Paediatric pathology: a work in progress

摘要

What is in fact the importance of Paediatric Pathology in developing countries? Why are there so few dedicated paediatric pathologists? The answers to these questions are not straightforward as there are probably many different reasons. What is perfectly understandable is the need for Paediatric Pathology to be practiced as a specialty and this can be demonstrated by some figures provided by the Instituto Brasileiro de Geografia e Estatística (IBGE). 1 Brazil has seen a dramatic change in demographics and vital statistics in recent decades and especially in the past 14 years, according to IBGE data. Population increased by 12.3% from 2000 to 2014 and general mortality decreased 9.15% in the same period. However, infant mortality rate per 1,000 live births plummeted 51.6% in the same period. The fall in infant mortality was far greater than the general mortality, reflecting socio-economic trends rather than medical intervention. Birth rate also dropped dramatically in the same period, from 20.9 per 1,000 people in the year 2000 to 14.5 per 1,000 in 2014, a decrease of 30.6%. Of course, this is coupled with fecundity rate, which presented a 27.2% fall in the same period. As a direct result of all these changes, population distribution according to age groups demonstrate the decrease in the number of children 0-14 years with a consequent increase in people aged 15-64 and 65 and above. 1 With a striking decrease in infant mortality it is reasonable to think that this would negatively affect paediatric pathology, but it is not that simple. The change in birth and fecundity rates indicate that the importance of any pregnancy is in fact greater, because it reflects better pregnancy planning. Childbearing age is changing towards older women, who tend to be better educated, dedicating more time for their professional career and imposing more challenges to the health system. This trend has been seen in developed countries in past decades and there is no reason it will be different in developing nations. In this setting, the loss of a fetus or baby is more likely to make parents willing to know what happened and therefore the demand for high quality investigation is necessary. As a sub-specialty, with its own body of knowledge and techniques, Paediatric Pathology would be ever more in demand. Paediatric Pathology involves a vast and complex developmental period ranging from embryos to teenagers, encompassing not only autopsy but paediatric surgical pathology and the special pathology of the placenta. In the UK, Paediatric Pathology is subdivided into Perinatal Pathology, dealing with post-mortem examinations and placenta pathology, and Paediatric Histopathology, dealing with surgical pathology. Some professionals can do both activities, usually in dedicated Children’s Hospitals, but others will do one or another. In Brazil there is no clear definition of the role of paediatric pathology. Most of the time, the occasional full time paediatric pathologist works in an academic institution rather than in a general hospital. The general histopathologist, especially those in private practice, however, may deal with placentas and products of conception rather than a proper autopsy. In any situation, the examination of a fetus without a placenta is usually pointless, since the cause of fetal demise or miscarriage may lie in the placenta in many cases. It is the latter that should always be examined by a trained pathologist to find or rule out abnormalities. But what is the kind of training most general pathologists have in terms of placenta examination? Except for the obvious implications of acute chorioamnionitis and infectious villitis, some relevant lesions will rarely be adequately evaluated by a general pathologist. These are usually those that may recur in subsequent pregnancies, such as the so called chronic villitis of unknown aetiology (VUE), placental floor infarction/massive perivillous fibrin deposition, fetal thrombotic vasculopathy (FTV), extensive subchorionic thrombosis (Breu’s mole) and Chronic Histiocytic Intervillositis. Another common problem is the apparently macro and microscopically normal looking placenta in a case of fetal demise, especially perinatal, due to its small size compared with that of the fetus. The placental disc weight without the membranes and umbilical cord must be compared with appropriate tables and so should be the fetoplacental weight ratio. When the fetus is large, the relative weight of the placenta to the fetus may be small, indicating that any lesion that decreases the availability of areas for fetomaternal transfer, such as placental infarct or fetal thrombotic vasculopathy, can tip the delicate balance and induce intrauterine hypoxia which can eventually lead to fetal demise. This is only a small sample of the need for adequate training in paediatric and placenta pathology seen in daily practice. There are excellent textbooks that bring up to date relevant information in place