Write an Explanation after each answer
Chen Yau, a 3-year-old Asian-American man, was admitted withsymptoms of a depressed immune system, including oral and groincandidiasis (thrush) and a herpesvirus infection. This is hisfourth admission in less than 2 years. Mr. Yau has engaged in analand oral homosexual intercourse since 20 years of age. At 30 yearsold, he tested positive for HIV. Chen has had four inpatient andthree outpatient admissions between 30 and 32 years of age. Hisprevious admissions were for Pneumocystis carinii pneumonia,anemia, gastrointestinal problems, and Kaposi sarcoma of the skin.Mr. Yau takes several medications to control his symptoms,including zidovudine (Azidothymidine (AZT)). Mr. Yau’s most recentadmission was preceded with symptoms of diarrhea, loss of appetite,a 10-pound weight loss over a 2-week period, a nonproductive cough,some shortness of breath, night sweats, fatigue, and a perianallesion. On admission, physical examination reveals painfulenlargement of multiple lymph nodes, whites exudate, andinflammation of the mouth and back of the throat, which isconsistent with candidiasis, and purplish brown palpable lesions onhis arms, legs, and trunk, which are consistent with Kaposisarcoma. A comprehensive baseline mental status examination revealsseveral subtle changes in personality and some mild confusion. Mr.Yau demonstrates limits in his visual field, and an ophthalmoscopicexamination of the eye shows evidence of inflammation andhemorrhage of the retina that is consistent with cytomegalovirus.Laboratory studies reveal a low white cell count with a fewlymphocytes, a reduced ratio of T4 helper cells to T8 suppressorcells, a positive stool for the Cryptosporidium parasite, and anx-ray with diffuse infiltrates compatible with Pneumocystis cariniipneumonia. During this most recent admission, Mr. Yau becameextremely confused and also became unable to fully control themuscles of his feet and legs. His condition continued todeteriorate until his death in the hospital a few weeks after hisadmission.
1. Acquired immune deficiency syndrome (AIDS) manifests asreduced resistance to opportunistic infections and malignanciesbecause of: A. An acquired deficiency of isoimmunity B. Anexaggerated immune response to counteract a T-cell deficiency C.Impaired functioning of one of the immune inflammatory responses D.Deficiency of antigen (HIV) recognition.
2. The T4 helper cell to T8 suppressor cell ratio is normallyabout 2:1. This ratio in Mr. Yau was severely reduced because: A.Bone marrow depression reduces hemoglobin and hematocrit levels. B.HIV infects and kills the host T4 cells, decreasing their numbers.C. The T8 suppressor cells are stimulated by HIV and their numbersincrease. D. y-Interferon is reduced, thereby reducing cytotoxic T8suppressor cell activity.
3. Pneumocystis carinii, a protozoan that is usually notpathogenic, caused severe respiratory problems for Mr. Yau becauseof his: A. T-cell function impairment B. Lack of knowledge abouthis disease C. Recent exposure to human immunodeficiency virus D.Immunosuppression from the AZT
4. Mr. Yau’s confusion and distal peripheral neuropathy are notsupported with any serological findings for neurological orinfectious disease. His peripheral neuropathy was most likelycaused by: A. Primary or secondary central nervous system lymphomaB. Toxoplasma, a protozoan infection of the central nervous systemC. Disturbance in normal brain patterns from drug therapy D.Presence of HIV in peripheral nerves and the central nervoussystem.
