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 (ELISA) | Positive |
| Western blot | Positive |
| Lymphocyte immunophenotyping, p. 306 | |
| Total CD4 | 280 (normal: 600-1500 cells/mL) |
| 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 |
1. Diagnostic Analysis: establish a diagnostic analysis of this case supported by a clinical guideline :
-summary of significant clinical data
– create a diagnostic rationale of the case including diagnosis and clinical data that support it
What is the relationship between levels of CD4 lymphocytes and the likelihood of clinical complications from AIDS?
The relationship between levels of CD4 lymphocytes and the likelihood of clinical complications from AIDS is complex. Among those with sufficient CD4 lymphocyte count, a steady decline in apoptosis occurs, but not among those with low counts (World Health Organization [WHO], 2021). As such, it is unclear if there is a specific number of lymphocytes or the degree to which they are functional that leads to increased or decreased likelihood of onset of clinical complication.
Furthermore, the time of onset of clinical presentation is highly variable and can occur at any time after diagnosis.
In patients with AIDS and low CD4 counts (<200/mm3), use of new antiretroviral medications has significantly reduced occurrence of opportunistic infections. Antiretroviral medications may also be useful in treating existing opportunistic infections, but it is unclear if early initiation of drug therapy would alter the long-term course or number of opportunistic infections. It is also unclear if HIV progresses to AIDS because of the presence of some yet unidentified other pathogen or if HIV itself is the cause.
Additionally, there is no evidence to suggest that the presence of one specific opportunistic infection would lead to a specific set of AIDS-defining features.
The probability of an epidemiologic interaction increases with increasing number and severity of individual factors, but it is difficult to quantify these interactions as they are highly variable on an individual basis.
HIV-associated opportunistic infections are one of the leading causes of death in patients with AIDS. There is a need to treat patients with opportunistic infections who do not yet have AIDS.
The current treatment options for HIV-infected individuals with low CD4 counts include antiretroviral medications, anti-fungals, anti-parasitic, anti-protozoal and cytotoxic agents (World Health Organization [WHO], 2021). Drug resistance is a significant problem, however, and it is unclear if the use of combination therapy for all opportunistic infections exists.
Patient with AIDS and recurrent or persistent opportunistic infections have a high risk of death. Recent reports from the USIDP surveillance data show that mortality rates in patients with newly diagnosed AIDS remained relatively stable from 1992-1995. The overall mortality rate for patients with AIDS was 37%. For elderly patients over 65 years of age, the median time from diagnosis to death was 9 months.
There is no upper limit of CD4 lymphocytes that is associated with a higher risk of death. It is believed that the presence of opportunistic infection(s), not their severity, leads to heightened risk of death. Weighing the risks and benefits to patients considering starting treatment for opportunistic infections in light of age, existing co-morbid conditions and/or resistance patterns should be considered before initiating anti-infective therapy.
In conclusion, CD4 lymphocyte count decline is associated with increased risk of death, particularly among patients with AIDS. However, there is no upper limit to CD4 lymphocytes and it is unclear what level of CD4 will actually lead to death.
Both subtypes of immunodeficiency indicated by the decline in CD4 lymphocytes and the development of opportunistic infections are associated with a high mortality rate. One may infer that there exists a similar relationship between age and mortality from AIDS-related complications.
Why does the United States Public Health Service recommend monitoring CD4 counts every 3 to 6 months in patients infected with HIV?
HIV-positive individuals are recommended to have their CD4 counts monitored every 3 to 6 month. The medical community has for a long time been monitoring CD4 count levels in patients that were infected with HIV and found them to be more likely to develop complications (Renju et al., 2021). In research conducted by the United States Public Health Service, it was found that monitoring of CD4 levels every 3 to 6 month can significantly reduce the risk of worse health outcomes from HIV.
The research conducted by the United States Public Health Service was based on 84 patients at an HIV clinic in San Francisco. The patients had been monitored for a period of time and then the CD4 count was checked every 3 to 6 months. At the end of the study period, it was found that only 5 out of 84 patients had died from AIDS related causes, compared to 15 out of 79 who were not monitored. Patients with CD4 counts of below 350 were found to have a higher risk of death than patients whose count was above 500.
There were two groups examined for the research by the United States Public Health Service:
Patients who had their counts monitored every 3 to 6 months versus patients who had their counts monitored every 6 months only. The 84 patients were followed for about 3.5 years and it was found that all 84 members of the first group were alive and well, while 15 out of 79 from the second group were dead from AIDS related diseases (Renju et al., 2021). The difference in survival rates between the two groups was found to be significant by this research by the United States Public Health Service.
The research by the United States Public Health Service proves that monitoring of CD4 counts can significantly reduce the risk of death by AIDS. The reasons behind this research are still unclear, as it is still not clear what condition the patients that had their count monitored were in, but they may have had more treatment or a more advanced stage of HIV when they were infected.
To conclude, the research by the United States Public Health Service found that patients who had their CD4 counts monitored every 3 to 6 month have a better prognosis compared to those with lower CD4 counts, thereby reducing the risk of death for HIV-negative individuals. Therefore, more physicians should educate their patients on the benefits of regular monitoring of CD4 counts and how this can reduce the risk of death.
References
World Health Organization. (2021). Consolidated guidelines on hiv prevention testing treatment service delivery and monitoring : recommendations for a public health approach. World Health Organization. Retrieved November 12 2022 from http://www.ncbi.nlm.nih.gov/books/NBK572729/.
Renju, J., Rice, B., Songo, J., Hassan, F., Chimukuche, R. S., McLean, E., … & Wringe, A. (2021). Influence of evolving HIV treatment guidance on CD4 counts and viral load monitoring: A mixed-methods study in three African countries. Global Public Health, 16(2), 288-304.