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

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    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.

    5CLINICAL MANIFESTATIONS

    4fever, 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

    3ACCEPTABLE METHOD FOR URINE COLLECTION

    Midstream clean catch

    Catheterization

    Suprapubic aspiration

    2MANAGEMENT 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

    1Patterns 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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