For anyone that has ever freaked out because they had an abnormal pap smear with HPV present, here is some useful information. These are clips from a pathophysiology case study that I got 100% on. References available upon request. Enjoy.
The cervix is a round, internal structure that presents as the opening of the uterus. The interior lining adjacent to the uterus consists of mucous-secreting ciliated epithelium, and the distal, or “vaginal end” is composed of stratified squamous epithelium (Schuiling & Likis, 2006). Estrogen production in the proliferative phase of the menstrual cycle stimulates cervical cell changes to promote thinning of the cervical wall and mucous secretions to better enable potential sperm passage. As the cycle progresses, hormone levels fluctuate in preparation for embryo implantation. Towards the end of the cycle, increases in progesterone production causessubsequent thickening of the cervical wall and increased mucous production (Marieb, 1998). With each new menstrual cycle, there is a sloughing and shedding of endometrial and cervical tissue that is then replaced with new, immature cells. It is during this time of epithelial shedding and replacement of immature squamous cells that the cervix is most vulnerable to HPV infection (Kumar et al., 2010). When there is a dysfunction in the cell cycle, such as with viral replication and koilocytosis, some of the infected cells are shed regularly, and can be detected with a Pap smear (Schuiling & Likis, 2006). The abnormalities can be seen primarily as koilocytosis, characterized by perinuclear halos and nuclear alterations. Furthermore, there may be expansion of basal cell layer with varied immature squamous cells, depending on the extent of the severity of the dysplasia (Kumar et al., 2010).
Although most cervical cell abnormalities are due to changes caused by HPV infections, the cervix consists of cells that are regularly changing and proliferating in response to hormonal fluctuations of the menstrual cycle. This makes the cervix susceptible to a variety of carcinogens and oncogenic factors that can alter and dysregulate the cell cycle (Kumar et al., 2010).
The most common causes of cervical dysplasia and neoplasms have been closely associated with infections by the human papilloma virus (Kumar, Abbas, Fausto, & Aster, 2010). There are several different types of HPV, however only a handful being linked to malignant cervical cell changes, usually type 16 and type 18. HPV is typically transmitted by sexual intercourse, classifying it as a sexually transmitted disease (Center for Disease Control and Prevention [CDC], 2009). Although there has been a significant decrease in mortality rates of cervical cancer due to early detection and prevention, there are a number of factors that have been shown to cause a marked increase in risk for cancer development from HPV precursor lesions. These include tobacco smoking, which doubles an individual’s risk due to the consumption of carcinogens, genetic predisposition by inherited gene mutations that impair tumor suppression, poor nutritional status, such as diets low in folate and vitamins E and C, and most recently, data has suggested oral contraceptives may have an impact on cervical cancer development (Schuiling & Likis, 2006).
The cellular components of the cervix have an abundance of immature squamous metaplastic epithelium. Since HPVs generally infect areas containing these kinds of cells, or in instances where there are epithelial breaks in the squamous basal epithelium, such as by intercourse or reproductive cycle factors, it is an area of the body that is significantly more vulnerable to HPV infection (Kumar et al., 2010).
Low risk types of HPV’s typically affect the superficial epithelium, and maturation of the epithelial tissue is generally preserved (Mitchell, Kumar, Abbas & Fausto, 2006), and the resulting process that is seen is koilocytosis. This is a pathognomic feature of HPV infection, in which there is vacuolation of the epithelial cytoplasm, and the cells develop a “perinuclear halo” (Lawson, 2009), and a subsequent development of benign condylomas, observed as endocervical polyps, or warts (Mitchell et al., 2006). This alteration in the structure with the HPV oncoproteins contributes to stimulation of cell proliferation, and impaires cell cycle regulation by inhibiting tumor suppressor genes, resulting in uncontrolled replication of virus-infected cells (Lawson, 2009).
The majority of women that have abnormal cervical cell changes identified by their pap smear are affected by these low risk HPV’s, and the koilocytosis that takes place in these women is generally insignificant, and will be cleared by the immune system within 8 months to 2 years without further complications (Kumar et al., 2010).
