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If malnutrition is judged by Western standards, then over 50% of children in many parts of the tropics fail to reach accepted growth percentiles, especially between the ages of 18 and 32 months, at the time when weaning has occurred or is started, depending on local customs (Fig.44.3). Prolonged breast feeding does not prevent florid rickets and the associated biochemical changes, including secondary hyperparathyroidism. This is particularly likely to occur in people with skin pigmentation, or those who wear abundant clothing or live a mainly indoor life, even in countries with plenty of sunshine.

Fig. 44.3. The sad picture of malnutrition aiid parasites, only too often the "normal" for children in the tropics. In 1993 the World Health Organization (Geneva) estimated that 16.3 million deaths occurred in the developing world from infectious and parasitic diseases, compared with 135,000 in the developed world. In the same year WHO estimated that 192.5 million (1 of every 3) children in the developing world under the age of 5 years suffered from malnutrition.

Apart from obvious illness, such as kwashiorkor (due to protein deficiency), malnutrition affects the clinical pattern of many infections. For example, the prodromal stage of measles in India or East Africa may be very difficult to recognize: even the classic rash may fail to appear, or may fade rapidly in malnourished children, particularly in marasmic (calorie-deficient) children compared with those suffering from kwashiorkor. This may lead to the belief that there is a lower incidence of measles in severely malnourished children when compared with the well nourished. This is debatable, but certainly the specific type of nutritional deficiency has an effect on the susceptibility of children to infection. Yet it is not easy to compare measles in India with measles in Africa. The death rates from measles in African children may be 33% or, under the age of 2 years, as high as 50% (the major cause of death), but this is not true in India, where the infection is less severe. But how can such a benign infection as measles kill children or adults? It was estimated that, in one year, 108,000 children in Nigeria died of measles and 54,000 were left with permanent disabilities. Vaccination is making inroads into these figures, but measles is still a lethal disease, causing pneumonia, diarrhea, encephalopathy, even axillary nerve palsy, pancreatitis, and corneal ulceration resulting in blindness. Patients who are apparently doing well may suddenly die because of disseminated intravascular clotting. Measles in Africa and in many other tropical countries is not just one of the passing rites of childhood.

Being underfed has its own geographic variations and effects; these start from the very beginning of life. Radiologists may be asked to estimate fetal or neonatal maturity, but comparative tables from Europe or North America cannot be used for this purpose; they are quite inaccurate (see section on the Skeleton). Chest radiographs of children may reveal rickets, one of the reasons the children are so likely to get pneumonia. Chronic malnutrition leads to shrinkage and insufficiency of the pancreas, which in kwashiorkor may be reversible (see Chapter 16 on Tropical Sprue), but in others may never return to normal. There are other hazards. In India there are over 220,000 cases of chronic arsenic poisoning and half the population of Bangladesh is at similar risk (Brit Med J March 25, 2000, p.822).

Format for This Chapter

It is possible to. describe disease patterns on the basis of anatomy or gross pathology. Because this chapter may be consulted by practitioners who are not expert radiologists, an anatomical classification is used, but related to the imaging findings; in this way, it may provide suggestions for differential diagnosis as well as indicate possible geographic variations. The comments apply only to the indigenous peoples and not to relatively recent immigrants. None of the information should be accepted as "final". Any experienced tropical radiologist can criticize all recorded geographic pathology because some aspects will undoubtedly differ from his or her own personal knowledge.

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Copyright: Palmer and Reeder