Porth's Essentials of Pathophysiology, 4e

1053

Sexually Transmitted Infections

C h a p t e r 4 1

schedules and increased compliance. Episodic interven- tion reduces the duration of viral shedding and the heal- ing time for recurrent lesions. For individuals who wish to prevent transmission to a susceptible partner or wish to prevent outbreaks, continuous antiviral suppressive therapy may be advised. These drugs are well tolerated, with few adverse effects. This long-term suppressive therapy does not limit latency, and reactivation of the disease frequently occurs after the drug is discontinued. In 2002, the FDA approved long-term suppressive ther- apy with valacyclovir and condom use for the preven- tion of HSV-2 transmission to an uninfected sexual partner. Infection with HSV-2 may predispose an indi- vidual to HIV infection and antiviral therapy does not reduce this risk. 4 Maternal/Neonatal Transmission Herpes simplex virus may be transmitted from mother to child around the time of delivery causing potentially fatal disease in the newborn. 1,5,14,15 Women who experi- ence their first genital HSV infection in pregnancy are at highest risk of transmitting the disease to their newborn. Disseminated neonatal infection carries high mortality and morbidity rates. Because of the risk involved, many authorities recommend that recently acquired HSV infections in pregnant women be treated with antiviral drugs (e.g., aciclovir or valaciclovir). Active infection during labor may necessitate cesar- ean delivery, ideally before membranes rupture, but this is not a guarantee that the infant will not acquire infec- tion. Pregnant women with a known history of HSV-2 infection should be treated with antiviral therapy from 36 weeks until delivery. If there are no active lesions at the time of labor, vaginal delivery is preferred. Neonatal HSV is treated with systemic antiviral therapy. Chancroid Chancroid is a disease of the external genitalia and lymph nodes caused by the gram-negative bacterium Haemophilus ducreyi . 2,4,11 The disease is most common in tropical and subtropical regions. It is one of the most common causes of genital ulcers in less developed coun- tries, especially in Africa and parts of Asia, where it prob- ably serves as an important cofactor in the transmission of HIV infection. 9 This STI has become uncommon in the United States. However, recent evidence suggests that chancroid may be underdiagnosed because many STI clinics do not have the facilities to test for H. ducreyi . Chancroid is highly infectious and is usually transmitted by sexual intercourse or through skin and mucous mem- brane abrasions. Autoinoculation may lead to multiple chancres. Lesions begin as macules, progress to pustules, and then rupture. On physical examination, lesions and regional lymphadenopathy (i.e., buboes) may be found. Secondary infection may cause significant tissue destruction. Diagnosis usually is made clinically, but may be con- firmed through culture. Gram stain rarely is used today because it is insensitive and nonspecific. There are no

FDA approved PCR tests for H. ducreyi . 4 The organism has shown resistance to treatment with sulfamethoxa- zole alone and to tetracycline. 4 Lymphogranuloma Venereum Lymphogranuloma venereum (LGV) is an acute and chronic venereal disease caused by Chlamydia tracho­ matis types L1, L2, and L3. The disease, although found worldwide, has a low incidence outside the tropics. Most cases reported in the United States are in men. There appears to be a new variant of L2 that is causing a resurgence of LGV in Europe and the United States, particularly in men who have sex with men. 4,11 The lesions of LGV can incubate for a few days to sev- eral weeks and thereafter cause small, painless papules or vesicles that may go undetected. An important char- acteristic of the infection is the early (1 to 4 weeks later) development of large, tender, and sometimes fluctuant inguinal lymph nodes called buboes . There may be flulike symptoms with joint pain, rash, weight loss, pneumonitis, tachycardia, splenomegaly, and proctitis. In later stages of the disease, a small percentage of affected persons develop elephantiasis (hypertrophy, edema, and fibrosis of the skin and subcutaneous tissues) of the external genitalia, caused by lymphatic obstruction or fibrous strictures of the rec- tum or urethra from inflammation and scarring. Urethral involvement may cause pyuria and dysuria. Cervicitis is a common manifestation of primary LGV in women, and could extend to perimetritis or salpingitis, which are known to occur in other chlamydial infections. 4 Anorectal structures may be compromised to the point of inconti- nence. Complications of LGV may be minor or extensive, involving compromise of whole systems or progression to a cancerous state. Diagnosis usually is accomplished by a complement fixation test for LGV-specific Chlamydia antibodies. High titers for this antibody differentiate this group from other chlamydial subgroups. PCR techniques, when more widely available, will provide a more practi- cal, cost-effective tool for diagnosis. 4 Treatment involves 3 weeks of doxycycline, tetracycline, or erythromycin. 4 Because doxycycline is contraindicated in pregnancy, erythromycin should be used. Surgery may be required to correct sequelae such as strictures or fistulas or to drain fluctuant lymph nodes.

SUMMARY CONCEPTS

■■ Sexually transmitted infections (STIs) are spread by sexual contact and involve both male and female partners. Portals of entry include the mouth, genitalia, urinary meatus, rectum, and skin. All STIs are more common in persons who have more than one sexual partner, and it is not uncommon for a person to be concurrently infected with more than one type of STI.

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