Differentiating Cystitis from Upper UTI: Diagnosis and Treatment
Cystitis is a lower urinary tract infection limited to the bladder, presenting with localized symptoms (dysuria, frequency, urgency) without fever, while upper UTI (pyelonephritis) involves the kidneys and presents with systemic symptoms including fever, flank pain, and costovertebral angle tenderness. 1
Clinical Differentiation
Cystitis (Lower UTI)
- Localized symptoms only: dysuria, urinary frequency, urgency, and suprapubic discomfort 1
- Absence of fever and systemic symptoms 1, 2
- No flank pain or costovertebral angle tenderness 1
- Physical examination typically normal or shows only suprapubic tenderness 3
Pyelonephritis (Upper UTI)
- Systemic symptoms: high fever, malaise, vomiting 1
- Flank pain or costovertebral angle tenderness 1, 2
- May include abdominal pain 1
- Pyuria and/or bacteriuria with fever are diagnostic 1
Important caveat: Up to one-third of acute cystitis cases may have silent upper tract involvement despite presenting with only lower tract symptoms 4. This underscores why clinical judgment remains critical.
Diagnostic Approach
For Suspected Uncomplicated Cystitis
In women with typical symptoms (dysuria, frequency, urgency) and absence of vaginal discharge, diagnosis can be made clinically without urinalysis 1. Dysuria and frequency without vaginal symptoms are highly predictive of cystitis 5, 6.
Obtain urine culture in these situations: 1
- Suspected acute pyelonephritis
- Symptoms not resolving or recurring within 4 weeks after treatment
- Atypical symptoms
- Pregnancy
For Suspected Pyelonephritis
- Urine culture is mandatory before starting antibiotics 1, 5
- Pyuria is typically present; its absence suggests an alternative diagnosis 2
- Blood cultures should be obtained if upper UTI is suspected 1
Treatment
Uncomplicated Cystitis - First-Line Options 1
- Fosfomycin trometamol: 3g single dose (1 day) - recommended only for women with uncomplicated cystitis
- Nitrofurantoin: 100mg twice daily for 5 days
- Pivmecillinam: 400mg three times daily for 3-5 days
- Trimethoprim-sulfamethoxazole: 160/800mg twice daily for 3 days (if local E. coli resistance <20%) 1, 7
Beta-lactam antibiotics (amoxicillin/clavulanate, cephalosporins) are not recommended for initial treatment due to resistance concerns 3.
Pyelonephritis Treatment
- Duration: 7-14 days (14 days for men when prostatitis cannot be excluded) 1
- Preferred agents: Fluoroquinolones or trimethoprim-sulfamethoxazole for high renal tissue penetration 4
- Ciprofloxacin should NOT be used if local resistance >10%, patient is from urology department, or fluoroquinolone use in last 6 months 1
- For complicated cases with systemic symptoms, use IV third-generation cephalosporin plus aminoglycoside or amoxicillin plus aminoglycoside 1
Treatment can be shortened to 7 days when the patient is hemodynamically stable and afebrile for at least 48 hours 1.
Key Clinical Pitfalls
When to Suspect Complicated UTI
Reclassify as complicated if: 1
- Bacterial cystitis recurs rapidly (within 2 weeks of treatment)
- Bacterial persistence without symptom resolution
- These patients require imaging to detect calculi, foreign bodies, diverticula, or anatomic abnormalities
Imaging Indications
Imaging is NOT routinely indicated for uncomplicated recurrent UTIs without risk factors 1. However, imaging is warranted when: 1
- Rapid recurrence suggesting complicated infection
- Difficulty differentiating lower from upper tract involvement
- Detection of treatable anatomic conditions
Treatment Failure
If symptoms persist or recur within 2 weeks: 1
- Obtain urine culture and susceptibility testing
- Assume organism is not susceptible to original agent
- Retreat with 7-day regimen using different antimicrobial
Most Common Pathogen
Escherichia coli causes approximately 75% of UTIs in all patient groups 1. Other common organisms include Enterococcus faecalis, Proteus mirabilis, Klebsiella, and Staphylococcus saprophyticus 1.