URINARY TRACT INFECTION

Dr.Mohammed Sharique Ahmed QuadriAssistant professor Almaarefa College

2

LEARNING OBJECTIVES• Cite organisms most responsible for urinary tract infections

(UTIs) and state why urinary catheters, obstruction, and reflux predispose to infections.

• List three physiologic mechanisms that protect against UTIs.

• Compare the signs and symptoms of upper and lower UTIs. • Describe factors that predispose to UTIs in children, sexually

active women, pregnant women and older adults.

• Compare the manifestations of UTIs in different age groups, including infants, toddlers, adults, and older adults.

• Cite measures used in the diagnosis and treatment of UTIs.

3

ANATOMY

4

Urinary Tract Infections

UTI Includes

• Asymptomatic bacteriuria

• Symptomatic lower UTI e.g. Acute cystitis

• Upper UTI e.g. Acute pyelonephritis

5

Epidemiology of UTI

• UTI is more common in females. (1-2% of young non-pregnant women)

• 40% of females will have a symptomatic UTI in their life time.

• In men: prevalence is 0.04%.• Incidence of UTI increases in old age.

(10% of men & 20% of women)

6

Routs of infection • Ascending infection from the urethra is the most common

route. Pyelonephritis most commonly results from ascent of infection up the ureter.

• Hematogenous spread to the urinary tract is uncommon, the exceptions being tuberculosis and cortical renal abscesses.

• Lymphogenous spread is rare.

• Direct extension from other organs may occur, especially from intraperitoneal abscesses in inflammatory bowel disease or pelvic inflammatory disease.

7

Risk factors for UTI

• In Females:– sexual activity ,use of spermicidal, diaphragm– Pregnancy.– Estrogen deficiency (Post menopausal )

• In Males:– lack of circumcision, – prostatic hypertrophy,

8

Risk factors for UTI

• In both sexes :– Obstruction, – Vesicoureteric reflux, – Instrumentation, & catheterization – Neurogenic disorders that impairs bladder,

emptying – Diabetes (increase risk of complications and

fungal infections)

9

• Obstruction : any microorganism that enter the bladder is washed out during voiding.

• When outflow is obstructed – Urine remains in bladder – medium for microbial

growth – Increase pressure in bladder- compresses vessels

in bladder wall- decrease in the mucosal defense

Risk factors for UTI

10

Obstruction :• Anatomic Obstruction– Stones – Prostatic hyperplasia– Pregnancy– Malformation of ureterovesical junction

• Functional obstruction – Neurogenic bladder– Infrequent voiding – Constipation – Detrusor muscle instability

Risk factors for UTI

11

• Urethrovesical reflux : urine from urethra moves into bladder– In women during coughing or squatting – Voiding abruptly interrupted

• Vesicouretral reflux: occurs at the level of bladder and ureter – Due to abnormality at the junction of ureter &

bladder– Associated with pyelonephritis and infection of

upper urinary tract

Risk factors for UTI

12

Risk factors for UTI

• CATHETER INDUCED INFECTION:– Provide A means for entry of microorganisms into

the urinary tract– Bacteria adhere to surface of catheter & initiate

the growth of biofilm that covers the surface of catheter.

– Biofilm protects the bacteria from antibiotics

13

Etiological Factors

• Uncomplicated Lower UTI– Escherichia Coli – Staphylococcus saprophyticus

• Complicated UTI– Proteus mirabilis– Klebsiella species– Enterobacter species– Pseudomonas aeruginosa– Staphylococcus aureus (gram- positive cocci)

Gram negative rods

14

Pathogenesis of UTI

HOST DEFENSES

PATHOGEN VIRULANCE

Pathogenesis of UTI involves interaction of host with agent .leading to letdown of host defenses against virulence

of infectious agents

15

Pathogenesis of UTIHost Defenses:• Urinary bladder is usually resistant to bacterial

colonization.• Host defences of bladder have many components.

– Washout Phenomenon: Bacteria removed during

voiding – Protective mucin layer: Protects against bacterial

invasion – Immune mechanisms: secretory immunoglobulin(IgA),

PMN cells – Normal flora in periurethral area in women and

prostatic secretion in males

16

Pathogen Virulance

• Only those strains of E-coli with increased ability to adhere to epithelial cells , produce UTI

• Most E.coli causing UTI belong to O,K and H serotypes.

• Uropathogenic E.coli virulence factors: - Have fimbria /Pilli (for adherence). - Secrete hemolysin & aerobactin. - Resist serum bactericidal action.

