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UTI. Ebadur Rahman FRCP ( Edin ),FASN, Specialty Certificate in Nephrology (UK) MRCP (UK), DIM (UK), DNeph (UK), MmedSciNephrology (UK). Consultant & clinical tutor Department of Nephrology Riyadh Armed Forces Hospital. Urinary Tract Infection (UTI). Background
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UTI EbadurRahman FRCP (Edin),FASN, Specialty Certificate in Nephrology (UK) MRCP (UK), DIM (UK), DNeph (UK), MmedSciNephrology (UK). Consultant & clinical tutor Department of Nephrology Riyadh Armed Forces Hospital
Urinary Tract Infection (UTI) Background 1. Bacterial infections of urinary tract are a very common reason to seek health services 2. Common in young females(50%) and uncommon in males under age 50 3. Common causative organisms • a. Escherichia coli (gram-negative enteral bacteria) causes most community acquired infections • b. Staphylococcus saprophyticus, gram-positive organism causes 10 – 15% • c. Catheter-associated UTI’s caused by gram-negative bacteria: Proteus, Klebsiella, Seratia, Pseudomonas
Natural protection Normal mechanisms that maintain sterility of urine • Adequate urine volume • Free-flow from kidneys through urinary meatus • Complete bladder emptying • Normal acidity of urine Peristaltic activity of ureters and competent ureterovesical junction • Increased intravesicular pressure preventing reflux • In males, antibacterial effect of zinc in prostatic fluid • IGA in urogenital tract
Pathophysiology 1. Pathogens which have colonized urethra, vagina, or perineal area enter urinary tract by ascending mucous membranes of perineal area into lower urinary tract • Bacteria can ascend from bladder to infect the kidneys • HEMATOGENOS ROUTE
Reinfection is a new episode of bacteriuria with a microorganism that is different from the original one (eg, bacteriuria with Klebsiella species when the original infection was caused by E coli). • Recurrence is infection that usually occurs within 2 weeks of stopping antibiotic therapy with same organism.
To obtain a clean-catch, midstream specimen, • the urethral opening is washed with a mild, nonfoaming disinfectant and air dried. • Contact of the urinary stream with the mucosa should be minimized by spreading the labia in women • and by pulling back the foreskin in uncircumcised men. • The first 5 mL of urine is not captured; the next 5 to 10 mL is collected in a sterile container. • A specimen obtained by catheterization is preferable in older women • culture, should be done within 2 h of specimen collection; if not, the sample should be refrigerated.
Microscopic examination • Pyuriais defined as ≥ 8 WBCs/μL of uncentrifuged urine, • which corresponds to 2 to 5 WBCs/high-power field in spun sediment. • Most truly infected patients have > 10 WBCs/μL. • The presence of bacteria in the absence of pyuria, especially when several strains are found, is usually due to contamination during sampling. • Microscopic hematuria occurs in up to 50% of patients, but gross hematuria is uncommon. • WBC casts, can be present in pyelonephritis, and noninfectivetubulointerstitial nephritis
Sterile pyuria • Pyuria in the absence of bacteriuria • if patients have nephrolithiasis, • a uroepithelial tumor, • TB • Women who have dysuria and pyuria but without significant bacteriuria have the urethral syndrome or dysuria-pyuria syndrome
Dipstick tests • A positive nitrite test on a freshly voided specimen is highly specific for UTI, but the test is not very sensitive. • The leukocyte esterase test is very specific for the presence of > 10 WBCs/μL and is fairly sensitive.
For outpatient treatment of uncomplicated pyelonephritis • ciprofloxacin(500 mg orally twice daily for seven days or 1000 mg extended release once daily for seven days) • or levofloxacin (750 mg orally once daily for five to seven days) • The bioavailability and urinary penetration of fluoroquinolones with oral dosing is comparable to intravenous dosing. • In women who have severe pyelonephritis, and resistance suspected -IV therapy ceftriaxone (1 gram) or an aminoglycoside (consolidated 24 hour dose) .
LOWER UTI ●Nitrofurantoin(100 mg orally twice daily for 5 days); • 90 to 95 percent cure rate • Nitrofurantoinshould be avoided if there is suspicion for early pyelonephritis, and is contraindicated when creatinine clearance is <60 mL/minute. ●Trimethoprim-sulfamethoxazole • twice daily for 3 days • clinical efficacy rate 90 to 100 percent
Medication duration • Short-course therapy: 3 day course of antibiotics for uncomplicated lower urinary tract infection; (single dose associated with recurrent infection) • 7 – 10 days course of treatment: for pyelonephritis, urinary tract abnormalities or stones, or history of previous infection with antibiotic-resistant infections
Surgery • Surgical removal calculus from renal pelvis • cystoscopic removal of bladder calculi • extracorporeal shock wave lithotripsy (ESWL) • Ureteroplasty: surgical repair of ureter for stricture or structural abnormality; • reimplantationif vesicoureteralreflux