A Case Report on Renal Abscess With Subsequent Perinephric Extension in a Patient With Poorly Controlled Type 2 Diabetes Mellitus.

Renal and perinephric abscesses are rare but potentially life-threatening complications of urinary tract infections (UTIs), especially in patients with diabetes mellitus. Diagnosis is often overlooked and delayed due to nonspecific clinical features and incomplete response to antimicrobial therapy. We report a case of a 62-year-old female with a history of poorly controlled type 2 diabetes mellitus (T2DM) who presented with flank pain, dysuria, vomiting, and fever. Imaging with contrast-enhanced computed tomography of the kidneys, ureters, and bladder (CT KUB) revealed right-sided acute pyelonephritis with an abscess in the mid-pole measuring over 5 cm, extending into the perinephric space. In spite of initial intravenous (IV) antibiotics, persistent clinical symptoms and elevated inflammatory markers required broad-spectrum antibiotics and image-guided percutaneous drainage. Culture of the abscess grew Klebsiella Pneumoniae, consistent with a urinary source of infection. Following drainage and targeted antibiotic therapy, the patient showed significant improvement in symptoms and inflammatory parameters, with complete recovery on follow-up. This case emphasizes the significance of early imaging, rapid emphasis on antibiotic use, and punctual percutaneous drainage in diabetic patients with recurrent UTIs to prevent septic complications and long-term renal damage.