Urinary tract infections – Introduction, clinical features and diagnosis Dr.

Urinary tract infections – Urinary tract infections – Introduction, clinical features Introduction, clinical features

and diagnosisand diagnosis

DrDr

OverviewOverview

Urinary tract infections (UTI)Urinary tract infections (UTI) IntroductionIntroduction Some definitionsSome definitions Clinical settingsClinical settings Clinical featuresClinical features DiagnosisDiagnosis

ConclusionsConclusions

Introduction Introduction

UTI UTI The third most common infection experienced The third most common infection experienced

by humans by humans (After respiratory and gastro-intestinal infections)(After respiratory and gastro-intestinal infections)

Distressing and occasionally life threatening Distressing and occasionally life threatening Most common cause of both community Most common cause of both community

acquired and nosocomial infections for acquired and nosocomial infections for patients admitted to hospitals in United States patients admitted to hospitals in United States

Indian J Nephrol 2009;19:129-39.

Introduction Introduction (Contd)(Contd)

UTI UTI (Contd)(Contd)

May be defined as a condition in which May be defined as a condition in which bacteria are established and multiplying within bacteria are established and multiplying within the urinary tractthe urinary tract

Diagnosis requires demonstration of Diagnosis requires demonstration of bacteriuriabacteriuria Exceptions to this include patients with pyogenic Exceptions to this include patients with pyogenic

abscess of kidney or perinephric tissue, obstructed abscess of kidney or perinephric tissue, obstructed pyonephrosis or bacterial prostatitis in whom the pyonephrosis or bacterial prostatitis in whom the urine may be sterile. urine may be sterile.


Introduction Introduction (Contd)(Contd)

Some definitions Some definitions Are necessary because the infection of the Are necessary because the infection of the

urinary tract may result from microbial urinary tract may result from microbial invasion of any of the tissues extending from invasion of any of the tissues extending from urethral orifice to the renal cortexurethral orifice to the renal cortex Although the infection and resultant symptoms Although the infection and resultant symptoms

may be localized, the presence of bacteria in urine may be localized, the presence of bacteria in urine places the entire urinary system at risk of invasion places the entire urinary system at risk of invasion by bacteriaby bacteria


Some definitionsSome definitions

Significant bacteriuriaSignificant bacteriuria Defined as the presence of 100 000 (10 Defined as the presence of 100 000 (10 55) or more ) or more

colony forming units (CFU)/ml of urinecolony forming units (CFU)/ml of urine This Kass criteria has been questioned This Kass criteria has been questioned

Bacterial counts of 10 Bacterial counts of 10 22 or more organism/ml or more organism/ml particularly when accompanied by pyuria (>10 particularly when accompanied by pyuria (>10 wbc/mm wbc/mm 33 ) provide impressive evidence of urinary ) provide impressive evidence of urinary tract infection in symptomatic young womentract infection in symptomatic young women

The Infectious Disease Society of America (IDSA) The Infectious Disease Society of America (IDSA) gave a slightly more relaxed consensus definition gave a slightly more relaxed consensus definition requiring requiring 10 10 33 organisms per ml to diagnose cystitis and organisms per ml to diagnose cystitis and 10 10 44 per ml for pyelonephritis per ml for pyelonephritis


Some definitions Some definitions (Contd)(Contd)

Anatomic location Anatomic location Useful to distinguish between upper (kidney) Useful to distinguish between upper (kidney)

and lower (bladder, prostate and urethra) UTIand lower (bladder, prostate and urethra) UTI Infections confined to lower urinary tract commonly Infections confined to lower urinary tract commonly

cause dysuria, frequency and urgencycause dysuria, frequency and urgency Pyelonephritis (inflammation of the renal Pyelonephritis (inflammation of the renal

parenchyma) is a clinical syndrome characterized parenchyma) is a clinical syndrome characterized by chills and fever, flank pain and constitutional by chills and fever, flank pain and constitutional symptoms caused by bacterial invasion of the symptoms caused by bacterial invasion of the kidneykidney



Anatomic location Anatomic location (Contd)(Contd)

