whatsupwithat
12-01-2006, 09:53 AM
Wear a condom.
Respect yourself. And everyone else.
Peace all.
Be safe.
Acquired Immunodeficiency Syndrome (AIDS)
When the CD4 lymphocyte count drops below 200/microliter, then the stage of clinical AIDS has been reached. This is the point at which the characteristic opportunistic infections and neoplasms of AIDS appear. Listed below are some of the more common complications seen with AIDS with images that illustrate gross and microscopic pathologic findings.
The organ involvement of infections with AIDS represents the typical appearance of opportunistic infections in the immunocompromised host--that of an overwhelming infection--that makes treatment more difficult. The strategies employed in AIDS patients to meet this challenge consist of (1) preserving immune function as long as possible with antiretroviral therapies, (2) using prophylactic pharmacologic therapies to prevent infections (such as Pneumocystis carinii pneumonia), and (3) diagnosing and treating acute infections as soon as possible.
Pneumocystis carinii
Pneumocystis carinii is the most frequent opportunistic infection seen with AIDS. It produces a pulmonary infection, called Pneumocystis carinii pneumonia (PCP), but rarely disseminates outside of lung. The most common clinical findings in patients with PCP are acute onset of fever, non-productive cough, and dyspnea. Chest radiograph may show perihilar infiltrates. Diagnosis is made histologically by finding the organisms in cytologic (bronchoalveolar lavage) or biopsy (transbronchial biopsy) material from lung, typically via bronchoscopy. The cysts of P carinii stain brown to black with the Gomori methenamine silver stain. With Giemsa or Dif-Quik stain on cytologic smears, the dot-like intracystic bodies are seen.
Cytomegalovirus
Cytomegalovirus (CMV) is the most frequent disseminated opportunistic infection seen with AIDS. It causes the most serious disease as a pneumonia in the lung, but it can also cause serious disease in the brain and gastrointestinal tract. It is also a common cause for retinitis and blindness in persons with AIDS. CMV is identified by the presence of very large cytomegalic cells with enlarged nuclei that contain a violaceous intranuclear inclusion surrounded by a clear halo. Sometimes, basophilic stippling is present in the cytoplasm.
Mycobacteria
Mycobacterial infections are frequently seen with AIDS. Mycobacterium tuberculosis has been increasing in frequency since the start of the AIDS epidemic. The appearance of M tuberculosis with AIDS is similar to that of non-AIDS patients, with granulomatous pulmonary disease, though the infection may be more extensive or may be disseminated to other organs. Mycobacterium avium complex (MAC) infection is more unique to AIDS and is characterized by involvement mostly of the organs of the mononuclear phagocyte system (lymph node, spleen, liver, marrow). MAC infections are less likely to produce visible granulomas, and the lesions often consist of clusters of macrophages filled with numerous mycobacteria. Definitive diagnosis of mycobacterial disease is made by culture.
Fungal Infections
There are many types of fungi that can complicate the course of AIDS. One of the most frequent (though uncommonly life-threatening) is Candida. Oral candidiasis is often seen with HIV infection and may presage the progression to AIDS. Candida can occasionally produce invasive infections in esophagus, upper respiratory tract, and lung.
Infections with the pathogenic fungi Cryptococcus neoformans, Histoplasma capsulatum, and Coccidioides immitis are more serious infections that are often widely disseminated. C neoformans often produces pneumonia and meningitis.
Toxoplasmosis
Toxoplasma gondii is a protozoan parasite that most often leads to infection of the brain with AIDS. The lesions are usually multiple and have the appearance of abscesses. Less commonly, T gondii infection is disseminated to other organs.
Gastrointestinal Protozoal Infections
Cryptosporidium, Microsporidium, and Isospora are all capable of producing a voluminous watery diarrhea in patients with AIDS. Diagnosis can be made by examination of stool specimens and/or intestinal biopsy.
Malignant Neoplasms
Kaposi's sarcoma (KS) produces reddish purple patches, plaques, or nodules over the skin and can be diagnosed with skin biopsy. Visceral organ involvement eventually occurs in 3/4 of patients with KS.
Malignant lymphomas seen with AIDS are typically of a high grade and extranodal, often in the brain. They are very aggressive and respond poorly to therapy.
