Nonspecific urethritis

Introduction to non-specific urethritis Nonspecific urethritis (NGU), also known as non-gonococcal urethritis, is a more common sexually transmitted disease. It usually refers to males with purulent or serous secretions of urethra within a few days or weeks after sexual intercourse. And accompanied by dysuria; urethral secretions contain a large number of pus cells, but Gram-stained microscopic examination or culture can not detect gonococcus. basic knowledge The proportion of illness: 0.12% Susceptible people: good for young men and women Mode of infection: non-infectious Complications: Epididymitis Prostatitis Seminal vesicle pelvic inflammatory disease

Causes of non-specific urethritis

(1) Causes of the disease:

It has been confirmed that at least two pathogenic microorganisms are involved in the pathogenesis of this disease, namely Chlamydia trachomatis and Ureaplasma urealyticum, and other microorganisms have also been found to be associated with this disease.

The disease may also be caused by some non-sexually transmitted causes. Bacterial urethritis may be secondary to upper urinary tract infections, bacterial prostatitis, urethral stricture, phimosis and urethral intubation, in addition, congenital malformations, chemical stimuli Tumors and certain allergic factors can also cause urethritis. Systemic diseases such as Stevens-Johnson syndrome may cause urethritis. There is no evidence of masturbation, drinking coffee, alcohol abuse, certain foods, too little sexual activity or excessive frequency. Can cause urethritis.

History: Human diseases caused by Chlamydia trachomatis, the ancients have discovered that the first separation from the reproductive tract to Chlamydia was in 1959, Jones, Collier and Smith, who discovered trachoma from the cervix of a newborn infant with ophthalmia Chlamydia, in 1964, the first time Chlamydia was found in the urethra of men with an epidemiological relationship with conjunctivitis.

Etiology: Chlamydia trachomatis is the most common pathogen of NGU, followed by mycoplasma, Trichomonas vaginalis, Candida albicans and herpes simplex virus.

According to the US CDC, 25% to 55% of NGU patients are caused by Chlamydia: trochomatis (Ct), and 20% to 40% of cases are caused by Ureaplasma: Ureaplasma (Uu), 2% ~5% of cases are caused by Trichomonas vaginalis, and herpes simplex virus is occasionally the cause of NGU. There are still a few cases where the cause is still unknown.

1. Chlamydia: Chlamydia is widely parasitic in humans, mammals and birds, and only a few are pathogenic. Among them, C. trachomatis, C. pneumoniae and Chlamydia psittaci (C. psittaci) cause human diseases. ).

Chlamydia trachomatis contains four biological variants (biovar), which may be different microorganisms. Rat and pig subtypes have not been found to infect humans, and the third is a biotype that causes lymphogranuloma venereum (LGV). That is, the LGV type, the fourth type of biotype (the trachoma type) mainly causes genital tract infections and trachoma.

Trachoma biological variants can be further divided into A ~ K, 12 kinds of serum variants (serovars), serovars, A, B, Ba, C, 4 serotypes cause trachoma, D ~ K, 8 serotypes cause genitourinary system infection.

LGV can be divided into L1, L2, L3, three serotypes, causing sexually transmitted lymphogranuloma.

Chlamydia grows and multiplies in cells and has a unique developmental cycle. Two different particle structures can be observed, one being the initial body (reproductive type), which is round or oval; the other is the original (elementary body, infective), spherical, requiring approximately 40 hours per developmental cycle.

Chlamydia is sensitive to heat, can only survive for 5 to 10 minutes at 56-60 °C, and can be stored for several years at -70 °C. 0.1% formaldehyde or 0.5% phenol (carbonic acid) can kill chlamydia in a short period of time, 75% ethanol in half a minute. Chlamydia can be killed inside.

2. Mycoplasma: Mycoplasma is widely distributed in nature, with more than 80 species. Mycoplasma related to humans are M. pneumonie (Mp), M. hominis (Mh), Ureaplasma Ureaplasma Urealyticum, Uu) and M. genitalium (Mg), the former causes pneumonia, the latter causes genitourinary infections.

Mycoplasma is a kind of prokaryotic microorganism that can pass through a bacterial filter, without cell walls and precursors, and has a morphological shape. It belongs to the class of soft skin, and is the smallest microorganism that is known to grow and reproduce in an inanimate medium. The size of mycoplasma It is 0.2-2.3m, rarely more than 1.0m. Mycoplasma is multi-divided and has various forms. It is basically spherical and silky. Mycoplasma can grow on chicken chorioallantoic membrane or cell culture, culture with medium, nutrition. Requirements are higher than bacteria.