The localization of the site of infection on the The localization of the site of infection on the basis of symptoms and signs can be basis of symptoms and signs can be inaccurateinaccurate

Using ureteral catheterization, it has been Using ureteral catheterization, it has been shown that approximately 50% of women with shown that approximately 50% of women with asymptomatic bacteriuria had infection in their asymptomatic bacteriuria had infection in their upper tractsupper tracts



Anatomic location Anatomic location (Contd)(Contd)

Response to treatment is now used to distinguish Response to treatment is now used to distinguish between the two upper versus lower UTIbetween the two upper versus lower UTI This is based on the observation that many women with This is based on the observation that many women with

symptoms of cystitis shown by localization studies to be symptoms of cystitis shown by localization studies to be confined to bladder can be cured by a single dose of confined to bladder can be cured by a single dose of antibioticantibiotic

Recurrence of bacteriuria with the same organism within Recurrence of bacteriuria with the same organism within seven days of single dose therapy was reported to be most seven days of single dose therapy was reported to be most often associated with upper tract infection often associated with upper tract infection



Complicated and uncomplicated UTIComplicated and uncomplicated UTI For best management of patients with UTI, important For best management of patients with UTI, important

to distinguish between complicated and to distinguish between complicated and uncomplicated infectionsuncomplicated infections

Complicated infections include those involving the Complicated infections include those involving the Parenchyma (pyelonephritis or prostatitis) and frequently Parenchyma (pyelonephritis or prostatitis) and frequently

occur in the setting of obstructive uropathy or after occur in the setting of obstructive uropathy or after instrumentationinstrumentation

The presence of obstruction, stones or high-pressure vesico-The presence of obstruction, stones or high-pressure vesico-ureteric reflux, perinephric abscess, life-threatening ureteric reflux, perinephric abscess, life-threatening septicemia or a combination of these predispose to kidney septicemia or a combination of these predispose to kidney damage damage


Classification of complicated and uncomplicated Classification of complicated and uncomplicated UTIUTI



Complicated UTIComplicated UTI Episodes may be refractory to therapy, often resulting Episodes may be refractory to therapy, often resulting

in relapses and occasionally leading to significant in relapses and occasionally leading to significant sequelae such as sepsis, metastatic abscess and sequelae such as sepsis, metastatic abscess and rarely acute renal failurerarely acute renal failure

Uncomplicated UTIUncomplicated UTI An episode of cysto-urethritis following bacterial An episode of cysto-urethritis following bacterial

colonization of the ureteral and bladder mucosaecolonization of the ureteral and bladder mucosae Considered to be uncomplicated because sequelae are rare Considered to be uncomplicated because sequelae are rare

and exclusive due to the morbidity associated with and exclusive due to the morbidity associated with reinfection in a subset of women reinfection in a subset of women

A subset of patients with pyelonephritis (acute uncomplicated A subset of patients with pyelonephritis (acute uncomplicated pyelonephritis), namely, young women who respond well to pyelonephritis), namely, young women who respond well to therapy may also have a low incidence of sequelaetherapy may also have a low incidence of sequelae



Recurrent infection-reinfection, relapseRecurrent infection-reinfection, relapse Reinfection Reinfection

A recurring infection due to a different A recurring infection due to a different microorganism that is usually drug susceptiblemicroorganism that is usually drug susceptible

Most recurring episodes of cysto-uretheritis are Most recurring episodes of cysto-uretheritis are due to reinfections that are much more common due to reinfections that are much more common than relapse and accounts for about 80% of than relapse and accounts for about 80% of recurrent infectionsrecurrent infections

Does not represent failure to eradicate infection Does not represent failure to eradicate infection from urinary tract (unlike relapse) but is due to from urinary tract (unlike relapse) but is due to reinvasion of the systemreinvasion of the system

Prophylactic measures must be initiatedProphylactic measures must be initiated



Recurrent infection-reinfection, relapse Recurrent infection-reinfection, relapse Relapse Relapse

A return of infection due to the same micro-A return of infection due to the same micro-organism which is often drug resistantorganism which is often drug resistant

