TABLE IV-114 Risk Factors for Active Tuberculosis Among Persons Who Have Been Infected With Tubercle Bacilli 2 page

IV-131. The answer is B. (Chap. 174) This patient demonstrates evidence of Rocky Mountain spotted fever (RMSF), which has progressed over the course of several days because of a lack of initial recognition and treatment. RMSF is caused by infection with Rickettsia rickettsii and is transmitted through the bite of an infected dog tick. RMSF has been diagnosed in 47 states and is most commonly diagnosed in the south-central and southeastern states. Symptoms typically begin about 1 week after inoculation. The initial symptoms are vague and are easily misdiagnosed as a viral infection with fever, myalgias, malaise, and headache predominating. Although almost all patients with RMSF develop a rash during the course of the illness, rash is present in only 14% on the first day, and the lack of rash in a patient who is at risk for RMSF should not delay treatment. By day 3, 49% of individuals develop a rash. The rash initially is a macular rash that begins on the wrists and ankles and progresses to involve the extremities and trunk. Over time, hemorrhaging into the macules occurs and has a petechial appearance. As the illness progresses, respiratory failure and central nervous system (CNS) manifestations can develop. Encephalitis, presenting as confusion and lethargy, is present about 25% of the time. Other manifestations can include renal failure, hepatic injury, and anemia. Treatment for RMSF is doxycycline 100 mg twice daily. It can be administered orally or intravenously. Because this patient shows progressive disease with CNS involvement, hospital admission for treatment is warranted to monitor for further decompensation in the patient’s condition. If the patient were more clinically stable, outpatient therapy would be appropriate. Treatment should not be delayed while awaiting confirmatory serologic testing because untreated cases of RMSF are fatal, usually within 8 to 15 days. Treatment with any sulfa drugs should be avoided because these drugs are ineffective and can worsen the disease course. Intravenous ceftriaxone and vancomycin are appropriate agents for bacterial meningitis. Although this could be a consideration in this patient with fever, confusion, and a rash, meningococcemia would present with a more fulminant course, and the patient’s risk factor (hiking in an endemic area) would make RMSF more likely.

IV-132. The answer is D. (Chap. 175) This patient presents with symptoms of atypical pneumonia, and the most common causative organism for atypical pneumonia is Mycoplasma pneumoniae. Pneumonia caused by Mycoplasma occurs worldwide without a specific seasonal preference. M. pneumoniae is a highly infectious organism and is spread by respiratory droplets. It is estimated that about 80% of individuals within the same family will experience the infection after one person becomes infected. Outbreaks of M. pneumoniae also occur in institutional settings, including boarding schools and military bases. Clinical manifestations of M. pneumoniae typically are pharyngitis, tracheobronchitis, wheezing, or nonspecific upper respiratory syndrome. Although many commonly believe the organism is associated with otitis media and bullous myringitis, there are little clinical data to support this assertion. Atypical pneumonia occurs in fewer than 15% of individuals infected with M. pneumoniae. The onset of pneumonia typically is gradual with preceding symptoms of upper respiratory infection. Cough is present, and often extensive, but nonproductive. Examination typically demonstrates wheezing or rales in about 80% of patients. The most common radiographic findings are bilateral peribronchial

pneumonia with increased interstitial markings. Lobar consolidation is uncommon. Definitive diagnosis requires demonstration of M. pneumoniae nucleic acids on polymerase chain reaction of respiratory secretions or performance of serologic testing. Often, however, the patients are treating empirically without obtaining definitive diagnosis.

Other causes of atypical pneumonia are Chlamydia pneumoniae and Legionella pneumophila. C. pneumoniae more commonly causes pneumonia in school-aged children, although adults can become re-infected. Legionella pneumonia is often associated with outbreaks of disease caused by contaminated water supplies. Individuals with Legionella pneumonia can become quite sick and develop respiratory failure. Adenovirus is a common viral cause of upper respiratory tract infection and has been associated with outbreaks of pneumonia among military recruits. Streptococcus pneumoniae is the most common cause of community-acquired pneumonia, but it typically presents with lobar or segmental consolidation.

