A 34-year-old man comes to the office due to progressive low back pain for several years. The patient reports that the stiffness and pain are worst in the morning but gradually improve during the day. Lately, he has been taking over-the-counter ibuprofen, which provides some relief. Laboratory evaluation shows a positive HLA-B27 antigen. X-ray imaging reveals fusion of the sacroiliac joints. Which of the following is most helpful to monitor disease progression in this patient?

Question

A 34-year-old man comes to the office due to progressive low back pain for several years.  The patient reports that the stiffness and pain are worst in the morning but gradually improve during the day.  Lately, he has been taking over-the-counter ibuprofen, which provides some relief.  Laboratory evaluation shows a positive HLA-B27 antigen.  X-ray imaging reveals fusion of the sacroiliac joints.  Which of the following is most helpful to monitor disease progression in this patient?

Quizplus · Accepted Answer

11ec160b_3b61_5ad0_9249_d3ee89247b44_MD0001_00 The symptoms of low back pain and morning stiffness in a young man suggest ankylosing spondylitis (AS), a chronic inflammatory condition associated with the HLA-B27 serotype. AS is characterized by stiffness and fusion (ankylosis) of the axial joints. The sacroiliac and apophyseal joints of the spine are the most commonly affected, leading to restricted spinal mobility. Many patients also develop peripheral arthritis and enthesitis, which is defined as pain, tenderness, and swelling at the sites of tendon insertion into bone (eg, Achilles tendon insertion). In addition, AS can cause complications in extraskeletal systems: (Choice B) Hand joint mobility testing is part of the assessment of rheumatoid arthritis severity. However, the small joints of the hands are not prominently affected by AS. (Choice C) Peak expiratory flow is determined by airway resistance (obstruction) and chest and abdominal wall muscular function. These variables are not affected by chest wall restriction and are normal in AS. Regular measurement of expiratory flow rates is important in patients with asthma. (Choice D) Rheumatoid factor can be found in a variety of rheumatic (eg, rheumatoid arthritis, Sjögren's syndrome, systemic lupus erythematosus [SLE]) and nonrheumatic disorders (eg, hepatitis C) and in up to 4% of young and healthy individuals. However, it is not associated with AS. (Choice E) Urine protein excretion should be monitored in SLE and diabetes mellitus. Renal involvement is rare in AS. Educational objective: Ankylosing spondylitis is characterized by stiffness and fusion of axial joints (ankylosis) and inflammation at the site of insertion of tendons into bone (enthesitis). Involvement of the thoracic spine and costovertebral and costosternal junctions can limit chest wall expansion, leading to hypoventilation. __________ References: Restrictive pulmonary function is more prevalent in patients with ankylosing spondylitis than in matched population controls and is associated with impaired spinal mobility: a comparative study. (http://www.ncbi.nlm.nih.gov/pubmed/22277377)

A 34-Year-Old Man Comes to the Office Due to Progressive