British Journal of Obstetricsand Gynaecology zyxwvut October zyxwvuts 1997, Vol. 104, pp. 1165-1 172 Single photon emission and cerebral computerised tomographic scan and transcranial Doppler sonographic findings in eclampsia *K. Naidu zyxwvuts Research Fellow, *J. Moodley Consultant (Obstetrics), tP. Corr Consultant (Radiology), *M. Hoffmann Consultant (Neurology) MRC PregnancyHypertension Research Unit, *Department of Obstetrics and Gynaecologyand ?Department of Radiology, Faculty of Medicine, University of Natal, SouthAfiica Objective To define more clearly the neuropathophysiology of eclampsia utilising single-photon emission computed tomography (SPECT), cerebral computerised tomography (CT) and transcranial Doppler (TCD) ultrasonography. Design A prospective study Setting The obstetric unit in King Edward VIII Hospital, a large tertiary referral centre in Kwa-Zulu Natal, South Africa. Participants Sixty-five women with eclampsia. Interventions Imaging and ultrasonographic investigations were performed within zyx 48 hours postpartum. Unenhanced cerebral CT scans were performed in all the women and SPECT scans were performed on 63 women using Technetium-99m-hexamethylpropyleneamineoxime (99mTc-J3MPAO) as a tracer of regional cerebral blood flow. Middle cerebral artery blood flow velocity waveforms were measured using 2 MHz pulsed Doppler ultrasound via the transtemporal approach. Main outcome measures Abnormalities in SPECT scan, CT scan and TCD ultrasound findings. Results SPECT scanning revealed perfusion deficits in the watershed areas in all women, 75% of whom had concomitant deficits in the parieto-occipital areas of the brain. Hypodensities (cerebral oedema) were reported in 38 CT scans zyxwvu (58-5%), with parieto-occipital involvement in 97.4% of cases. Increased flow velocity measurements in the middle and posterior cerebral arteries were recorded in 36 (85.7%) women in whom TCD ultrasound was performed. Conclusion The pathophysiological mechanism of eclamptic seizures is primary cerebral vasospasm with resultant ischaemia and cerebral oedema involving mainly the watershed areas and parieto- occipital lobes of the brain. SPECT scanning has been shown to be superior to CT scanning and TCD ultrasonography in detecting neuropathophysiologic alterations in eclampsia. However, each of the three investigative tools provide its own unique information and all three are necessary research techniques to improve our understanding of the neuropathophysiological mechanism of eclamptic seizures. INTRODUCTION Eclampsia is defined as the occurrence of one or more convulsions in association with raised blood pressure and proteinuria in pregnancy. In Europe and other developed countries, eclampsia complicates about 1 in 2000 deliveries, while in developing countries, esti- mates vary widely from 1 in 100 to 1 in 1700'. Although rare, eclampsia probably accounts for 50,000 maternal deaths a year worldwide'-*. Cerebral complications Correspondence: Professor J. Moodley, MRC/UN Pregnancy Hypertension Research Unit, Faculty of Medicine, University of Natal, P O Box 17039, Congella4013, South Africa. zyxwvuts 0 RCOG 1997 British Journal of Obstetrics and Gynaecology are the cause of many eclamptic deaths3, but the neuropathophysiology of eclamptic seizures remains unresolved. Various imaging modalities have been used in women with eclampsia to exclude serious central nervous system pathologic conditions, such as haemorrhage z , tumour, abscess, aneurysm, arteriovenous malforma- tion, sagittal sinus thrombosis or i n f a r c t i ~ n ~ ~ . These studies have added to the knowledge of central nervous system abnormalities in eclampsia, but important ques- tions are still unanswered. Although women with eclampsia may initially mani- fest a variety of neurological abnormalities, including cortical blindness, focal motor deficits and coma, most 1165