IV-133. The answer is D. (Chap. 175) Mycoplasma pneumoniae is a common cause of pneumonia that is often underdiagnosed based on difficult and time-consuming culture techniques, because it likely causes mild respiratory symptoms, and because it is adequately treated with standard antibiotic regimens for community-acquired pneumonia. It is spread easily person to person, and outbreaks in crowded conditions, such as schools or barracks, are common. Most patients develop a cough without radiographic abnormalities. When radiographic abnormalities are present, there is usually a diffuse bronchopneumonia pattern without any lobar consolidation. Pharyngitis and rhinitis are also common. M. pneumoniae commonly induces the production of cold agglutinins, which in turn can cause an IgM-and complement-mediated intravascular hemolytic anemia. The presence of cold agglutinins is specific for M. pneumoniae infection only in the context of a consistent clinical picture for infection, as in this patient. Cold agglutinins are more common in children. Blood smear shows no abnormality, which is in contrast to IgG or warm-type hemolytic anemia in which spherocytes are seen. Because there is no easy diagnostic test, empirical therapy is often administered.

IV-134. The answer is C. (Chap. 176) This patient likely has pneumonia caused by infection with Chlamydia psittaci. This organisms is a relatively rare cause of pneumonia with only about 50 confirmed cases yearly in the United States. Contrary to common belief, the organism is not limited to psittacine birds (parrots, parakeets, cockatiels, macaws), but any bird can be infected, including poultry. Most infections are seen in owners of pet birds, poultry farmers, or poultry processing workers, and outbreaks of pneumonia have been seen in poultry processing factories. Untreated psittacosis has a mortality rate of as high as 10%. The illness presents with nonspecific symptoms of fevers, chills, myalgias, and severe headache. Gastrointestinal symptoms with hepatosplenomegaly are also common. Severe pneumonia requiring ventilatory support can occur, and other rare manifestations include endocarditis, myocarditis, and neurologic complications. The current diagnostic tool of choice is the microimmunofluorescence test, which is a serologic test. Any titer greater than 1:16 is considered evidence of exposure to psittacosis, and paired acute and convalescent titers showing a fourfold rise in titer are consistent with psittacosis. Complement fixation tests are also used. Treatment of choice for psittacosis is tetracycline 250 mg four times daily for a minimum of 4 weeks. Public health officials should be notified to assess other workers in the factory for disease and limit exposure. Although this patient has immigrated from an area endemic for tuberculosis, she had a previous negative purified protein derivative result and no known tuberculosis exposures. Her chest radiograph shows diffuse consolidation, which would not be typical for reactivation of tuberculosis. Systemic infection

with Staphylococcus aureus from an abscess or endocarditis could present with respiratory failure related to septic emboli. However, her chest imaging is not consistent with this, and she has no risk factors (i.e., intravenous drug use, indwelling intravenous catheter) for development of S. aureus bloodstream infection. Legionella pneumophila is associated with outbreaks of disease related to contaminated water supplies or air conditioning. It should be considered in this patient in light of her ill coworkers. However, hepatosplenomegaly is not consistent with this diagnosis. Influenza A is also a consideration for this patient, but the time of year is not consistent for seasonal influenza. In outbreaks of pandemic influenza, this would be more likely.

IV-135. The answer is D. (Chap. 176) Congenital infection from maternal transmission can lead to severe consequences for the neonate; thus, prenatal care and screening for infection are very important. Chlamydia trachomatis is associated with up to 25% of exposed neonates who develop inclusion conjunctivitis. It can also be associated with pneumonia and otitis media in the newborn. Pneumonia in the newborn has been associated with later development of bronchitis and asthma. Hydrocephalus can be associated with toxoplasmosis. Hutchinson triad, which is Hutchinson teeth (blunted upper incisors), interstitial keratitis, and eighth nerve deafness, is caused by congenital syphilis. Sensorineural deafness can be associated with congenital rubella exposure. Treatment of C. trachomatis infection in infants consists of oral erythromycin.

