Hyponatremia: Special Considerations in Older Patients.

Hyponatremia is especially common in older people. Recent evidence highlights that even mild, chronic hyponatremia can lead to cognitive impairment, falls and fractures, the latter being in part due to bone demineralization and reduced bone quality. Hyponatremia is therefore of special significance in frail older people. Management of hyponatremia in elderly individuals is particularly challenging. The underlying cause is often multi-factorial, a clear history may be difficult to obtain and clinical examination is unreliable. Established treatment modalities are often ineffective and carry considerable risks, especially if the diagnosis of underlying causes is incorrect. Nevertheless, there is some evidence that correction of hyponatremia can improve cognitive performance and postural balance, potentially minimizing the risk of falls and fractures. Oral vasopressin receptor antagonists (vaptans) are a promising innovation, but evidence of their safety and effect on important clinical outcomes in frail elderly individuals is limited.

Early deaths in Jamaican children with sickle cell disease

In Jamaican children with homozygous sickle cell (SS) disease diagnosed at birth two-year survival was 87 percent, compared with 95 percent in children with sickle cell-haemoglobin C (SC) disease, and 99 percent in normal controls. Death among those with SS disease occurred most often between the ages of 6 and 12 months. Principal causes were acute splenic sequestration and pneumococcal infection. Neonatal diagnosis of haemoglobinopathies must be followed by close observation if mortality is to be reduced by early diagnosis and treatment of these complications. (AU)

Homozygous sickle cell disease in Jamaica in the first year of life

Fifty (50) infants with homozygous sickle cell anaemia were detected by electrophoresis of cord bloods of infants born at a large maternity hospital in Kingston, Jamaica. They were followed prospectively with 106 age and sex-matched control infants with normal genotype for haemoglobin. Haematological, anthropometric and clinical data were recorded. During the first twelve months of life there was no significant difference in the weight, height and head circumference of the two genotypes. Haemolytic anaemia was detected at the age of six weeks. 3 of the 55 SS infants had haemoglobins o 10gm/dl at the age of twelve months. The mean haemoglobin for the SS infants fell throughout the year and at twelve months was 7.8gm/dl and was not related to the folic acid and serum levels at a year. Hypoplastic anaemia was found in 4 infants, one of whom had measles. Megaloblastic anaemia was found in one infant who responded to folic acid. The red cell characteristics in the SS infants varied from the normal infants. The mean MCV was greater than the control infants and this was related to reticulocyte count and the foetal haemoglobin level. Both normal and affected infants were relatively hypochromic regardless of the presence of presumed adequate iron stores. The MCH was varied in the same way as the MCV. The red cell count in the sickle cell infants fell to a lower but relatively steady level as opposed to that of the control infants which increased after the initial fall. The PCV changes mirrored those of the haemoglobin level. The white cell count was elevated and the platelet counts showed no significant difference from those of the control infants but an association was demonstrated with previous vaso-occlusive episodes and elevated platelet counts. Upper respiratory tract infections and gastroenteritis were the most common clinical problems for both genotypes. Features that occured in both genotypes but were significantly more frequent in the SS infants included hepatomegaly (x1.5), splenomegaly (x4.9), hepatosplenomegaly (x6.9), and pneumonia (x4.8). Death occurred in 10 percent of the sickle cell infants and in 3 percent of the controls. All SS infant deaths occurred after six months of age and in 3 of the 5 pneumonia was found. The pneumonococcus were isolated in 2 infants. The 8 episodes of the hand-foot syndrome occurred in 10 SS infants, and the youngest was aged three months. Three infants had long bone infarcts. Acute splenic sequestration occurred in 10 infants and recurred twice in hospital admissions were more common in sickle cell infants and were attributed to an excess of admissions for sickle cell related conditions. 52 percent of infants developed sickle cell related illness in the first year of life but no haematological parameter could predict the susceptible infants. The mean head circumference of the infants with sickle cell related conditions was greater at both six months and twelve months than that of those with no sickle cell related illnesses during the first year of life. The persistence of foetal haemoglobin and the susceptibility to infection in infants with sickle cell anaemia are discussed (AU)