Rheumatoid arthritis (RA) affects ~ 1% of adults. Importantly, RA is is a systemic disease, affecting the skeletal system as well as the cardiac and pulmonary systems and often leading to a vasculitis. Patients on DMDs are at increased risk for infection.
Diagnosis is primarily clinical and notable for morning stiffness and metacarpophalangeal involvement (unlike OA which affects the distal interphalangeals). Rheumatoid factor is elevated in 90% of patients. CRP and ESR are elevated. Commonly used disease-modifying drugs (DMDs) include methotrexate, hydroxychloroquine, sulfasalazine, infliximab (Remicade), etanercept (Enbrel), and leflunomide (Arava, inhibits dihydroorotate dehydrogenase which is involved in pyrimidine synthesis), all of which are associated with an increased risk of infection. Patients may also be on NSAIDs and/or glucocorticoids.
Airway management can be challenging due to limited mandibular motion and mouth opening, a narrowed glottis, and cervical instability (subluxation, which is caused by ligamentous laxity, is present in almost 50%). According to Stoelting, “The most significant abnormality of the cervical spine is atlantoaxial subluxation and consequent separation of the atlanto-odontoid articulation. This deformity is best seen on a lateral radiograph of the neck. With the neck flexed, the separation of the anterior margin of the odontoid process from the posterior margin of the anterior arch of the atlas can exceed 3 mm. When this separation is severe, the odontoid process could protrude into the foramen magnum and exert pressure on the spinal cord or impair blood flow through the vertebral arteries” (Chapter 18). If flexion or awkward positioning is anticipated, preoperative imaging may be prudent. Range of neck motion should always be evaluated preoperatively by asking the patient to demonstrate head movement or positioning.
Cardiac pathology includes CAD, aortic regurgitation, conduction abnormalities, and pericardial effusion. Pulmonary complications include decreased thoracic mobility (restrictive lung disease), interstitial fibrosis, and pleural effusions. Vasculitis may lead to peripheral neuropathy and renal dysfunction (worsened by NSAIDs).
Anesthetic Considerations in RA (adapted from Table 70-3 in Miller)
- Airway: cervical instability, narrow glottis, limited TMJ. Consider awake FOB. Consider flex/ex/odontoid imaging. Preop ROM assessment
- Cardiac: pericarditis, tamponade, conduction abnormalities, AI is common
- Pulmonary: fibrosis, restrictive lung disease (thoracic restriction)
- Renal: chronic NSAID use (insufficiency)
- GI: chronic NSAID use (bleeding)
- Infectious: higher risk if on DMDs