Makindo Medical Notes.com

Related Subjects: |Monoarticular arthritis |Polyarticular arthritis |Seronegative Spondyloarthropathies |Ankylosing spondylitis |Enteropathic Spondyloarthritis |Reactive Arthritis |Psoriatic Arthritis

Chronic progressive inflammatory disease of the axial skeleton with a loss of lumbar lordosis and increased kyphosis and sacroiliitis which may affect other joints

About

• Seronegative Spondylarthritis (Rheumatoid factor negative)
• Causes lower back pain and progressive stiffness
• Age 15-40 years affects predominantly Males (M > F 4:1)
• Inflammatory spine pain ascends from sacroiliac joints

Pathology

• There is a gradual fusion of the spine (ankylosis)
• Restriction of movement in three planes
• There is also deterioration of chest expansion and inflammatory back pain

Aetiology

• Strong linkage with HLA B27 in over 90% of cases
• Suggested infectious component or trigger - e.g. Klebsiella

Condition and Incidence of HLAB27 and disease

• Caucasions 8 %
• Ankylosing spondylitis 90%
• Reiters syndrome 70%
• Enteropathic 50%
• Psoriatic arthritis 20%
• Psoriasis and Sacroiliitis 50%

Clinical: spinal

• Classically a young male with lower back pain
• Associated with morning stiffness > 1 hour
• Pain and stiffness improve with activity
• Progressive restriction of spinal movement.
• Loss of lumbar lordosis and increased kyphosis
• Eventually kyphosis with question mark posture
• Alternating Buttock pain suggests sacroiliitis
• Spinal - Fractures and Cauda equina and Cord compression syndromes
• Spinal rigidity makes them more prone to spinal fractures

Clinical Extra articular

• Cardiac - Aortitis, Aortic Regurgitation and Conduction defects
• Pulmonary - Apical fibrosis and restrictive lung pattern
• Eye - iritis (Acute anterior uveitis is the most typical extra-articular complication)
• Rarely asymmetrical peripheral arthritis - hip, shoulders
• Plantar fasciitis and Achilles tendonitis
• Secondary amyloidosis (AA) is rare

Aide-Memoire - the 9 A's

• Ankylosis of spine, Acute anterior uveitis
• Amyloidosis, Aortic incompetence, Aortitis
• AV Block, Apical fibrosis, Achilles tendonitis
• Anti-TNF alpha therapy

Formal Examination to demonstrate restricted spinal movements

• There is limited flexion and extension as well as lateral flexion and rotation. These can be assessed clinically.
• Modified Schober test - Ventral: with the patient standing upright, a line is drawn across the lumbar spine connecting the two posterior superior iliac spines. Marks are made in the midline over the spine 10 cm cranial and 5 cm caudal to this horizontal line. The patient then bends with legs straight and the distance is measured again. It normally increases by more than 3 cm.
• Lateral: the distance between the longest fingertip and the floor is measured in the upright position. This is repeated when the patient tries to flex laterally towards the ground as far as possible, normally moving by more than 10 cm.
• Thoracic excursion. The circumference of the thorax is measured in the fourth intercostal space after maximal inspiration and expiration. It normally alters by more than 3 cm.
• Occiput to wall distance. In the upright position, the patient leans back against a wall and should normally be able to touch the wall with their occiput.
• Chin to sternum distance. The chin is maximally bent towards the sternum, and should normally be able to touch it.
• Cervical rotation. The head is rotated to the left and right sides, with the angles of rotation measured (normally more than 50 degrees).
• Intermalleolar distance. The patient tries to stand with their feet together: the malleoli should normally touch.

Schober test

Investigations

• FBC - anaemia due to NSAID or AOC
• Elevated ESR / CRP in some cases
• RF and other autoantibodies classically negative
• CXR - apical fibrosis and ECG - conduction defects
• Lung function tests - restrictive pattern
• HLA-B27 testing not needed for diagnosis
• Echocardiogram - if aortic incompetence suspected
• Radiology: AP and lateral of the spine can show Bamboo spine - due to fusion of syndesmophyte which is a bony outgrowth that grows cranially from the ligament attachment point of the vertebra which can become squared below to fuse into the vertebrae above. In later stages, there is calcification of the anterior and lateral spinal ligaments and formation of a "bamboo" spine. Sacroiliac joints - the blurring of the joint margin, later erosions, sclerosis and fusion at the sacroiliac joint
• MRI shows sacroiliitis earlier than plain X-ray.

Spinal X ray showing areas of fusion

Differential of causes of sacroiliitis

• Ankylosing spondylitis, Reiter's syndrome
• Enteropathic arthropathy (with inflammatory bowel disease)
• Psoriatic arthropathy

Management

• Regular daily exercises and physical therapy and regular exercises to improve back flexibility and posture and spinal mobility
• NSAIDs - can reduce symptoms. Classically Indomethacin 75 mg OD
• Sulfasalazine 2-3 g/day is more effective for peripheral arthropathy. Methotrexate is also useful but mainly helps any peripheral arthritis.
• TNF-α-blocking drugs: highly effective managing both spinal and peripheral joint inflammation and in doing so improve function and quality of life. Does not reduce bony progression. Expensive. See Rheumatoid Arthritis.

References

• ANKYLOSING SPONDYLITIS: A REVIEW Farrouq Mahmood, Philip Helliwell