Respect yourself. And everyone else.
Peace all.
Be safe.
Acquired Immunodeficiency Syndrome (AIDS)
When the CD4 lymphocyte count drops below 200/microliter, then the stage of clinical AIDS has been reached. This is the point at which the characteristic opportunistic infections and neoplasms of AIDS appear. Listed below are some of the more common complications seen with AIDS with images that illustrate gross and microscopic pathologic findings.
The organ involvement of infections with AIDS represents the typical appearance of opportunistic infections in the immunocompromised host--that of an overwhelming infection--that makes treatment more difficult. The strategies employed in AIDS patients to meet this challenge consist of (1) preserving immune function as long as possible with antiretroviral therapies, (2) using prophylactic pharmacologic therapies to prevent infections (such as Pneumocystis carinii pneumonia), and (3) diagnosing and treating acute infections as soon as possible.
Pneumocystis carinii
Pneumocystis carinii is the most frequent opportunistic infection seen with AIDS. It produces a pulmonary infection, called Pneumocystis carinii pneumonia (PCP), but rarely disseminates outside of lung. The most common clinical findings in patients with PCP are acute onset of fever, non-productive cough, and dyspnea. Chest radiograph may show perihilar infiltrates. Diagnosis is made histologically by finding the organisms in cytologic (bronchoalveolar lavage) or biopsy (transbronchial biopsy) material from lung, typically via bronchoscopy. The cysts of P carinii stain brown to black with the Gomori methenamine silver stain. With Giemsa or Dif-Quik stain on cytologic smears, the dot-like intracystic bodies are seen.
Cytomegalovirus
Cytomegalovirus (CMV) is the most frequent disseminated opportunistic infection seen with AIDS. It causes the most serious disease as a pneumonia in the lung, but it can also cause serious disease in the brain and gastrointestinal tract. It is also a common cause for retinitis and blindness in persons with AIDS. CMV is identified by the presence of very large cytomegalic cells with enlarged nuclei that contain a violaceous intranuclear inclusion surrounded by a clear halo. Sometimes, basophilic stippling is present in the cytoplasm.
Mycobacteria
Mycobacterial infections are frequently seen with AIDS. Mycobacterium tuberculosis has been increasing in frequency since the start of the AIDS epidemic. The appearance of M tuberculosis with AIDS is similar to that of non-AIDS patients, with granulomatous pulmonary disease, though the infection may be more extensive or may be disseminated to other organs. Mycobacterium avium complex (MAC) infection is more unique to AIDS and is characterized by involvement mostly of the organs of the mononuclear phagocyte system (lymph node, spleen, liver, marrow). MAC infections are less likely to produce visible granulomas, and the lesions often consist of clusters of macrophages filled with numerous mycobacteria. Definitive diagnosis of mycobacterial disease is made by culture.
Fungal Infections
There are many types of fungi that can complicate the course of AIDS. One of the most frequent (though uncommonly life-threatening) is Candida. Oral candidiasis is often seen with HIV infection and may presage the progression to AIDS. Candida can occasionally produce invasive infections in esophagus, upper respiratory tract, and lung.
Infections with the pathogenic fungi Cryptococcus neoformans, Histoplasma capsulatum, and Coccidioides immitis are more serious infections that are often widely disseminated. C neoformans often produces pneumonia and meningitis.
Toxoplasmosis
Toxoplasma gondii is a protozoan parasite that most often leads to infection of the brain with AIDS. The lesions are usually multiple and have the appearance of abscesses. Less commonly, T gondii infection is disseminated to other organs.
Gastrointestinal Protozoal Infections
Cryptosporidium, Microsporidium, and Isospora are all capable of producing a voluminous watery diarrhea in patients with AIDS. Diagnosis can be made by examination of stool specimens and/or intestinal biopsy.
Malignant Neoplasms
Kaposi's sarcoma (KS) produces reddish purple patches, plaques, or nodules over the skin and can be diagnosed with skin biopsy. Visceral organ involvement eventually occurs in 3/4 of patients with KS.
Malignant lymphomas seen with AIDS are typically of a high grade and extranodal, often in the brain. They are very aggressive and respond poorly to therapy.