Diagnosing AIDS and Emerging Infections in Resource-Limited Settings:
The Role of the Pathologist in Patient Care and Disease Surveillance
Section 3 -
AIDS In Children
Cecilia Ridaura Sanz
Children were latecomers in the global awareness of the disease. The western world first perceived
AIDS as a disease of a particular group of male adults with specific risk factors. The spread of the
disease from the original at risk group to a more diversified population brought the problem of pediatric
AIDS to the forefront.
AIDS IN CHILDREN AS DIFFERENT FROM AIDS IN ADULTS
Children acquire AIDS in their own particular way. What is in adults a disease transmitted by sexual
contact or anomalous intravenous entry and as we later understood, with transfused blood, becomes in
children an infection usually contracted through maternal intermediation. Regardless of the mode of
infection in the mother, the child can become infected in utero, at the
moment of birth or during lactation.
The same microorganism, through different pathogenic mechanisms and in a different host, produces
different biologic, clinical and pathological components of the disease.
This produces a different disease. The following table illustrates differences in the pathological
|Thymic involution ||No|
|HIV encephalitis ||Infrequent|
|Lymphoid interstitial pneumonia ||Lymphoma|
|Smooth muscle tumors ||Kaposi|
|Progressive encephalopathy ||Seldom|
|Growth arrest ||Wasting syndrome|
|Bacterial infections ||Opportunistic infections.|
|Tuberculosis infrequent ||Tuberculosis frequent|
Differences also arise in the infectious complications. Published reports from several sources
including series from Latin America and from Africa underscore a low frequency of tuberculosis,
acknowledgly frequent in adults.
Children infected perinatally with HIV have a higher frequency of encephalopathy during the first year
of life whereas the frequency after the age of three years is similar to that in the adult. It has been
proposed that this early encephalopathy in infants has a different pathogenic mechanism from that
occurring in late survivors.
THE ROLE OF THE AUTOPSY
The autopsy offers a perspective on the causes and circumstances of mortality of a disease, reveals
associated pathology that could not be supported clinically and is able to formulate questions and
answers that were not possible in the living patient.
In the case of the Human Immunodeficiency virus (HIV) and its clinical expression as Acquired
Immunodeficiency Syndrome (AIDS), an important component of mortality is infection, often by
opportunistic microorganisms present in the environment and which usually do not give rise to disease in
the immunologically intact population.
A reasonable assumption would be that a patient with a compromised immune system will become infected
with germs present in his particular surroundings and therefore information obtained from a particular
geographic and ecologic context are not necessarily applicable to a different context. It is therefore
imperative to document carefully the prevailing infections in AIDS patients in each site.
Populations at risk vary in different geographical contexts by virtue of particular social en economic
determinants. The examination of a subset of pediatric patients with HIV/AIDS that die and undergo
autopsy can provide information that becomes a reference point for the evaluation and management of the
diseased population and in the definition of the local biology of the disease.
It must be emphasized that opportunistic infections were first described at autopsy and even at
present these complications are clinically under diagnosed in as much as 50% as compared with autopsy
The autopsy continues to describe new pathological states such as HIV infection related pulmonary
emphysema and provides accurate correlation and reference for new imaging studies.
The autopsy also monitors the impact of therapy with highly active antiretroviral therapy (HAART). As
a result of longer survival of patients with AIDS and their exposure to different treatment regimens, new
pathologic expressions of the disease have been described.
Early autopsy studies demonstrated the high prevalence of HIV encephalitis and of opportunistic
central nervous system infections. After the introduction of nucleoside reverse transcriptase
inhibitors, the prevalence of opportunistic infections decreased but a concurrent increase in HIV
encephalitis was noted. With the subsequent introduction of protease inhibitors a decline in both was
observed. Or more recent emergence are descriptions of severe forms of encephalitic disease with
massive infiltration of HIV infected cells and with white matter destruction that are currently
attributed the interaction of the infection with the drugs used in therapy.
THE PATHOLOGY OF AIDS IN CHILDREN. THE LITERATURE
Children develop a gamut of primary lesions directly derived from infection with HIV:
- Lymphohematopoietic disturbances.
- Germinal center hyperplasia.
- Lymphoid depletion.
- Multinucleated giant cells.
- Extreme thymic atrophy (pseudodysplasia)
- Cardiovascular disturbances
- Idiopathic myocarditis.
- Myocardiopathy with left ventricular dysfunction.
- Central nervous system disturbances.
- Encephalitis with multinucleated giant cells.
- Diffuse poliodystrophy.
- Mineralized vessels in basal ganglia.
The infectious complications reported from autopsy series of children (177 cases from 6 selected
publications) list among those more frequent: Bacterial infections, Pneumocystis pneumonia,
cytomegalovirus, Candida infections, herpes, non tuberculous mycobacterioses and histoplasmosis.
Isolated cases include tuberculosis, aspergillosis, toxoplasmosis, measles, adenovirus infection and
THE MEXICAN EXPERIENCE
Between 1986 and 2005, thirty six autopsies were performed on children dying with AIDS or with
evidence of HIV infection at the National Institute of Pediatrics in Mexico City. These were 18 boys and
18 girls ranging form four months to 19 years of age. The disease was contracted by maternal
transmission in 25, in 7 it was secondary to transfusion and one patient appears to have been infected by
sexual contact. No source of infection was identified in three cases.
Of the 25 cases of maternal transmission, the mother was infected by blood traansfusion in 10 and
probably by sexual contact in 13. In two cases the source was not identified.
Specific AIDS related pathology was identified in 27 cases. Twenty one had central nervous system
involvement with a diverse combination of changes including foci of gliosis, multi nucleated giant cells,
necrosis and demyelination. In the immune and hemopoietic system, 21 had lymphoid depletion of the
thymus with a dysplastic appearance and bone marrow depletion in different combinations. Interstitial
nephritis was present in one case and another had glomerular disease. Two cases showed large vessel
vasculopathy (coronary 2, aorta 1).
Bacterial infection was the main pathology in a majority of cases, we found it in 20 of 36 patients.
Other infections were present as follows: cytomegalovirus 15, Candida species in 8, Pneumocystis
infection in 9, herpes/varicella was present in 6, histoplasmosis in 5 and non-tuberculous mycobacteria
in 3. Adenovirus infection was present in 2 patients. Single cases of measles, respiratory syncitial
virus infections and toxoplasmosis were detected.
Neoplasia arose in two patients, Hodgkin lymphoma and angiocentric non-Hodgkin lymphoma post renal
transplantation. However in both cases the HIV infection was acquired from blood transfusion in the
course of management of the primary disease.
Worth noting is the absence of tuberculosis in our material and the fact that in none of the five
cases of histoplasmosis was this microorganisms suspected clinically.
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