textbook of oral pathology (2/e): part 2

Chia sẻ: 123vr 123vr | Ngày: | Loại File: PDF | Số trang:502

Thêm vào BST

Báo xấu

26
lượt xem 1
download

Download Vui lòng tải xuống để xem tài liệu đầy đủ

(bq) part 2 book “textbook of oral pathology” has contents: acquired immunodeficiency syndrome, odontogenic infection and pulp pathology, tongue disorders, temporomandibular joint pathology, chemical and physical injuries, blood pathology, skin disorders,… and other contents.

Chủ đề:

Bình luận(0) Đăng nhập để gửi bình luận!

Lưu

Nội dung Text: textbook of oral pathology (2/e): part 2

21 Acquired Immunodeficiency Syndrome Anil Govindrao Ghom, Shubhangi Mhaske (Jedhe) Chapter Outline Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Definition AIDS related complex Prevalence Etiology Characteristic of HIV virus Mechanism of action Transmission Clinical features Oral manifestations Candidiasis Kaposi’s sarcoma Hairy leukoplakia Periodontal disease associated with HIV Non-Hodgkin lymphoma Recurrent herpes labialis Oral human papilloma virus lesions Acquired immunodeficiency syndrome (AIDS) is a devastating fatal disease, which is in epidemic form throughout the world. It is an incurable viral STD caused by human immunodeficiency virus (HIV). It stands for: ∙ A: Acquired, i.e. contagious not inherited ∙ I: Immune, i.e. power to receive disease ∙ D: Deficiency ∙ S: Syndrome, i.e. number of signs and complains indicative of particular disease. Four identified etiological agents are of substantially lenti virus (HIV-I an HIV-II) that cause slow infection in which sign and symptoms only appear after many months or years of infection and two member of oncovirus (HTLV-I Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Herpes zoster HIV associated salivary gland diseases Idiopathic thrombocytopenic purpura Mycobacterium infection Hyperpigmentation Histoplasmosis Recurrent aphthous stomatitis Molluscum contagiosum Oral squamous cell carcinoma Diagnostic tests Screening test for AIDS Enzyme-linked immunosorbant assay The Western Blot method Viral culture and polymerase chain reaction Surrogate marker for progression of HIV-I infection Management and HTLV-II) that are capable of oncogenic transformation and are usually associated with leukemia or lymphoma. The case of AIDS was detected in June 1981 when 5 young homosexuals men came with the suffering from rare lung infection due to microorganism called Pneumocystis carinii. In India, the first description of AIDS came in Madras where 6 women out of 125 who were screened were HIV positive in high-risk group of prostitutes. The AIDS appear to be endemic in central and equatorial Africa and it may be old disease of Africa that has gone unrecognized. The HIV-1 infection has also become the primary emphasis of effort at controlling Acquired Immunodeficiency Syndrome sexually transmitted diseases (STDs). Moreover, the knowledge gain about sexual and other behavior associated with transmission of HIV, as well as strategies that have been effective in modifying those behaviors, is transferable to other sexually transmittable and bloodborne infections and has revolutionized standard approaches to the control of these infections. Oral and perioral lesions are common presenting features in patient with human immunodeficiency virus and may have deterioration of general health and a poor prognosis. DEFINITION World Health Organization (WHO) has given following definition of AIDS: One or more opportunistic infections listed in clinical features that are at least moderately indicative of underlying cellular immune deficiency. Absence of all known underlying causes of cellular immune deficiency (other than HIV infection) and absence of all other causes of reduced resistance reported to be associated with at least one of those opportunistic diseases. CLASSIFICATION 1st Classification (given in 1993) by Center for Disease Control (CDC) CD4 + T-cell categories A Asymptomatic, acute HIV and PGL B Symptomatic, not A or C conditions C AIDS indicator condition More 500/µL A1 B1 C1 200 to 499/µL A2 B2 C2 Less than 200/µL AIDS indicator T-cell count A3 B3 C3 Category A: In adolescent less than 13 years with documented HIV infection: ∙ Persistence generalized lymphadenopathy ∙ Active condition. ∙ ∙ Category B: Condition is attributed to HIV infection or indicative of defect in the cell-mediated immunity. ∙ Bacillary angiomatosis ∙ Oropharyngeal and vulvovaginal candidiasis ∙ Cervical carcinoma in situ ∙ Constitutional symptoms like fever (38.5˚C) and diarrhea ∙ Oral hairy leukoplakia and herpes zoster ∙ Idiopathic thrombocytopenic purpura. ∙ ∙ ∙ ∙ Category C: AIDS indicative condition ∙ Candidiasis of bronchi, trachea or lung and esophageal candidiasis ∙ ∙ ∙ Invasive cervical cancer Disseminated or extrapulmonary coccidioidomycosis, extrapulmonary cryptococcosis Chronic intestinal cryptosporidiosis more than 1 month duration Cytomegalovirus retinitis with loss of vision HIV related encephalopathy Herpes simplex bronchitis, pneumonitis and esophagitis Kaposi sarcoma, Burkitt’s lymphoma and immunoblastic lymphoma Mycobacterium tuberculosis infection at any pulmonary or extrapulmonary sites Pneumocystic carinii pneumonia and recurrent pneumonia Progressive multifocal leukoencephalopathy Toxoplasmosis of brain and wasting syndrome Recurrent Salmonella septicemia. ∙ ∙ ∙ 525 Textbook of Oral Pathology 2nd Classification by USPHS-CDC 526 ∙ ∙ ∙ ∙ Group I: Acute infection Group II: Asymptomatic infection Group III: Persistence generalized lymphadenopathy. Group IV: Other disease – Subgroup A: Constitutional diseases – Subgroup B: Neurological diseases – Subgroup C: Secondary infectious diseases - - C1: Specified secondary infectious diseases listed in CDC surveillance definition for AIDS. C2: Other specified secondary infectious stages. – Subgroup D: Secondary cancer – Subgroup E: Other conditions. AIDS RELATED COMPLEX For clinical and research studies, persons exhibiting complex clinical problems and immunological or hematological abnormalities on the laboratory tests, have been classified as having AIDS related complex (ARC). The ARC requires any two or more symptoms and two or more abnormal laboratory findings. It must be present for at least 3 months. Symptoms Laboratory findings • Lymphadenopathy • Weight loss of 15 lbs or 10% of body weight • Fever of 38.5˚C which is intermittent or continuous • Diarrhea, fatigue and malaise • Night sweats • • • • • • • Decreased number of T helper cell Decreased ratio of T helper cells to T suppressor cells Anemia or leukopenia or thrombocytopenia or lymphopenia Increased serum globulin level Decreased blastogenic response of lymphocytes to mitogen Increased level of circulating immune complex Cutaneous anergy to multiple the skin test antigens PREVALENCE It is more common in Western countries particularly in the United State. Largest population of AIDS is in homosexuals, intravenous drug users and, heterosexuals with sexual contact with AIDS patient. Patients who received transfusion of blood or blood pigments donated by the person with risk factors. Ninety-two percent of victims are males, 6.5 percent female with 1 percent children. It is common at the age of 25 to 49 years. Etiology T lymphocytes: There is quantitative and qualitative deficiency of T4 helper cells in AIDS patients, which lead to certain investigators to focus their efforts on determining if etiologic agent was a virus that manifested a particular tropism for T4 helper lymphocytes. HTLV-III virus: Dr Robent C Galleo determined that type C retrovirus was tropic for T4 lymphocytes in adult T-cell leukemia/lymphoma. He named the virus, Humans T-cell leukemia/lymphoma virus (HTLV–I). So it is considered to be etiological agent for AIDS. But as it causes lymphoproliferation in T-cell leukemia, where as AIDS is a disease of lymphodepletion. The answer came in the discovery of type D retrovirus of HTLV family that has been termed as HTLV-III. LAV virus: On the other hand, virus called lymphadenopathy associated virus (LAV), was being isolated from the AIDS patient in Europe. HTLV-III and LAV is closely related members of same class of virus. Finally, it is proved that HTLV and LAV are cytopathic human T–lymphocytotropic viruses that manifested selective infectivity for the helper/inducer subset of T-cells that as phenotypically designated reactivity with monoclonal antibody T4 or Leu3. HIV: In order to avoid different nomenclatures retrovirus responsible for the AIDS are named ‘Human immunodeficiency virus’ which belong to family of retroviruses. Risk person: Six groups are at risk of developing AIDS. These are homosexuals or bisexuals—71.4 percent, intravenous drug users—18.4 percent, hemophilia, recipient of multiple blood transfusion, infant born of parents belonging to first three high-risk groups and heterosexual contacts of high-risk group. Acquired Immunodeficiency Syndrome CHARACTERISTIC OF HIV VIRUS The HIV is a spherical enveloped virus, about 90 to 120 nm in size (Fig. 21.1). The nucleocapsid has an outer icosahedral shell and inner cone shaped core, enclosing the ribonucleoproteins. The genome is diploid, composed of two identical single stranded, positive sense RNA copies. Inside the envelope is a protein core, which contain enzymes reverse transcriptase, intregrase, protease, etc. all essential for viral replication and maturation. When the virus infects a cell, the viral RNA is transcribed by the enzymes, first