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The pathogenic track to urinary tract URINARY TRACT INFECTIONS Ibrahim Al-Orainey,FACP,FRCP(Lond) Professor of medicine Faculty of Medicine, King Saud University Urinary tract infections • Asymptomatic bacteriuria • Acute cystitis • Acute pyelonephritis Uncomplicated / complicated UTI Epidemiology of UTI • UTI is more common in females. (1-2% of young nonpregnant women) • 40% of females will have a symptomatic UTI in their life time. • In men: prevalence is 0.04%. • Incidence of UTI increases in old age. (10% of men & 20% of women) Risk factors for UTI • in females: pregnancy, spermicidal contraceptives, diaphragm, estrogen deficiency, diabetes. • In males: lack of circumcision, prostatic hypertrophy, use of condom catheter. • in both : old age , obstruction, vesicoureteric reflux, instrumentation, neurogenic bladder, renal transplantation. Infecting organisms E.coli Klebsiella Enterobacter Staphylococci Proteus Pseudomonas Enterococci Candida Pathogenesis of UTI Host defences: • Urinary bladder is usually resistant to bacterial colonisation. • Bacteria accessing the bladder are eliminated by: - flushing mechanism - urine inhibitors (PH, osmolality, urea) - uroepithelial defences (cytokines,PMNs) - Tamm- Horsfall protien Pathogenesis of UTI Organism features: • Most E.coli causing UTI belong to O,K and H serotypes. • Uropathogenic E.coli virulence factors: - Have fimbria (for adherence). - Secrete hemolysin & aerobactin. - Resist serum bacterical action. - Have higher K capsular antigen. • Adherence is important in other bacteria. Pathogenesis of UTI • Periutheral area & urethra are colonised by bacteria. • Bacteria enter bladder in susceptable host. • Adherence properties enable pathogens to colonise bladder. • Pathogens attach to uroepithelial mucosa secretion of cytokines recruitment of PMNs inflammation. • Pathogens may ascend through ureter to kidney pyelonephritis. Clinical presentation of UTI Asymptomatic bacteriuria: • • • • Common in females & elderly. 25% develop symptomatic UTI . 25% clear spontaneously. Spontaneous cure & reinfection are common. Cystitis: • Frequency, dysurea , urgency. • Suprapubic discomfort +/- tenderness. • Fever is often absent. Clinical presentation of UTI Acute pyelonephritis: • • • • • Fever, abdominal pain, vomiting. Dysuria ,frequency, flank or loin pain. Flank or loin tenderness. In elderly: symptoms are often atypical. Bacteremia is common. Acute pyelonephritis Acute pyelonephritis Special situations Special situations UTI in pregnancy: • Asymptomatic bacteriuria occurs in 4-8%. • Of these: 25% develop acute pyelonephritis. • Pyelonephritis in pregnancy predisposes to: - premature delivery. - low birth weight infant. - increased newborn mortality. Special situations Catheter associated UTI : • Bacteriuria occurs in 10-15% of cathed pts. • All chronicly cathed pts. develop bacteriuria. • Organisms: E.coli, Proteus, Klebsiella, Serratia Pseudomonas, Enterococci, Candida. • Antibiotic resistance is common. • Symptoms are often absent or minimal. • Intermittent cathing reduces infections. Diagnosis of UTI • Urine dipstick: - leukocyte esterase - nitrite • Urine microscopy: -WBCs, WBC casts, RBCs - Bacteria ( 1 bact/hpf = significant ) Diagnosis of UTI Urine culture: • • • • • Significant bacteriuria= 100K cfu/ml symptoms: 1 +ve cuture = infection Symptoms: 10K cfu/ml = propable infection Asymptomatic: 2 +ve cultures = infection False negative : antibiotics, antiseptics, urethral syndrome,TB kidney, diuresis. Natural history of UTI • Treatment of uncomplicated UTI leads to complete resolution and cure. • Recurrences occur in some patients usually within 2-3 monthes of initial infection. • Frequent recurrences usually occur in clusters followed by long remissions. • Recurrent uncomplicated UTI does not lead to chronic renal impairment or failure. • Recurrent complicated UTI may lead to renal failure. • UTI may accelerate progression of underlying renal disease. Treatment of UTI Acute pyelonephritis: • Mild infections are treated orally. (fluoroquinolones,co-trimoxazole,cefuroxime) • Moderate - severe infections – parenteral trt. (aminoglycosides,ceftriaxone,aztreonam,tazocin) • Therapymarked decline in bact.count after 48hrs. • Persistant fever, +ve blood culture after 3 days of therapy..R/O obstruction, abscess. • After defervescence..change to oral therapy to complete 2 weeks. • In males look for a predisposing cause. • FU urine cultures 2 weeks after end of therapy. Treatment of UTI • Cystitis: • young females: 3 days of oral therapy (fluoroquinolone,cotrimoxazole,cefuroxime,augmentin) • In females: symptoms x 7 days or history of previous infection 7 days therapy. • In males : oral therapy for 7-10 days. Treatment of UTI Asymptomatic bacteriuria • No urgency to treat – confirm by 2 cultures. • Treatment is indicated in : - Pregnancy - Children with VU reflux - Urinary obstruction • Treatment is not indicated in : - Young nonpregnant women without structural abnormalities - Elderly patients Structural abnormalities should be corrected Treatment of UTI • Relapse of infection: • Relapse may be due to : - renal invovement - structural abnormalities - chronic bacterial prostatitis • Relapses need to be treated for 2 weeks. • Obstuction should be corrected . • If uncorrectable obstruction: treatment is prolonged for 4-6 weeks or as required. • The latter group needs FU by monthly cultures and annual assessment of kidneys. • In males R/O chronic prostatitis. Treatment of UTI Recurrent UTI: • Infrequent symptomatic UTI : treat attacks. • In females, reinfections may be related to sexual activity – attacks may be reduced by: - avioding use of spermicidal contraceptives - voiding after intercourse - post coital single dose therapy • If no precipitating factors – long term prophylaxis. • Long term prophylaxis is also indicated for frequent asymptomatic infection in: - Children with VU reflux - Patients with obtructive uropathy What is the prognosis ? So I learned something ,how about you ? وقل رب زدني علما صدق هللا العظيم Confused..I did not understand any thing,did you?