AMSTERDAM, The Netherlands – Clinical and laboratory findings tend to be unhelpful in distinguishing between rheumatoid arthritis (RA) and polymyalgia rheumatica (PMR) in the elderly. Instead, the symmetric involvement of peripheral joints and the rapid response to low-dose oral corticosteroid therapy should be considered key diagnostic features of PMR, Carlo Salvarani, MD, from Reggio Emilia, Italy, told the 2006 EULAR meeting.1

PMR, one of the most frequent inflammatory conditions affecting the elderly, is characterized by "severe pain and stiffness in the neck, shoulder, and pelvic girdle, which is worse in the morning," and a rapid response to oral steroids.

"Anti-CCP, widely seen as the gold standard test in distinguishing between RA and PMR in the elderly, has proved far less promising than we expected it would be."  —Carlo Salvarani, MD
In the last few years, the anti-cyclic citrullinated peptide (anti-CCP) antibody has been considered to be a sensitive marker of the very intense inflammation in PMR. "It has been widely seen as the gold standard test in distinguishing between RA and PMR," Dr. Salvarani said. "The truth is, however, that this blood test has proved far less promising than we expected it would be."

Instead, clinicians should rely on observing bilateral bursitis, particularly in the shoulders and hips. "MRI scans of patients with PMR show a fusing of the bursa in the long bicep tendon in 100% of patients with PMR compared with 30% of patients with RA," he told the meeting. "There is an overlap of around 10% between RA and PMR patients. But this symmetric shoulder or hip pain that radiates distally and is most apparent in the morning is one of the most prominent features of PMR."

The meeting also heard a novel explanation of why PMR patients respond so quickly to corticosteroids. Maurizio Cutolo, MD, of the University of Genoa, Italy, said that the treatment could best be understood as steroid replacement therapy.2

"PMR is at least partly caused by age-related damage to the nervous and endocrine system, due to an age-related decrease in gonadal and adrenal hormones. It may also be caused by chronic stress in the elderly as a result of interpersonal relationships, psychosocial stressors, and variables such as coping and personality," Dr. Cutolo said. "Chronic systemic inflammatory stimuli such as chronic infections may also play a part. As a result, the adrenal gland activity is insufficient in PMR. Steroids do not simply act to damp down inflammation, they act as a replacement therapy, which explains why they work so well and so quickly."

And when should PMR patients take their medication? Dr. Cutolo said that cortisol levels were lowest at 3:00 to 4:00 in the morning. "That is why most people wake up feeling stiff and with aching joints. It makes sense therefore to take corticosteroids either very late at night or very early in the morning—this way, the steroids have a better effect and the dosage may be reduced," he said.

When pressed to advise between taking steroids late at night or early in the morning, Dr. Cutolo opted for the latter. "Steroids can interfere with melatonin production and therefore may interfere with sleep if taken in the evening," he said.

References

  1. Salvarani, C. Distinguishing rheumatoid arthritis from polymyalgia rheumatica in the elderly. Presented at: 2006 EULAR meeting; June 21–24 2006; Amsterdam, the Netherlands.
  2. Cutolo M, et al. Polymyalgia rheumatica versus elderly-onset rheumatoid arthritis. Presented at: 2006 EULAR meeting; June 21–24 2006; Amsterdam, the Netherlands. Abstract SP0074.