IV-136. The answer is D. (Chap. 176) Urethritis in men causes dysuria with or without discharge, usually without frequency. The most common causes of urethritis in men include Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium, Ureaplasma urealyticum, Trichomonas vaginalis, herpes simplex virus, and possibly adenovirus. Until recently, C. trachomatis accounted for 30% to 40% of cases; however, this number may be decreasing. Recent studies suggest that M. genitalium is a common cause of nonchlamy-dial cases. Currently, the initial diagnosis of urethritis in men includes specific tests only for N. gonorrhoeae and C. trachomatis. Tenets of urethral discharge treatment include providing treatment for the most common causes of urethritis with the assumption that the patient may be lost to follow-up. Therefore, prompt empirical treatment for gonorrhea and Chlamydia infections with ceftriaxone and azithromycin should be given on the day of presentation to the clinic to the patient, and recent partners should be contacted for treatment. Azithromycin will also be effective for M. genitalium. If pus can be milked from the urethra, cultures should be sent for definitive diagnosis and to allow for contact tracing by the health department because both of these are reportable diseases. Urine nucleic acid amplification tests are an acceptable substitute in the absence of pus. It is also critical to provide empirical treatment for at-risk sexual contacts. If symptoms do not respond to the initial empirical therapy, patients should be reevaluated for compliance with therapy, reexposure, and T. vaginalis infection.

IV-137. The answer is A. (Chap. 177) Persistent viral infection is speculated to be pathogenically important in up to 20% of human malignancies. Strong associations based on epidemiology, the presence of viral nucleotides in tumor cells, the transformational ability of viruses on human cells, and animal models have been established. Most hepatocellular carcinoma is thought to be related to chronic infection with hepatitis B or C virus. Most cervical cancer is caused by persistent infection with human papilloma virus type 16 or 18. Epstein-Barr virus plays a role in the development of many B-lymphocyte and epithelial cell malignancies such as Hodgkin’s lymphoma, Burkitt’s lymphoma, and nasopharyngeal carcinoma. HTLV- 1 is associated with a number of T-cell lymphomas and leukemias.

KSHV (Kaposi’s sarcoma associated herpes virus, HHV-8) is associated with Kaposi’s sarcoma, pleural effusion lymphoma, and multicentric Castleman’s disease. Dengue fever virus, a flavovirus, is the cause of dengue fever and has not been associated with human malignancy.

IV-138. The answer is A. (Chap. 178) Compared with the large number of antimicrobials directed against bacterial, antiviral therapies have been fewer, and advances in antiviral therapy have come more slowly. However, in recent years, a large number of antiviral medications have been introduced, and it is generally important to be familiar with the common side effects of these medications. Acyclovir and valacyclovir are most commonly used for the treatment of herpes simplex viruses I and II as well as varicella-zoster virus. Acyclovir is generally a well-tolerated drug, but it can crystallize in the kidneys, leading to acute renal failure if the patient is not properly hydrated. Valacyclovir is an ester of acyclovir that significantly improves the bioavailability of the drug. It is also well tolerated but has been associated with thrombotic thrombocytopenic purpura or hemolytic uremic syndrome when used at high doses. Ganciclovir and foscarnet are medications used to treat cytomegalovirus (CMV) infection. Ganciclovir is primarily given intravenously because the oral bioavailability is less than 10%. Ganciclovir is associated with bone marrow suppression and can cause renal dysfunction. Foscarnet is used for ganciclovir-resistant CMV infections. Renal impairment commonly occurs with its use and causes hypokalemia, hypocalcemia, and hypomagnesemia. Thus, careful monitoring of electrolytes and renal function is warranted with foscarnet use. Amantadine is an antiviral medication used for the treatment of influenza A. It has been demonstrated to have a variety of central nervous system (CNS) side effects, including dizziness, anxiety, insomnia, and difficulty concentrating. Although initially used as an antiviral drug, the CNS effects of amantadine have led to its use in Parkinson’s disease. Interferons are a group of cytokines produced endogenously in response to a variety of pathogens, including viruses and bacteria. Therapeutically, interferons have been studied extensively in the treatment of patients with chronic hepatitis B and C. Interferons lead to a host of systemic effects, including symptoms of a viral syndrome (fevers, chills, fatigue, and myalgias) as well as leukopenia.

IV-139. The answer is E. (Chap. 179) Antibodies to herpes simplex virus-2 (HSV-2) are not routinely detected until puberty, consistent with the typical sexual transmission of the virus. Serosurveys suggest that 15% to 20% of American adults have HSV-2 infection; however, only 10% report a history of genital lesions. Seroprevalence is similar or higher in Central America, South America, and Africa. Recent studies in African obstetric clinics have found seroprevalence rates as high as 70%. HSV-2 infection is believed to be so pervasive in the general population based on ease of transmission, both in symptomatic and asymptomatic states. Therefore, this sexually transmitted disease (STD) is significantly more common in individuals who less frequently engage in high-risk behavior than other STDs. HSV-2 is an independent risk factor for HIV acquisition and transmission. HIV virion is shed from herpetic lesions, thus promoting transmission.

