Retrograde bacterial infections are when bacteria enter the urinary system from the urethra up through the urethra to the bladder and even into the kidneys or the parametrium or prostate. Most of the bacteria come from the intestinal tract, especially E. coli is the most common. The differential diagnosis should be made with the following symptoms: 1. Urethritis In women, UTI and vaginitis are the cause of most urinary tract symptoms when urine specimens are negative for bacterial cultures. Candida albicans, Trichomonas vaginalis or bacterial vaginitis can cause painful urination when urine flows to the inflamed labia. Although primarily painful to urinate, vaginal discharge, foul odor, and difficulty with intercourse also occur in most women. UTIs caused by sexually transmitted diseases such as Chlamydia trachomatis, Neisseria gonorrhoeae or herpes simplex virus cause mild symptoms with a slow onset and no urinary tract symptoms other than painful urination. Hematuria is often absent in mid-phase urinalysis. 2. Cystitis The presence of naked-eye hematuria strongly suggests bacterial cystitis. Microscopic examination of urine (bacterial and leukocytes) and urine culture confirm the diagnosis. Almost all female patients have pus urine, and up to 50% have microscopic hematuria. Midstream urine culture specimens generally show pathogenic bacteria, but about 30% of patients have cystitis-like symptoms without obvious bacteriuria. 3, prostatitis Because acute cystitis is often accompanied by acute prostatitis, the culture of urine excreted through the bladder can often confirm the bacterial pathogen. Because of the risk of bacteremia, doctors should not massage the acutely inflamed prostate until after the appropriate antibacterial medication reaches sufficient blood levels. Chronic prostatitis may be more insidious. It usually presents only as recurrent bacteriuria or with low-grade fever and back or pelvic discomfort. Chronic prostatitis is the most common cause of recurrent symptomatic urinary tract infections in men, as the infection continues to enter the bladder. A positive culture of prostate massage fluid confirms the diagnosis. After cleaning the periurethral region the patient urinates and an initial 5-10 ml (VB1) and a specimen from the middle section (VB2) are used for quantitative culture. The patient stops urinating before the bladder is emptied and prostate massage is performed. Any squeezed out prostatic secretion and the first 5-10 ml of urine subsequently expelled (VB3) were used for culture. The test results were interpreted as requiring 12 WBC/high magnification of bladder urine (VB2) to suspect chronic prostatitis. Culture of urine or squeezed out prostatic secretions is almost always positive in chronic prostatitis, but a negative culture cannot exclude the diagnosis. 4. Acute pyelonephritis Typical signs and symptoms of sepsis and pyelonephritis (back pain, fever, chills, painful urination) with leukocytosis found in Gram stain of uncentrifuged urine, pus and bacteriuria strongly support the diagnosis. Infections of the renal pelvis and renal parenchyma are not clinically distinguishable and usually both parts are involved at the same time. Pathologically, the finding of neutrophilic leukocytes in the tubules is equivalent to the finding of leukocytic tubular pattern in the urine. Physical examination sometimes shows a slightly tense abdomen, which should be differentiated from intra-abdominal disease. Special staining is required to identify leukocytes and tubular patterns of renal tubules. When leukocytic tubular patterns are seen, they are characteristic of the pathology of pyelonephritis, but they can also be seen in glomerulonephritis and noninfectious tubulointerstitial nephritis. Urine pH may be alkaline because of microbial breakdown of urea.