High postmortem concentrations of hypoxanthine and urate in the vitreous humor of infants are not confined to cases of sudden infant death syndrome.

OBJECTIVE

High concentrations of hypoxanthine and urate have been found in the blood of rats who died suddenly during induced respiratory alkalosis as well as in cases of sudden death in malignant hyperthermia-susceptible pigs challenged with halothane. The origin of these metabolites is the excessive hydrolysis of adenine nucleotides, which is associated with the production of free radicals. We wished to establish whether high levels of these compounds were also to be found in sudden infant death syndrome (SIDS) victims, compared with other causes of death.

DESIGN

Vitreous humor samples were analysed for hypoxanthine and urate by high-performance liquid chromatography.

SETTING

Forensic Laboratories, Salt River, Cape Town.

PARTICIPANTS

Vitreous humor samples were collected from 91 infants presented for postmortem examination.

MAIN OUTCOME AND RESULTS

From autopsy reports, cause of death was classified as: (i) SIDS (N = 50); (ii) acute sudden death (N = 5); and (iii) all other causes of death (N = 36). There were no differences in the hypoxanthine or urate levels of groups (i) and (iii) over the first 5 days of the postmortem period. Group (ii) levels were lower than those of both (i) and (iii).

CONCLUSION

Adenine nucleotide hydrolysis is not only a feature of SIDS, and possibly results from antemortem hypoxia in most deaths. The lower concentrations found in cases of acute sudden death probably resulted only from postmortem hydrolysis of the nucleotides.