IV-140. The answer is E. (Chap. 179) Primary genital herpes caused by herpes simplex virus-2 (HSV-2) is characterized by fever, headache, malaise, inguinal lymphadenopathy, and diffuse genital lesions of varying stage. The cervix and urethra are usually involved in women. Although both HSV-2 and HSV-1 can involve the genitals, the recurrence rate of HSV-2 is much higher (90% in the first year) than with HSV-1 (55% in the first year). The rate of reactivation for HSV-2 is very high. Acyclovir, valacyclovir, and famciclovir are effective in shortening the duration of symptoms and lesions in genital herpes. Chronic daily therapy can reduce the frequency of recurrences in those with frequent

reactivation. Valacyclovir has been shown to reduce transmission of HSV-2 between sexual partners.

IV-141. The answer is C. (Chap. 179) Herpes encephalitis accounts for 10% to 20% of sporadic cases of viral encephalitis in the United States. It most commonly occurs in patients 5 to 30 years and older than 50 years old. HSV-1 accounts for more than 95% of cases, and most adults have clinical or serologic evidence of HSV-1 mucocutaneous infection before onset of central nervous system symptoms. Herpes simplex virus (HSV) encephalitis is characterized by the acute onset of fever and focal neurologic signs, particularly in the temporal lobe. Electroencephalographic (EEG) abnormalities in the temporal lobe are common. The cerebrospinal fluid (CSF) will show elevated protein, lymphocyte leukocytosis with red blood cells, and normal glucose. HSV polymerase chain reaction testing of CSF is highly sensitive and specific for diagnosis. Treatment with acyclovir reduces mortality; however, neurologic sequelae are common, particularly in older patients. Differentiation of HSV encephalitis from other viral forms is difficult. Most experts recommend initiation of empiric acyclovir in any patient with suspected encephalitis pending a confirmed or alternative diagnosis. Tuberculosis meningitis presents typically as a basilar meningitis and not encephalitis. The history, clinical findings, EEG abnormalities, and radiologic findings make fungal meningitis unlikely. CSF oligoclonal bands are typically seen in patient with multiple sclerosis.

IV-142. The answer is C. (Chap. 180) Recently, a varicella-zoster virus vaccine that has 18 times the viral content of the live-attenuated virus vaccine used in children was shown efficacious for shingles in patients older than 60 years of age. The vaccine decreased the incidence of shingles by 51%, the burden of illness by 61%, and the incidence of postherpetic neuralgia by 66%. The Advisory Committee on Immunization Practices has therefore recommended that persons in this age group be offered this vaccine to reduce the frequency of shingles and the severity of postherpetic neuralgia. Because is it a live virus vaccine, it should not be used in immunocompromised patients.

IV-143 and IV-144. The answers are C and E, respectively. (Chap. 181) Epstein-Barr virus (EBV) is the cause of heterophile-positive infectious mononucleosis (IM), which is characterized by fever, sore throat, lymphadenopathy, and atypical lymphocytosis. EBV is also associated with several human tumors, including nasopharyngeal carcinoma, Burkitt’s lymphoma, Hodgkin’s disease, and (in patients with immunodeficiencies) B-cell lymphoma. EBV infection occurs worldwide with more than 90% of adults seropositive. In the developing world, most are infected as young children, and IM is uncommon; in the more developed world, most are infected as adolescents or young adults, and IM is more common. The virus is spread by contaminated saliva. Asymptomatic seropositive individuals shed the virus in saliva. In young children, the EBV infection causes mild disease with sore throat. Adolescents and young adults develop IM as described above plus often splenomegaly in the second to third week of disease. The white blood cell count is usually elevated and peaks at 10,000 to 20,000/μL during the second or third week of illness. Lymphocytosis is usually demonstrable, with greater than 10% atypical lymphocytes. A morbilliform rash may occur in about 5% of patients as part of the acute illness. Most patients treated with ampicillin develop a macular rash as pictured; this rash is not predictive of future adverse reactions to penicillins. Heterophile antibody testing results will be positive in up to 40% of cases of IM in the first week of illness and up to 90% by the third week. If heterophile antibody testing results are negative, the more expensive testing for immunoglobulin M (IgM) antibodies to viral capsid antigen is more sensitive and specific. IgG antibodies to viral capsid antigen will stay present indefinitely after initial infection and are not useful for diagnosing acute disease. Treatment of

