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Difficulty: HardRheumatology and Immunology

Match each clinical scenario describing a medication adverse effect or monitoring requirement in a patient with a rheumatologic condition to the most likely responsible pharmacologic agent.

  • A 55-year-old woman with rheumatoid arthritis develops sudden, severe abdominal pain. Imaging reveals free intraperitoneal air indicating bowel perforation. She recently started a new biologic disease-modifying antirheumatic drug.Tocilizumab
  • A 32-year-old woman with severe lupus nephritis presents with painless gross hematuria. She has been receiving monthly intravenous infusions for her lupus. Cystoscopy reveals a bladder neoplasm.Cyclophosphamide
  • A 45-year-old man with ankylosing spondylitis develops a new-onset photosensitive malar rash, pleuritis, and positive anti-histone antibodies six months after starting a biologic therapy.Infliximab
  • A 29-year-old woman with rheumatoid arthritis desires pregnancy. She is currently taking a non-biologic DMARD that requires an accelerated elimination procedure with cholestyramine prior to conception.Leflunomide
  • A 38-year-old woman with systemic lupus erythematosus presents for her annual ophthalmologic screening, which includes spectral-domain optical coherence tomography to evaluate for maculopathy.Hydroxychloroquine

Answer

The scenarios match with Tocilizumab (bowel perforation), Cyclophosphamide (bladder neoplasm), Infliximab (drug-induced lupus), Leflunomide (cholestyramine washout), and Hydroxychloroquine (maculopathy screening).
Each rheumatologic medication carries a distinct side effect and monitoring profile. Tocilizumab (IL-6 inhibitor) increases the risk of bowel perforation. Cyclophosphamide causes urothelial toxicity (hemorrhagic cystitis, bladder cancer) via its metabolite acrolein. Infliximab (TNF-alpha inhibitor) is classically associated with drug-induced lupus. Leflunomide is teratogenic and undergoes enterohepatic circulation, requiring cholestyramine for rapid clearance. Hydroxychloroquine causes retinal toxicity requiring rigorous OCT or visual field screening.

Step-by-Step Solution

1
Analyze the first scenario featuring bowel perforation on a biologic.
Identify Tocilizumab (IL-6 inhibitor) as the most likely causative agent.
IL-6 inhibition is uniquely associated with lower gastrointestinal perforation compared to other biologics.
2
Analyze the second scenario featuring a bladder neoplasm after IV infusions for lupus.
Identify Cyclophosphamide as the causative agent.
Cyclophosphamide metabolism produces acrolein, which is highly toxic to the urothelium and oncogenic.
3
Analyze the third scenario featuring drug-induced lupus on a biologic.
Identify Infliximab (TNF-alpha inhibitor) as the causative agent.
Anti-TNF agents are the most common biologics implicated in drug-induced lupus.
4
Analyze the fourth scenario featuring a teratogenic DMARD requiring cholestyramine washout.
Identify Leflunomide as the responsible agent.
Leflunomide undergoes extensive enterohepatic circulation, and cholestyramine binds the drug in the gut to accelerate its elimination.
5
Analyze the fifth scenario featuring regular OCT screening for maculopathy.
Identify Hydroxychloroquine as the responsible agent.
Hydroxychloroquine binds to melanin in the retinal pigment epithelium, leading to dose-dependent, irreversible retinal toxicity.

Key Concept

Adverse effects and screening requirements of rheumatologic pharmacotherapy
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Topics

Rheumatology and Immunology

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