Recurring infections

Introduction Urinary tract infections can occur with repeated infections. Urinary tract infections are caused by direct attack by bacteria (very few can be caused by fungi, protozoa, viruses). Urinary tract infections are classified 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. Pyelonephritis is further divided into acute pyelonephritis and chronic pyelonephritis. Occurs in women.

Cause

(1) Causes of the disease

More than 95% of urinary tract infections are caused by a single bacterium. Among them, 90% of outpatients and about 50% of inpatients, the pathogen is Escherichia coli, the serotype of the bacteria can reach more than 140, the urinary Escherichia coli and the large intestine isolated from the patient's feces The same type of bacteria is more common in asymptomatic bacteriuria or uncomplicated urinary sensation; Proteus, Aerobacter, Klebsiella pneumoniae, Pseudomonas aeruginosa, Streptococcus faecalis, etc. Catheter, urinary tract with complications, Candida albicans, Cryptococcus neoformans infection are more common in patients with diabetes and glucocorticoids and immunosuppressive drugs, and after kidney transplantation, Staphylococcus aureus is more common in skin trauma and drug users. Caused by bacteremia and sepsis; although viral and mycoplasma infections are rare, there has been an increasing trend in recent years. A variety of bacterial infections are found in indwelling catheters, neurogenic bladder, stones, congenital malformations, and vaginal, intestinal, and urethral fistulas.

(two) pathogenesis

Urinary tract infection is caused by the invasion of pathogenic bacteria, and its pathogenesis is related to pathogen infection. The ways and ways of pathogen invasion and infection are roughly divided into the following.

Ascending infection

About 95% of urinary tract infections, the pathogens from the urethra through the bladder, ureter and up to the kidneys. Under normal circumstances, a small amount of bacteria is present at the upper end of the urethral opening 1 to 2 cm. Only when the body's resistance is reduced or the urethral mucosa is damaged, the bacteria can invade and multiply. Urine flushing, IgA in urine, lysozyme, organic acids, mucosal integrity, and mucosin secreted by the bladder transitional epithelium can resist the invasion of pathogens. In recent years, electron microscopy confirmed that there are many P-pilus on the surface of Escherichia coli, which can specifically recognize and bind to the corresponding receptors on the surface of urothelial cells, so that the cells adhere closely to the urothelial cells and avoid being Rinse off the urine. Escherichia coli has bacterial (O) antigen, flagellar (H) antigen, and capsular (K) antigen. The K antigen of polysaccharide can inhibit the bactericidal activity of phagocytic cells, which is directly related to its pathogenicity. Proteus has no P-pilus and K-antigen and is not easy to adhere to the transitional epithelium of the bladder, but can adhere to the squamous epithelial cells of the external genitalia. Indwelling catheter, urinary calculi, planing injury, tumor, prostatic hyperplasia, congenital urinary tract malformation (including ureteral ureter and sphincter dysplasia caused by sphincter dysplasia), neurogenic bladder, etc. are all ascending Risk factors for infection.

2. Hematogenous infection

Hematogenous infections account for only 3% of urinary tract infections. The blood flow of the kidney accounts for 20% to 25% of the cardiac output. When sepsis and bacteremia occur, the bacteria in the circulating blood easily reach the renal cortex. Diabetes, polycystic kidney disease, transplanted kidney, urinary tract obstruction, renal vascular stenosis, analgesics or the use of sulfonamides increase the vulnerability of kidney tissue. Common pathogens such as Staphylococcus aureus, Salmonella, Pseudomonas, and Candida albicans are rare, and lymphatic infection has not been confirmed.

3. Susceptibility factors

(1) urinary tract obstruction: urinary tract obstruction caused by various reasons, such as kidney and ureteral calculi, urethral stricture, urinary tract tumor, prostatic hypertrophy, etc. can cause urine retention, so that bacteria can easily breed and produce infection. Pregnancy uterus compression of the ureter, renal ptosis or hydronephrosis can cause poor urine excretion and cause the disease.