uncomplicated IM is with rest, supportive measures, and reassurance. Excessive physical activity should be avoided in the first month to avoid splenic trauma. Prednisone is not indicated and may predispose to secondary infection. It has been used at high dose when IM is complicated by airway compromise caused by pharyngeal swelling, autoimmune hemolytic anemia, severe thrombocytopenia, hemophagocytic syndrome, or other severe complications. Controlled trials have shown that acyclovir has no significant impact on the course of uncomplicated IM. One study showed no benefit for combined prednisone plus acyclovir.

IV-145. The answer is D. (Chap. 182) Cytomegalovirus (CMV) retinitis, a common CMV infection in HIV patients, occurs less commonly in solid organ transplant patients. CMV does affect the lung in a majority of transplant patients if either the donor or recipient is CMV-seropositive pretransplant. CMV disease in transplant recipients typically develops 30 to 90 days after transplant. It rarely occurs within 2 weeks of transplantation. CMV very commonly causes a pneumonitis that clinically is difficult to distinguish from acute rejection. Prior CMV infection has been associated with bronchiolitis obliterans syndrome (chronic rejection) in lung transplant recipients. As with HIV, the gastrointestinal tract is commonly involved with CMV infection. Endoscopy with biopsy showing characteristic giant cells, not serum polymerase chain reaction (PCR), is necessary to make this diagnosis. The CMV syndrome is also common in lung transplant patients. Serum CMV PCR should be sent as part of the workup for all nonspecific fevers, worsening lung function, liver function abnormalities, or falling leukocyte counts occurring more than a couple of weeks after transplant.

IV-146. The answer is A. (Chap. 182) When the transplant donor is cytomegalovirus (CMV) immunoglobulin G (IgG) positive and the recipient is negative, there is a very high risk of primary CMV infection in the recipient. However, if the recipient is IgG positive, CMV occurs as a reactivation infection. When both the donor and recipient are seronegative, then the risk of any CMV infection is lowest, but not zero, because contact with an infected host could prompt primary CMV infection. Unlike nearly all other transplant patients, many donor and recipient seronegative patients do not receive chemoprophylaxis with ganciclovir. In patients who are CMV IgG negative and received a CMV IgG negative transplant, transfusions should be from CMV IgG negative donors or white blood cell filtered products administered to reduce the risk of primary CMV infection. It is not clear whether universal prophylaxis or preemptive therapy is the preferable approach in CMV-seropositive immunocompromised hosts. Both ganciclovir and valganciclovir have been used successfully for prophylaxis and preemptive therapy in transplant recipients. A CMV glycoprotein B vaccine reduced infections in a placebo-controlled trial among 464 CMV-seronegative women; this outcome raises the possibility that this experimental vaccine will reduce congenital infections, but further studies must validate this approach.

IV-147. The answer is A. (Chap. 182) Human herpes virus-8 (HHV-8) or Kaposi’s sarcoma–associated herpes virus (KSHV infects B lymphocytes, macrophages, and both endothelial and epithelial cells) appears to be causally related to Kaposi’s sarcoma and a subgroup of AIDS-related B-cell body cavity–based lymphomas (primary effusion lymphomas) and to multicentric Castleman’s disease. HHV-8 infection is more common in parts of Africa than in the United States. Primary HHV-8 infection in immunocompetent children may manifest as fever and maculopapular rash. Among individuals with intact immunity, chronic asymptomatic infection is the rule, and neoplastic disorders generally develop only after subsequent immunocompromise. In patients with AIDS, effective antiretroviral therapy has

caused improvement in HHV-8–related disease. The virus is sensitive to ganciclovir, foscarnet, and cidofovir, but clinical benefit has not been demonstrated in trials. Invasive cervical carcinoma has been causally implicated with human papilloma virus infection.

