Urinary Tract Infections

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Overview of UTI

7 million office visits yearly 1 million hospitalizations About 2/3rds of patients are women

◦ 40% to 50% of women have UTI at some point during their lives

Important complications of pregnancy, diabetes mellitus, polycystic disease, renal transplantation, conditions that impede urine flow (structural and neurologic)

Terms

Urinary tract infection Significant bacteriuria Asymptomatic bacteriuria Acute pyelonephritis Chronic pyelonephritis Chronic interstisial nephritis Pyuria Urethral syndrome

UTI: the finding of microorganisms in bladder urine with or without clinical symptoms and with or without renal disease Women: Presence of at least 100,000 colony-forming units (cfu)/mL in a pure culture of voided clean-catch urine.

Men: Presence of just 1,000 cfu/mL

Significant bacteriuria: the number of bacteria in the voided urine exceeds the number that can be expected from contamination (i.e. ≥ 10⁵ cfu/ml)

Asymptomatic bacteriuria: Significant bacteriuria (>105 cfu/ml) without clinical symptoms.

Acute bacterial pyelonephritis: a clinical syndrome of fever, flank pain, and / or tenderness

Chronic bacterial pyelonephritis: Long-standing infection associated with active bacterial growth in the kidney; or the residum of lesions caused by such infection in the past

Chronic interstitial nephritis: renal disease with histologic findings resembling chronic bacterial pyelonephritis but without evidence of infection

Pyuria: the presence of pus (WBC’s) in urine, which may or may not be caused by UTI. The preferred method for quantification is enumeration in unspun urine. The leukocyte esterase nitrite test has a sensitivity of between 70% and 90% for symptomatic UTI

Urethral syndrome: characterized by frequency, dysuria, and suprapubic discomfort without demonstrable infection

Some Classifications of

UTI

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Presentation of UTIs Urethritis

o The inflammation and infection is limited to the urethrao It is usually a sexually transmitted disease.o Present in men and women

Cystitiso Irritation of the lower urinary tract mucosa (i.e. bladder)o Dysuria (painful urination)o Urgency & frequency but smallo Suprapubic tendernesso Pyuria

Haemorrhagic cystitiso Large quantities of visible blood in the urineo Caused by an infection (bacterial or viral)o Irritation when voiding

Pyelonephritiso Kidney infection from lower UTI infectiono Complications – Sepsis, septic shock and death

Uncomplicated vs Complicated UTI

Uncomplicated UTI: infection that occurs in a structurally and neurologically normal urinary tract

Females > Males

Complicated UTI: infection in a urinary tract with functional or structural abnormalities (including indwelling catheters and renal calculi)

Females = Males In elderly men are always considered complicated In women are complicated when:

Hx of recurrent UTI Secondary to structural abnormalities Catheters Stones Urinary retention Abscess formation or urosepsis

Primary Vs. Recurrent

Primary UTI Infection that occurs in the urinary

tract for the first time. No previous episodes of infections.

Recurrent UTI Presence of past history of urinary

tract infection

RecurrentRelapse Vs. Reinfection

Relapse  Recurrence within 2 weeks of

treatment and mainly due to treatment failure, the initial organism is not totally cleared.

The Same Organism

Occurs in case of:• Acute Upper UTI.• Presence of obstruction like stone

disease.

ReinfectionRecurrence within several weeks after

the antibiotic therapy has cleared up the initial episode.

Different Organisms

Lower Urinary Tract Infection(Urethritis and Cystitis)

Vs

Upper Urinary tract Infection(Pyelonephritis)

Acute Uncomplicated Cystitis Acute bacterial cystitis is usually

characterized by sudden onset, multiple urinary symptoms, pyuria, and sometimes hematuria

Acute dysuria in young women usually indicates: acute bacterial cystitis; the urethral syndrome; or vaginitis

Although most patients have lower urinary symptoms only, 30% to 50% may have subclinical renal involvement

Causes: E. coli (80%), S. saprophyticus (10% to 15%), and occasionally Klebsiella, Proteus mirabilis, and other microorganisms.

Acute Uncomplicated Pyelonephritis Largely a clinical diagnosis Pyuria is usually present; about 20%

have positive blood cultures; causative organisms the same as with cystitis

Predisposing factors: structural abnormalities; strains of E. coli with unique markers; genetically-determined carbohydrate receptors on uroepithelial cells

Highly significant! Presence of WBC casts suggests pyelonephritis

Physiologic changes with aging in the urinary tractAge-Related Changes Men WomenDecreased bladder capacity and increased urine production (especially at night)

Decreased voided volume

Decreased estrogen w/menopause leads to thinning of vaginal & urethral mucosa

Decreased lower urinary tract sensory threshold

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√Palmer, 2004

Urinary Tract InfectionPhysiologic Changes

Physiologic changes with aging in the urinary tract

Age-Related Changes Men Women

Problems of urinary storage & emptying

↑incidence of overflow incontinence from urethral obstruction or stricture

Decreased estrogen levels leads to pH changes in vagina, favoring colonization of E. coli, ↑risk of UTI

Prostatic enlargement can lead to urinary obstruction, increased residual urine & infection

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Palmer, 2004

Risk Factors Organisms Rout of Infection Symptoms - History Signs – Physical Exam Differential Diagnosis Investigation Treatment Complications

Urinary Tract Infections

Risk Factors

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Risk Factors

General Conditions Diabetes Previous urinary tract infection Kidney Problems Immunosuppression Sickle Cell Disease Functional or mental impairment Urinary Stone Disease Urinary Tract Anomalies Neurogenic Bladde

Urologic instrumentation or surgery Urethral catheterization Renal transplantation spinal injury

Risk Factors

Specific for Females

Structure of Urinary Tract. Sexual Behavior. It is not STD Contraception. Pregnancy Menopause

Risk Factors

Specific for Males

Benign Prostatic Hypertrophy

Prostatitis

Risk Factors

Specific for Children

Uncircumcised Males

Vesicoureteral Reflux Disease.

