Case Studies

Case Studies

The patient, a 30-year-old homosexual man, complained of unexplained weight loss, chronic diarrhea, and respiratory congestion during the past 6 months. Physical examination revealed right-sided pneumonitis. The following studies were performed:





Studies Results
Complete blood cell count (CBC), p. 174  
Hemoglobin (Hgb), p. 259 12 g/dL (normal: 14-18 g/dL)
Hematocrit (Hct), p. 256 36% (normal: 42%-52%)
Chest X-ray, p. 1014 Right-sided consolidation affecting the posterior

lower lung

Bronchoscopy, p. 587 No tumor seen
Lung biopsy, p. 738 Pneumocystis jiroveci pneumonia (PCP)
Stool culture, p. 855 Cryptosporidium muris
Acquired immunodeficiency syndrome

(AIDS) serology, p. 297

p24 antigen Positive
Enzyme-linked immunosorbent assay


Western blot Positive
Lymphocyte immunophenotyping, p. 306  
Total CD4 280 (normal: 600-1500 cells/L)
CD4% 18% (normal: 60%-75%)
CD4/CD8 ratio 0.58 (normal: >1.0)
Human immune deficiency virus (HIV)

viral load, p. 297

75,000 copies/mL








Diagnostic Analysis

The detection of Pneumocystis jiroveci pneumonia (PCP) supports the diagnosis of AIDS. PCP is an opportunistic infection occurring only in immunocompromised patients and is the most common infection in persons with AIDS. The patient’s diarrhea was caused by Cryptosporidium muris, an enteric pathogen, which occurs frequently with AIDS and can be identified on a stool culture. The AIDS serology tests made the diagnoses. His viral load is significant, and his prognosis is poor.

The patient was hospitalized for a short time for treatment of PCP. Several months after he was discharged, he developed Kaposi sarcoma. He developed psychoneurologic problems eventually and died 18 months after the AIDS diagnosis.



Critical Thinking Questions

1. What is the relationship between levels of CD4 lymphocytes and the likelihood of clinical complications from AIDS?

2. Why does the United States Public Health Service recommend monitoring CD4 counts every 3 to 6 months in patients infected with HIV?