The incidence of gonorrhoea (GC) in developing countries has fallen dramatically since the early 1970s but in Asia and Africa it still remains high. In 1990 WHO estimated 35 million cases worldwide, second to Chlamydia trachomatis amongst STDs. The causative organism, Neisseria gonorrhoeae (gonococcus), is a Gram-negative intracellular diplococcus which infects epithelium particularly of the urogenital tract, rectum, pharynx and conjunctivae. Humans are the only host and the organism is spread by intimate physical contact. It is very intolerant to drying and although occasional reports of spread by fomites exist this route of infection is extremely rare.
Forty per cent of women and some men are asymptomatic. The incubation period ranges from 2 to 14 days with most symptoms occurring between days 2 and 5. In men the commonest syndrome is one of anterior urethritiscausing dysuria and/or urethral discharge. Complications include ascending infection involving the epididymis, testes or prostate leading to acute or chronic infection. In homosex ual men rectal infection may produce proctitis with pain, discharge and itch. In women the primary site of infection is usually the endocervical canal and symptoms consist of a vaginal discharge,dysuria and intermenstrual bleeding. Complications include ascending infection leading to salpingitis with associated pelvic pain and fever. In rare cases a perihepatitis may develop (Fitz-Hugh-Curtis syndrome).
Bartholin’s abscesses may develop. On a global basis GC is one of the commonest causes of female infertility. Rectal infection, due to local spread, may occur in women and is usually asymptomatic as in pharyngeal infection. Conjunctival infection is seen in neonates born to infected mothers and is one cause of ophthalmia neonatorum.Disseminated GC leads to arthritis (usually rnonoarticular or pauciarticular)and a characteristic purplish macular rash in association with fever and malaise.
The organism is identified from infected areas by Gram stain and culture on special media. Blood culture and synovial fluid investigations should be performed in cases of disseminated GC. Coexisting pathogens such as Chlamydia, Trichomonas and syphilis must be sought.
The gonococcus is sensitive to a wide range of antimicrobial agents but an increase in antibiotic resistance has been seen over the past two decades. Therapy initiated in the clinic on the basis of Gram-stained slides prior to culture results is influenced by travel history or details known from contacts.
Therapy with single-dose amoxycillin 3 g with probenecid 1 g is given in uncomplicated cases. Spectinomycin 2 g i.m. or ciprofloxacin 250 mg are used in penicillinresistant or allergic cases. Longer courses of antibiotics are required for complicated infections. Patients must be followed up to ensure that the organism has been eradicated and all sexual contacts should be examined and treated as necessary.
Chlamydia trachomatis is an obligate intracellular bacterial parasite which cannot be grown on artificial culture media. Cell culture systems are not universally available and indirect diagnostic methods are still being perfected. The organism has a worldwide distribution and silent infection is common. In men 30-40% of non-gonococcal and postgonococcal urethritis is due to Chlamydia. It is frequently found in association with other pathogens: 20% of men and 40% of women with gonorrhoea have been found to have coexisting chlarnydial infections.
In men Chlamydia gives rise to an anterior urethritis with dysuria and discharge; infection is often asymptomatic and detected by contact tracing. Ascending infection leadsto epididymitis. Rectal infection leading to proctitis may occur in men practising anoreceptive intercourse. In women the commonest site of infection is the endocervix where it may go unnoticed; ascending infection causes acute salpingitis. In women sub fertility may be the first problem encountered. Reiter’s syndrome has been related to infection with C. trachomatis. Neonatal infection, acquired from the birth canal, can result in mucopurulent conjunctivitis and pneumonia.
Cell culture systems are still considered the definitive method of diagnosis but are costly and not suitable for routine use. Antigen detection systems depending on either direct fluorescent antibody or enzyme immunoassay are increasingly available. In view of the intracellular nature of the organism care must be taken to obtain adequate specimens and it is essential that cells are collected. Wooden swabs may interfere with assay techniques. Special transport media are required.
Tetracyclines or macrolide antibiotics are most commonly used to treat Chlamydia. Oxytetracycline 500 mg 6-hourly or doxycycline 100 mg 12-hourly for 7 days areeffective. Tetracyclines are contraindicated in pregnancy and erythromycin 500 mg 6-hourly for 7-14 days can be given. Contacts must be traced and treated.
Urethritis is usually characterized in men by a discharge from the urethra, dysuria and varying degrees of discomfort within the penis. In 10-15% of cases there may be no symptoms. A wide array of aetiologies can give rise to the clinical picture, but may be divided into two broad bands: gonococcal or non-gonococcal urethritis (NGU). NGU occurring shortly after infection with gonorrhoea is known as postgonococcal urethritis (PGU). Gonococcal urethritis and chlamydial urethritis (a major cause of NGU) are discussed above.
In Chlamydia-negative NGU, Ureaplasma urealyticum is the next most frequent organism. Bacteroides sp. and Mycoplasma are responsible for a minority of cases. HSV can cause urethritis in about 30% of cases of primary infection, considerably fewer in recurrent episodes. Other causes include syphilitic chancres and warts within the urethra. Non-sexually transmitted NGU may be due to urinary tract infections, prostatic infection, foreign bodies and strictures.