(2) urinary system malformations or dysfunction: such as renal hypoplasia, polycystic kidney disease, sponge kidney, hoof iron kidney, double renal pelvis or ureteral malformation and huge ureter, etc., are easy to reduce the resistance of local tissue to bacteria. Bladder ureteral reflux causes urine to flow back from the bladder to the renal pelvis, thus increasing the chance of illness. The urinary function of the neuronal bladder is dysfunctional, leading to urinary retention and bacterial infection.

(3) urethral intubation and device examination: catheterization, cystoscopy, urinary tract surgery can cause local mucosal damage, the pathogenic bacteria of the anterior urethra into the bladder or upper urinary tract and cause infection. According to statistics, the incidence of persistent bacteriuria after a catheterization is 1% to 2%; the indwelling catheterization for more than 4 days, the incidence of persistent bacteriuria is more than 90%, and severe pyelonephritis and Gram-negative bacteria The danger of sepsis.

(4) Female urinary tract anatomy and physiology characteristics: Female urethra length is only 3 ~ 5cm, straight and wide, urethral sphincter is weak, bacteria easily rise to the bladder along the urethra, and the urethral orifice is close to the anus, providing conditions for bacteria to invade the urethra. Local irritation around the urethra, menstrual period genital area is susceptible to bacterial contamination, vaginal diseases such as vaginitis and cervicitis, and changes in sex hormones during pregnancy, postpartum and sexual life can cause changes in vaginal and urethral mucosa and facilitate pathogen invasion. . Therefore, the incidence of urinary tract infection in adult women is 8 to 10 times higher than that in men.

(5) weakened body resistance: systemic diseases such as diabetes, high blood pressure, chronic kidney disease, chronic diarrhea, long-term use of adrenal cortex hormones, etc., reduce the body's resistance, and the incidence of urinary tract infections is significantly increased.

In summary, the occurrence of urinary tract infections is a fairly complex process that can be summarized as follows:

1 Bacterial colonies with P hairs are scattered around the intestines and urethra and spread to the urethra.

2 By urinary reflux, the bacteria are retrograde in the urinary tract and bind to the corresponding receptors of the epithelial cells of the urinary tract, locally proliferating, producing inflammation.

3 Through the turbulent flow of urine in the ureter, the bacteria ascend to the kidney. If the inflammation is not controlled in time, the kidney tissue is damaged and fibrosis eventually occurs.

an examination

Related inspection

Blood routine urine routine

diagnosis

Due to the wide range of urinary tract infections, from dysuria-urinary frequency syndrome to paroxysmal pyelonephritis, from symptomatic bacteriuria to asymptomatic bacteriuria, it is not only clinically possible to make "urinary tract infections". Diagnosis, it is also necessary to conduct etiological diagnosis and localization diagnosis for UTI patients, so that patients can get correct and effective treatment and follow-up measures, thereby reducing the incidence of chronic renal damage after several years.

In fact, clinicians have limited ability to accurately determine the cause of urinary tract infections and the location of the affected sites. If the patient has obvious clinical manifestations such as chills, high fever, severe low back pain, and obvious signs of Gram-negative sepsis, it is easy to make a diagnosis of pyelonephritis. However, without the above symptoms and signs, the possibility of kidney disease, such as occult pyelonephritis, cannot be ruled out. Therefore, in the diagnosis and treatment of patients with suspected UTI, the following comprehensive analysis and diagnosis should be made:

1. Principle of diagnosis

(1) Identify pathogenic bacteria that produce symptoms and choose the ideal antibiotic treatment.

(2) Identify the anatomical site of the infection, that is, whether the infection is invading the upper or lower urinary tract, or is limited to the lower urinary tract. For male patients, it should also be determined whether the infection affects the prostate or bladder.

(3) Determining whether there is abnormal structure or function of the urethra and selecting reasonable clinical treatment measures, such as cystoscopy, evacuation of bladder urethra, ultrasound, etc.

2. History and physical examination Although there is no clear correlation between clinical symptoms and different parts of urinary tract infections, useful information can usually be obtained from the detailed medical history collected.

