Vitreous humour and cerebrospinal fluid hypoxanthine concentration as a marker of pre-mortem hypoxia in SIDS.

Aims: To assess the rate at which premortem hypoxia occurs in sudden infant death syndrome (SIDS) when compared with death in early childhood.

Methods: The hypoxanthine concentration was measured as a marker of premortem hypoxia in vitreous humour and cerebrospinal fluid samples obtained at necropsy from 119 children whose ages ranged from 1 week to 2 years.

Results: Increasing interval between death and necropsy was accompanied by an increase in the hypoxanthine concentration of vitreous humour for the first 24 hours, at a rate of 8.3 mumol/l/hour. Thereafter, there was little change with time, and the results wer corrected to 24 hours according to a regression equation. Cerebrospinal fluid concentrations showed no significant change with time following death. Patients were divided into three groups according to the cause of death: SIDS, cardiac or pulmonary disease, and others. Median values for the cerebrospinal fluid hypoxanthine concentrations were not significantly different among the groups and no difference could be shown between the vitreous humour hypoxanthine concentration in cases of SIDS and those children dying from other causes. Patients with established cardiac or pulmonary disease had a significantly reduced vitreous humour hypoxanthine concentration which may have reflected the premortem use of artificial ventilation.

Conclusions: The results of this study do not support the view that pre-mortem hypoxia is a common feature in SIDS when compared with other causes of death.