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Rheumatoid Arthritis — SCE Rheumatology MCQ

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HardRheumatology EmergenciesRheumatoid ArthritisSCE Rheumatology

A 42-year-old woman with RA and cervical spine involvement undergoes pre-operative lateral cervical spine flexion-extension X-rays before elective surgery. The atlantodental interval (ADI) is measured at 7 mm. What does this indicate?

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Correct answer: B — Atlantoaxial instability requiring cervical specialist assessment before anaesthesia

The best answer is “Atlantoaxial instability requiring cervical specialist assessment before anaesthesia”. An atlantodental interval (ADI) >3 mm in adults (>5 mm on flexion views) indicates atlantoaxial subluxation, a serious complication of RA affecting the cervical spine. With an ADI of 7 mm, neurosurgical assessment is required, particularly before intubation for general anaesthesia as forced neck extension can cause spinal cord compression. All RA patients undergoing general anaesthesia should have cervical spine assessment. Posterior atlantodental interval (PADI) <14 mm indicates cord compression risk. The competing options represent related diagnoses, tests or treatments, but they do not match the decisive phenotype, safety constraint or management point in this stem.

Reference: NICE NG100 rheumatoid arthritis recommendations: https://www.nice.org.uk/guidance/ng100/chapter/Recommendations