The urethral discharge is often mucoid and worse in the mornings. It may be noted as crusting at the meatus or stains on underwear. Dysuria is common but not universal. Discomfort or itch within the penis may be present. The incubation is from 1 to 5 weeks with a mean of 2- 3 weeks. The importance of asymptomatic urethritis must be recognized as a major reservoir of infection. Associated features of conjunctivitis and/or arthritis may occur, particularly in HLA B27-positive individuals.
Smears should be taken from the urethra when the patient has not voided urine for at least 4 hours and should be Gram stained and examined under a high power (x 1000) oil immersion lens. The presence of five or morepolymorphonucleocytes per high power field is diagnos tic. Men who are symptomatic but have no objective evidence of urethritis should be re-examined and tested after holding urine overnight. Cultures for gonorrhoea must be taken together with swabs for Chlamydia testing.
Therapy is with tetracyclines initially, using either oxytetracycline 500 mg 6-hourly or doxycycline 100 mg 12- hourly for 7 days. Sexual intercourse should be avoided. The vast majority of patients will show partial or total response. For those left with objective evidence of urethritis, erythromycin 500 mg 6-hourly for 1-2 weeks should be prescribed. Sexual partners must be traced and treated; C. trachomatis can be isolated from the cervix in 50-60% of the female partners of men with gonorrhoea or N GU, many of whom are asymptomatic. This causes long-term morbidity in such women, acts as a reservoir of infection for the community and may lead to reinfection in the index case if not treated.
This is a common and difficult clinical problem. The usual time for patients to re-present is 2-3 weeks following treatment. Tests for Chlamydia and Ureaplasma are usually negative. It is important to document objective evidence of urethritis, check compliance and establish any possible contact with untreated sexual partners. Investigations should include wet preparation and culture of a urethral smear for Trichomonas vaginalis and fungi. Cultures should be taken for HSV. A mid-stream urine sample should be examined and cultured. A further 2 weeks’ treatment with erythromycin may be given and any specific additional infection treated appropriately. If symptoms are mild and all partners have been treated patients should be reassured and further antibiotic therapy avoided. In cases of frequent recurrence and/or florid unresponsive urethritis the prostate should be investigated and urethroscopy or cystoscopy performed to investigate possible strictures, periurethral fistulae or foreign bodies.
The causative organism, Treponema pal/idum (TP), is a motile spirochaete that is generally acquired by close sexual contact and transplacentally from mother to fetus. The organism enters the new host through breaches in squamous or columnar epithelium. Primary infection of non-genital sites may occasionally occur but is rare. Syphilis is a chronic systemic disease which can be quiescent or show protean manifestations. Both congenital and acquired syphilis have early and late stages, each of which has classical clinical features.
Between 10 and 90 days (mean 21 days) after exposure to the pathogen a papule develops at the site of inoculation. This ulcerates to become a painless, firm chancre. There is usually painless regional lymphadenopathy in association. The primary lesion may go unnoticed especially if it is on the cervix or within the rectum. Healing occurs spontaneously within 2-3 weeks.
Classification and clinical features of syphilis.
Between 4 and 10 weeks after the appearance of the primary lesion constitutional symptoms with fever, sore throat, malaise and arthralgia appear. Signs include:
GENERALIZED LYMPHADENOPATHY (50%)
GENERALIZED SKIN RASHES involving the whole body including the palms and soles but excluding the face (75%)
CONDYLOMATA LATA-warty, plaque-like lesions found in the perianal area and other moist body sites
SUPERFICIAL CONFLUENT ULCERATION OF MUCOSAL SURFACEs-found in the mouth and on the genitalia
ACUTE NEUROLOGICAL SIGNS (less than 10%) Without treatment, symptoms and signs abate over 3-12 weeks, but in up to 20% of individuals may recur during a period known as early latency, a 2-year period in the UK (I year in USA). Late latency is based on reactive syphilis serology with no clinical manifestations for at least 2 years. This may continue for many years before the late stages of syphilis become apparent.
Late benign syphilis, so called because of its response to therapy rather than its clinical manifestations, generally involves the skin and the bones. The characteristic lesion, the gumma (granulomatous, sometimes ulcerating, lesions), can occur anywhere in the skin, frequently at sites of trauma. Gummas are commonly found in the skull, tibia, fibula and clavicle, although any bone may be involved. Visceral gummas occur mainly in the liver (hepar lobatum) and the testes. Cardiovascular and neurosyphilis.
Congenital syphilis usually becomes apparent between the second and sixth week after birth, early signs being nasal discharge, skin and mucous membrane lesions, and failure to thrive. Signs of late syphilis generally do not appear until after 2 years of age and take the form of ‘stigmata’ relating to early damage to developing structures, particularly teeth and long bones. Other late manifestations parallel those of adult tertiary syphilis.