Defined as the recurrence of bacteriuria with the Defined as the recurrence of bacteriuria with the same organism within three weeks of completing same organism within three weeks of completing treatment, which during treatment rendered the treatment, which during treatment rendered the urine sterileurine sterile

Implies that there has been a failure to eradicate Implies that there has been a failure to eradicate the infectionthe infection

This most often occurs in association with renal scars, This most often occurs in association with renal scars, stones, cystic disease or prostatitis and in patients with stones, cystic disease or prostatitis and in patients with chronic interstitial disease or in those who are immune chronic interstitial disease or in those who are immune compromised compromised



Recurrent infection-treatment failure Recurrent infection-treatment failure Failure to eradicate bacteriuria during treatment and Failure to eradicate bacteriuria during treatment and

failure to prevent relapsefailure to prevent relapse Factors predisposing to treatment failure:Factors predisposing to treatment failure:

Recent antibiotic treatment Recent antibiotic treatment Hospital acquired infection Hospital acquired infection Renal or bladder calculi Renal or bladder calculi Obstructive uropathy Obstructive uropathy Renal cysts Renal cysts Renal diseases such as reflux nephropathy, chronic Renal diseases such as reflux nephropathy, chronic

interstitial nephropathy, analgesic nephropathy, diabetic interstitial nephropathy, analgesic nephropathy, diabetic nephropathy, sickle cell nephropathy, immunosuppression, nephropathy, sickle cell nephropathy, immunosuppression, and prostatitisand prostatitis


Risk factorsRisk factors

The understanding The understanding Can facilitate early recognition and possible Can facilitate early recognition and possible

preventionprevention Associations have been established between Associations have been established between

UTI and UTI and Age, pregnancy, sexual intercourse, use of Age, pregnancy, sexual intercourse, use of

diaphragm and a spermicide, delayed post-coital diaphragm and a spermicide, delayed post-coital micturition, menopause and a history of recent UTImicturition, menopause and a history of recent UTI

N Engl J Med 1996;335:468-74.

Risk factors Risk factors (Contd)(Contd)

Factors that do not seem to increase the Factors that do not seem to increase the risk of UTI include risk of UTI include Diet, use of tampons, clothing and personal Diet, use of tampons, clothing and personal

hygiene including methods of wiping after hygiene including methods of wiping after defecation and bathing practicesdefecation and bathing practices

N Engl J Med 1996;335:468-74.

Pathogenesis of UTI caused by Pathogenesis of UTI caused by uropathogenic uropathogenic E. coliE. coli. .

Nature Reviews Microbiology 2004; 2, 123-40.

Clinical settingClinical setting

Asymptomatic bacteriuriaAsymptomatic bacteriuria

Symptomatic UTISymptomatic UTI


Clinical setting Clinical setting

Asymptomatic bacteriuriaAsymptomatic bacteriuria This is especially common in women as This is especially common in women as

evidenced by a minimum prevalence of 2-4% evidenced by a minimum prevalence of 2-4% in young and 10% in elderly womenin young and 10% in elderly women

The cumulative prevalence of asymptomatic The cumulative prevalence of asymptomatic bacteriuria in women increases about 1% per bacteriuria in women increases about 1% per decade throughout life regardless of ethnicity decade throughout life regardless of ethnicity and geographic locations and geographic locations


Asymptomatic bacteriuria Asymptomatic bacteriuria (Contd)(Contd)

In contrast to women, the occurrence of In contrast to women, the occurrence of asymptomatic bacteriuria in men is rare asymptomatic bacteriuria in men is rare until after 55 years of age, at which time until after 55 years of age, at which time the prevalence increases per decade and the prevalence increases per decade and approaches the rate in elderly womenapproaches the rate in elderly women Prostatic hypertrophy and increased likelihood Prostatic hypertrophy and increased likelihood

of instrumentation account for the bacteriuria of instrumentation account for the bacteriuria in older men in older men


Asymptomatic bacteriuria Asymptomatic bacteriuria (Contd)(Contd)

Differences between men and women in Differences between men and women in the rates of bacteriuria have been the rates of bacteriuria have been attributed to the shorter female urethra attributed to the shorter female urethra and its proximity to the vagina and rectal and its proximity to the vagina and rectal mucosa and their abundant microbial flora mucosa and their abundant microbial flora