When examining a patient with an acute onset of UTI symptoms, first consider whether there are symptoms and signs suggesting systemic sepsis or impending sepsis, such as chills, fever, shortness of breath, abdominal cramps and Such patients with acute low back pain need immediate hospitalization. If the patient does not have acute sepsis, then the patient should be aware of the presence of UTI, kidney disease, diabetes, multiple sclerosis, other neurological diseases, kidney stones, or previous urogenital device operation. . These conditions often cause UTI and affect the effectiveness of the treatment. In addition, careful neurological examination is particularly important for suggesting the presence of a neurogenic bladder.

For patients with recurrent UTI, special attention should be paid to the relationship between sexual life history, response to treatment, cessation of treatment and recurrence: female patients with UTI recurrence and sexual intercourse may be effective for antibiotic treatment after each sexual intercourse; Female patients with acute urethral syndrome caused by chlamydial infection may be temporarily effective against chlamydia treatment, but they may re-infect from untreated sexual partners (so-called ping-pong infection), which can only be cured when both sides are treated at the same time. To determine whether a female UTI recurrence is a relapse or a re-infection, refer to the length of time between the end of the previous treatment and the next infection. The recurrence of most female infections occurs in 4 to 7 days. Female reinfection, if there is no bladder dysfunction or some other urinary tract dysfunction, there is usually a longer interval between the two episodes.

In male patients with persistent prostate infections, the infection can recur quickly after similar conventional treatment. In addition, should actively seek out the presence of prostate obstruction on the flow of urine (for example: fine urine flow, urinary incontinence, nocturia or drips).

For patients with suspected chronic pyelonephritis and reflux nephropathy, care should be taken to ask if there is a history of UTI in children and during pregnancy; and if there are abnormalities in renal function, such as hypertension, proteinuria, polyuria, nocturia, and frequent urination. Wait.

The diagnosis of urinary sensation can not rely solely on clinical symptoms and signs, but rely on laboratory tests. Some people have reported the analysis of 297 patients with urinary sensation, and only 66.5% of those with symptoms. Anyone with true bacterial urine should be diagnosed with urinary sensation. True bacterial urine refers to: bacterial growth in qualitative culture of bladder puncture; quantitative culture of urinary bacteria 100,000/ml; quantitative culture of clean middle urinary 100,000/ml, and the same strain can be determined as true bacterial urine. It must be pointed out that women with obvious urinary frequency and dysuria may have more white blood cells in the urine. For example, the number of bacteria in the middle part of the urine is >100/ml, and it can be diagnosed as urinary sensation. Even when waiting for the culture report, it may be diagnosed first. For the urine.

Differential diagnosis

1. Repeated genital ulcers: International classification criteria for Behcet's disease 1. Repeated oral ulcers are observed by the physician or the patient is affirmed to have aphthous or herpetic ulcers, repeated 3 times in 1 year. 2. Repeated genital ulcers are observed by the physician or the patient affirms that the genitals have aphthous ulcers or cramps, especially men. 3. Eye disease uveitis (pre and/or post), cells visible in the vitreous during slit lamp examination, retinal vasculitis. 4. Skin lesions nodular erythematous lesions, pseudo folliculitis, purulent papules, acne-like rash (not seen with prednisone). 5. Acupuncture test positive with sterile 20 small needle, oblique into the thorn skin, after 24 to 48 hours, the doctor judged the results. Anyone with repeated oral ulcers and more than 2 of the remaining 4 can diagnose the disease.

Behcet's disease is a chronic progressive recurrent, multi-systemic disease in which small-scale vasculitis of unknown cause is pathological. Oral vulvar ulcer, ophthalmia, skin damage as a clinical feature Behcet's disease is also called Behcet's syndrome or eye, mouth, genital syndrome clinically with oral ulcers, genital ulcers, iridocyclitis triad is more common Among them, various eye symptoms can be manifested as blurred vision, vision loss, eyeball pain, photophobia, foreign body sensation and floating mosquitoes can cause blindness.

2, repeated infections: medical infections, refers to bacterial, viral, fungal, parasitic and other pathogens invading the human body caused by local tissue and systemic inflammatory response. Repeated infection refers to repeated frequent infections. There are many causes of repeated infections, including non-immune factors (such as skin mucosal barrier damage) and immune causes. Modern medicine believes that the correlation between repeated infection and immune factors is a very complex subject.

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