(ESBL)-producing E. coli<\/em>, following which antimicrobial therapy was changed to ertapenem according to the susceptibility pattern. She underwent definitive management of the obstructing calculus with subsequent clinical improvement. This case highlights the importance of maintaining a broad differential diagnosis in acute febrile illness, recognising localising urinary symptoms, identifying structural predisposition to recurrent urinary infection, and tailoring antimicrobial therapy according to microbiological susceptibility.<\/p>\n Acute undifferentiated fever (AUF) is a common presentation in clinical practice, particularly in tropical settings. The differential diagnosis is broad and includes viral infections, vector-borne diseases, zoonotic infections, enteric fever, respiratory infections, and UTIs. Careful history and examination are therefore essential to identify localising features that can narrow the diagnostic possibilities.<\/p>\n Pyelonephritis may present with fever, chills, and rigors, but the presence of dysuria and unilateral flank pain provides important clues towards a urinary source. When urinary infection is accompanied by obstruction or recurrent episodes, underlying structural or functional abnormalities of the urinary tract should be actively sought.<\/p>\n We report a young woman with a history of childhood ureteric reimplantation for a duplicated ureter who presented with an acute febrile illness and was subsequently found to have ESBL-producing E. coli <\/em>pyelonephritis associated with an obstructing VUJ calculus.<\/p>\n A 23-year-old woman presented with a two-day history of high-grade fever associated with chills and rigors. She also complained of burning micturition and left-sided flank pain radiating from the loin to the groin. This was associated with nausea and three episodes of vomiting on the preceding day. There was no history of cough, cold symptoms, loose stools, or recent travel.<\/p>\n The patient was febrile on presentation with a pulse rate of 120 beats per minute and a blood pressure of 100\/60 mmHg.<\/p>\n She also had left flank tenderness. The examination was otherwise unremarkable.<\/p>\n The initial presentation represented an acute undifferentiated febrile illness. In the local epidemiological setting, important differentials included dengue, malaria, scrub typhus, leptospirosis, enteric fever, and LRTI, in addition to UTI.<\/p>\n The absence of respiratory symptoms made a lower respiratory tract source less likely. Similarly, there were no prominent gastrointestinal symptoms or relevant travel history to suggest an alternative systemic infectious source. In contrast, the presence of dysuria and unilateral flank pain radiating from the loin to the groin provided important localising clues towards the urinary tract.<\/p>\n The combination of high-grade fever with chills and rigors, urinary symptoms, and focal flank pain raised the possibility of acute pyelonephritis with associated ureteric pathology.<\/p>\n The patient had undergone genitourinary surgery at approximately three years of age, reportedly involving left ureteric reimplantation for a duplicated left ureter.<\/p>\n This history was clinically significant because structural and functional abnormalities of the urinary tract are important predisposing factors for recurrent UTI. She was also known to have polycystic ovarian syndrome (PCOS) and reported an allergy to mushrooms.<\/p>\n The patient\u2019s initial WBC counts were 16,000 \/ cu. mm and CRP was 250 mg\/dL. Her creatinine was 0.6 mg\/dL and hemoglobin was 11g\/dL.<\/p>\n Urine culture grew Escherichia coli<\/em>, which demonstrated an ESBL phenotype.<\/p>\n Urological evaluation with NCCT-KUB demonstrated a duplicated left ureter with a 6-mm calculus at the VUJ and associated hydroureteronephrosis and left perinephric fat stranding.<\/p>\n The final diagnosis was:<\/p>\n ESBL-producing E. coli <\/em>pyelonephritis secondary to an obstructing left VUJ calculus in a duplicated left ureter, in a patient with previous childhood ureteric reimplantation.<\/strong><\/p>\n Empirical antimicrobial therapy was initiated with intravenous cefoperazone-sulbactam (Magnex) while awaiting microbiological results.<\/p>\n Urine culture and sensitivity subsequently demonstrated ESBL-producing E. coli<\/em>. Based on the susceptibility profile, antimicrobial therapy was changed to ertapenem.<\/p>\n Thus, antimicrobial treatment evolved from empirical therapy to culture-directed therapy following identification of a resistant Gram-negative pathogen.<\/p>\n In view of the obstructing calculus and underlying duplicated ureter, the patient underwent definitive endourological management with cystoscopy, retrograde evaluation, ureteroscopy (URS), laser lithotripsy, and double-J (DJ) stenting.<\/p>\n Following antimicrobial therapy and management of the obstructive pathology, the patient’s clinical condition improved, with normalisation of WBC counts, fall in CRP and absence of fever spikes and she was discharged in a clinically stable condition with urological follow-up to remove the DJ stent after repeat imaging in 2 weeks.<\/p>\n This case illustrates the importance of approaching acute fever through both syndromic diagnosis and anatomical localisation.<\/p>\n High-grade fever with chills and rigors in a tropical setting warrants consideration of malaria, dengue, scrub typhus, and leptospirosis, along with common bacterial infections such as enteric fever, respiratory infection, and UTI. However, careful attention to localising symptoms can substantially narrow the differential diagnosis.