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Referral and warning signs
When to refer
Hospital admission (HC3/HC4/H) required for severe cases, sepsis, vomiting, pregnancy, significant co-morbidities, suspected obstruction/complication. Referral to Urology/Nephrology if: Obstructive cause identified. Recurrent pyelonephritis. Renal abscess requiring drainage. Failure to respond to appropriate antibiotics within 72 hours.
Red flags
- Signs of sepsis (hypotension, tachycardia, altered mental status, high fever/hypothermia)
- Severe flank pain, vomiting, inability to tolerate oral intake
- Oliguria / Signs of AKI
- Known urinary tract obstruction or stone
- Pregnancy
- Failure to improve after 48-72 hours of appropriate antibiotics
Signs and symptoms
- Fever (often high, >38°C)
- Chills / Rigors
- Flank pain or tenderness (costovertebral angle - CVA tenderness).
- Nausea, vomiting.
- Malaise, fatigue.
- May or may not have associated lower UTI symptoms (dysuria, frequency, urgency).
- Symptoms may be atypical in infants (fever, poor feeding, vomiting) and elderly (confusion, falls, general decline).
Risk factors
- Untreated or recurrent cystitis
- Female gender
- Pregnancy
- Urinary tract obstruction (stones, BPH, strictures, tumours)
- Vesicoureteral reflux (VUR) - especially in children
- Urinary catheterization or instrumentation
- Diabetes mellitus
- Immunosuppression
- Neurogenic bladder / Incomplete bladder emptying
- Structural abnormalities of the urinary tract
Diagnosis
Clinical assessment
Diagnosis based on clinical presentation of fever, flank pain/CVA tenderness, +/- lower UTI symptoms. Assess for signs of sepsis/complicated infection. Differential diagnosis: Appendicitis, Cholecystitis, Pancreatitis, Diverticulitis, Pneumonia (lower lobe), Renal colic, Pelvic Inflammatory Disease.
Investigations
- Urinalysis (MSU): Pyuria (WBCs), Bacteriuria, +/- Haematuria, Leucocyte esterase (+), Nitrites (+/-). White blood cell casts are suggestive but rarely seen.
- Urine Culture & Sensitivity (MSU): Essential to confirm bacteriuria and guide antibiotic therapy.
- Blood tests: CBC (leucocytosis), U&Es, Creatinine (assess renal function, dehydration), Blood cultures (obtain if systemic signs/sepsis suspected, or hospitalized).
- Imaging (Not routine for uncomplicated cases, consider if severe, persistent fever >48-72h, recurrent, suspected obstruction/abscess):
- - Kidney Ultrasound: Rule out obstruction (hydronephrosis), stones, abscess.
- - CT Scan (Abdomen/Pelvis with contrast): More sensitive for detecting complications (abscess, emphysematous pyelonephritis), obstruction, anatomical abnormalities.
Diagnostic criteria
Clinical syndrome (fever, flank pain) + Evidence of UTI (positive urinalysis +/- positive urine culture).
Management
Non-pharmacological management
- Adequate hydration (oral or IV).
- Hospitalization often required for moderate/severe cases, inability to tolerate oral intake/meds, pregnancy, significant co-morbidities, suspected complications, or diagnostic uncertainty.
- Monitor vital signs, urine output.
Pharmacological treatment
- Antibiotics: Choice based on severity, local resistance patterns, and culture results when available. Longer duration than cystitis needed.
- - Outpatient (Mild-moderate, able to tolerate oral, reliable follow-up): Fluoroquinolones (e.g., Ciprofloxacin 500mg PO BID or 750mg PO OD for 7-10 days) OR Trimethoprim-Sulfamethoxazole (if susceptible) OR Cephalosporins (e.g., Cefixime, Cefpodoxime). Initial IV dose (e.g., Ceftriaxone 1g) often given.
- - Inpatient (Severe illness, sepsis, unable to take oral, pregnant, complicated): IV antibiotics initially.
- - UCG Rec: IV Ceftriaxone 1g daily (Child 50-80mg/kg daily).
- - UCG Alternative: IV Gentamicin 5-7mg/kg daily +/- IV Ampicillin 2g Q6H.
- - Other options: Piperacillin/Tazobactam, Carbapenems (for resistant organisms/severe sepsis).
- - Switch to appropriate oral antibiotic based on clinical improvement and culture results to complete total course (typically 10-14 days).
- Analgesia/Antipyretics: Paracetamol.
- Antiemetics if needed.
Monitoring
Monitor clinical response (fever, pain, vital signs) within 48-72 hours. Monitor renal function if impaired or using potentially nephrotoxic agents. Follow up urine culture usually not needed if clinically resolved, but consider in pregnancy or recurrent cases.
Complications
- Sepsis / Septic shock
- Acute Kidney Injury (AKI)
- Renal abscess / Perinephric abscess
- Papillary necrosis
- Emphysematous pyelonephritis (gas formation - diabetic emergency)
- Chronic pyelonephritis / Renal scarring -> CKD (esp. if recurrent/obstructed/VUR)
- Pyonephrosis (pus in obstructed collecting system)
Prevention
- Prompt treatment of cystitis.
- Manage underlying risk factors (obstruction, reflux, diabetes control).
- Adequate hydration.
- Good hygiene practices.
Patient education
- Explain kidney infection and importance of completing full antibiotic course.
- Need for adequate hydration.
- Pain/fever management.
- Recognizing signs of worsening illness or complications requiring return.
- Importance of follow-up if recommended.
- Prevention strategies for future UTIs.
Uganda-specific notes
Common cause of fever and flank pain. Empirical treatment often necessary due to limited culture access. Ceftriaxone and Gentamicin +/- Ampicillin commonly used inpatient. Consider underlying TB or Schistosomiasis in relevant contexts. Rule out malaria.
References
- Uganda Clinical Guidelines (UCG) 2023
Chapter 7, Section 7.2.2