Some of the higher risk HPV’s on the other hand, are often associated with a persistent infection that is not as readily cleared from the body. Because the infection is present longer, the increased exposure of the cells to the virus sustains greater damage than that of the lower risk types. In addition, koilocytosis and viral replication are more potent in the high-risk types, as they readily affect all of the cell layers, and significantly reduce the cellular maturation by interfering with the mitotic cell cycle (Mitchell et al., 2006). The virus integrates its DNA into the host cell’s genome, and produces viral oncoproteins that inactivate and mutate the host’s primary tumor suppressor genes inhibiting repair of damaged DNA and apoptosis (Schuiling & Likis, 2006). This interference results in genomic instability by altering the regulation of the cell cycle and promoting uncontrolled cell growth resulting in neoplasms (Mitchell et al., 2006).
Diagnosis of cervical dysplasia is dependant of the progression of cellular atypia, and the degree of maturation of the involved epithelial cells (Mitchell et al., 2006). A classification system has been developed to determine the severity of the dysplasia or carcinoma, and is know as the cervical intraepithelial neoplasia (CIN) system. This system was based on the progression of mild, moderate, and severe dysplasia, termed CIN I, CIN II, and CIN III, respectively. Because of recent regards to observation and surgical treatment in patient management, the system was reduced to a two level system, known as the Bethesda System in which mild dysplasia, or CIN I, was classified as low-grade squamous intraepithelial lesion (LSIL), and moderate and severe dysplasia (CIN II and III) were both combined and classified as high-grade squamous intraepithelial lesion (HSIL). As defined per Kumar et al. (2010),
The grading of SIL into low or high grade is based on expansion of the immature cell layer from its normal, basal location. If the atypical, immature squamous cells are confined to the lower one third of the epithelium, the lesion is graded as LSIL; if they expand to two thirds of the epithelial thickness, it is graded as HSIL. (p.1020)
Investigation of the morphology is typically preceded by a colposcopy and/or a biopsy of the areas of cervical abnormality after one or more abnormal Pap smear results (American College of Obstetricians and Gynecologists [ACOG], 2009). Abnormal diagnostic findings on the colposcopy may include a smooth surface that, when doused with acetic acid, is interrupted by whitish areas with dense, sharp or irregular outer borders in a mosaic pattern (Zheng, 2009).
Generally, there are usually no physical symptoms that are associated with HPV infections or cervical dysplasia. Some individuals infected with certain strains of HPV may experience benign polyps or “genital warts,” but many times the body is capable of fighting off the virus before changes are noticed (CDC, 2009). Similarly, cervical changes that are caused by HPV infections are also usually asymptomatic, and any abnormalities are only detected with a Pap smear, or further testing via colposcopy or cervical biopsy. Occasionally, women may experience mild symptoms such as a scant, watery discharge, lower back pain, abnormal heavy menses, or pain and spotting after intercourse (Schuiling & Likis, 2006). More often than not, these symptoms may be associated with other problems, and typically are not indicative of HPV or cervical abnormalities, and detection through screening tests are the best way to achieve a definitive conclusion (CDC, 2009).
Epidemiological studies have seen increased incidences of cervical dysplasia in women with HPV infections. Because HPV is becoming a significantly more common STD, it is estimated that most women infected with HPV will experience some degree of cervical dysplasia at some point in their lives (CDC, 2004). Because there are only a handful of cancer linked types of HPV, only a very small fraction of these infected individuals will progress to cervical cancer development. However, the presence of associated risk factors make some individuals more susceptible than others. This is especially true in immunosuppressed patients, those with genetic predispositions, high parity, and tobacco use (Schuiling & Likis, 2006). Furthermore, Smith et al. (2003) suggest increased incidences of HPV infections and cervical changes in women that use oral contraceptives. This finding is believed to be due to the theory that women using oral contraceptives (OC) are less likely to use condoms during sex than women that do not use OC’s, thus predisposing them to more STI’s and increased exposure to a variety of HPV types (Smith et al., 2003).