Mycoplasma genitalium is a newly discovered mycoplasma. It was first isolated from urinary tract specimens from two patients with non-gonococcal urethritis by Tully in 1981. It has been shown that genital mycoplasma is one of the pathogens of urinary tract and reproductive tract infections. Sexually transmitted, and the urinary tract and reproductive tract may be the primary site of genital mycoplasma colonization or infection. Because the isolation and culture of genital mycoplasma in vitro shows slow growth and complex nutrients, it is very difficult to isolate genital mycoplasma from clinical specimens. At present, the detection of Mycoplasma genitalium is mainly through the PCR method.

Mycoplasma is similar to bacteria in heat resistance, but some mycoplasma have poor resistance, such as 45 ° C, 15 ~ 30 min or 55 ° C, 5 to 15 min is killed, with phenol or to Suer easy to kill, mycoplasma in After being covered with paraffin in a sugar-free medium, it can survive for 1 month at 37 ° C, and can be stored for a long time at low temperature or freeze-drying.

(two) pathogenesis

The pathogenesis of Chlamydia trachomatis infection remains unclear. The disease process and clinical manifestations of Chlamydia infection may be the combined effects of tissue damage caused by Chlamydia and the inflammatory reaction induced by Chlamydia and necrotic substances destroyed by host cells. Chlamydia infection causes a large amount of immunity. The reaction (in the presence of circulating antibodies and cell-mediated responses), there is evidence that the part of Chlamydia disease is caused by an allergic reaction, or is an immunopathological disease, the so-called sensitizing antigen, which has been identified as a HSP60 heat shock protein (heat Shock proteins).

Most chlamydial infections are only infected with a relatively small number of cells in the affected area. Since each inclusion body releases a large number of viables at a time, and relatively few cells are infected nearby, it is certainly limited to contagious. Control mechanism, this mechanism is still not fully understood, but T cell function seems to be very important. It has been found that lymphokines have an inhibitory effect on chlamydia, Chlamydia trachomatis is sensitive to , , interferon, interferon seems to be more important, interference It seems to prolong the developmental cycle and cause the net body to exist for a long time. This may cause persistent latent infection and play a role in immunopathology.

The obvious effect of gamma interferon may be the control of infection rather than the protection of new infections, so it may be related to the clearance of infection, and neutralizing antibodies may also play a role, but the mechanism of action of neutralizing antibodies is also to be clarified, antibodies It can neutralize the infectivity of Chlamydia in cell culture. Antibodies can inhibit the adhesion of Chlamydia to the surface of non-professional phagocytic cells, or prevent it from inhibiting phagocytic lysosomal fusion, or prevent the formation of protoplasts and nets by cross-linking surface proteins. Learning to change.

Mycoplasma does not invade tissues and blood, and can only adhere to receptors on the surface of epithelial cells in the respiratory tract and genitourinary tract. After adhesion of mycoplasma, cell damage can be further caused by:

1. Adhere to the surface of the host cell to absorb nutrients from the cells, obtain lipids and cholesterol from the cell membrane, and cause cell damage.

2. Mycoplasma releases toxic metabolites, such as lysosomes, which can produce neurotoxins, causing cell membrane damage; Ureaplasma urealyticum has urease, which can hydrolyze urea to produce a large amount of ammonia, which is toxic to cells. In addition, mycoplasma can also adhere to red blood cells. On the surface of macrophages and sperm, Ureaplasma urealyticum adheres to the surface of sperm, which can hinder sperm movement. The neuraminidase-like substance produced by it can interfere with the combination of sperm and egg, causing infertility and infertility.

(1) The role of chlamydia in genitourinary tract diseases: 35% to 50% of NGU is caused by Chlamydia trachomatis. Chlamydia trachomatis urinary tract infections are more common than gonococcal urinary tract infections. If symptoms are present, they are often more common. light.

Among the young men with active sex, acute epididymitis, more than 70% are chlamydial infections, and patients over 35 years old with epididymitis are generally Gram-negative bacterial infections, and have a history of urinary diseases or device operation.