Symptomatic UTISymptomatic UTI

These occur in all age groupsThese occur in all age groups Among newborns and infants, boys are affected more Among newborns and infants, boys are affected more

than the girlsthan the girls When urinary tract is the source of neonatal sepsis, serious When urinary tract is the source of neonatal sepsis, serious

underlying congenital anomalies are frequently present underlying congenital anomalies are frequently present

During childhood, persistent bacteriuria with or During childhood, persistent bacteriuria with or without repeated symptomatic episodes occurs in a without repeated symptomatic episodes occurs in a small group (< 2%) of school-aged girlssmall group (< 2%) of school-aged girls Such girls and also school-aged boys with bacteriuria should Such girls and also school-aged boys with bacteriuria should

have a urological evaluation to detect correctable structural have a urological evaluation to detect correctable structural abnormalities when UTIs are documented abnormalities when UTIs are documented


Frequency Frequency distribution of distribution of symptomatic UTI symptomatic UTI and prevalence of and prevalence of asymptomatic asymptomatic bacteriuria by age bacteriuria by age

and sexand sex (Male – shaded area; (Male – shaded area; Female – line)Female – line)


Symptomatic UTI Symptomatic UTI (Contd)(Contd)

Sexually active women have a markedly Sexually active women have a markedly increased risk of cystitisincreased risk of cystitis Vast majority of acute symptomatic infections involve Vast majority of acute symptomatic infections involve

young womenyoung women A prospective study demonstrated an annual A prospective study demonstrated an annual

incidence of 0.5-0.7 episodes/patient year in this incidence of 0.5-0.7 episodes/patient year in this groupgroup

In the absence of prostatitis, bacteriuria and In the absence of prostatitis, bacteriuria and symptomatic UTIs are unusual in mensymptomatic UTIs are unusual in men

The risk of cystitis in young men due to uropathogenic The risk of cystitis in young men due to uropathogenic colicoli increases because of lack of circumcision or increases because of lack of circumcision or having a partner with vaginal colonization with such having a partner with vaginal colonization with such P-fimbriated P-fimbriated E. coliE. coli..


Symptomatic UTI Symptomatic UTI (Contd)(Contd)

At any age, both sexes may develop symptomatic At any age, both sexes may develop symptomatic infections in the presence of risk factors that alter infections in the presence of risk factors that alter urinary flow. These include:urinary flow. These include:1. Congenital anomalies1. Congenital anomalies2. Renal calculi2. Renal calculi3. Ureteral occlusion (partial or total)3. Ureteral occlusion (partial or total)4. Vesico-ureteral reflux4. Vesico-ureteral reflux5. Residual Urine in bladder, neurogenic bladder, 5. Residual Urine in bladder, neurogenic bladder, urethral stricture, prostatic hypertrophyurethral stricture, prostatic hypertrophy6. Instrumentation of urinary tract indwelling urinary 6. Instrumentation of urinary tract indwelling urinary catheters, catheterization, urethral dilatation, catheters, catheterization, urethral dilatation, cystocopycystocopy


Clinical features Clinical features

Acute urethral syndromeAcute urethral syndrome The cardinal symptoms of frequency and dysuria The cardinal symptoms of frequency and dysuria

occur in > 90% of ambulatory patients with acute occur in > 90% of ambulatory patients with acute genitourinary tract infectionsgenitourinary tract infections However, one-third to one- half of all these patients do However, one-third to one- half of all these patients do

not have significant bacteriuria, although most have not have significant bacteriuria, although most have pyuriapyuria

These patients have acute urethral syndrome which can These patients have acute urethral syndrome which can mimic both bladder and renal infectionsmimic both bladder and renal infections

Vaginitis, urethritis and prostatitis are common Vaginitis, urethritis and prostatitis are common causes of the acute urethral syndromecauses of the acute urethral syndrome


Clinical featuresClinical features(Contd)(Contd)

VaginitisVaginitis The presence of an abnormal vaginal discharge The presence of an abnormal vaginal discharge

