Chapter 47 - Sexually Transmitted Infections

• a relation between HPV and genital neoplasms has become increasingly apparent since the mid-1970s
• with newer technologies, HPV DNA has been identified in almost all of cervical cancers worldwide and in approximately 50% to 80% of vaginal, vulvular, and anogenital carcinomas
• 100 types of HPV have been identified, with more than 30 of which affect the anogenital area
• HPV types 16 and 18 appear to be the most virulent and are associated with most invasive squamous cell cancers
• HPV types 16 and 18 are strongly associated with cervical dysplasia and anogenital cancers and are considered high-risk
• HPV is listed as an STI, therefore, the acquiring of this infection would be by those methods of transferring an STI
• risk factors for acquiring HPV include young age (<25 years), early age of first intercourse (<16 years), increasing number of sex partners, and having a male partner with multiple sex partners
• HPV infection can occur with any type of vaginal or anal penetration and is common in homosexual individuals
• oral-genital and manual genital contact are less likely means of spreading HPV
• there is currently no treatment to eradicate HPV once a person has become infected
• the treatment goals of HPV are aimed at elimination of symptomatic warts, surveillance for malignancy and premalignant changes, and education and counselling to decrease psychosocial distress
• the recent release of a quadrivalent vaccine to protect against HPV types 6, 11, 16, and 18 may eventually reduce the risk of cervical cancer associated with HPV
• accurate diagnosis of a yeast infection, although the symptoms are somewhat conclusive, is made by the identification of budding yeast filaments or spores on a wet-mount slide using 20% potassium hydroxide
• the pH of the discharge in yeast infections, which is checked with a litmus paper, typically is less than 4.5
• when the wet-mount technique for diagnosis of a yeast infection is negative, but the clinical manifestations are suggestive of candidiasis, a culture may be necessary
• antibiotic therapy is a risk factor for the overgrowth of C. albicans, which suppressed the normal protective bacterial flora
• high hormone levels due to pregnancy is a risk factor for candidiasis
• the use of oral contraceptives is a risk factor for candidiasis as they cause an increase in vaginal glycogen stores
• uncontrolled diabetes mellitus or HIV infection are risk factors for candidiasis because they compromise the immune system
• food allergies, hypothyroidism, endocrine disorders, dietary influences, tight-fitting clothing, and douching have been suggested as possible contributors to the development of vulvovaginal candidiasis
• antifungal agents in various forms are effective in treating candidiasis
• oral fluconazole has been shown to be safe and effective as the standard intravaginal regimens for candidiasis
• STIs encompass a broad range of infectious diseases that are spread by sexual contact
• STIs are frequently asymptomatic which promotes the spread of infection
• agents of transmission of STIs include:

  • bacteria
  • chlamydia trachomatis
  • viruses (e.g., HIV, HSV, HPV)
  • fungi
  • protozoa
  • parasites
  • unidentified microorganisms
• portals of entry for STIs:

  • mouth
  • genitalia
  • urinary meatus
  • rectum
  • skin
• STIs can selectively infect the mucocutaneous tissues of the external genitalia
• STIs can cause vaginitis
• STIs can produce both GU and systemic effects
• some STIs may be transmitted by an infected mother to a fetus or newborn, causing congenital defects or death of the child
• infection with some HPV types results in:

  • genital warts (HPV 6 and 11)
  • cervical dysplasia (HPV 16 and 18)
  • cervical cancer (HPV 16 and 18)
• neurotropic alpha-group viruses:

  • herpes simplex virus type 1 (e.g., cold sores)
  • herpes simplex virus type 2 (e.g., genital herpes)
  • varicella-zoster virus (e.g., chicken pox, shingles)
• lymphotropic beta-group viruses

  • cytomegalovirus
  • Epstein-Barr virus
  • human herpesvirus type 8
• herpes viruses replicate in the skin and mucous membranes at the site of the infection (oropharynx or genitalia)
• HSV viruses grow in neurons and share the biologic property of latency
• in genital herpes, the virus ascends through the peripheral nerves to the sacral dorsal root ganglia
• during the dormant or latent period, HSV replicates in a different manner so that the immune system or available treatments have no effect on it
• host responses to infection influence the initial development of HSV, severity of infection, development and maintenance of latency, and frequency of HSV recurrences
• diagnosis of HSV:

  • based on the symptoms
  • based on the appearance of lesions
  • identification of the virus from cultures taken from the lesions
• candidiasis is not considered an STI