The role of Chlamydia trachomatis in non-bacterial prostatitis is still controversial. In general, it is not possible to draw a positive conclusion on the role of Chlamydia trachomatis in non-bacterial prostatitis. Further research requires a strict case definition ( Including the number of cells in the prostate eluate), using conventional histological examination, immunohistochemical examination of biopsy tissue, serological examination, sensitive molecular examination techniques (such as PCR or in situ DNA hybridization to examine Chlamydia in the prostate) and treatment Evaluation and so on.

Reiter syndrome (urethritis, conjunctivitis, arthritis and typical skin mucosal damage) and reactive tenosynovitis or arthritis without other Reiter syndrome manifestations have been found to be associated with Chlamydia trachomatis genital infection with micro-immunofluorescence (micro- IF) antibody assay for untreated typical Reiter syndrome men found that more than 80% of Chlamydia trachomatis were first or concomitant, and Reiter syndrome was also found in HLA-B27 haplotypes. Class I HLA-B27 The haplotype seems to increase the incidence of Reiter syndrome by a factor of 10, and 60% to 70% of patients with this syndrome are HLA-B27 positive.

Chlamydia trachomatis can cause cervicitis and endometritis. Like gonococcal, Chlamydia trachomatis can also cause vestibular glandular duct infection.

The rate of Chlamydia trachomatis in acute salpingitis varies by region and study population. Seattle has shown that 80% to 90% of women with endometritis confirmed by laparoscopy confirmed salpingitis and histological examination Chlamydia or gonococcal infection, the ratio of chlamydia and gonococcal infection are almost equal. Many patients with chlamydial salpingitis continue to progress to the scarring of the fallopian tube, resulting in infertility, but no symptoms or slight, so it is called It is "silent: salpingitis" caused by chlamydia.

Since Fitz-Hugh and Curtis first reported perihepatitis (Fitz-Hugh-Curtis syndrome), perihepatitis that occurs simultaneously with or after salpingitis is considered a complication of gonococcal infection, but The research in the past 15 years suggests that the relationship between chlamydial infection and perihepatitis may be more closely related to gonococcal bacteria. Young women with active sexual activity, such as upper abdominal pain, fever, nausea and vomiting, should think of perihepatitis. Possible.

(2) The role of mycoplasma in genitourinary tract diseases: the role of mycoplasma in non-gonococcal urethritis is still controversial. According to the results of culture separation, it does not indicate that human mycoplasma may cause non-gonococcal urethritis. The clinical response of antibacterial drugs does not support the relationship between this mycoplasma and non-gonococcal urethritis.

As for Ureaplasma, current data support that Ureaplasma can cause non-gonococcal urethritis in a few cases, although it is unclear exactly how many patients can be detected by Ureaplasma, from non-gonococcal urethra The detection of ureaplasma in the urethra of an inflammatory male patient does not necessarily mean that this is the cause of his illness.

Compared with Ureaplasma, this mycoplasma shows a stronger association with acute non-gonococcal urethritis. In male patients with recurrent disease after persistent or acute attack, 12% to 20% can be detected in the urethra. Reproductive mycoplasma.

Studies have shown that the role of genital mycoplasma in true chronic prostatitis is minimal, and the relationship with epididymitis has not been determined, the role of Reiter disease is still unclear.

There is some evidence that Mycoplasma hominis may be the cause of pelvic inflammatory disease in women, but there is no evidence that Ureaplasma has a similar effect.

It has been reported that Ureaplasma can reduce sperm motility and reduce the number of sperm, and is related to the abnormal appearance of sperm. Removal of Ureaplasma can improve sperm motility, quantity and appearance, although Ureaplasma may and sperm motility The change is related, but there is no convincing evidence that ureaplasma is an important cause of infertility.

The relationship between mycoplasma and HIV infection and AIDS: In the late 1980s, some researchers in the United States cultured a mycoplasma, called Mycoplasma incognitus, in the organs and tissues of AIDS patients, which was subsequently identified as fermentation. Mycoplasma, before this, has been isolated from the genitourinary tract to a small amount of fermented mycoplasma, but more often as a pollutant isolated from cell culture, its pathogenicity is still unknown, the study found that mycoplasma can enhance HIV in cell culture Replication can cause cell death.

Non-specific urethritis prevention

Adhere to regular treatment, avoid halfway, when the treatment is completed, go to the hospital for review or evaluation. If symptoms persist or recur, you should go to the hospital immediately, avoid sexual contact before using the patient and his sexual partner, and use condoms. For contraceptives, the patient's sexual partner should also be examined and treated. The newborn should be eye-catching with erythromycin or tetracycline after birth.

