American Board of Internal Medicine (ABIM) Certification Practice Exam

In the event of pyelonephritis with persistent fever after 72 hours of antibiotics, what should be done next?

1. Start a new antibiotic regimen

2. Perform kidney ultrasonography, CT, or MRI

3. Observe without intervention

4. Consult a specialist immediately

The correct answer is: Perform kidney ultrasonography, CT, or MRI

In cases of pyelonephritis where a patient continues to experience a persistent fever after 72 hours of appropriate antibiotic therapy, it is vital to investigate further for potential complications or underlying issues. The correct approach involves performing imaging studies such as kidney ultrasonography, CT, or MRI. These imaging modalities can help identify complications, such as abscess formation, obstruction, or other anatomical anomalies that may impede recovery. Persistent fever despite treatment suggests that the existing infection is not responding adequately to the antibiotics, which may be due to factors such as renal abscess or a kidney stone causing urinary obstruction. Therefore, imaging studies are essential to visualize the anatomy of the kidneys and surrounding structures, which can guide further management effectively. Starting a new antibiotic regimen without identifying the cause of the ongoing fever may be premature and could delay appropriate treatment for complications. Similarly, observing without intervention does not provide a resolution and could further exacerbate the patient’s condition. Consulting a specialist can be beneficial in certain cases, but the initial step should be to clarify the clinical situation through imaging, allowing for informed decisions to be made moving forward.