FEATURE ANAESTHESIOLOGY 063
ETIOLOGY Rheumatoid arthritis is a disease caused by autoimmune attack on synovial tissues throughout the body. The first phase is inflammation, which causes pain, swelling (synovitis) and can create joint effusion. The pain is often the symptom that leads the patient to seek medical attention and leads to the diagnosis. In juvenile rheumatoid arthritis, the effusion can be large, and subject to infection, a medical emergency. As the inflammation is sustained, there is progressive scarring, calcification, and reduced range of motion of the joint. When the inflammation is sustained, joint surface destruction, angulation, and/or fusion, depending on the structure of the joint, can occur.
PRESENTATION Rheumatoid arthritis is really two different diseases, depending on the age at onset. Juvenile rheumatoid arthritis (also known as Sill’s Disease) is typically identified in school-age children. The presentation is acute, with wide-spread, bilateral, symmetrical synovitis and systemic signs of inflammation (fever, chills, malaise). Airway involvement is uncommon. Fortunately, there are rarely indications for surgery unless coincident with another surgical diagnosis or unless a synovial effusion in a joint becomes infected. Also fortunately for these unlucky children, juvenile rheumatoid arthritis does not continue or evolve into adult rheumatoid arthritis in most cases. Adult rheumatoid arthritis (RA) is typically identified during the
third decade of life, during work up of sustained back or neck pain not explained by trauma. Work up confirms this diagnosis using lab studies and x-ray studies. The manifestation is often asymmetric, and some joints are involved more than others. The most common joint manifestations are ulnar deviation of the metacarpal-phalangeal joints or valgus deformity of the knee. There is clearly a genetic component, with a peak in incidence in Anglo-Saxon and Nordic backgrounds and a decreased incidence in the countries around the equator. There is also an environmental component, evident from the observation that age-matched individuals from the same ethnic origin will be more likely to develop RA if they live in an industrial setting compared to a rural setting.
INDICATIONS FOR SURGERY The most common indication for elective surgery in RA patients is lower extremity joint replacement, especially total knee replacement. Another common indication is lumbar decompression and fusion, related to mechanical deformity of the lumbar spine. Thoracic spine surgery is relatively uncommon related to RA, because involvement of the thoracic spine is uncommon as a consequence of RA. The cervical spine, on the other hand, is commonly affected and can present an indication for surgery for either decompression, stabilization, or both. One of the highest acuity procedures for RA patients is C2- Occiput fusion for atlanto- axial instability. Other indications include synovectomy and fusion for painful deformity, co-incident diseases and emergency procedures.
For whatever reason, the body identifies synovial surfaces as antigenic and the resultant autoimmune attack leads to destruction of the surface and deposition of nodular material. Virtually every joint in the body can be the target, although some joints are affected more than others, and the pattern is variable by individual. The consequences of the disease and its treatment can present preoperative issues.
R
heumatoid arthritis is an autoimmune disease of synovial membrane destruction that causes many patients to present for orthopaedic surgery or represent a significant co- morbidity in others requiring unrelated surgical procedures.
PRE-ANAESTHETIC PREPARATION ISSUES Several organ systems present issues for anaesthetic management which should be identified pre-operatively. The systems most significantly involved include the skin, respiratory system, cardiovascular system, spinal column, and the airway. The skin is involved from pathophysiology of RA and its treatment with steroids and/or anti-metabolites. The integrity of the skin is reduced and the tensile strength to sheer force is greatly reduced, placing the patient at risk for skin injury. Adhesive tape, automated blood pressure cuffs, and surgical positioning devices must be used
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