UTI Symptoms (complicated V.s Complicated): Simplified

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Urinary tract infection (UTI) is an inflammation of the urinary bladder and the kidneys. It is caused by bacteria traveling from the outside to the urinary tract through the urethra.

Not all urinary tract infections are symptomatic. Also, UTI may become complicated in certain high-risk groups of patients with symptoms of sepsis (bacteria invading the blood and affecting other organs of the body beyond the kidney.

Today, I will explain to you the different clinical scenarios of UTI. UTI can be either:

Acute simple UTI (acute cystitis) is when the infection is confined to the urinary bladder.
Acute complicated UTI (acute pyelonephritis): Spread of the infection to the kidneys or even to the bloodstream and other body organs.

Asymptomatic UTI (Asymptomatic bacteriuria): Presence of UTI without symptoms.
Mimics of UTI: Presence of the symptoms of UTI (as dysuria) without evidence of infection.
Urethritis: infection confined to the urethra (without kidney or bladder infection).

1. Uncomplicated UTI (acute cystitis).

Acute cystitis (uncomplicated UTI) is an infection of the urinary bladder. It is the most common and simple form of UTI.

Approximately more than 90% of the cases of UTIs are confined to the urinary bladder (acute cysitis or uncomplicated UTI).

The infection is most common in females due to the following:

Shorter or wider urethra.
The urethral opening is closer to the anal opening (the source of bacteria).
The urethral opening lies in a moist media (close to the vaginal opening). Moisture is a good medium for bacterial growth.

Symptoms of acute cystitis (uncomplicated UTI):

Dysuria (pain during urination).
Urinary frequency.

Frequent waking up to pee at night (nocturia).
Sudden urge to pee (urgency):
Bladder pain (suprapubic pain):

Blood in the urine (hematuria):
Cloudy (turbid urine).

A special notice about UTI symptoms in older women:

Symptoms of UTI in older women (more than 60) are difficult to assess because:

Many older women have chronic nonspecific urinary symptoms such as painful urination and incontinence) that mimic the symptoms of cystitis.
Also, they often have urinary frequency (especially at night).

Recurrent cystitis:

Women are most commonly affected with simple acute cystitis. However, a significant proportion may suffer from recurrent UTIs.

Recurrent UTI has defined as two or more infections within six months OR three or more infections within a year (reference).

Studies estimate that 27% of women will experience recurrent UTIs (a second UTI within six months).

Common causes & risk factors of recurrent UTIs are discussed in this article.

2. Complicated UTI.

A complicated Urinary tract infection is defined as a UTI that:

Extend beyond the bladder affecting the kidneys (acute pyelonephritis).

Associated with systemic symptoms of bacteremia (bacteria invading the bloodstream).

Symptoms of complicated UTI include (reference):

All the classic symptoms of acute cystitis (dysuria, urgency, frequency, blood in urine, etc.).

Fever >37.7°C (>99.9°F).
Chills or rigors.
Significant fatigue, muscle aches, or any other feature of systemic illness.

Flank pain.
Pelvic or perineal pain in men.
Tenderness over the kidney area when your doctor examines it (A tender costovertebral angle at the upper back just below the ribs).

3. Asymptomatic UTI (asymptomatic bacteriuria).

Bacteria may be found & isolated from the urine of people without any symptoms or signs of UTI. This condition is called asymptomatic bacteriuria (reference).

Asymptomatic bacteria is common, especially in females. Also, the incidence of asymptomatic bacteria increases with advancing age (reference):

Asymptomatic bacteria is present in only 1% of school girls.

The prevalence gradually increases to more than 20% in women above 80.

The absence of symptoms may be explained by:

Bladder microbiome (bacteria normally live in the bladder).

Some types of bacteria can cause infection without provoking symptoms.
Host factors: Different people respond differently to bacteria inside the bladder. The immune system may not respond to infection in some people.

Current evidence doesn’t suggest initiating treatment for asymptomatic bacteriuria, Even with the presence of pus cells in urine (reference).

Your doctor may decide to treat asymptomatic bacteria under special conditions, as with:

Pregnancy.
Before urologic interventions such as cystoscopy.

Renal transplant recipients.

4. Mimics of UTI symptoms.

Common mimics of UTI symptoms (dysuria, frequency, urgency, etc.) are (reference):

Vaginitis: Vaginal infection is often associated with UTI symptoms such as dysuria. The most common symptom of vaginitis is smelly vaginal discharge and vaginal itching.

Urethritis: Urethritis is the inflammation of the urethra (the tube connecting the urinary bladder to the outside. Learn More.
Painful bladder syndrome/interstitial cystitis (PBS/IC): is a condition of chronic bladder pain and dysuria (UTI symptoms) without actual UTI. The exact cause is still unclear. Learn More.
Pelvic inflammatory disease (PID) is an infection of the female reproductive system that mainly presents with fever and lower abdominal pain. It may cause symptoms of mincing UTI.

Others (less common), such as urinary stones, chemical irritation, eosinophilic cystitis, pinworms, idiopathic hypercalciuria, virginal vaginal ulcers, etc.