17

18

Pathogenesis of UTI• Periutheral area & urethra are colonised by

bacteria.• Bacteria enter bladder in susceptible host.• Adherence properties enable pathogens to

colonise bladder.• Pathogens attach to uroepithelial mucosa

secretion of cytokines recruitment of PMNs inflammation.

• Pathogens may ascend through ureter to kidney pyelonephritis.

Clinical presentation of UTI• Asymptomatic bacteriuria:– Common in females & elderly.– 25% develop symptomatic UTI .– 25% clear spontaneously.– Spontaneous cure & reinfection are common.

• Cystitis:– Frequency, dysuria , urgency.– Suprapubic discomfort +/- tenderness.– Fever is often absent.– Ocasionally urine is cloudy and foul smelling

Clinical presentation of UTI

• Acute pyelonephritis:

– Fever, abdominal pain, vomiting.

– Dysuria ,frequency, flank or loin pain.

– Flank or loin tenderness.

– In elderly: symptoms are often atypical.

– Bacteremia is common.

21

UTI in Special Populations

22

UTI in Pregnant women

• Changes occurring in urinary tract during pregnancy predispose to UTI– Dilation of calyces, pelvis and ureters.– Reduction in peristaltic activity of ureters (thought

to be muscle relaxing effect of progesterone and mechanical obstruction from enlarge uterus)

23

UTI in Pregnant women

• Complications:– Persistent bacteriurea • UTI during pregnancy may be the result of preexisting

asymptomatic bactriurea• Urine culture is recommended at first prenatal visit

– Acute or chronic pyelonephritis – premature delivery.– low birth weight infant.– Increased newborn mortality

24

UTI in Children

• UTI is more frequent in females than males at all ages with the exception of the neonatal period.

• Uncircumcised males have a higher incidence than circumcised males.

• Uncircumcised male infants have a higher incidence of UTI than female infants.

Frequency of UTI

• Excluding neonates, females younger than 11 years have a 3-5% risk; boys of the same age have a 1% risk.

• UTI is the source of infection in up to 6-8% of febrile infants in the first 3 months of life.

Frequency of UTI

Clinical Features • vary with the age of the patient.• Symptoms in Neonates:– Hypothermia or fever– Failure to thrive– Poor feeding– Vomiting

• Symptoms in Infants:– Poor feeding– Fever– Vomiting, diarrhea– Strong-smelling urine

Clinical Features

• Preschoolers– Vomiting, diarrhea, abdominal pain– Fever– Strong-smelling urine, enuresis, dysuria, urgency, frequency

• School-aged children– Fever– Vomiting, abdominal pain– Strong-smelling urine, frequency, urgency, dysuria, flank

pain, or new enuresis• Adolescents are more likely to have some of the

classic adult symptoms.

Complications • Even in the absence of urinary tract

abnormalities, cystitis may lead to vesicoureteral reflux, and it may worsen a pre-existing reflux.

• Untreated reflux causes pyelonephritis. Chronic or recurrent pyelonephritis results in renal damage and scarring that may progress to chronic renal failure.

• Prevalence varies based on age and sex

30

UTI IN ELDERLY

31

UTI IN ELDERLY

• Second most common cause of infection after respiratory tract infection.

• Predisposing factors:– Immobility leading to poor bladder emptying – Obstruction (BEP, stones)– Bladder ischemia caused by urinary retention – Constipation – Senile vaginitis – Other problems necessitating catheterisisation.

32

UTI IN ELDERLY

• Varying symptoms.• Difficult to interpretate because elderly

people without UTI also commonly experiences, urgency, frequency and incontinence.

• May have vague symptoms like– Anorexia– Fatigue– Weakness

33

DIAGNOSIS

Diagnosis of UTI

• Urine microscopy:-WBCs, RBCs

• Urine dipstick:- more markers of infection

Diagnosis of UTI

Urine culture & sensitivity to antibiotics • Significant bacteriuria= 100000 cfu/ml• symptoms: 1 +ve cuture = infection• Symptoms: 10000 cfu/ml = propable infection• Asymptomatic: 2 +ve cultures = infection• False negative : antibiotics, antiseptics,

diuresis.

36

Diagnosis of UTI

• Others – CBC, BLOOD CULTURE – KIDNEY FUNCTION TEST – X-ray – Ultrasonography– CT scan – Renal scansUsed to identify Contributing factors like obstruction