Male prevention:

1. Deaf patients avoid sexual behavior before they are cured; prohibit alcohol, do not eat spicy food, drink plenty of water.

2. Do the necessary isolation in the home, bath towels, washbasins, bathtubs, toilets, etc., or disinfect them after use.

3. Tell the patient what is safe sex, what is dangerous behavior, and how to avoid dangerous behavior.

4. Encourage the use of condoms.

Non-specific urethritis complications Complications epididymitis prostatitis seminal vesicle pelvic inflammatory disease

Complications in male patients: epididymitis, prostatitis, seminal vesiculitis, etc.

Complications of women with endometritis: endometritis, salpingitis, pelvic inflammatory disease, peritoneum, etc.

Non-specific symptoms of urethritis Common symptoms Abdominal discomfort, urinary flow, urinary frequency, urinary pain, chills, high fever, abdominal pain, urinary pain, urethral itching

NGU occurs in the youthful period, and the incubation period can range from several days to several months, but most of them are 1 to 3 weeks.

1. Male NGU: Symptoms are similar to gonococcal urethritis, but to a lesser extent, may have urinary tract itching, burning sensation and urination pain, a few have frequent urination, mild urethral swelling, thin secretions, small amount, serous or Purulent, more need to squeeze the urethra by hand to see the secretion overflow, long time no urination or morning urination before the first urinary discharge can sometimes see the secretions of the urethral orifice contaminated underwear, formed into a sticky paste can seal the urethra ( Some people (30% to 40%) can have no symptoms, and many patients have atypical symptoms. Therefore, about half of the patients are easily misdiagnosed or missed at the time of initial diagnosis, and 19% to 45% of patients At the same time, accompanied by gonococcal infection, 50% to 70% of male patients can heal within 1 to 3 months without treatment. Untreated chlamydial urethritis symptoms can be relieved by themselves, and the condition is relieved, but asymptomatic chlamydia infection It can also last for months to years.

2. Female NGU: The clinical features of female NGU or NSGI are that the symptoms are not obvious or asymptomatic. When causing urethritis, about 50% of patients have frequent urination and dysuria, but no symptoms of dysuria or only very mild urine. Pain, there may be a small amount of urethral secretions, if the infection is mainly in the cervix, it is characterized by cervical mucus purulent discharge (37% women) and hypertrophic ectopic (19%), hypertrophicectopy refers to hypertrophicectopy Edema of edema, congestion and bleeding, may have vaginal and genital itching, lower abdominal discomfort and other symptoms, often misdiagnosed as general gynecological diseases, untreated cervical chlamydia infection can last 1 year or more, and There will be various clinical manifestations and complications, such as urethritis, acute urethritis syndrome, endometritis, adult Chlamydia trachomatis infection, etc., the risk of cervical-centered Chlamydia trachomatis dissemination may be less than reproductive system gonorrhea The danger of spreading.

3. Complications: Epididymitis is the main complication of male NGU. Its main symptoms are swollen epididymis, hard and tender, such as pain, tenderness, scrotal edema and thickening of the vas deferens when the testicles are involved. The liquid is extracted from the swollen epididymis, sometimes it can be separated into chlamydia. Clinically, epididymitis and urethritis can be seen at the same time. When prostatitis is present, there may be a posterior urethra, a heavy fall of the perineum and anus, and a dull pain. The pain can be radiated. To the following parts of the diaphragm, it is more obvious in the morning, which can produce sexual dysfunction. The rectal examination can touch the swollen and tender prostate. In the acute phase, due to severe congestion of the prostate, swollen glands can cause Obstructive symptoms of the urethra such as fine urine flow, weak urination, frequent urination and interruption of urinary flow, are rare in men, systemic complications and infection of external organs of the genitals. Common follicular conjunctivitis is common, Reiter synthesis Signs (ie urethritis, polyarthritis, conjunctivitis triad), ocular uveitis and ankylosing spondylitis, etc., it has been reported that Ureaplasma urealyticum can be adsorbed on sperm, inhibiting Fertilization causes low fertility.