(leucorrhoea) and irritation makes vaginitis the (leucorrhoea) and irritation makes vaginitis the likely cause of dysuria unless a concomitant UTI likely cause of dysuria unless a concomitant UTI can be confirmed by culturecan be confirmed by culture

Candida albicansCandida albicans The most common specific cause of vaginitis, can be The most common specific cause of vaginitis, can be

demonstrated by culture or by finding yeast cells in a demonstrated by culture or by finding yeast cells in a gram-stained smear of vaginal secretions or in a saline gram-stained smear of vaginal secretions or in a saline preparation with the addition of potassium hydroxidepreparation with the addition of potassium hydroxide


Clinical features Clinical features (Contd)(Contd)

VaginitisVaginitis Trichomoniasis can be documented with a saline Trichomoniasis can be documented with a saline

preparation that shows the motile protozoa of preparation that shows the motile protozoa of trichomonas vaginitistrichomonas vaginitis

Generally, nonspecific vaginitis is associated with Generally, nonspecific vaginitis is associated with gardenerella vaginitisgardenerella vaginitis A clue of this diagnosis is the presence of many small Gram-A clue of this diagnosis is the presence of many small Gram-

negative bacilli that adhere to vaginal epithelial cells negative bacilli that adhere to vaginal epithelial cells



Urethritis Urethritis Acute urinary frequency, dysuria and pyuria in the Acute urinary frequency, dysuria and pyuria in the

absence of vaginal symptoms favor the diagnosis absence of vaginal symptoms favor the diagnosis of urethritis or UTIof urethritis or UTI

Chlamydia trachomatisChlamydia trachomatis is the common cause of is the common cause of the acute urethral syndrome in women and of the acute urethral syndrome in women and of nonspecific urethritis in mennonspecific urethritis in men

Neisseria gonorrhoeaeNeisseria gonorrhoeae is an important cause of is an important cause of urethritis and dysuriaurethritis and dysuria



Urethritis Urethritis (Contd)(Contd)

Herpes simplex virus, usually type 2, is another Herpes simplex virus, usually type 2, is another sexually transmitted agent that can cause severe sexually transmitted agent that can cause severe dysuria through ulceration in close proximity to dysuria through ulceration in close proximity to the urethral orificethe urethral orifice The diagnosis of Herpes progenitalis can be confirmed The diagnosis of Herpes progenitalis can be confirmed

by finding giant multinucleated transformed cells in by finding giant multinucleated transformed cells in epidermal scrapings stained with Wright's stain (Tzanck epidermal scrapings stained with Wright's stain (Tzanck Smear), by isolating the virus in tissue cultures or by Smear), by isolating the virus in tissue cultures or by direct fluorescent antibody test.direct fluorescent antibody test.



ProstatitisProstatitis Prostatitis is a common problem in men that Prostatitis is a common problem in men that

causes dysuria and urinary frequency in middle-causes dysuria and urinary frequency in middle-aged and younger men more frequently than UTI aged and younger men more frequently than UTI dodo

Prostate syndromes have classically been Prostate syndromes have classically been divided into four clinical entitiesdivided into four clinical entities1.1. Acute bacterial prostatitis Acute bacterial prostatitis

2.2. Chronic bacterial prostatitis Chronic bacterial prostatitis

3.3. Nonbacterial prostatitis Nonbacterial prostatitis

4.4. ProstatodyniaProstatodynia



Prostatitis Prostatitis (Contd)(Contd)

Consensus classification of prostatitis Consensus classification of prostatitis syndromes has come upsyndromes has come up This classification includes four categories and two This classification includes four categories and two

subcategories. subcategories. 1.1. Acute bacterial prostatitis; Acute bacterial prostatitis; 2.2. Chronic bacterial prostatitis; Chronic bacterial prostatitis; 3.3. Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS); Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS); 4.4. Asymptomatic inflammatory prostatitisAsymptomatic inflammatory prostatitis

CP/CPPS has been divided in to two sub-categories:CP/CPPS has been divided in to two sub-categories: Inflammatory CP/CPPS; and Inflammatory CP/CPPS; and Non- inflammatory CP/CPPSNon- inflammatory CP/CPPS

JAMA 1999;282:236-7.

