents to allow target practice (pun intended).
Making the Right Decision?
As Ted Pincus has pointed out, many people with putatively active RA have a normal ESR, especially when adjusted for age and gender. However, the observation begs the question of whether, in the range of values we consider normal, there are important physiological or pathophysiological differences that could affect the course of RA and the likelihood for joint damage. Thus, ESR values of 1 and 30 are both “normal,” but a value of 30 may indicate the presence of proteins in the blood that reflect mischief in the joints. Such proteins could fuel inflammation just as they coat red cells to make them propel down a thin tube under the watchful eye of a laboratory technician.
In view of the discrepancy between the clinical and laboratory findings, perhaps Mr. Jones’ disease was inactive, with the ESR of 1 a bona fide measure of the quiescence of his immune system. The swelling that both the house officer and I felt could be fibrosis, indicating a process of healing or repair of past inflammation, a time of nastier events when the synovium teemed with angry macrophages, T cells, and fibroblasts. In this scenario, the tenderness could represent the aftermath of damage. Maybe in RA, joints with erosion are chronically tender, just as joints with osteoarthritis—pock marked with cysts and encrusted with spurs—are tender even if the synovium in osteoarthritis shows only a scant smattering of synovial cells.
