genitourinary disorders
Bacterial Urinary Tract Infections
Pathophysiology of Bacterial UTIs
The urinary tract, from the kidneys to the urethral meatus, is normally sterile and resistant to bacterial colonization despite frequent contamination of the distal urethra with colonic bacteria. The major defense against urinary tract infection (UTI) is complete emptying of the bladder during urination. Other mechanisms that maintain the tract’s sterility include urine acidity, the vesicoureteral valve, and various immunologic and mucosal barriers. About 95% of UTIs occur when bacteria ascend the urethra to the bladder and, in the case of pyelonephritis, ascend the ureter to the kidney. The remainder of UTIs are hematogenous. Systemic infection can result from UTI, particularly in older patients. Urinary tract infections are a common cause of hospital-acquired Bacteremia ( is usually considered to be Cystitis or The rare UTIs that occur in men aged 15 to 50 years are usually in men who have unprotected anal intercourse or in those who have an uncircumcised penis, and they are generally considered uncomplicated. UTIs in men this age who do not have unprotected anal intercourse or an uncircumcised penis are very rare and, although also considered uncomplicated, warrant evaluation for urologic abnormalities. Complicated UTIcan involve either sex at any age. It is usually considered to be pyelonephritis or cystitis that does not fulfill criteria to be considered uncomplicated. A UTI is considered complicated if the patient is a child, is pregnant, or has any of the following: A structural or functional urinary tract abnormality and Obstructive Uropathy None A comorbidity that increases risk of acquiring infection or resistance to treatment, such as poorly controlled Diabetes Mellitus (DM) , Recent instrumentation or surgery of the urinary tract Risk factors for development of UTI in women include the following: Sexual intercourse Diaphragm and spermicide use Antibiotic use New sex partner within the past year History of UTIs in first-degree female relatives History of recurrent UTIs First UTI at early age Risk factors for UTI in males include the following: Benign Prostatic Hyperplasia (BPH) with obstruction, common in men over 50 years Any other cause of obstruction of the urinary tract (eg, Prostate Cancer , Recent instrumentation or Catheter-Associated Urinary Tract Infections None Structural abnormalities, such as bladder diverticula Neurologic conditions that interfere with normal voiding (eg, spinal cord injury) Cognitive impairment, Fecal Incontinence or . In older women, soiling of the perineum due to Fecal Incontinence increases risk. Anatomic, structural, and functional abnormalities are risk factors for UTI. A common consequence of anatomic abnormality is Vesicoureteral Reflux (VUR) (VUR), which is present in 30 to 45% of Structural and functional urinary tract abnormalities that predispose to UTI usually involve obstruction of urine flow and poor bladder emptying. Urine flow can be compromised by Urinary Calculi and tumors. Bladder emptying can be impaired by Other risk factors for UTI include instrumentation (eg, Bladder Catheterization , stent placement, 1.Weinstein MP, Towns ML, Quartey SM, et al: The clinical significance of positive blood cultures in the 1990s: A prospective comprehensive evaluation of the microbiology, epidemiology, and outcome of bacteremia and fungemia in adults.Clin Infect Dis24(4):584-602, 1997. doi: 10.1093/clind/24.4.584 