A 20-year-old woman comes to the office due to atraumatic heel pain over the last week. For the past 6-8 months, the patient has also experienced bilateral hip pain that has progressively worsened and now awakens her during the early-morning hours. When this occurs, she gets up and walks around for a few minutes before going back to sleep. The patient also has difficulty tying her shoelaces in the morning due to back pain and stiffness; however, she does not feel limited when performing other daytime activities. She has tried over-the-counter pain medications and found ibuprofen to be more effective than acetaminophen. A year ago, she had an episode of intense pain, photophobia, and redness involving her left eye, which improved with corticosteroid eye drops. The patient also occasionally has mouth ulcers, usually around the time of her menstrual periods. Family history is significant for breast cancer in her mother and multiple sclerosis in her aunt. The patient does not use tobacco, alcohol, or illicit drugs. She is sexually active and uses oral contraceptives for birth control.
Vital signs are normal. The oral mucosa is moist with mild tonsillar swelling, but there are no ulcers or other lesions. There is tenderness and swelling of the heel, as shown in the exhibit. Examination of the ankle and other joints shows no synovitis or effusion. Flexion and external rotation of the hip joints elicits intense pain at the gluteal region.
Laboratory results are as follows:
Which of the following is the best next step in evaluation of this patient's condition?

Question

A 20-year-old woman comes to the office due to atraumatic heel pain over the last week.  For the past 6-8 months, the patient has also experienced bilateral hip pain that has progressively worsened and now awakens her during the early-morning hours.  When this occurs, she gets up and walks around for a few minutes before going back to sleep.  The patient also has difficulty tying her shoelaces in the morning due to back pain and stiffness; however, she does not feel limited when performing other daytime activities.  She has tried over-the-counter pain medications and found ibuprofen to be more effective than acetaminophen.  A year ago, she had an episode of intense pain, photophobia, and redness involving her left eye, which improved with corticosteroid eye drops.  The patient also occasionally has mouth ulcers, usually around the time of her menstrual periods.  Family history is significant for breast cancer in her mother and multiple sclerosis in her aunt.  The patient does not use tobacco, alcohol, or illicit drugs.  She is sexually active and uses oral contraceptives for birth control.
Vital signs are normal.  The oral mucosa is moist with mild tonsillar swelling, but there are no ulcers or other lesions.  There is tenderness and swelling of the heel, as shown in the exhibit.  Examination of the ankle and other joints shows no synovitis or effusion.  Flexion and external rotation of the hip joints elicits intense pain at the gluteal region.
Laboratory results are as follows:
 Which of the following is the best next step in evaluation of this patient's condition?

Quizplus · Accepted Answer

11ec193a_991f_5ddf_853d_b52789bd0b90_MD0002_00 Enthesitis is characterized by swelling, tenderness, and pain at tendon insertion sites (eg, Achilles tendon at the heel, costosternal junction, shoulders, elbows, hips, iliac crests, tibial tuberosities). Enthesitis may occur as an isolated disorder (eg, plantar fasciitis) but is a characteristic finding in the spondyloarthropathies (eg, ankylosing spondylitis [AS], psoriatic arthritis, reactive arthritis). This patient has features suggesting AS, including enthesitis at the heel and hips, inflammatory back pain (ie, insidious onset, stiffness, worse in the morning/with rest), and possible uveitis. The incidence of AS is highest at age 20-30. Examination often shows decreases in chest expansion (<2 cm expansion with inspiration suggests AS), cervical extension, and lumbar flexion. Dactylitis and peripheral joint synovitis are also possible. An anteroposterior x-ray of the pelvis revealing arthritis and erosions of the sacroiliac joints can confirm the diagnosis in most patients. Inflammatory markers (eg, C-reactive protein) are commonly elevated. HLA-B27 is positive in most patients and correlates with aggressive disease. Initial treatment includes nonsteroidal anti-inflammatory drugs and range-of-motion exercises. (Choice A) Enthesitis can occur in patients with systemic lupus erythematosus, but synovitis is more common. In addition, this patient does not have more characteristic findings of lupus (eg, malar rash, anemia); therefore, anti-double-stranded DNA antibody testing is not indicated. (Choice B) Disseminated gonococcal infection presents as purulent monoarthritis or a triad of tenosynovitis, dermatitis, and migratory polyarthralgias. Reactive arthritis is a spondyloarthropathy that resembles AS with inflammatory back pain, enthesitis, and peripheral arthritis but more commonly follows nongonococcal (eg, Chlamydia trachomatis) rather than gonococcal urethritis. (Choice C) Sarcoidosis can cause uveitis and arthritis of the ankle and knee joints, but enthesitis and inflammatory back pain are uncommon. Chest x-ray to evaluate for hilar adenopathy is not needed. (Choice D) Pathergy testing (formation of an inflammatory papule following insertion of a sterile needle into the skin) is useful for diagnosing Behçet disease. This disorder causes aphthous ulcers, uveitis, and genital ulcers but does not typically cause inflammatory back pain. Aphthous ulcers are a common, nonspecific finding often seen in association with menstrual periods and/or stress. Educational objective: Common manifestations of ankylosing spondylitis include enthesitis, inflammatory back pain, and uveitis. Examination shows decreases in chest expansion, cervical extension, and lumbar flexion. An anteroposterior x-ray of the pelvis can confirm the diagnosis, and HLA-B27 is usually positive. Initial treatment includes nonsteroidal anti-inflammatory drugs and range-of-motion exercises. __________ References: Early diagnosis crucial in ankylosing spondylitis. (http://www.ncbi.nlm.nih.gov/pubmed/22272527) Spondyloarthritis in women: differences in disease onset, clinical presentation, and Bath Ankylosing Spondylitis Disease Activity and Functional indices (BASDAI and BASFI) between men and women with spondyloarthritides. (http://www.ncbi.nlm.nih.gov/pubmed/20882310)

A 20-Year-Old Woman Comes to the Office Due to Atraumatic