Urinary tract infection (UTI) is an inflammation caused by the growth and multiplication of pathogens (mostly bacteria, rarely can be fungi, protozoa, viruses) in the urinary tract and invasion of the mucosa or tissues of the urinary tract, and is the most common type of infection among bacterial infections. Urinary tract infections are divided into upper urinary tract infections and lower urinary tract infections. Upper urinary tract infections refer to pyelonephritis, and lower urinary tract infections include urethritis and cystitis. Depending on the presence or absence of underlying disease, urinary tract infections can also be divided into complicated and uncomplicated urinary tract infections. Pyelonephritis is further divided into acute pyelonephritis and chronic pyelonephritis.
Typical symptoms: frequent urination (73%) hematuria (65%) incomplete urination (65%) urinary urgency (63%) diabetes (60%) painful urination (52%)
The disease is most common in women of childbearing age, with a male to female ratio of about 1:8. Clinical manifestations include the following four groups.
I. Cystitis.
That is usually referred to as lower urinary tract infection. The main manifestations of cystitis in adult women are urinary tract irritation, i.e., frequent, urgent, and painful urination, leukocyturia, occasionally hematuria, or even flesh-eye hematuria, and discomfort in the bladder area. There are usually no obvious symptoms of systemic infection, but a few patients may have back pain, low fever (usually not more than 38°C), and blood leukocyte count is often not increased. About 30% or more of cystitis is self-limiting and can heal spontaneously within 7-10 days.
Second, acute pyelonephritis.
The manifestations include the following two symptom clusters.
①Urological symptoms: including bladder irritation signs such as urinary frequency, urinary urgency, and painful urination, low back pain and/or lower abdominal pain.
② Symptoms of systemic infection: such as chills, fever, headache, nausea, vomiting, loss of appetite, etc., often accompanied by elevated blood white blood cell count and increased blood sedimentation. There is usually no hypertension or azotemia.
III. Chronic pyelonephritis.
Chronic pyelonephritis has a very insidious course. Clinical manifestations are divided into the following three categories.
① manifestations of urinary tract infection: symptomatic pyelonephritis may occur intermittently in only a few patients, but more commonly manifests as intermittent asymptomatic bacteriuria, and/or intermittent urinary urgency, frequency and other symptoms of lower urinary tract infection, lumbar and abdominal discomfort and/or intermittent low-grade fever.
(ii) Chronic interstitial nephritis manifestations, such as hypertension, polyuria, increased nocturia, and susceptibility to dehydration.
(③) manifestations associated with chronic kidney disease.
IV. Atypical urinary tract infections.
① Systemic acute infection symptoms as the main manifestation, while the local symptoms of urinary tract are not obvious.
②Urinary tract symptoms are not obvious, while the main manifestations are acute abdominal pain and symptoms of gastrointestinal dysfunction.
③The main manifestations are hematuria, mild fever and back pain.
④No obvious urinary tract symptoms, only back pain or lumbago.
⑤A few people showed renal colic and hematuria.
⑥No clinical symptoms at all, but quantitative urine bacterial culture with colonies ≥105/ml.
Among women with symptoms of urinary tract infection, 40% to 50% of patients belong to acute urethral syndrome, and women with this syndrome can be clinically classified into 2 basic categories.
1, pus urine and true urinary tract infection: about 70% of women with acute urethral syndrome have pus urine and true urinary tract infection present on urinalysis, most of these patients have Chlamydia trachomatis or common non-pathogenic bacteria such as Escherichia coli, Staphylococcus putrefaciens infections with less than meaningful bacterial counts (100-10,000/ml), other patients have urethral tuberculosis, fungal urinary tract infection, or rare inflammation of the adjoining urethra due to an intra-abdominal or pelvic abscess.