IV-148. The answer is B. (Chap. 183) Molluscum contagiosum is a cutaneous poxvirus infection with a distinctive cutaneous appearance. The rash typically consists of collections of 2- to 5-mm umbilicated papules that can occur anywhere on the body except the palms and soles. It can be accompanied by an eczematous reaction. Molluscum contagiosum is transmitted through close contact, including sexual contact, which causes genital involvement. Unlike other poxvirus lesions, molluscum contagiosum is not associated with inflammation or necrosis. In immunocompetent patients, the disease is usually self-limited; rash will subside within several months. Systemic involvement does not occur.

IV-149. The answer is C. (Chap. 184) Immunocompromised patients occasionally cannot clear parvovirus infection because of a lack of T-cell function. Because parvovirus B19 selectively infects red cell precursors, persistent infection can lead to a prolonged red blood cell aplasia and a persistent drop in hematocrit, with low or absent reticulocytes. Pure red blood cell aplasia has been reported in HIV infection, lymphoproliferative diseases, and after transplantation. Iron studies show adequate iron but decreased utilization. The peripheral smear usually shows no abnormalities other than normocytic anemia and the absence of reticulocytes. Antibody tests are not useful in this setting because immunocompromised patients do not produce adequate antibodies against the virus. Therefore, polymerase chain reaction (PCR) is the most useful diagnostic test. Bone marrow biopsy may be suggestive because it will show no red blood cell precursors, but usually a less invasive PCR test is adequate. Immediate therapy is with red blood cell transfusion followed by intravenous immunoglobulins, which contain adequate titers of antibody against parvovirus B19.

IV-150. The answer is D. (Chap. 184) The most likely diagnosis based on the patient’s antecedent illness with a facial rash is parvovirus infection. Arthropathy is uncommon in childhood parvovirus infection but may cause a diffuse symmetric arthritis in up to 50% of adults. This corresponds to the immune phase of illness when immunoglobulin M antibodies are developed. The arthropathy syndrome is more common in women than men. The distribution of affected joints is typically symmetric, most commonly in the small joints of the hands and less commonly the ankles, knees, and wrists. Occasionally the arthritis persists over months and can mimic rheumatoid arthritis. Rheumatoid factor can be detected in serum. Parvovirus B19V infection may trigger rheumatoid disease in some patients and has been associated with juvenile idiopathic arthritis. Reactive arthritis caused by Chlamydia spp. or a list of other bacterial pathogens tends to affect large joints such as the sacroiliac joints and spine. It is also sometimes accompanied by uveitis and urethritis. The large number of joints involved with a symmetric distribution argues against crystal or septic arthropathy.

IV-151. The answer is E. (Chap. 185) The currently available human papillomavirus (HPV) vaccines dramatically reduce rates of infection and disease produced by the HPV types in the vaccines. These products are directed against virus types that cause anogenital tract disease. Both vaccines consist of virus-like particles without any viral nucleic acid and therefore are not active. To date, one quadrivalent product (Gardasil, Merck) containing HPV types 6, 11, 16, and 18 and one bivalent product (Cervarix, GlaxoSmithKline) containing HPV types 16 and 18 have been licensed in the United States. HPV types 6 and 11 cause 90% of anogenital warts, and types 16 and 18 are responsible for 70% of cervical cancers. Efficacy has varied according to the immunologic and virologic

characteristics of study populations at baseline and according to the endpoints evaluated. Among study participants who are shown at baseline not to be infected with a specific virus type contained in the vaccine and who adhere to the study protocol, rates of vaccine efficacy regularly exceed 90%, as measured by both infection and disease caused by that specific virus type. Study participants who are already infected at baseline with a specific virus type contained in the vaccine do not benefit from vaccination against that type but may benefit from vaccination against other virus types contained in the vaccine preparation. Thus, the available HPV vaccines have potent prophylactic effects but no therapeutic effects. The Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention has recommended that HPV vaccination be routinely offered to girls and young women 9 to 26 years of age. The quadrivalent vaccine has also been licensed in the United States for use in boys and young men; the ACIP has stated that this product may be used to prevent anogenital warts in boys and young men 9 to 26 years of age. Because 30% of cervical cancers are caused by HPV types not contained in the vaccines, no changes in cervical cancer screening programs are currently recommended. Ongoing studies are examining self-testing for HPV to replace many Pap studies in patients with no evidence of cervical infection. Recent studies implicate HPV in some forms of squamous cell carcinoma of the oropharynx. The utility of the current vaccines in preventing these cancers in not yet known.

Date: 2016-04-22; view: 864