Ankylosing Spondylitis - Imaging - USA

Ankylosing Spondylitis: 

Ankylosing Spondylitis Role of Imaging in Management and Diagnosis Created by: Andy Jaquay, SPT Catherine Rada, SPT Morgan White, SPT

General Description: 

General Description Ankylosing spondylitis also known as “ Marie- Strumpell disease, Bechterew ’ s disease, pelovospondylitis ossisficans and rheumatoid spondylitis ” is a chronic progressive spondyloarthritis. 1 The disease generally affects the synovial sacral joints and the joints of the spine and soft tissues, however other peripheral joints such as the hips, knees and shoulders can also be impacted. 1,2 Joints affected result in surrounding ossification known as “ boney ankylosis . ” 1

Incidence: 

Incidence Ankylosing Spondylitis is seen more commonly in males with a ratio of 7:1. 2 It affects a younger population. Age of onset is usually in the late teens, but can be as late as 30 years of age. 1,2 The etiology is unknown but 95-96% of patients with the disease tend to carry a histocompatibility antigen known as HLA-B27. The presence of this genetic marker can be used as a predisposing factor in diagnosis. 1,2

Pathogenesis: 

Pathogenesis Ankylosing Spondylitis attacks the entheses or tendon insertions and fibrosis and ossification of periarticular soft tissues, that later results in boney ankylosis of the joint. 1 It starts in the SI joints and slowly progresses in a superior fashion up the lumbar spine, and can affect the entire spine. 1 The spine becomes a thick rigid mass of bone resulting in the commonly described “ bamboo spine ” .1

Signs and Symptoms: 

Signs and Symptoms Patients present with a gradual onset of low back pain, often at night, that is not relieved by rest . Early on they may c/o pain at the insertion of tendo Achilles. The patent will often have pain and tenderness over the SI joint, and a present with a loss of lumbar lordosis. 1 As the disease progresses the affected become even more kyphotic, they may have trouble breathing due to decreased rib expansion, as well as difficulty walking especially if the hips are affected. 1 Patients may also demonstrate clinical features that are not joint specific such as pulmonary fibrosis, aortic incompetence, cardiac compression, anorexia and fatigue. 2

Diagnosis : 

Diagnosis Ankylosing Spondylisis is diagnosed using three items: Physical Evaluation Patient experience stiffness, pain, and decreased range of motion of the spine. 4 Patient may also complain of tenderness of the sacroiliac joints of the upper buttocks. 4 Blood Testing Identifying the presence of the genetic marker HLA-B27 in 20% of cases 3 Elevated erythrocyte sedimentation rate (ESR) and anemia 1 Radiographic Evidence Appears first as an abnormal narrowing of the upper half of the SI joint and subchondral cartilage. 1

Prognosis: 

Prognosis Approximately 2/3 of the cases will have a good prognosis Use of nonsteroidal anti-inflammatory drugs (NSAIDs), good postures, and daily exercise can help control the progression. 1 Poor prognostic indicators include peripheral joint involvement, young age of onset, elevated ESR, and poor response to NSAIDs. 5 Patients may develop cardiovascular disease, pulmonary fibrosis, cauda equina syndrome, or amyloidosis. 5

Role of Imaging: 

Role of Imaging Confirms Diagnosis Currently the standard radiograph is used to initially identify the disease formation. 1 Used to monitor the disease process Standard X-rays are the single most important imaging technique for disease progress monitoring. 1 CT scans is useful in selected situations and in the evaluation of complications. 6 MRI is useful in assessing early cartilage abnormalities and bone marrow edema. 7

Imaging: 

Imaging Standard radiographs, as mentioned previously, are the most frequently used imaging technique for determining the presence of ankylosing spondylitis . Radiographs will provide a visual image of the sacroiliac joint and surrounding subchondral cartilage. 1,8 The presence of decreased joint space near the sacroiliac joint will be present. 8 As the disease progresses fusion of the SI joint spaces will eventually occur. 8 A distinct "squaring-off" of the vertebral bodies will be seen as the disease progresses up the lumbar spine. 8 This gives the characteristic "bamboo spine" look seen in patients with ankylosing spondylitis . 8

Standard Radiograph: 

Standard Radiograph A: “ Squaring off ” of the lumbar vertabra B: Decreased joint space at the SI joint Note the bamboo spine appearance in this radiograph. This is characteristic in ankylosing spondylitis. 9

Imaging: 

Imaging Computed tomography is also used for diagnosing spondylitis. Shows degenerative changes at the sacroiliac joint indicated by narrowed joint spaces. Subchondral sclerosis is also detectable on CT. It shows up as bright areas near the joint line. Most commonly on the ilium at the sacroiliac joint.

