URINARY TRACT INFECTIONSURINARY TRACT INFECTIONS: DEFINITION, CAUSES,TYPES,TREATMENT AND MANAGMENTS




Definitions:
Bacteriuria
Frequently used term; meaning bacteria inthe urine
Can be ascertained by quantifying the
bacteria in voided urine or in urine obtained
via uretheral catherization.

Significant Bacteriuria
Indicates that number of bacteria in the voided urine
exceeds the number that can be expected from
contamination from the anterior urethra (i.e, ≥ 105
bacteria/ml)
Asymptomatic Bacteriuria
Refers to significant bacteriuria w/o symptoms
Affecting mostly women in old age groups

Localization:
A.) Lower Urinary Tract
CYSTITIS
URETHRITIS
A syndrome involving dysuria, frequency,
urgency & suprapubic tenderness

B.) Upper Tract Infection
– are acute pyelonephritis, prostatitis, intrarenal& perinephric abscess
– characterized by flank pain or tenderness,fever and often associated with dysuria, urgency& frequency
– however, these symptoms may occur w/oinfection. i.e renal infection or renal calculus.

Uncomplicated UTI
– Refers to the infection in structurally and neurologically normal urinary tract.

URINARY TRACT INFECTIONS: DEFINITION, CAUSES,TYPES,TREATMENT AND MANAGMENTS.

Complicated UTI

Refers to infection w/ functional or structural abnormalities (including individually catheters and calculi).



Recurrences:
Relapse of bacteriuria
– A recurrence of bacteriuria with the same infecting microorganism that was present before therapy was started and persisted.

Reinfection

A recurrence of bacteriuria w/ a microorganism different from the original infecting bacteriuria.

A new infection
UROSEPSIS
– a sepsis syndrome due to UTI
– Includes evidence of UTI plus 2 or more of the following:
a. temperature: > 38oC or less than 36oC.

b.heart rate : > 90 beats/ min

c. respiratory rate : > 20/min or PaCO2> than 30mmHg
d. WBC : > 12,000/mm,or  < than 4,000/mmor > 10% band forms

PATHOLOGIC
CHARACTHERISTICS
ACUTE PYELONEPHRITIS

– kidneys are enlarged especially severe
pyelonephritis
– with discrete yellowish abscess on the surface

– pathognomonic feature historically
suppurative necrosis or abscess formation within the renal substance.


CHRONIC PYELONEPHRITIS

– or chronic interstitial nephritis

– one or both kidneys contain gross scars due to changes in pelvic wall w/ papillary atrophy and blunting

– its parenchyma shows interstitial fibrosis w/ an inflammatory infiltrate of lymphocytes, plasma cells and occasionally neutrophils

– tubules are dilated and contracted by atrophy of the lining epithelium,

– tubules contained colloids casts, sometimes called thyroidization of the kidney Papillary Necrosis.

– Affecting the pyramids which replaced by wedge-shaped areas of yellow necrotic tissue with the base
located at the cortico medullary junction.

– as it progress – necrotic papilla may break off proceeding a calyceal deformity

– once with infection, the collecting tubules are filled w/ bacteria and polymorphonuclear leukocytes.

 

PATHOGENESIS OF UTI

I.Ascending Route
– urethra is usually colonized with bacteria, especially in women since it’s short & is in proximity to the warm moist
vulvar and perianal areas

– initially starts as colonization in vaginal introitus and periuretheral area > invades bladder > bacteria multiply and then pass up to the ureters (more among with vesicoureteral reflux) then to the renal pelvis and parenchyma.




– colonization occurs in massage of the urethra in women and sexual intercourse

– condom use may heighten the traumatic effects

– catheterization of the bladder

– both diaphragm of monoxynal, 9 contraceptive jelly in women and condom catheter in men may predispose to
infection and also spermicides due to adherence of E.coli to vaginal epithetial cells.

URINARY TRACT INFECTIONS: DEFINITION, CAUSES,TYPES,TREATMENT AND MANAGMENTS.

– also with estrogen, as predisposing factor to cause recurrent UTI among post-menopausal women due to vaginal
flora changes, its lacto bacilli is replaced by coliform and other uropathogens.

II. Hematogenous Route;

refers to  most common organism is staphylococcus aureus, causing bacteriuria or endocarditis also candida

III. Lymphatic Route

– involves the renal lymphatic once there is increase pressure in the bladder can cause lymphatic flow to the directed toward the kidney

CONDITIONS AFFECTING
PATHOGENESIS

GENDER and SEXUAL ACTIVITY

Sexual intercourse cause the introduction of bacteria into the bladder – onset of cystitis.

Voiding after intercourse reduces the risk of cystitis which promotes the clearance of bacteria

Male population – common source is due to prostatic obstruction and also rectal intercourse


Pregnancy
ASB in pregnancy is the presence of >100,000 CFU/mL of the same uropathogen in two consecutive midstream urine specimens or ≥100
CFU/mL of a single uropathogen in one
catheterized urine specimen.

Symptoms attributable to urinary infection should be absent.

