URINARY TRACT INFECTION (UTI)

Definition

To describe urinary tract infections, qualifying: low or high, or primitive Secondary should be avoided; because they are confusing. It's simple to call: complicate and simple
Complicated urinary tract infection
Is a urinary tract infection occurring with risk factor that can make the infection worse and more complex treatment
Risk Factor:
- Pregnancy, elderly (≥ 65 years) associated with disease,
- Organic or functional abnormality of the urinary tract (bladder residue,
reflux, stones, tumor, invasive bladder maneuver)
- Co-morbidity: diabetes, immunosuppression, renal failure

Note: UTI in men is rare to man due to its long urethra and protected by prostatic secretion. Usually accompanied by organic or functional abnormality of the urinary tract
Recurrent cystitis

A recurrent cystitis is described as if there were at least 4 episodes in a year or 2 in 6 months

Urinary Colonization / asymptomatic bacteriuria
It corresponds to the presence of a microorganism in the urine without clinical manifestation associated. Abstention therapeutic is the rule unless the patient is at risk: pregnant, neutropenia, immunosuppression, urological maneuvers

Epidemiology-Pathophysiology

The urinary tract infections are a very common disease, particularly in women, since it is estimated that nearly 50% of women will have at least one UTI in their lifetime

1. Pathogenic agents

Many microorganisms can be responsible for UTI, but Gram negative bacilli are far the most common.

2. Dissemination

The ascending pathway is the most common (97% of cases). The infection is therefore go through the urethra. The proliferation of bacteria in the bladder is facilitated by:
- Stasis (Urine)- Foreign body: Stone or urinary catheter- Glycosuria
The hematogenous (renal localization of sepsis) is very rare (at most 3% of cases). The main microorganisms involved are:
- Staphylococcus aureus
- Salmonella
- Pseudomonas
- And finally the Candida albicans

Infected urine can reach upper organs during a transitional vesico-urethral reflux, secondary to inflammation of the bladder trigone.

The Enterobacteria strains (including Escherichia coli), the most uropathogens, are those with pili (capable of adhesion to urothelium)

Diagnostic of UTI

1. Dipstick

Dipsticks detect Leukocyte esterase produced by the neutrophils. The sensitivity threshold of 10⁴ cells per ml

Nitrites which testify to the presence of bacteria, mainly enterobacteria, with nitrate reductase capable of converting nitrate to nitrite

The urine sample must be taken from the second urine stream without

prior perineal toilet. The strip must be soaked in freshly emitted urine in a clean, dry container but not sterile

The test strips have a sensitivity 90% and a specificity of 70%; There is a very low risk (≈ 3%) false

negative testing nitrites:

- low bacteriuria

- Restricted arrangements nitrates

- Acid urinary pH

- diuretic therapy

- Unproductive nitrite bacteria: streptococci, enterococci, Acinetobacter spp, Staphylococcus saprophyticus

A strip is considered positive if it detects leucocyturia and/or nitrites

Indication

Cystitis suspicion: first line of diagnosis of UTI

If dipstick test is negative, others diagnosis (vaginitis, cystalgia, ...) should be considered

Dipstick test can not be considered an effective method of diagnosis. A urine culture is necessary for the identification and understanding of antibiotic sensitivity of the bacteria

2. Urinalysis

Urinalysis should be performed before starting any antibiotic treatment

Condition

The following conditions must be met:

- Careful perineal toilet and drying

- Urine mid-stream (to avoid soiling of the skin flora or urethral)

- If possible, take sample in the morning, on the first urine that is concentrated (if the sample is taken during the day, try not to urinate and do not drink for 4 hours before harvesting)

- Analysis within 2 hours of collection. If it is not possible, the sample should be kept refrigerated at 4 ° C for up to 24 hours

The interpretation varies depending on the clinical manifestations and microbial species

When you suspect tuberculosis, Koch's bacillus search must be specified in the order; because it requires the implementation of specific culture techniques

Acute cystitis

1. Typical clinical presentation

Burning urination, supra-pubic discomfort or pain

Urinary frequency, urgency

Cloudy urine, +/- hematuria

Fever and lumber pain are absent

2. Para-clinic investigation

Dipstick test (Sensibility 90%)
Urinalysis not recommended for the first episode

Without treatment, the prognosis of selfheal is 50%

Recurrent cystitis

Acute cystitis is call recurrent if there’re at least 4 episodes in a year and no risk factor

Contributed factors of recurrent cystitis:

• Sexual activity
• Spermicide utilization
• Episode of UTI before 15 years old
• Menopause

Para-clinic: Urinalysis is a routine, others investigation (Ultrasonography, cystography…) are not recommended but, can be discuses depend on clinical manifestations

Acute pyelonephritis

1. Clinical manifestation

• High fever (> 38.5°C), usually with chilling
• Lumbar pain, usually unilateral radiated to external genital organ
• Cystitis syndrome (Inconstant), may present before fever
• Sometime the clinical appearance is incomplete: Only fever, Cystitis syndrome with chill but no lumbar pain. Dipstick test is recommended

In certain patients, especially diabetic, chronic alcoholic, malnourished, renal transplantation can be painless, but will develop to septic choc

Diagnosis in elderly is difficult, because:

• Fever absent in 30%
• Abdominal pain instead of lumbar pain 20%
• Vital signs alteration, confusion

*Severity signs must be checked:

• Septic choc or septicemia
• Urinary retention due to obstruction
• Pyonephrosis or renal abscess
• Diabetes
• Immune deficiency
• New born < 18 months
• Associated uropathie or solitary kidney

Hospitalization:

• Severity signs presented
• Hyperalgia (Intolerance pain)
• Unclear diagnosis
• Para-clinic can not be performed (Urinalysis, Ultrasonography)
• Treatment is unfavorable or need observation

2. Para-clinic investigation

Biology:
Urinalysis (with antibiogram) must be performed before treatment

Blood culture: Blood cultures (2 or 3) systematically made for patients in the hospital. Positive when they found the same germ that isolated in urine

CBC: Neutrophilic leukocytosis

CRP: Increased

Creatininemia: Renal function state 

Imagery

Renal ultrasonography and excretory tract:

- Not invasive and easy to access

- For search complications rather than diagnosis: Stone, Hydronephrosis, Suppuration… Should be performed before surgical procedures

Renal scan is not performed as a first line; However,
it should be considered in case of diagnostic uncertainty or unfavorable

Retrograde urethrocystography (man, women after 2 episodes of acute pyelonephritis) for searching vesicoureteral reflux. It must be performed after verifying urine sterilization

Acute Prostatitis

1. Definition: Acute inflammation of the prostate gland caused by microbial

2. Contamination:

Mostly by ascending pathway. The germs involved are same as those responsible for acute pyelonephritis (mainly Enterobacteria, including E. Coli 80%)

Contamination can also be iatrogenic (urine catheter), with the risk of multi-resistant germs

3. Clinical manifestation

• Fever +/- chill
• Dysuria, frequency, urgency
• Pubic pain, perineal pain
• Pain when performing rectal touch

4. Complication

Prostatic abscess (surgical drainage)

Acute urinary retention: the occurrence of urinary retention completely (rare). Urethra catheterization is strongly against indication, and imposes a suprapubic bladder drainage instead

Septicemia: promoted by a endo-urological maneuver or risk patient

5. Investigation

Urinalysis should be performed as routine: leukocyturia and bacteriuria

Blood culture are often necessary

PSA dosing is not recommended in the acute phase

Ultrasonography of the urinary tract by suprapubic is recommended. Ultrasound for prostate duct is against-indicated in acute phase