Computed Tomography: 

Computed Tomography B: Decreased joint space at SI joint. A: Bright areas of subchondral sclerosis 10

Biomechanical and Physical Impairments: 

Biomechanical and Physical Impairments As mentioned previously, ankylosing spondylitis presents with numerous physiological and biomechanical impairments which will eventually lead to loss of function and increased pain. Increased pain in the low back as well as in the sacral sulcus due to decreased joint space and possible fusion of SI joint which eventually spreads cephalically. 1 Loss of lumbar lordosis with resulting in increased kyphosis . Increased kyphosis is secondary to decreased motion in the lumbar spine causing the patient to maintain a forward flexed posture. 1

Biomechanical and Physical Impairments: 

Biomechanical and Physical Impairments Decreased spine and hip range of motion due to decreased joint spaces and fusion of segments in the spine. Hip range of motion is often affected due to limited mobility of the innominate . As the disease progresses superiorly, the patient will have difficulty with respiration due to stiffness in the thoracic spine. 1 Overall, the patient will have limited mobility, decreased activity tolerance, and decreased quality of life due to the pain and difficulty with movement. 1,2

PowerPoint Presentation: 

Considering the postural changes and clinical manifestations of the disease, what would be an appropriate plan of care for this individual after initial diagnosis? You evaluated an adolescent male patient, and you are suspecting that he may have signs of Ankylosing Spondylitis . What pieces of evidence from your evaluation would you use to communicate your concerns to the physician?

References: 

References 1. Salter RB. Textbook of Disorders and Injuries of the Musculoskeletal System. Third edition. Baltimore, MD: Lippincott Williams & Wilkins;1999. 2. Greenspan A. Orthopedic Imaging: A Practical Approach . Fifth edition. Philadelphia, PA: Lippincott Williams & Wilkins; 2011. 3. Schlosstein L, Terasaki PI, Bluestone R, et al. High association of an HL-A antigen, W27, with ankylosing spondylitis. N Engl J Med . Apr 5 1973;288(14):704-6. 4. van der Linden S, van der Heijde D. Clinical aspects, outcome assessment, and management of ankylosing spondylitis and postenteric reactive arthritis. Curr Opin Rheumatol . Jul 2000;12(4):263-8 5. Braun J, Pincus T. Mortality, course of disease and prognosis of patients with ankylosing spondylitis. Clin Exp Rheumatol . Nov-Dec 2002;20(6 Suppl 28):S16-22

References: 

References 6. Tan S, Yao J, Ward MM, Yao L, Summers RM. Computer aided evaluation of ankylosing spondylitis using high-resolution CT. IEEE Trans Med Imaging . Sep 2008;27(9):1252-67 7. Jee WH, McCauley TR, Lee SH, et al. Sacroiliitis in patients with ankylosing spondylitis: association of MR findings with disease activity. Magn Reson Imaging . Feb 2004;22(2):245-50. 8. McKinnis LN, Fundamentals of Musculoskeletal Imaging: 3 rd Edition . Philadelphia: F.A. Davis Company; 2010. Available at: http://www.radswiki.net/main/images/thumb/d/d8/Ankylosing-spondylitis-001.jpg/350px-Ankylosing-spondylitis-001.jpg . Accessed February 9, 2012. Available at: http://www.bing.com/images/search?q=CT+of+ankylosing+spondylitis&view=detail&id=B098A0D0F3963235791EFB3FE6076EF766469EE9&first=0&FORM=IDFRIR . Accessed February 9, 2012.