Rheumatologists distinguish themselves from their medical colleagues in several ways: exceptional joint exam and joint injection skills, interpretation of complex immunologic findings and cost-efficient ways of managing common musculoskeletal disorders. But what’s the one trait, skill or question that defines the acumen of the rheumatologist? Please don’t say morning stiffness.
Yesterday, I was referred a 25 year old young woman with chronic back pain for 7 years. She had been worked up by a very reliable orthopedic spine specialist, who after an evaluation, exam and MRI,told her she had unilateral sacroiliitis although she had a negative MRI of her lumbosacral spine.
Low back pain is her only complaint. Her survey form said she had 15 minutes of morning stiffness. But upon further questioning, she said it’s sometimes as long as 1-2 hours of morning stiffness “but it depends”. Depends on how late she works, how good/bad her sleep is, how her morning goes. So, it’s somewhere between 15 and 120 minutes and not necessarily improved by activity. Clearly I’m trying to assess the likelihood of spondyloarthritis and hanging my initial impressions on if she has inflammatory back pain. I’m left without an answer and will await her SI X-rays, lab tests and HLA-B27.
But this is not the first time “morning stiffness” has let me down. In patients with OA, FM, lupus, RA and PsA, the morning stiffness durations were 60, 45, 15, 30 and 15 minutes respectively. And all of these patients were doing well and without other signs of inflammation.
Once while visiting Dr. Fred Wolfe in Wichita, I remarked about the inaccuracies of the AM stiffness (AMS) quantification; he responded by stating his studies showed stiffness severity and not the duration in minutes or hour (http://buff.ly/285SjeK). Thereafter, I changed my patient intake forms, removing the AMS time duration, and replaced it with a 0-10cm visual analogue scale for AMS severity. Although not formally or statistically studied, I was left unimpressed with the same view that AMS, no matter how measured, seldom revealed diagnostic information and had little specificity for inflammatory disease.
While AMS may be a useful serial measure to gauge improvement, it would be one amongst many I follow (TJC, SJC, Patient Global, CDAI, GAS, ESR, CRP, etc.), also making it almost irrelevant.
There’s an additional problem with “morning stiffness”. Despite how the question is posed, many patients are unable to distinguish between stiffness and pain and soreness and aching, etc. While it should be different between morning and daytime/evening stiffness – patients can’t confirm or fathom the difference. I would guestimate that somewhere between 20-40% of my patients don’t understand the difference and I’m left to interpret what they report. This only goes well when I’m wearing my Buster Brown Decoder ring.
But how does AMS perform in other inflammatory and noninflammatory articular disorders?
Osteoarthritis & AM stiffness. AMS is a very frequently reported symptom in patients with focal or polyarticular osteoarthritis (OA) or those with degenerative and inflammatory low back pain. The magnitude or severity may be different from those with RA and other inflammatory disorders, but the overlap is considerable. OA clinical trials have used AMS as an outcome measure and therapeutic success usually notes the significant improvement in AMS with the study drug. With degenerative diseases far outweighing the prevalence of inflammatory disorders, findings of significant AMS is more likely to indicate a degenerative than inflammatory etiology.
Rheumatoid arthritis & AM stiffness. Van Tuyl et al undertook a systematic review of AMS in RA patients with low disease activity and found that among 788 studies only two reported validity of stiffness measures within low disease activity (http://buff.ly/1t4kgDM). One study found that among RA patients in remission, 16% still had AMS >30 minutes and half of these were >60 minutes. They concluded that severity of AMS (not duration) may discriminate better between high and low disease activity. Numerous studies have shown AMS to be a poor to modest discriminator between inflammatory and noninflammatory disease. (http://buff.ly/1t4kmv9 http://buff.ly/1UiJELY)
Fibromyalgia & AM stiffness. Up to 90% of all fibromyalgia (FM) will report significant AMS (>30 min) as a troublesome and continuing feature. The range of AMS severity in this condition has no correlates with other inflammatory indices. The 5:1 prevalence of FM: RA, frequency and magnitude of AMS thereby negates the discriminatory value of AMS in routine clinical assessments.
Polymyalgia rheumatica & AM stiffness. Every criteria ever developed for PMR has included an AMS >45 minutes as a key criterion, the strength of evidence usually being high. The correlations with other clinical parameters and biologic measures have also been strong. Thus, AMS is a clinically important, if not critical, measure in the diagnosis and management of PMR. While my objections on AMS are quieted in the PMR arena, it should be noted that AMS determinations done by rheumatologists do perform very well here. I doubt AMS would perform as well by non-rheumatologists.
Thus, other than the patient with PMR or GCA, I have a hard time hanging my clinical judgments on AMS when so many other clinical or laboratory measures of inflammation exist.
Do, I measure AMS in every patient? The answer is yes, but for 30 years I keep wondering if this makes me a better clinician with more certain diagnoses.