Absence of pus and presence of causative organisms: The remaining 30% of women with acute urethral syndrome have acute urethral syndrome without the presence of pus or causative organisms, presumably due to trauma, injury from sexual intercourse, local irritation or allergy (e.g., allergy to topical contraceptives, organic fibers on underwear, dyes, etc.), or other factors that have not yet been identified, but require 3 negative cultures of clean middle urine and exclusion of Urinary tract tuberculosis, fungi, anaerobic bacteria, chlamydia, gonococcal infection.
2, asymptomatic bacteriuria: asymptomatic bacteriuria (asymptomatic bacteriuria) refers to the absence of urinary tract infection, only occasionally some mild fever, malaise, but repeatedly positive urine bacterial culture, and the number of colonies greater than 10,000-100,000/ml. this disease is mostly seen in adult women, the incidence of about 2%, the past that this is a benign process, no treatment, now by a large number of studies It is confirmed that long-term asymptomatic bacteriuria can also damage kidney function, so treatment should be the same as symptomatic urinary tract infections, especially in children, because there is often bladder-ureteral reflux, asymptomatic bacteriuria is easy to cause upper urinary tract infections, asymptomatic bacteriuria in pregnant women is often easy to develop into acute pyelonephritis and lead to sepsis, so in early pregnancy should be actively prevented.
3, complex urinary tract infections: this concept includes a wide range of clinical syndromes, such as asymptomatic bacteriuria, cystitis, pyelonephritis, overt urinary sepsis, structural abnormalities in the urinary tract (urethral or bladder neck obstruction, polycystic kidney, stone obstruction, presence of catheters and other foreign bodies), or functional abnormalities (cremasteric injury, neuronal bladder due to diabetes or multiple sclerosis), hereditary When urogenital renal disease or a systemic disease process makes the patient highly susceptible to bacterial invasion and other factors, patients often have the presence of urinary tract infections. In the presence of these conditions, the pathogenic microorganisms that can cause infection are more widespread than in simple urinary tract infections, and the resistance of these bacteria to antibiotics is also much greater than in the general population, and because the diagnosis and treatment of complicated UTIs differs from those of uncomplicated infections. Therefore, it is important to treat them clinically differently.
4. Giant renal abscess and perinephric abscess: Two uncommon types of renal infections are giant renal abscess and perinephric abscess. In the past, most renal abscesses were secondary to hematogenous infection with Staphylococcus aureus or, less commonly, group A streptococcal infection, and the abscesses were located mainly in the cortex of the kidney. Currently, most abscesses are secondary to renal calculi, renal or ureteral obstruction caused by the common bacterium Escherichia coli, typically located at the corticomedullary junction of the kidney, less commonly formed by infection of a pre-existing renal cyst, and less commonly due to local spread of a lesion from an adjacent site such as a colonic or lower rib abscess, which can extend into the perirenal tissue. The clinical manifestations of renal and perirenal abscesses are often insidious, with fever, weight loss, night sweats, anorexia, chronic inflammatory symptoms such as abdominal pain and back pain, and sometimes acute clinical manifestations related to bacteremia due to obstruction, or specific urinary tract infection symptoms such as painful urination, hematuria and significant urinary retention, and physical examination may reveal tenderness at the angle of the cribriform ridge, or even palpable masses, but 30% to 50% of patients The physical examination may reveal tenderness at the angle of the cribriform ridge or even a palpable mass, but in 30% to 50% of patients the physical examination may be normal. If the abscess is not drained or treated with antibiotics, it can spread to the abdomen, chest or skin causing complications.
Diagnostic principles
(1) Identify the pathogenic organism producing the symptoms and select the ideal antibiotic therapy.
(2) Define the anatomical site of the infection, i.e. whether the infection invades the upper or lower urinary tract or is limited to the lower urinary tract, and in male patients, also determine whether the infection involves the prostate or bladder.
(3) To clarify whether there are structural or functional abnormalities of the urethra and to select reasonable clinical management measures, such as cystoscopy, voiding cystourethrography, ultrasound, etc. can be performed on the patient.