DIAGNOSIS
HIV and Burkitt's Lymphoma.
TOPIC REVIEW
Epidemiology statistics for HIV1 show the burden of disease at 40 million individuals with HIV worldwide, the majority of whom live in the developing world. Statistics for paediatric HIV show 2.7 million children living with HIV worldwide with 90% living in sub-Saharan African region. Zimbabwe (pop 11.6 million in 2002), in southern Africa had an adult burden of HIV 33.7% in 2002. This compares with a US adult burden of HIV 0.6% for the same time frame. Morbidity and mortality also differs greatly from the developing to the developed world. At 3years of age in Sub-Saharan Africa mortality for paediatric HIV2 is as high as 89%, with 10% of affected children showing mild or moderate disease, and 1% with asymptomatic disease. Similar statistics for European and North American paediatric patients3 show that by 3 yoa 18% are deceased, 12% have severe disease, 36% moderate disease, 24% mild disease, and 10% remain asymptomatic.
A recent paper by Graham3 reviews the impact of HIV on respiratory illness,
highlighting contrasts between the developed and the developing world.
Factors that likely contribute to this difference in disease presentation
include differences in the use of antiretroviral therapy, PCP prophylaxis,
immunization, endemic TB, nutrition and micronutrient supplementation.
Bacterial pneumonia is common in both North American and Sub-Suharan
African children with HIV with pathogens being similar except for Salmonella
species which are seen in the African population possibly because of
the higher incidence of sickle cell disease. As a result of PCP prophylaxis,
PCP in uncommon in North America but remains a significant problem in
areas were prophylaxis is not widely available. Viral pneumonias are
seen in this population of children in both the developed and developing
world with vaccine preventable disease, such as measles and varicella,
seen in the sub-saharan African HIV population. Bronchiectasis is a
common finding in paediatric HIV patients in North America but is uncommon
in sub-saharan Africa, likely because of the confounding mortality at
a young age. LIP in common in both populations in those children who
survive to 2 years of age.
A bimodal distribution of HIV disease is seen in children in both the
developed and the developing world. Children who are rapid progressors
develop early and severe disease, with an increased frequency of AIDS-defining
illness and death in the first year of life. Long-term non-progressors
remain asymptomatic or are only mildly symptomatic over a period of
years whereas long-term progressors survive despite clinical and lab
evidence of progression of disease.
Nielson et al. 4 published a descriptive survey
of pediatric long-term survivors. This US cross-sectional study reported
143 children with perinatally acquired HIV and 54 children who acquired
HIV through blood transfusion in the first month of life. All children
were 8 years of age or older with 95 having AIDS defining illness. Twenty-five
percent had bacterial infections including bacterial pneumonia as an
AIDS defining illness, 23% LIP, 7% Mycobacterium avium infections,
6% Pneumocystis carinii pneumonia, 3% tuberculosis, and 1% lymphoma.
Differences in AIDS defining illness was seen by CD4 count. CD4 counts
equal to or greater than 500 were most commonly associated with lymphoid
interstitial pneumonitis and those with counts less than 500 most commonly
associated with recurrent bacterial infections. The authors concluded
that respiratory illness is common in the populations of HIV long term
survivors, the degree of immunocompromise is important in the differential
diagnosis of respiratory presentation, and that LIP is common in long
term HIV survivors.
When reviewing the case presentation, one feature that suggests chronic
respiratory disease in the presence of clubbing. Does the presence of
clubbing help in establishing a differential diagnosis? Zar and Hussey
5 in 2001 reported on a group of 150 HIV infected
children hospitalized for acute pneumonia in South Africa. Twenty percent
of the children showed evidence of clubbing with a rate of 1% in a control
population of children hospitalized for pneumonia who were HIV negative.
Those children who were HIV positive with clubbing were more likely
to be of older age, have chest x-rays showing hyperinflation, diffuse
nodular changes or hilar adenopathy, and have a clinical diagnosis of
LIP. The same group was also less likely to have tuberculosis or PCP,
though these differences did not reach statistical significance, and
had significantly lower mortality during hospitalization. The authors
concluded that clubbing was associated with better long-term survival
and that LIP was associated with clubbing.
To summarize the review so far, respiratory presentation of HIV differs between the developed and developing world as well as with severity of the disease. Clubbing appears to be associated with a more favourable outcome. LIP shows no difference by location, occurs in HIV long term survivors and is associated with clubbing.
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