Rick is a 27-year-old who works in an accounting firm. He had started to experience lower back pain and stiffness that he thought were a result of the long hours he spent at his desk. More recently, however, he began to have sleep difficulties

Question

He found that he often woke up during the night feeling hot and sometimes sweaty. Furthermore, his back pain disrupted his sleep, particularly when it radiated around his pelvis and into his thighs. When his lack of sleep began to interfere with his work, he went to an osteopath to see what was wrong. She listened to his case history carefully. Upon physical examination, she noted a slight decrease in his lumbar lordosis and a reduced range of movement in his lumbar spine. His blood tests revealed the presence of HLA-B27, an elevated ESR, and absence of RH. His radiograph showed evidence of sacroiliitis.

What is the likely diagnosis Rick received? What are the common clinical presentation and manifestations of the disease?

Why is osteoarthritis of the hips a potential secondary complication of this disease? What are the structural changes that occur in the articular cartilage of an osteoarthritic joint?

What is the effect of advanced ankylosing spondylitis on lung function?

Answer 1

Rick is likely presenting with ankylosing spondylitis. His serum indicates the presence of HLA-B27, elevated ESR, and absence of RH, features typical of a seronegative spondyloarthropathy. Physically, his radiograph indicates an inflammatory process involving the sacroiliac joints. AS begins at the sacroiliac level and progresses up the spine, causing bony ankylosis of the vertebrae as it ascends. Rick is also experiencing the aching pain in the lumber spine with radiations into the hips and thighs. Typical of the pain pattern seen with ankylosing spondylitis, Rick is experiencing this pain with inactivity and during sleep. Finally, the sweating at night indicates the presence of fever, a systemic manifestation of this inflammatory condition.

Osteoarthritis of the hips is a potential complication of ankylosing spondylitis because of the abnormal weight-bearing forces that move through the hips when the spine is compromised. The mechanical wear and tear through the hips is what generates the osteoarthritic change. Initially the cartilage becomes edematous, and chondrocytes reorganize within the tissue. These preliminary changes alter the properties of the cartilage and microfractures develop. As synovial fluid penetrates these cracks, they become wider and deeper until they reach subchondral bone. The articular surface is rough, and cartilaginous fragments can become dislodged to float in the joint space.

As the disease progresses, there is a loss of the lumbar lordosis and the development of an exaggerated thoracic kyphosis. The kyphosis has a tendency to decrease thoracic movement and constrict lung tissue. Additionally, the costovertebral joints are affected so that rib excursion is reduced. This has the effect of reducing lung expansion and total capacity.