Ankylosing Spondylitis (AS)

(see also: Spondyloarthropathies)

Discussion

• affects young men (ages 15 to 25 years), but may also begin in middle-aged men;
  • disease is often more severe when it occurs early in life;
• disease characterized by insidious onset of pain and stiffness in lower back associated w/ gradual loss of spinal mobility;
• illness may cause inflammation in uveal tract (iritis in 25%) & in intima of aorta;
• symptoms are typically worse in the morning and in the middle of the night;
• note: that in women, the symptoms of ankylosing spondylitis often first present during pregnancy;
• labs: HLA-B27 (may be present in up to 8% of unaffected white population);
  • may also be present in Reiter's syndrome;

Spine in Ankylosing Spondylitis »

• disorder has a tendency to progress slowly, w/ diminished mobility of the spine and sacroiliac joints;
• early diagnosis can often be made with a CT scan of the sacroiliac joints;
• cervical spine in ankylosing spondylitis:
  • acute neck pain in pt w/ AS is usually caused by frx thru ankylosed spine;
  • frx involves all columns & may be assoc w/ dramatic change in neck alignment;

reference: Uncommon Complication After Revision Hip Surgery

Peripheral Arthritis

• may involve hips, knees, ankles, toes, (rare upper extremities).
• these may precede the back pain by several years;
• arthritis is acutely painful but rarely chronic or destructive;

hip joint

• is affected in up to 50 % of patients with AS, and when it occurs it is often bilateral;
• protrusio and hip flexion contractures are common;
• heterotopic ossification may follow THR;
• total hip replacement:
  • hetertopic ossification of the hip;
    • occurs in 20-40 % of hip replacements and is more common w/ trochanteric osteotomy;
  • to avoid heterotopic ossification consider insertion of a cemented acetabular component followed by 750 rads around the component;

Childhood AS

• AS may develop in children & resembles pauciarticular JRA;
• usually boys over 8 years of age
• asymmetric peripheral arthritis of lower extremities.
• must be differentiated from DISH;

Management

• NSAIDS: patients should be placed on indocin as soon as the diagnosis is made;
• tumor necrosis factor inhibitors:
  • reference: Treatment of Ankylosing Spondylitis by Inhibition of Tumor Necrosis Factor
• sulfasalazine:
  • may attenuate the inflammatory exacerbations;
    • effect starts within the first 2 to 3 months;
    • dose can be gradually decreased after 6 months, and then slowly stopped;
    • begin with full dose (2 g/day) or start with 500 mg/day weekly increasing the dose to 1 g/bid;
    • dose can be increased up to 3 g/day;
  • less effective in chronic cases

References

• Disorders of the sacro-iliac joint in children.
• Total hip replacement for patients who have ankylosing spondylitis. The importance of the formation of heterotopic bone and of the durability of fixation of cemented components.
• The Shoulder Girdle in Ankylosing Spondylitis.
• Ankylosing spondylitis: experience in surgical management of 21 patients
• The clinical spectrum of ankylosing spondylitis.
• Long term results of total hip replacement in young patients who had ankylosing spondylitis. Eighteen to thirty-year results with survivorship analysis.