Eclampsia and seasonal variation in the tropics - a study in Nigeria.

Background: A retrospective observational study on the seasonal variation in the admission of eclampsia patients to the multi-disciplinary intensive care unit (ICU) of National Hospital, Abuja, Nigeria over a five-year span (March 2000 - March 2005) was carried out.

Method: The patient's case files and ICU records were used to extract the needed data. The diagnosis of eclampsia was based on clinical and laboratory findings by the obstetricians.

Results: There were a total of 5,987 deliveries during the study period. Forty-six eclamptics were admitted to the ICU during the study period giving an ICU admission rate of 7.6/1000 deliveries. The average age of the patients was 28.6 years. Six patients (13%) were booked for antenatal care in the hospital, while forty patients (87%) were referred. Average duration of stay in the ICU was 4.6 days (range 1-42 days). Thirty-one eclamptics (67.4%) were admitted to the ICU during the rainy season (April to October) and fifteen (32.6%) during the dry season (November to April). The rainy season is associated with a lower average high temperature and a higher humidity than the dry season. There is a view that holds that increasing humidity and a lower temperature is associated with increased incidence of eclampsia. There were thirteen deaths giving a case fatality rate of 28.2%. The causes of death were HELLP (haemolysis, elevated liver enzymes, low platelet count) syndrome in six patients, disseminated intravascular coagulation in two patients, and acute renal failure (ARF) in two patients. Septicemia, lobar pneumonia/heart failure and cerebrovascular accident accounted for one death each.

Conclusion: In this study, we found an association between the rainy season and the incidence of eclampsia to our intensive care unit. This association should be further explored.