A 38-year-old woman comes to the office due to abdominal pain. For the last 2-3 weeks, she has had increasingly severe abdominal pain associated with watery diarrhea. The patient has a history of Crohn disease treated for the last year with adalimumab, which has controlled the symptoms until now. Vital signs are normal except for a temperature of 37.8 C (100 F). Examination shows moderate tenderness in the right lower quadrant with no peritoneal signs. Laboratory results show an undetectable trough adalimumab level. Which of the following is the most likely explanation for this patient's worsening symptoms?

Question

A 38-year-old woman comes to the office due to abdominal pain.  For the last 2-3 weeks, she has had increasingly severe abdominal pain associated with watery diarrhea.  The patient has a history of Crohn disease treated for the last year with adalimumab, which has controlled the symptoms until now.  Vital signs are normal except for a temperature of 37.8 C (100 F).  Examination shows moderate tenderness in the right lower quadrant with no peritoneal signs.  Laboratory results show an undetectable trough adalimumab level.  Which of the following is the most likely explanation for this patient's worsening symptoms?

Quizplus · Accepted Answer

Eductional Objective: Adalimumab is a recombinant human IgG that binds tumor necrosis factor-alpha (TNF-alpha).  Antidrug antibodies can develop against adalimumab (or other immunoglobulin-based anti-TNF agents) that can block its interaction with TNF-alpha, preventing the drug from functioning and leading to more rapid drug clearance.

A 38-Year-Old Woman Comes to the Office Due to Abdominal