What is the most likely cause of a 4-year-old girl's condition, characterized by fever, vomiting, back pain, and a fluid-filled, thick-walled cavity in the upper pole of the left kidney, despite oral cephalexin (Cephalexin) therapy for a urinary tract infection (UTI)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: April 11, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

Differential Diagnosis

  • Single most likely diagnosis
    • C) Renal abscess: The patient's symptoms, including high fever, vomiting, back pain, and left costovertebral angle tenderness, along with the ultrasonography findings of a fluid-filled, thick-walled cavity in the upper pole of the left kidney, are highly suggestive of a renal abscess. The patient's history of vesicoureteral reflux and recurrent urinary tract infections also increases the risk of developing a renal abscess.
  • Other Likely diagnoses
    • A) Granulomatous pyelonephritis: This condition can present with similar symptoms, including fever, back pain, and costovertebral angle tenderness. However, it is less likely than a renal abscess given the ultrasonography findings.
    • B) Nephroblastoma: Although this is a type of renal tumor that can present with a mass in the kidney, it is less likely to cause acute symptoms like high fever and vomiting. The ultrasonography findings could be consistent with a tumor, but the clinical presentation is more suggestive of an infectious process.
  • Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
    • D) Renal infarction: This is a rare but potentially life-threatening condition that can present with acute back pain and fever. Although the ultrasonography findings do not suggest infarction, it is essential to consider this diagnosis to avoid missing a potentially fatal condition.
  • Rare diagnoses
    • E) Renal tubular acidosis: This is a metabolic disorder that can cause a variety of symptoms, including back pain and fever. However, it is a rare condition and is unlikely to cause the acute symptoms and ultrasonography findings seen in this patient.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.