Diagnosis Diagnosis Microscopic examination of urineMicroscopic examination of urine A centrifuged sediment, patients with significant A centrifuged sediment, patients with significant

bacteriuria almost always show bacilli in the urine, bacteriuria almost always show bacilli in the urine, whereas whereas

Only app. 10% of patients with < 10 Only app. 10% of patients with < 10 55 CFU/ml show CFU/ml show bacteriabacteria

About 60-85% of patients with significant bacteriuria About 60-85% of patients with significant bacteriuria have have ≥≥10 wbc/hpf in the segment of mid-stream urine10 wbc/hpf in the segment of mid-stream urine

Also 25% of patients with negative urine cultures also Also 25% of patients with negative urine cultures also have pyuria, have pyuria, ≥≥ 10 wbc/hpf and 10 wbc/hpf and

Only approximately 40% of patients with pyuria have 10 Only approximately 40% of patients with pyuria have 10 55 or more bacteria per ml of urine by qualitative culturesor more bacteria per ml of urine by qualitative cultures

Wbc/hpf – white blood cells per high power fieldIndian J Nephrol 2009;19:129-39.

Diagnosis Diagnosis (Contd)(Contd)

PyuriaPyuria 95% of patients with pyuria have a 95% of patients with pyuria have a

genitourinary tract infection; however, genitourinary tract infection; however, pyuria cannot distinguish a bacterial UTI pyuria cannot distinguish a bacterial UTI from acute urethral syndromefrom acute urethral syndrome Tuberculosis, analgesic nephropathy, Tuberculosis, analgesic nephropathy,

interstitial nephritis, perinephric abscess, interstitial nephritis, perinephric abscess, renal cortical abscess, disseminated fungal renal cortical abscess, disseminated fungal infection and appendicitis may also result in infection and appendicitis may also result in pyuriapyuria



Gram strainGram strain A simple Gram-stained smear can A simple Gram-stained smear can

enhance the specificity of the test because enhance the specificity of the test because morphology and stain characteristics aid in morphology and stain characteristics aid in identifying the likely pathogen and in identifying the likely pathogen and in targeting empiric therapy targeting empiric therapy



Examination of Gram Stains of UrineExamination of Gram Stains of Urine Escherichia coliEscherichia coli


Examination of Gram Stains of UrineExamination of Gram Stains of UrineStaphylococcus saprophyticusStaphylococcus saprophyticus


Urine cultureUrine culture The diagnosis of UTI from simple cystitis to complicated The diagnosis of UTI from simple cystitis to complicated

pyelonephritis with sepsis can be established with pyelonephritis with sepsis can be established with absolute certainty only by cultures of urineabsolute certainty only by cultures of urine

The major indications for urine cultures are:The major indications for urine cultures are: Patients with symptoms or signs of UTIs; Patients with symptoms or signs of UTIs; Follow-up of recently treated UTI; Follow-up of recently treated UTI; Removal of indwelling urinary catheter; Removal of indwelling urinary catheter; Screening for asymptomatic bacteriuria during pregnancy; and Screening for asymptomatic bacteriuria during pregnancy; and Patients with obstructive uropathy and stasis, before Patients with obstructive uropathy and stasis, before

instrumentationinstrumentation



Urine cultureUrine culture (Contd)(Contd)

Urine specimens must be cultured promptly Urine specimens must be cultured promptly within 2h or can be preserved by refrigeration or within 2h or can be preserved by refrigeration or a suitable chemical additive (boric acid sodium a suitable chemical additive (boric acid sodium formate). formate).