2 – 8 % are detected
Usually asymptomatic but once reach the renal pelvis develop pyelonephritis
Due to decrease ureteral tone, decreased ureteral peristalsis and incompetence of the vesico ureteral valves.

Screen ALL pregnant women for asymptomatic bacteriuria once, between the 19th to 17th week age of gestation (AOG), preferably on the 16thweek
AOG

A standard urine culture of clean-catch midstream urine is the test of choice in screening for asymptomatic bateriuria.
Urinalysis is not recommended as an initial screening test.

Antibiotic Treatment:

 

Antibiotic treatment for asymptomatic bacteriuria is indicated to reduce the risk of acute cystitits and
pyelonephritis in pregnancy as well as the risk of low
birth weight neonates and preterm infants

Treatment with antibiotics should be initiated upon diagnosis of ASB in pregnancy. Among the antibiotics
that can be used are nitrofurantoin (not for near term),co-amoxiclav, cephalexin, cefuroxime, fosfomycin, and TMP-SMX (not on the first and third trimester)
depending on the sensitivity results of the urine isolate Duration of treatment will depend in the antibiotics that will be used, but short-course (seven days)
treatment is preferred over single-does regimens.

A follow-up urine culture should be done one week after completing the course of treatment Monitoring should be done every trimester untild elivery



Neurogenic Bladder Dysfunction

In spinal cord injury, diseases like tables dorsalis, multiple sclerosis, DM

Due to interference with bladder innervation

VESICOURETERAL REFLUX

Common among children with anatomic
abnormalities of the urinary tract
Some population, reflux disappears with advancing age.

But need to have long-term follow-up – might result to failure of renal growth and scarring

Do retrograde psychopathy with contrast media

Bacterial Virulence Factors

E.coli strains O, K & H serogroups
Due to its virulence genes, contains hairlike proteinaceous surface appendages, fimbriae.which adheres to uroepithelial cells of the host. E.coli produce also cytotoxins hemolysis and aerobactin.

ETIOLOGY

E. coli = 80% causing acute infection
Proteins
Pseudomonas
Klebsiella
Enterbacter species
Staphylococci
Staphylococci Aureus
Staphylococci Saprophyticus
Staphylococci Epidermis
Candida.

5. CLINICAL MANIFESTATIONS

4. fever, sometimes with chills
Flank pains
urgency
Infancy
Dysuria
Hematuria
Microscopic Gross

DIAGNOSIS

Presumptive Diagnosis

Urinalysis – midstream urine with at least 10 leukolyte/mm3

Dipstick leukocyte esterase test
– rapid screening test for detecting pyuria
– WBC 10/mm3

c. Microscopic/gross hematuria

d. Proteinuria

e. gram-staining

3. ACCEPTABLE METHOD FOR URINE COLLECTION

Midstream clean catch

Catheterization

Suprapubic aspiration

2. MANAGEMENT OF UTI

– generally, must treat the infection

– for asymptomatic, must have two cultures

– fear of reinfection and complication especially among DM and other immunocompromised patients and also among elderly patients.

– for children with vesicoureteral reflux (if congenital anomalies) can result to stunted growth of the kidneys,
scan formation but rarely renal failure.

– and also pregnant women

– hospitalized patients especially with in dwelling catheters – that is high mortality rates.

Hydration Produces rapid dilution of the bacteria and removal of infected urine by frequent bladder emptying

Acidification of urine pH

Nitroformation may be used to lower pH 5.5

Ascorbic acid – but form oxalate stones
Cranberry juice

Analgesics
With the word of phenazopyridine hydrochloride
(pyridium)





.Antimicrobial Therapy
– Among patients with renal insufficiency – need to modify the dosage according to creatinine clearance especially aminoglycosides

1. Patterns of response of
Bacteriuria to Antimicrobial
Therapy

Bacteriologic cure

– Defined as (–)urine cultures on hemotherapy and during the follow-up period (usually 1 – 2 weeks)

2. Bacteriologic Persistence

a.) persistence of significant bacteriuria after 48 hours of treatment
b.) persistence of the infecting organism in low numbers in urine after 48 hours

– this may occur when the infecting strain is resistant
to the urinary attained e.g. resistant organism or because the levels of the drug are inordinarily low e.g.
not taking the medicine, insufficient dosage, poor intestinal absorption or poor renal excretion among renal insufficiency.

3. Bacteriologic Relapse
– usually occur 1 – 2 weeks after the cessation of the drugs.
– also presence of structural abnormalities of the urinal tract
– relapse indicates that the infecting microorganism has persisted in the urinary tract during the therapy.

4. Reinfection

– after initial sterilization of the urine, reinfection may occur – also called as super infection

Classification and
Antimicrobial Therapy for
Different Groups

ACUTE PYELONEPHRITIS
– severely ill – hospitalization
– mild to moderate – may start oral therapy –outpatient
– may start ampicillin or amoxicillin (for gram positive cocci in chain and may use also first generation cephalexin

– gram (–)bacillus first generation cephalosporin are 35% resistant and also to Trimethoprim –Sulfamethoxazole

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URINARY TRACT INFECTIONS: DEFINITION, CAUSES,TYPES,TREATMENT AND MANAGMENTS.

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