into single stranded DNA and then to double stranded DNA (provirus), which is integrated into the host cell chromosomes. The virus is extremely sensitive to heat, thus boiling and autoclaving are very effective measure of inactivating the virus. Mechanism of Action The HIV attacks the immune system of the body. Due to that an individual is not able to protect himself from potentially harmful organism. Normal mechanism: Pathogenic viruses → identified by macrophage → it activates T lymphocytes → it get differentiated into effecter cell like T helper cell or T4 and T suppresser cell or T8 → T4 cells secrete various lymphokines which induce lymphocyte to differentiated into plasma cell → it secrete specific antibodies against viral antigen → it destroy the virus. Mechanism in AIDS: HIV virus is lymphotropic virus → its primary target is T4 cell → when the virus enters the bloodstream, it integrates into gene into DNA of some primary T4 lymphocyte → this viral DNA then becomes integrated into the host chromosomes → the chromosomal integration is prerequisite for replication of retroviruses, but also for the latency → once the viral genes are integrated into cells of own DNA, they can apparently remain dormant for an indefinite period of time, without causing its affects. This is called ‘incubation period’ → once the viral gene is activated, virus particles convert T4 lymphocytes into AIDS virus factory → when the number of T4 lymphocyte is severely depleted, the immune system collapses and variety of infections occur → at this stage patient is said to have AIDS. Transmission Repeated intimate contact: It is in 90 percent of cases. It depends upon number of sexual partners, receptive anal intercourse and presence of other STDs. All these are in high-risk group. Prostitution is a major heterosexual factor associated with AIDS. Use of contaminated blood products: Intravenous drug users, HIV contaminated blood transfusion, blood clotting concentrate and organ transplantation. Perinatal transmission: It occurs in 13 percent among children born to HIV seropositive mother. Other nosocomial routes: Transmission from patient to patient due to reuse of contaminated and shared needles. Professional hazards: The risk of transmission from HIV infected patient to health care workers is more than health care workers to patient. CLINICAL FEATURES (FIG. 21.2) Protozoan and helminthes infection: Cryptosporidiosis (intestinal) causing diarrhea for over one month. The most common opportunistic infection is by Pneumocystis carinii which causes pneumonia. CNS infection or other disseminated infections and toxoplasmosis. Fungal infection: Candidiasis causing esophagitis, cryptococcosis causing CNS infection, disseminated histoplasmosis and bronchial or pulmonary candidiasis. Bacterial infections: Mycobacterium avium intracellulare causing infection disseminated beyond lung and lymph node. Mycobacterium tuberculosis will cause tuberculosis. Figure 21.1 HIV virus Viral infections: Cytomegalovirus causing infection in the internal organs other than liver, spleen and lymph nodes. Herpes simplex virus, causing chronic mucocutaneous infection with ulcers persisting more than one month. 527 Textbook of Oral Pathology 528 Figure 21.2 Features of HIV infection Malignancy: Kaposi’s sarcoma and squamous cell carcinoma. Lymphoma limited to bronchi and nonHodgkin’s lymphoma. AIDS dementia complex: This occur in patient with HIV infection and causes progressive encephalopathy. ORAL MANIFESTATIONS Oral manifestations of HIV disease are common and include oral lesions and novel presentations of previously known opportunistic diseases. Careful history taking and detailed examination of the patient’s oral cavity are important parts of the physical examination and diagnosis requires appropriate investigative techniques. Early recognition, diagnosis and treatment of HIVassociated oral lesions may reduce morbidity. The presence of these lesions may be an early diagnostic indicator of immunodeficiency and HIV infection may change the classification of the stage of HIV infection and is a predictor of the progression of HIV disease. Around 95 percent of AIDS patients have head and neck lesions and about 55 percent have important oral manifestation. They are described below. Oral Disorders in HIV Disease ∙ Fungal More common – Candidiasis Less common – Aspergillosis – Histoplasmosis – Cryptococcus neoformans – Geotrichosis ∙ Bacterial More common – HIV gingivitis – HIV periodontitis – Necrotizing gingivitis Less common – Mycobacterium avium intracellulare – Klebsiella pneumoniae – Enterobacter cloacae – E. coli – Salmonella enteritidis – Sinusitis – Exacerbation of apical periodontitis – Submandibular cellulitis