American Board of Internal Medicine (ABIM) Certification Practice Exam

What condition is associated with persistent symptoms of fever lasting more than 72 hours, necessitating imaging?

1. Acute cystitis

2. Pyelonephritis

3. Kidney stones

4. Urinary tract infection

The correct answer is: Pyelonephritis

Persistent symptoms of fever lasting more than 72 hours are particularly associated with pyelonephritis. This condition involves a bacterial infection of the kidney that typically presents with systemic symptoms such as high fever, chills, flank pain, and potentially dysuria or frequency, but with more systemic manifestations compared to a simple urinary tract infection. Imaging is necessitated in cases where pyelonephritis does not respond to initial treatment, to assess for complications such as the formation of an abscess or obstruction due to kidney stones. It can also help determine the extent of the disease and guide further management decisions. In contrast, conditions like acute cystitis and urinary tract infections generally present with more localized symptoms (such as dysuria and increased frequency) and do not typically cause significant systemic manifestations or warrant imaging unless symptoms persist or complications arise. Kidney stones can cause fever, especially if they lead to pyelonephritis, but the persistent fever for over 72 hours would more directly indicate an infectious process, hence pointing towards pyelonephritis as the most fitting condition requiring imaging in this clinical scenario.