Acceptable methods of collection are:Acceptable methods of collection are: Midstream urine after careful washing; Midstream urine after careful washing; Urine obtained by single catheterization; Urine obtained by single catheterization; Urine obtained by supra pubic needle aspiration; and Urine obtained by supra pubic needle aspiration; and Sterile needle aspiration of urine from the tube of a Sterile needle aspiration of urine from the tube of a

closed catheter drainage systemclosed catheter drainage system



Urine cultureUrine culture (Contd)(Contd)

Results of cultures depend on the clinical setting in Results of cultures depend on the clinical setting in which bacteriuria occurswhich bacteriuria occurs

For example, For example, E. coliE. coli are found in the urine of 80-90% of are found in the urine of 80-90% of patients with acute uncomplicated cystitis and acute patients with acute uncomplicated cystitis and acute uncomplicated pyelonephritisuncomplicated pyelonephritis

Many patients with staghorn calculi harbour urea-splitting Many patients with staghorn calculi harbour urea-splitting proteus organisms in their urineproteus organisms in their urine

KlebsiellaKlebsiella, , Pseudomonas Pseudomonas and and EnterobacterEnterobacter infections infections are commonly acquired in the hospitalare commonly acquired in the hospital

The presence of The presence of Staphylococcus aureusStaphylococcus aureus often is a clue often is a clue to concomitant to concomitant StaphylococcalStaphylococcal bacteremia, unless an bacteremia, unless an underlying risk factor existsunderlying risk factor exists



Urine culture with greater than 100,000 colony-Urine culture with greater than 100,000 colony-forming units (CFU) of forming units (CFU) of Escherichia coliEscherichia coli


Urine cultureUrine culture Micro-organisms in young men are similar to the organisms that Micro-organisms in young men are similar to the organisms that

cause uncomplicated infections in womencause uncomplicated infections in women Enterococci and coagulase-negative staphylococci are more Enterococci and coagulase-negative staphylococci are more

common in elderly men; most likely representing recent common in elderly men; most likely representing recent instrumentation or catheterizationinstrumentation or catheterization

C. albicansC. albicans is rarely encountered except in patients with indwelling is rarely encountered except in patients with indwelling catheters, nosocomial UTIs or relapsing infections after multiple catheters, nosocomial UTIs or relapsing infections after multiple courses of antibioticscourses of antibiotics

Although the likely organism and usual susceptible patterns are Although the likely organism and usual susceptible patterns are sufficient to guide initial empiric therapy of uncomplicated UTI,sufficient to guide initial empiric therapy of uncomplicated UTI, Adequate treatment of acute bacterial pyelonephritis and complicated Adequate treatment of acute bacterial pyelonephritis and complicated

UTIs necessitates precise therapy based on isolation of the causative UTIs necessitates precise therapy based on isolation of the causative bacterium and its antimicrobial susceptibility bacterium and its antimicrobial susceptibility



Imaging studiesImaging studies In general, imaging should be done 3-6 weeks In general, imaging should be done 3-6 weeks

after cure of acute infection to identify after cure of acute infection to identify abnormalities predisposing to infection or renal abnormalities predisposing to infection or renal damage or which may affect managementdamage or which may affect management Rarely, imaging is carried out in the acute phase, Rarely, imaging is carried out in the acute phase,

particularly where there is severe loin pain, to identify particularly where there is severe loin pain, to identify possible sepsis (pyonephrosis or abscess) or to possible sepsis (pyonephrosis or abscess) or to differentiate acute pyelonephritis from ureteric colicdifferentiate acute pyelonephritis from ureteric colic

It is important to recognize that abnormalities will be It is important to recognize that abnormalities will be found in < 5% of unselected cases found in < 5% of unselected cases



Imaging studies Imaging studies (Contd)(Contd)

Plain X-ray of abdomenPlain X-ray of abdomen These are used to show the presence and extent These are used to show the presence and extent

of calcification in the urinary tractof calcification in the urinary tract Less sensitive in the detection of ureteric calculiLess sensitive in the detection of ureteric calculi Plain films are of value in monitoring change in Plain films are of value in monitoring change in

position, size and number of calculiposition, size and number of calculi




Ultrasound (USG) Ultrasound (USG) Combined with plain X-ray has become the Combined with plain X-ray has become the

imaging method of choice in patients with imaging method of choice in patients with recurrent infectionsrecurrent infections

Sensitive detector of pelvicalyceal dilatation, Sensitive detector of pelvicalyceal dilatation, indicative of possible obstructionindicative of possible obstruction Echoes within a dilated pelvicalyceal system, either Echoes within a dilated pelvicalyceal system, either

diffuse or layered, suggest the presence of diffuse or layered, suggest the presence of pyonephrosispyonephrosis

