Kamis, 17 Mei 2012

Acquired immune deficiency syndrome (AIDS) and its oral manifestations

Description:  Acquired immune deficiency syndrome is characterized by relentless destruction of CD4 T lymphocytes, key cells of the immune system. The eventual collapse of both the cellular and humoral arms of immunity leaves the host vulnerable to  a wide variety of pathogenic organisms including bacteria, viruses, fungi and protozoa.  It is important for health care workers to recognize that it is difficult to transmit the AIDS virus in the health care setting, from patient to worker or the reverse. However, opportunistic infectious diseases that AIDS patients are apt to have including tuberculosis, herpes-virus infections, hepatitis B and hepatitis C are readily transmissible.

Etiology:  The causes of AIDS is an RNA  retrovirus of the lentivirus group. It is designated the human immunodeficiency virus (HIV) and there are several variants:  HIV- 1 is the most common cases of AIDS. The virus attaches to the surface of cells that bear the  CD4  receptor  including  helper  T  lymphocytes,  B  lymphocytes  and  macrophages.
Although they lack a CD4 receptor, microglia, skin fibroblasts, and bowel epithelium become  infected.  The  virus  destroys  the  infected  cells.  With  gradual  depletion  of  the cells of immunity, especially T-helper lymphocytes and macrophages, the host becomes increasingly vulnerable to pathogenic organisms.

Oral Manifestations:

Candidiasis  -  Colonization  and  infection  of  the  oral  mucosa  by  Candida  species  is among the earliest and most common findings in HIV-infected patients. In one study, 88% had oral candidiasis. Lesions range from white to red or red/white combinations.
Fig. 1 illustrates the typical appearance of candidiasis. The lesions may be asymptomatic or there may be mild discomfort. For stubborn infection, fluconazole is recommended.  

Kaposi's  sarcoma  -  AIDS  patients  are  vulnerable  to  a  variety  of  oral  malignancies including Kaposi's sarcoma, malignant lymphoma and squamous carcinoma. Kaposi's sarcoma is the most common. In one study, 20% of AIDS patients had Kaposi's sarcoma and of these, the tumor was in the oral cavity in 1 of every 5 patients; the palate is the most common site. In the early stage, the tumor appears as a red to purple bruise (Fig. 2). The tumor grows and eventually appears as a hemorrhagic mass (Fig. 3). The cell of origin  is  endothelium;  thus  Kaposi's  sarcoma  is  a  variety  of  angiosarcoma.  They  are locally invasive, cause pain and bleeding and interfere with normal function. Low-dose radiation  therapy  and  intralesional  or  systemic  chemotherapy  are  the  treatments  of choice. Herpes virus type VIII is thought to play a role in the pathogenesis of this tumor.

Hairy leukoplakia  -  This  variety  of  leukoplakia  was  first  recognized  in  HIV-infected patients but has been encountered in other immune deficiency states such as organ transplant patients who are intentionally immune suppressed. The lateral tongue is the most common location (Fig. 4). Lesions are of rough texture, adherent and asymptomatic. The diagnosis of hairy leukoplakia can be suspected on routine biopsy specimens, but confirmation requires demonstration of the presence of the causative virus, the Epstein-Barr herpesvirus. This is ordinarily achieved by DNA in situ hybridization. A word of caution: hairy leukoplakia may be confused with candidiasis. A patient who presents with a white lesion should be treated with antifungal therapy first. If it fails to heal, it most likely is hairy leukoplakia.

Gingival and periodontal lesions  - HIV-infected patients are vulnerable to necrotizing gingivitis and periodontitis (Fig. 5). The organisms recovered from these lesions are the same as those in non-HIV-positive patients. Lesions are treated by dental prophylaxis, debridement, and metronidazole. Good oral hygiene and daily rinses with chlorhexidine are beneficial.

Others - HIV patients also develop major aphthous-like lesions that respond to tetracycline and topical steroid therapy.

Thalidomide has been used successfully in their management. The human papillomavirus has also been found in both condylomas and focal epithelial hyperplasia. Cytomegalovirus infections and several fungal infections such as histoplasmosis  and  coccidiodomycosis  are  also  common.  Lastly,  xerostomia  secondary  to  salivary  gland  destructions  has  been reported. 

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