<\/p>\n In this patient, dysuria and unilateral loin-to-groin pain were particularly important. Dysuria suggested a urinary source, while the characteristic radiation of pain suggested ureteric involvement. The combination of infection and obstruction subsequently established the diagnosis of complicated upper UTI.<\/p>\n An important aspect of this case is the presence of a congenital urinary tract abnormality that may predispose to repeated urinary infection.<\/p>\n CAKUT stands for Congenital Anomalies of the Kidney and Urinary Tract. It is a group of structural birth defects that happen when the kidneys, ureters, bladder, or urethra do not form the right way during pregnancy. These conditions range from mild to severe and are a major cause of kidney failure in children.<\/p>\n Factors associated with recurrent UTI include structural abnormalities of the urinary tract, urinary obstruction, urinary stasis, vesicoureteric reflux (VUR), urinary calculi, dysfunctional bladder emptying, foreign bodies, and previous urinary tract instrumentation or reconstruction. Host factors such as diabetes mellitus, pregnancy, sexual activity and barrier contraceptive use in females, immunosuppression, and postmenopausal estrogen deficiency may also increase susceptibility.<\/p>\n In this patient, several of these mechanisms converged:<\/p>\n Congenital duplicated ureter\u2013> altered urinary drainage \u2013> urinary stasis and recurrent infection \u2013> VUJ calculus formation \u2013> acute obstruction and hydroureteronephrosis \u2013> selection of resistant organisms \/ complicated ESBL pyelonephritis.<\/p>\n This anatomical predisposition is particularly relevant in a young woman with a complicated urinary infection, because the absence of conventional risk factors should prompt consideration of an underlying structural abnormality.<\/p>\n The microbiological findings added a further dimension to the case. The urine culture demonstrated ESBL-producing E. coli<\/em>, an important cause of antimicrobial-resistant UTI. Recurrent UTIs directly predispose to the selection of drug-resistant pathogens – through Selective Pressure and Flora Dysbiosis as well as Intracellular Persistence .<\/p>\n The initial use of empirical cefoperazone-sulbactam (Magnex) was subsequently revised after culture and susceptibility results became available. Ertapenem was selected as definitive antimicrobial therapy according to the susceptibility pattern. This illustrates the importance of obtaining urine cultures in complicated UTIs and subsequently tailoring antimicrobial therapy to the identified pathogen and its susceptibility profile.<\/p>\n The ESBL phenotype may be considered an important feature of the current infection and its treatment, whereas the underlying anatomical abnormality and obstruction provide the pathophysiological mechanism for recurrent and complicated infections.<\/p>\n The case demonstrates three sequential levels of clinical reasoning:<\/p>\n This approach prevented the fever from being viewed solely through the lens of common tropical infections and allowed rapid recognition and management of an infected, obstructed urinary system.<\/p>\n Acute high-grade fever with chills and rigors requires a broad differential diagnosis, particularly in tropical regions where dengue, malaria, scrub typhus, and leptospirosis are prevalent.<\/p>\n Localising symptoms remain crucial in identifying the source of infection. In this patient, dysuria and unilateral loin-to-groin pain pointed towards complicated pyelonephritis with ureteric obstruction. Urine culture demonstrated ESBL-producing E. coli<\/em>, prompting a change from empirical cefoperazone-sulbactam (Magnex) to culture-directed ertapenem. The duplicated ureter, previous ureteric reimplantation, and obstructing VUJ calculus provided an anatomical basis for complicated and potentially recurrent urinary infection. The case emphasises the importance of integrating clinical localisation, structural urinary tract abnormalities, and microbiological susceptibility when evaluating acute febrile illness.<\/p>\n Dr. Arjun Swaminathan, Dr. A Ashwin Subramaniam,Introduction<\/h2>\n
Case Presentation<\/h2>\n
Relevant Past History<\/h2>\n
Diagnostic Evaluation<\/h2>\n
Antimicrobial Therapy<\/h2>\n
Management and Outcome<\/h2>\n
Discussion<\/h2>\n
Predisposition to Recurrent Urinary Tract Infection<\/h2>\n
ESBL-Producing E. coli<\/em><\/h2>\n
Diagnostic Hierarchy<\/h2>\n
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Conclusion<\/h2>\n
![\"Dr.](\"https:\/\/www.kauveryhospital.com\/ima-journal\/wp-content\/uploads\/2026\/05\/dr-arjun.jpg\")
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\nDNB Internal Medicine Resident<\/strong>
\nKauvery Hospital, Chennai.<\/a><\/b><\/p>\n<\/div>\n<\/div>\n![\"Dr-Ashwin-Subramaniam\"](\"https:\/\/www.kauveryhospital.com\/ima-journal\/wp-content\/uploads\/2026\/02\/Dr-Ashwin-Subramaniam.jpg\")
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\nAcademic Director and Senior Consultant Internal Medicine and Diabetology<\/strong>
\nKauvery Hospital, Chennai.<\/a><\/b><\/p>\n<\/div>\n<\/div>\n
![\"anu](\"https:\/\/www.kauveryhospital.com\/ima-journal\/wp-content\/uploads\/2021\/05\/Dr.-Anu-Ramesh2021-01-23-10-23-30am1.jpg\")
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