Can guide drainage of an obstructed kidney Can guide drainage of an obstructed kidney




Ultrasound (USG) Ultrasound (USG) (Contd)(Contd)

Provides accurate renal length measurements Provides accurate renal length measurements and identifies the majority of renal scars, and identifies the majority of renal scars, abscesses and perinephric fluid collectionsabscesses and perinephric fluid collections

May show short segments of dilated ureter May show short segments of dilated ureter adjacent to the renal pelvis, at pelvic brim level adjacent to the renal pelvis, at pelvic brim level or behind the full bladderor behind the full bladder

Can also assess the bladder for wall thickness, Can also assess the bladder for wall thickness, calculi, diverticula and emptying as well as calculi, diverticula and emptying as well as assess prostate sizeassess prostate size




Intravenous urography (IVU)Intravenous urography (IVU) Provides anatomical detail of the calyces, pelvis Provides anatomical detail of the calyces, pelvis

and ureter not obtained from USGand ureter not obtained from USG Calyceal detail is essential to diagnose papillary Calyceal detail is essential to diagnose papillary

necrosis and medullary sponge kidney and necrosis and medullary sponge kidney and careful assessment of the calyces and overlying careful assessment of the calyces and overlying parenchyma is necessary to diagnose reflex parenchyma is necessary to diagnose reflex nephropathynephropathy




Intravenous urography (IVU) Intravenous urography (IVU) (Contd)(Contd)

Gram-negative bacilli have the ability to Gram-negative bacilli have the ability to impede ureteral peristalsis and transient impede ureteral peristalsis and transient abnormalities of the IVU are common with abnormalities of the IVU are common with acute pyelonephritisacute pyelonephritis Include hydroureter, vesico-ureteric reflux, diminished Include hydroureter, vesico-ureteric reflux, diminished

pyelogram, loss of renal outline and renal enlargementpyelogram, loss of renal outline and renal enlargement Should also be avoided for the first 6-12 weeks after Should also be avoided for the first 6-12 weeks after

pregnancy to allow resolution of the physiological dilatation pregnancy to allow resolution of the physiological dilatation of the pelvicalyceal system and ureterof the pelvicalyceal system and ureter




Computed tomography (CT)Computed tomography (CT) The most common method of detecting renal and ureteric The most common method of detecting renal and ureteric

calculi, including calculi that are lucent on plain calculi, including calculi that are lucent on plain radiographsradiographs

Sensitive detector of pelvicalyceal dilatations, renal Sensitive detector of pelvicalyceal dilatations, renal abscesses and perinephric collections than USGabscesses and perinephric collections than USG

Contrast enhanced CT is very sensitive for acute Contrast enhanced CT is very sensitive for acute pyelonephritispyelonephritis

However, CT involves more radiation than even IVU, the However, CT involves more radiation than even IVU, the potential risks of contrast media and is more expensive and potential risks of contrast media and is more expensive and than USG than USG Therefore, it should be reserved as a second-line investigation Therefore, it should be reserved as a second-line investigation

for patients with severe infection not responding to for patients with severe infection not responding to appropriate treatment or for diagnostic problems not resolved appropriate treatment or for diagnostic problems not resolved by IVU or USGby IVU or USG



Imaging studiesImaging studies (Contd)(Contd)

Static renal scintigraphyStatic renal scintigraphy Di-mercapto-succinic acid (DMSA) Di-mercapto-succinic acid (DMSA)

scintigraphy scintigraphy is a sensitive detector of renal is a sensitive detector of renal parenchymal infection in childrenparenchymal infection in children


ConclusionsConclusions

UTI is common infectionUTI is common infection Understanding regarding upper/lower UTI, Understanding regarding upper/lower UTI,

complicated/uncomplicated UTI etc are complicated/uncomplicated UTI etc are helpful for better diagnosis and helpful for better diagnosis and managementmanagement

Clinical features and laboratory Clinical features and laboratory investigations are helpful for accurate investigations are helpful for accurate diagnosis and further approachdiagnosis and further approach

Urinary tract infections – Introduction, clinical features and diagnosis Dr.

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