01.21.2014
Rheuminations: A Cautionary Tale
by Nancy Walsh
Staff Writer, MedPage Today
A case report recently published in Pediatric Rheumatology offers a lesson in how physicians need to broaden their diagnostic thinking as girth across all patient age groups also broadens.
A 15-year-old Hispanic boy was seen in the orthopedic surgery department for pain in his right ankle that had begun a year earlier after a sports injury. He had been taking ibuprofen and seeing a physical therapist, according to Andrew J. White, MD, of Washington University School of Medicine in St. Louis, and colleagues.
His body mass index was 47.4 kg/m2, and vital signs were normal.
X-rays of the ankle revealed a healed lesion presumed to be osteochondritis dissecans, and the treating clinician advised the boy to continue with therapy.
Several months later he presented again, this time with pain in his left shoulder and limited range of motion. An MRI showed localized inflammation and synovitis, suggesting the possibility of juvenile idiopathic arthritis (JIA), so the boy was referred to the rheumatology clinic for consultation.
He reported pain and stiffness in the right elbow and wrist, several finger joints, and the left knee. The pain had been present daily for a few weeks and then would disappear, only to recur after several weeks.
His rheumatoid factor was elevated at 24.7 IV/mL, his anti-cyclic citrullinated peptide (CCP) antibody test was positive, his C-reactive protein was high at 6.7 mg/dL, and the erythrocyte sedimentation rate was 61 mm/h.
With a presumptive diagnosis of early-onset rheumatoid arthritis or rheumatoid factor-positive JIA, the patient was started on methotrexate and naproxen.
He returned to the clinic 2.5 months later, and although some of his joints were no longer painful, his right ankle was still very tender and swollen, and he was using crutches. Twice weekly etanercept (Enbrel) was started, with no relief, and he subsequently was switched to adalimumab (Humira) and eventually to rituximab (Rituxan).
Through the year of treatment with the biologics he continued to experience ankle pain, so arthroscopy with synovectomy was done, revealing the presence of a “crystalline white substance” in the joint that the surgeons suggested was debris from an earlier steroid injection (which had never happened).
The crystalline substance was removed but not sent for pathologic analysis.
Ultimately he was being treated with etanercept, methotrexate, sulfasalazine, naproxen, and prednisone, which adequately controlled his JIA symptoms, except for the right ankle.
After 2.5 years of diagnostic efforts, the patient also had developed nodules in his elbows, forearms, and knee, which were thought to be rheumatoid nodules. But 4 months later, he happened to notice that the ankle pain worsened after he’d eaten a meal of red meat.
That was the clue. A uric acid level was obtained, which was “extremely elevated at 13.3 mg/dL” (the usual cutoff for hyperuricemia is 6.8), and the nodules were “consistent with tophi, virtually pathognomonic for gout.”
Many patients have reported triggers such as red meat consumption for attacks of gout. Treatment with colchicine followed by allopurinol led to some improvement, and he continued to receive therapy for both JIA and gout.
“There were several missed opportunities to diagnose this patient earlier in his course,” the authors noted, pointing out that gout wasn’t included in the differential because it’s usually considered a disease of older people. Another important oversight was failure to send the crystal substance removed from the joint for analysis. The intermittent pattern of symptoms was an additional hint.
“As the epidemic of childhood obesity grows, adult conditions usually a result of long-term lifestyle consequences are being seen more frequently in the pediatric population, most notably type 2 diabetes but also musculoskeletal complaints and, as in this case, gout,” they wrote.