What are the symptoms of a urinary tract infection (UTI)?

Symptoms of Urinary Tract Infection

The diagnosis of UTI should be primarily based on clinical symptoms, with dysuria, frequency, and urgency forming the core symptom complex for uncomplicated lower tract infection (cystitis), while fever and flank pain indicate upper tract involvement (pyelonephritis). 1

Primary Lower Tract Symptoms (Cystitis)

• Dysuria (painful urination) is the cardinal symptom, with over 90% diagnostic accuracy in young women when vaginal symptoms are absent 2
• Urinary frequency manifests as needing to urinate more often than usual 2
• Urinary urgency presents as a sudden, intense need to urinate 2, 3
• Suprapubic pain or tenderness in the lower abdomen 2, 3
• Hematuria (blood in urine) may be visible or microscopic 2, 4
• New or worsening urinary incontinence 2

Upper Tract Symptoms (Pyelonephritis)

• Fever (temperature >37.8°C orally, or >37.5°C rectally) indicates systemic involvement 1, 5
• Flank pain or costoverteboral angle tenderness suggests kidney involvement 1, 5
• Systemic symptoms including rigors, shaking chills, malaise, nausea, and vomiting 1, 2

The presence of fever or flank pain distinguishes complicated upper tract infection from simple cystitis and requires more aggressive treatment 4, 5.

Atypical Presentations in Older Adults

In frail or geriatric patients (>70 years), UTI may present with nonspecific symptoms that differ markedly from younger adults. 1

Mental Status Changes

• New onset confusion or delirium (acute change in attention and awareness developing over hours to days) 1, 2
• Agitation or worsening aggression 1, 2

Functional Decline

• Decreased mobility or activities of daily living 1, 2
• New or worsening fatigue, weakness, or malaise 1, 2
• Dizziness or syncope 1, 2

Other Nonspecific Symptoms

• Decreased fluid or dietary intake 1, 2
• Nausea with or without vomiting 1, 2

Symptoms That Should NOT Solely Trigger UTI Diagnosis

The following symptoms alone, without the core urinary symptoms above, should not prompt antibiotic treatment for UTI: 1

• Cloudy urine, change in urine color, or urine odor - these occur commonly with asymptomatic bacteriuria and do not indicate infection requiring treatment 1, 2
• Nocturia alone 1
• Decreased urinary output alone 1

Critical Diagnostic Algorithm for Frail/Older Patients

For suspected UTI in older adults, antibiotics should only be prescribed if there is recent onset dysuria PLUS at least one of: frequency, incontinence, urgency, or costovertebral angle pain/tenderness. 1

Alternatively, antibiotics are indicated if systemic signs are present (fever, rigors, or clear-cut delirium) along with urinary symptoms, regardless of urinalysis results 1.

Important Clinical Pitfalls

• Pyuria alone does not diagnose UTI - it indicates genitourinary inflammation that can be noninfectious 1, 2
• Asymptomatic bacteriuria should not be treated in most patients, as it does not cause symptoms and treatment leads to unnecessary antibiotic use 1
• Vaginal discharge, vulvar lesions, or sexually transmitted diseases can mimic UTI symptoms and should be excluded 4
• In catheterized patients, pyuria does not differentiate infection from colonization 2