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

)Male – shaded area; Female – line(

Organisms

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OrganismsGram Negative Organisms

E.Coli In Acidic Urine (most common)

Proteus In Alkali Urine

Klebsiella

Citrobacter

Pseudomonas

OrganismsGram Positive Organisms

Staphylococcus Aureus

Staphylococcus Epidermidis

Streptococcus Feacalis

OrganismsFungal Infections

Mainly in Diabetic Patients.

Candida Species

Rout of Infection

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Rout of Infection

Ascending Infection.◦ The common route of nearly all forms of urinary

tract infection (bacteria initially colonize periurethral tissues)

◦ Common in females than in males because of shorter urethra

◦ Single bladder catheterization can result in UTI in 1% of the ambulatory population

Lymphatic Spread. Increase bladder pressure can cause lymphatic flow

to be directed toward the kidney

Local Spread.

Rout of Infection

Hematogenous Spread.• Frequently seen with Staphylococcus aureus

bacteremia or endocarditis• Also seen to occur in experimental models with

Candida• Infections with gram negative bacilli rarely occurs

by this route Descending From the Kidneys Local Spread.

Symptoms - History

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Symptoms - History

Lower Urinary Tract Infection

Frank Hematurea.

Painful Micturation.

Discomfort in the lower abdomen.

Urinary Frequency.

Urinary Urgency.

Symptoms - History

Upper Urinary Tract Infection

High Grade Fever, chills and rigor.

Flank Pain.

Nausea and Vomiting

Lower UTI Symptoms.

Signs – Physical Exam

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Signs – Physical Exam

Vital Signs

Suprapubic Tenderness

Flank Tenderness

Based on the symptoms both

a clinical diagnosis of a UTI and a differentiation between lower (cystitis) or upper (pyelonephritis) UTI should be made

Differential Diagnosis

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Differential Diagnosis

Lower UTI

Stones.

Vaginitis and STD

Interstitial Cystitis.

Menopausal Changes.

Prostate Disease.

Differential Diagnosis

Upper UTI

Pneumonia.

Cholecystitis.

Appendicitis.

Kidney Stones.

Investigation

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Investigation

Dipstick Test

Nitrites Test

Leukocyte Esterase Test.

Blood.

Proteins.

Investigation

Microscopic Examination

WBC’s Count.

RBC’s Count.

Cellular and Hyaline Casts.

Investigation

Clinical Symptoms

Plus

Suggestive Dipstick

Plus

Suggestive Microscopic ExamEqual

Urinary Tract Infection (75%)

Investigation

Gram Stain and Urine Culture

Urine culture is gold standard.

Used in every positive dipstick and urinalysis.

Used in negative dipstick and urinalysis if:

- Age less than 2 Years.

- UTI symptoms (25%).

Investigation

Helpful Laboratory Tests

CBC

Serum Electrolytes

KFT

Blood Culture.

Investigation

Imaging Studies

Recurrent cases of pyelonephritis

Structural abnormalities are suspected.

No response to treatment.

Suspicion of obstruction.

Children: age 2 - 24 months

Investigation

Ultrasound

Screening for hydronephrosis.

Kidney Stones.

Kidney Abscess.

Investigation

Nuclear Scan

Kidney Scar.

InvestigationX-rays

Stones. Structural Abnormalities. Urethral Narrowing. Incomplete Bladder Emptying. Examples:

- MCUG- IVP and KUB

Symptomaticpatient

Uncomplicated cystitisin a woman,

no risk factorsnot a relapse

Typical symptoms, < 2 infections / year,

patient familiar withher illness

Bacterial culture,"on the spot" testingto confirm diagnosis

Starttreatmentbased onresults

Antibiotictherapy

Yes

No

No

Yes

TreatmentUpper UTI

Good Hydration.

Oral TMP-SMX or Quinolones for 2 weeks.

Oral amoxicillin and clavulanic acid for 2 weeks.

TreatmentLower UTI

Good Hydration.

Oral TMP-SMX or Quinolones for 1 week.

Relapses are best treated with the same AB, long period.

Treatment

Reinfections

Long term AB prophylaxis.

Surgical reimplantation of the ureters >>> VUR disease

Treatment

Failure of Treatment

Compliance and AB Dose. Bacterial Resistance. Polymicrobial UTI. Azotemia. Papillary Necrosis. Staghorn Calculi.

Prophylaxis of recurrent cystitis with antimicrobial agents

prophylaxis should be considered when more than 3 infections per year

prophylaxis to continue for 6 months if infections recur after prophylactic

treatment, the prophylaxis is re-commenced for 6 – 12 months

Drugs of choice in UTI prophylaxis

First choice: trimethoprim 100 mg in the evenings nitrofurantoin 50 - 75 mg in the eveningsSecond choice: methenamine hippurate 1 g twice daily norfloxacin 200 mg daily or on 3 evenings per week nitrofurantoin (not if serum creatinine is above 150 μmol/l) quinolones (in cases where there is no response with other

prophylactic medication or tolerance to other medications is poor)

During pregnancy: nitrofurantoin 50 mg daily or methenamine hippurate 1 g daily for the rest of the

pregnancy particularly if recurrent bacteriuria is diagnosed in early

pregnancy

Complications

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Complications

Spread of Infection

- Sepsis.- Prostatitis.- Epididymitis.

Persistence of Infection

- Perinephric Abscess.- Chronic Infection.

Complications

Obstruction.

Kidney Scar.

Kidney Stones

That will be all … thanks for not falling asleep ;)Bye Bye