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Difficulty: Very hardRheumatology and Immunology

Match each clinical scenario describing a patient undergoing pharmacotherapy for a rheumatologic condition to the critical screening, prophylaxis, or adverse effect monitoring mandated by their specific medication.

  • A 55-year-old woman with severe, tophaceous gout refractory to standard urate-lowering therapies is scheduled to begin intravenous infusions of pegloticase.Requires mandatory pre-treatment screening for Glucose-6-phosphate dehydrogenase (G6PD) deficiency to prevent severe hemolytic anemia and methemoglobinemia.
  • A 62-year-old man with rheumatoid arthritis has an inadequate response to methotrexate and is initiated on tofacitinib, an oral Janus kinase (JAK) inhibitor.Requires close monitoring for herpes zoster reactivation and assessment for venous thromboembolic and major adverse cardiovascular events prior to initiation.
  • A 28-year-old woman with severe systemic lupus erythematosus and biopsy-proven class IV lupus nephritis is being induced with intravenous cyclophosphamide.Requires co-administration of 2-mercaptoethanesulfonate (mesna) and vigorous hydration to neutralize the toxic urinary metabolite acrolein and prevent hemorrhagic cystitis.
  • A 35-year-old man with ankylosing spondylitis is preparing to start infliximab, a chimeric monoclonal antibody directed against tumor necrosis factor-alpha.Requires pre-treatment screening with an interferon-gamma release assay (IGRA) or tuberculin skin test to prevent reactivation of latent tuberculosis due to granuloma destabilization.
  • A 45-year-old woman with seropositive rheumatoid arthritis is preparing to receive rituximab, a B-lymphocyte depleting agent, after failing multiple other therapies.Requires mandatory pre-treatment screening for Hepatitis B surface antigen (HBsAg) and core antibody (anti-HBc) to prevent fulminant viral reactivation and hepatic failure.

Answer

Pegloticase requires G6PD screening; Tofacitinib requires monitoring for cardiovascular events/thrombosis and herpes zoster; Cyclophosphamide requires Mesna prophylaxis for acrolein toxicity; Infliximab requires latent TB screening; Rituximab requires Hepatitis B screening.
Each immunosuppressive or immunomodulatory medication has a unique toxicity profile dictated by its mechanism of action. TNF inhibitors disrupt granulomas (TB risk). Rituximab depletes B-cells (HBV risk). Cyclophosphamide produces acrolein (bladder toxicity needing mesna). Pegloticase causes oxidative stress (hemolysis in G6PD deficiency). JAK inhibitors carry distinct risks for thrombosis and herpes zoster reactivation.

Step-by-Step Solution

1
Analyze the mechanism of action of pegloticase in gout management.
Pegloticase generates oxidative stress via hydrogen peroxide production, linking it to the need for G6PD deficiency screening.
G6PD deficient red blood cells cannot process oxidative stress, leading to hemolysis and methemoglobinemia.
2
Evaluate the specific boxed warnings associated with JAK inhibitors like tofacitinib.
JAK inhibitors are uniquely associated with increased risks of herpes zoster, venous thromboembolism (VTE), and major adverse cardiovascular events (MACE).
These specific adverse effects dictate pre-treatment cardiovascular risk stratification and zoster vaccination.
3
Recall the metabolism and target-organ toxicity of cyclophosphamide.
It metabolizes to acrolein, which concentrates in the bladder. Mesna acts as the specific antidote.
Mesna provides sulfhydryl groups that bind acrolein in the urinary tract, preventing hemorrhagic cystitis.
4
Identify the critical role of TNF-alpha in host immune defense.
TNF-alpha maintains granulomas; its inhibition by infliximab destabilizes them, risking tuberculosis reactivation.
Screening via IGRA or PPD is mandatory before initiating any TNF-alpha inhibitor.
5
Determine the unique infectious risks of severe B-cell depletion with rituximab.
Loss of antibody-mediated immunity drastically increases the risk of Hepatitis B reactivation.
Universal screening for HBsAg and anti-HBc is mandated prior to rituximab therapy to prevent fulminant hepatitis.

Key Concept

Essential pre-treatment screening, prophylaxis, and monitoring for targeted disease-modifying therapies in rheumatology.
Estimated Time:2m 30s
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Topics

Rheumatology and Immunology

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