Dramatic differences in COVID-19 outcomes in the group of patients with COVID-19 and newly diagnosed advanced HIV disease at the time of hospitalization and in the patient group with COVID-19 and previously diagnosed advanced HIV disease can be explained by the fact that that there are a number of signs that can mislead clinicians when providing care to patients with COVID-19 and advanced HIV disease.
First, differentiating COVID-19 pneumonia from other lung infections can be very difficult, especially from other viral or atypical pneumonia (
9). The spectrum of HIV-associated opportunistic pneumonia is wide and includes bacterial, mycobacterial, fungal, viral, and parasitic pneumonia (
10). In patients with immunodeficiency due to HIV infection and COVID-19, it is most often necessary to differentiate lung damage from
Pneumocystis pneumonia, cytomegalovirus pneumonitis, fungal infections, and bacterial pneumonia due to the similarity of the CT image (
11).
Pneumonia, which is caused by
Pneumocystis jirovecii, is characterized by long-term increases in shortness of breath (for weeks or months), fever, and dry cough.
Pneumocystis pneumonia is often combined with oropharyngeal candidiasis (
12,
13). During a CT examination, the following signs should be taken into account: A “ground glass” pattern, the affected areas are located more often in the root of the lung and the middle zone, thickening of the interlobular septa, which, in combination with ground glass type consolidations, can form a cobblestone pattern pavement (
11,
14-
19). Air cysts, areas of consolidation, focal compaction, and a complication of
pneumocystis pneumonia-spontaneous pneumothorax can also form (
14-
19). To confirm the diagnosis, the PCR testing of sputum and bronchoalveolar lavage should be used if the patient’s condition is stable (
12).
Isolated lung damage during CMV infection develops only with severe immunodeficiency (CD4 + below 50 cells/mm
3) (
20); however, combined damage with other opportunistic infections can occur with a higher immune status. Clinically, CMV pneumonitis is indistinguishable from
pneumocystis pneumonia; however, one should remember the possible multiple organ damage during CMV infection: In addition to pneumonitis, the development of retinitis, encephalitis, ulcerative colitis, esophagitis, pancreatitis, and polyneuropathy is possible (
21). The CT scan of the lungs with CMV pneumonitis is similar to the lesions with
pneumocystis pneumonia and can be combined; however, there are a number of differences: Ground glass lesions with cytomegalovirus infection appear in the peripheral parts of the lower lobes of the lungs and gradually spread to the roots, and with
pneumocystis pneumonia, lesions spread from the roots to the periphery “like the wings of a butterfly” (
10,
20). The small focal consolidation characteristics of CMV infection are also relatively uncommon in pneumocystis pneumonia (PCP) (
10), as it is a pleural effusion (
22). The diagnosis of CMV infection of target organs is usually made based on the clinical picture and, if possible, the presence of the virus in tissues. Histological examination reveals cytomegaly and intracellular inclusions, surrounded by a clear halo in the form of an “owl’s eye” (
23). The pp65 antigen test is highly sensitive but cannot be used in patients with leukopenia because this test detects antigens in neutrophils (
24). A combination of clinical manifestations, a significant decrease in CD4+ cells per mm
3, CT imaging, and PCR analysis of blood, sputum, and bronchoalveolar lavage can also provide valuable information.
Aspergillosis is extremely rare, even in patients with HIV infection (
25), but the widespread use of corticosteroids for COVID-19 has led to an increased incidence of Aspergillosis in the general population (
26). Risk factors for aspergillosis include neutropenia (absolute neutrophil count less than 1,000) and a history of corticosteroid use (
24,
25). Clinical manifestations may vary depending on the form but are generally not specific: Fever, cough, and shortness of breath. Hemoptysis can occur when the cavity is localized in the upper lobes of the lungs or in the obstructive form of bronchopulmonary aspergillosis (
25-
29). Typical pulmonary CT findings include multiple poorly defined peripheral small lesions, predominantly in the upper lobes of the lungs, which gradually coalesce into larger masses or areas of lobular to diffuse consolidation. These lesions consist of a hemorrhagic component and post-infarction lung tissue. When reabsorption of necrotic tissue begins, this is manifested by the retraction of the infarct zone, and air fills the space between them - the 'air crescent sign' manifests as the presence of a crescent-shaped air pocket surrounding the soft tissue component of the pathological cavity. Additionally, the 'Monod sign' may be observed, wherein the Aspergillus-formed ball within the cavity shifts when the patient's body position changes during a CT examination (
10,
11,
16).
The clinical picture of community-acquired pneumonia does not differ from that of patients without HIV, but there is a tendency for rapid progression (
30). Typical CT findings include unilateral focal consolidation. Other CT findings include cavity formation, pleural effusion, and lymphadenopathy. Ground glass changes may be present very early in the disease (
11). Pleural empyema may be present in pneumonia caused by
Staphylococcus aureus (
11,
30).
Second, lymphopenia of COVID-19 is also present in HIV infection, especially in the later stages (
31). Acute SARS-CoV-2 infection is associated with lymphopenia in approximately 80% of patients (
32). This may be due to the production of excessive amounts of pro-inflammatory cytokines due to COVID-19 infection, which induces lymphocyte apoptosis (
33-
35). There is also evidence that during severe COVID-19, blood lactate levels increase, and this may suppress lymphocyte production (
36). As for HIV infection, during its natural course, during the acute phase, there is a sharp decrease in CD4+T lymphocytes, and when infected CD4+T lymphocytes are completely destroyed, they release more copies of HIV into the bloodstream (
37). These new copies of the virus find and attack more CD4 cells, and the cycle continues. This results in far fewer HIV-free, functionally active CD4 cells. In the absence of HIV suppression by ART, the lymphocyte population becomes depleted over time and is characterized by a low CD4/CD8 ratio (
38).
Third, in patients with severe immunodeficiency, SARS-CoV-2 viral shedding persists for an extremely long time (
39,
40) and, having a confirmed diagnosis in hand, the practitioner may not continue the diagnostic search in the area of concomitant infections, which may determine the severity of the patient’s condition.
5.1. Conclusions
The similarity of CT picture, lymphopenia, and prolonged viral shedding of SARS-CoV-2 may mislead doctors who treat patients with COVID-19. We recommend HIV testing in patients with severe COVID-19 to determine appropriate management because mortality in the patient group with COVID-19 and newly diagnosed advanced HIV disease at the time of hospitalization was extremely high and amounted to 46.2% (CI, 38.2 - 54.3%). The presence of this factor in the overall study cohort of patients increased the risk of death by 2.21 times.