Laboratory and Diagnostic Tests
The most significant diagnostic finding is the presence of abnormal cervical cells due to koilocytosis on the Papanicolaou test. As the cervix undergoes cellular changes in response to the menstrual cycle, abnormal cells from a cervical lesion are sloughed off, and can be scrapped from the cervical surface during a pelvic exam, and viewed for abnormalities under a microscope (Schuiling & Likis, 2006). Furthermore, a colposcopy and cervical biopsy can be performed on any lesions, as identified by acetic acid. Findings conclusive of dysplasia are associated with the presence of nuclear atypia by enlargement, and cytoskeletal disruption, as indicated by perinuclear halos on microscopic examination (Kumar et al., 2010). Recently, an alternative test, known as Thin Prep, has been developed to replace conventional Pap smears, using liquid-based methods of cytology (Shuiling & Likis, 2006). This new test offers an improved system for detection of abnormal cells through computer imaging that readily identifies abnormal cellular characteristics in a more accurate representation of the specimen. The liquid-based system also allows for improved specimen preservation that enhances the ability to detect koilocytosis and nuclear atypia (Hologic, 2010).
Additionally, an HPV assay may be performed using the specimen collected from the Pap test or biopsy, which looks for HPV DNA, known as the Hybrid Capture 2 assay. This test can be used to identify the HPV typing to in order to determine the level of risk present for progression to cervical malignancy (Schuiling & Likis, 2006). The Food and Drug Administration ([FDA], 2003) recommends that the HC2 test should be used in conjunction with Pap smears in early detection and screening for cervical dysplasia and cancers.
Management of these findings is through consistent follow-up cervical cancer screening recommendations, as proposed by the American Cancer Society. It is recommended that women over the age of 21 receive a pap test at least every 2 years if results are normal, and for women over the age of 30, they may get them every 3 years if they have had at least 3 consistent normal pap smears in a row (ACOG, 2010).
Health Assessment Findings
The patient’s past medical history of HPV infection and abnormal pap smears indicate the need for additional testing and observation. Based on physical findings on the pelvic exam, the areas highlighted by acetic acid that consist of pale pink and white tissue are suggestive of tissue abnormalities or lesions, as would be expected in cases of dysplasia. Further physical examination revealing tenderness upon palpation is also a consistent finding indicating the possibility of inflamed lesions or infection, especially in the presence of HPV infections. Furthermore, the patient reports a history of pain with sexual intercourse, with subsequent vaginal bleeding and spotting, which may be due to irritation of the lesions and areas of inflammation. Additionally, mild lymphadenopathy was noted in her inguinal nodes. These nodes may be affected from the cervical inflammation, but in the presence of a possible malignancy in the cervical tissue, these lymph nodes may be involved.
HPV Vaccination and Cervical Cancer
Although cervical cancer can arise from a variety of etiologies, infection by human papilloma virus has been seen to be the most prevalent cause associated with cervical cancer development, found in at least 70% of cancer cases. While there are many different HPV types, and infection at some point in one’s life is not uncommon, infections by type 16 have been strongly associated with cervical cancer development, and these are the most commonly found HPV infections worldwide (Smith et al., 2007). Due to the severe implications of HPV and cervical cancer, a vaccine has been developed to protect against many of the subtypes of HPV associated with cancer. Jenkins (2008) performed a study that examined the efficacy and impact of the cross-protective effects of the HPV vaccine. This was a longitudinal study to explore the long-term effects of the vaccine in cervical cancer prevention. In Jenkins’s study, he not only confirmed the efficacy of the vaccine in preventing infection by high risk HPV types, but he also found that they played a protective role in preventing cervical abnormalities by other HPV oncogenes not originally intended for vaccination. This finding contributes to significant reduction in precancerous cervical lesions and subsequent cervical cancers. Due to the increased health benefits established by the HPV vaccine, the World Health Organization ([WHO], 2006) has recommended vaccinations for adolescent and young adult females to further decrease HPV infections and cervical cancer.