In women, the main complication is acute salpingitis. In the acute phase, there may be chills, high fever and lower abdominal pain. There may be pain in the ankle and radiation to the thigh. Gynecological examination of the cervix may have a press pain, and the uterus may have obvious tenderness. And rebound tenderness, about 25% of patients can lick and thicken the fallopian tube and accessory inflammatory mass, chronic salpingitis is characterized by lower abdominal pain, low back pain, menstrual abnormalities and infertility, in addition, chlamydial infection can also cause different Pregnancy, infertility, miscarriage, intrauterine stillbirth and neonatal death, but many patients have no symptoms other than infertility.

Non-specific urethritis examination

1. Smear staining examination: exclusion of Neisseria gonorrhoeae, Candida and other bacterial infections; urethral secretion smear high power oil white lens > 4 / 5 mean field of view; cervical secretion smear high power oil microscope white blood cells > 10 /5 average fields of view.

2. Urinary leukocyte esterase test: Men less than 60 years old, no kidney disease or bladder infection, no prostatitis or mechanical damage to the urinary tract, urinary leukocyte esterase positive can also be diagnosed as NGU.

3. Chlamydia trachomatis (CT) examination

(1) Cytological examination: The secretion smear is taken and fixed for Giemsa staining or iodine staining.

(2) Tissue cell culture examination: For the standard method for the diagnosis of CT infection, the specificity of CT detection by tissue culture method is 100%, and the sensitivity is 80% to 90%.

(3) Serological examination: including complement fixation test, micro immunofluorescence test and convection immunoelectrophoresis test.

(4) Immunological examination: mainly used for further identification of CT.

1 Direct immunofluorescence test (DFA): After smear, fluorescein-labeled monoclonal antibody was used for staining, but there were also false positives. Most authors thought that it was not as sensitive as culture method and more specific.

2 Enzyme immunoassay (EIA): There are kits such as Kodak sure cell, chlamydiazyme, Syva:micro:trak and IDEIA, and the CT antigen in the first morning urine (FCU) sediment samples was detected by EIA technique.

3 solid phase enzyme immunoassay: such as clearview test pack, etc. is a rapid immunoassay test, mainly used to detect chlamydial antibodies in cervical specimens.

(5) Molecular biology examination:

1 Nucleic acid probe detection method: The Gen-Probe PACE2 system and the improved PACE2 method applied in recent years.

2 nucleic acid amplification detection method: divided into two methods.

A. Polymerase chain reaction (PCR): The CT major outer membrane protein (OMP-1) was used as a primer to determine the true positive result. The method is fast, simple, and requires low detection materials, but also has false positives, false negatives and There are many problems with different primers and different results.

B. Ligase chain reaction (LCR): The OPM-1 target gene of CT was examined by this method, and the sensitivity and specificity were extremely strong.

4. Mycoplasma examination

(1) Culture examination: a standard method for confirming mycoplasma infection.

(2) Serological examination: including agar diffusion method, fluorescein-labeled antibody method and micro-enzyme-linked immunosorbent assay.

(3) Molecular biology examination: Chlamydia examination.

Diagnosis and identification of non-specific urethritis

According to the medical history, clinical manifestations and laboratory data is not difficult to make a diagnosis.

Urethritis should first be distinguished from gonorrhea urethritis. Gonorrhea urethritis is a sexually transmitted disease with specific infection. There is purulent discharge in the urethra. Sputum smear staining can be seen as Gram-negative in lobular granulocytes. Dicocci, followed by non-gonococcal urethritis and trichomonas urethritis, women easily find trichomoniasis in the vagina, but not easy to find trichomoniasis in men, often under the foreskin, urethral secretions, prostatic fluid As well as urine, check for trichomoniasis, make a diagnosis, Reiter syndrome in addition to urethritis, conjunctivitis and arthritis.

NGU should be differentiated from gonococcal urethritis, genital herpes, genital candidiasis.

Clinically, Chlamydia trachomatis infection is often closely related to gonococcal infection. Both pathogens can cause male urethritis, epididymitis, proctitis, female cervicitis, urethritis, pelvic inflammatory disease, etc. Symptoms and signs are not different, so it is difficult to distinguish by clinical observation alone, and Chlamydia trachomatis and Neisseria gonorrhoeae can be combined with infection. Accurate differential diagnosis depends on laboratory examination. In clinical practice, it is often determined to be gonococcal infection. Regardless of whether or not Chlamydia trachomatis infection is detected, the treatment of two pathogens, gonococcus and Chlamydia trachomatis, is routinely administered.

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