1. URINARY TRACT INFECTION

2. Urinary tract infection (UTI) is the most common bacterial infection managed in general medical practice
The prevalence of UTI in women is about 3% at the age of 20, increasing by about 1% in each subsequent decade.
In males UTI is uncommon, except in the first year of life and in men over 60,(prostatic hypertrophy)

3. UTI is defined as multiplication of organisms in the urinary tract
UTI is defined as multiplication of organisms in the urinary tract. It is usually associated with the presence of neutrophils and > 105 organisms/ml in a midstream sample of urine (MSU).

4. The following hosts defence mechanisms are necessary to prevent UTI:
Neutrophils - impaired function of neutrophils predisposes an individual to severe UTI.
Urine osmolality and pH - urinary osmolality > 800 mOsm/kg and low or high pH reduce bacterial survival.
Complement - complement activation with IgA production also plays a major role in defence against UTI.
Commensal organisms - Eradication of these commensal organisms by spermicidal jelly or disruption by certain antibiotics results in overgrowth of E. coli.
Urine flow - urine flow and normal micturition wash out bacteria. Urine stasis promotes UTI.
Uroepithelium - Disruption of this uroepithelium by trauma (e.g. sexual intercourse or catheterization) predisposes to UTI.

5. RISK FACTORS FOR URINARY TRACT INFECTION Incomplete bladder emptying
Bladder outflow obstruction
Neurological problems (e.g. multiple sclerosis, diabetic neuropathy)
Gynaecological abnormalities (e.g. uterine prolapse)
Vesico-ureteric reflux
Foreign bodies
Urethral catheter or ureteric stent
Loss of host defences
Atrophic urethritis and vaginitis in post-menopausal women
Diabetes mellitus

6. Aetiology Organisms causing UTI in the community include:
Escherichia coli derived from the gastrointestinal tract (about 75% of infections)
Proteus
Pseudomonas species
streptococci
Staphylococcus epidermidis.

7. Instrumentation of the bladder may also introduce organisms.
In women, the ascent of organisms into the bladder is easier than in men because of
the relatively short urethra
absence of bactericidal prostatic secretions.
Sexual intercourse may cause minor urethral trauma and transfer bacteria from the perineum into the bladder.
Instrumentation of the bladder may also introduce organisms.

8. THE SPECTRUM OF PRESENTATIONS OF URINARY TRACT INFECTION
Asymptomatic bacteriuria
Symptomatic acute urethritis and cystitis
Acute pyelonephritis
Acute prostatitis
Septicaemia (usually Gram-negative bacteria)

9. ASYMPTOMATIC BACTERIURIA
This is defined as > 105/ml organisms in the urine of apparently healthy asymptomatic patients.
There is no evidence that this condition causes renal scarring in adults who are not pregnant and have a normal urinary tract, and in general, treatment is not indicated.
In infants, pregnant women, and abnormal urinary tract treatment is required and investigation is indicated.

10. acute urethritis and cystitis
Typical features of cystitis and urethritis include:
abrupt onset of frequency of micturition
pain in the urethra during micturition (dysuria)
suprapubic pain during and after voiding
intense desire to pass more urine after micturition, due to spasm of the inflamed bladder wall (urgency)
urine that may appear cloudy and have an unpleasant odour
microscopic or visible haematuria.
Systemic symptoms are usually slight or absent.

11. Acute pyelonephritis
There is usually acute onset of pain in one or both loins, which may radiate to the iliac fossae and suprapubic area and is associated with tenderness and guarding in the lumbar region.
About 30% of patients have dysuria due to associated cystitis.
Fever is usually present and may be associated with rigors, vomiting and hypotension.
Examination of urine reveals neutrophils, organisms, red cells and tubular epithelial cells.

12. Acute prostatitis
It can be caused by the same bacteria that are associated with UTI or, more commonly, may be 'non-bacterial' (no organisms cultured from urine).
Clinical features include frequency, dysuria, perineal or groin pain, difficulty passing urine and, in acute disease, considerable systemic disturbance.
The prostate is enlarged and tender.
Bacterial prostatitis is confirmed by a positive culture from urine or from urethral discharge obtained after prostatic massage,

13. Investigations
Definitive diagnosis rests on the combination of typical clinical features with findings in the urine.
Culture of MSU (Mid Stream Urine) sample
Microscopic examination of urine for white and red cells
Dipstick examination of urine for nitrite (produced by most bacteria) and leucocyte esterase (produced by neutrophils).
Dipstick examination of urine for blood, protein and glucose

14. Management
A fluid intake of at least 2 litres/day is usually recommended
Antibiotics are recommended in all cases of proven UTI

16. PROPHYLACTIC MEASURES TO BE ADOPTED BY WOMEN WITH RECURRENT URINARY INFECTIONS
Fluid intake of at least 2 litres/day
Regular complete emptying of bladder
If vesico-ureteric reflux is present, practise double micturition (empty the bladder then attempt micturition minutes later)
Good personal hygiene
Emptying of the bladder before and after sexual intercourse