Search

Many previous studies have investigated the use of post-mortem biochemistry to estimate the post-mortem interval (PMI). Vitreous humour (VH) potassium and sodium/chloride levels are well recognized to increase and decrease, respectively, in the post-mortem period but have limited ability in estimating PMI. Cerebrospinal fluid (CSF) is described to have different post-mortem biochemical properties than VH, but is not well studied in relation to estimating PMI. This exploratory study examined 20 paired cases of VH and CSF to investigate their use in estimating PMI. Linear univariate analysis showed Na+, Cl− and K+ in VH and CSF share similar trends, but only K+ in VH and CSF collected via lumbar puncture (LP) showed a significant regression coefficient (p < 0.01). In subsequent linear multivariate analysis, the coefficient for K+ in VH remained positive and significant but not for K+ in CSF. Only minor improvement was observed in the multivariate analysis. Our study showed changes in analytes in VH and CSF follow similar trends. K+ in VH is most accurate in estimating the PMI, with no significant improvement in accuracy when K+ in CSF is combined. Thus, the role of CSF electrolytes in estimating PMI may be very limited. [ABSTRACT FROM AUTHOR]

Cerebrospinal fluid (CSF) and vitreous humour (VH) can be biochemically analysed post-mortem. CSF can be aspirated from the ventricular system (VA) and from lumbar puncture (LP), whereas, VH is aspirated from the orbits. This study compared the biochemical constituents between CSF and VH in 20 post-mortem subjects as well as the effect post-mortem interval and subject age have on these variables. VH samples had significantly higher sodium (Na) and chloride (Cl) and lower magnesium (Mg), potassium (K), urea (Ur) and creatinine (Cr) compared with CSF samples. No statistically significant difference was demonstrated with beta-hydroxybutyrate (BHB) and glucose levels in both VH and both CSF samples. Interestingly, some of the differences in the biochemical analysis correlated with age, but none with post-mortem interval. In addition to sampling and pre-analytical sample processing differences, there may also be ante- and post-mortem factors explaining these observations. This study suggests that post-mortem CSF and VH are biochemically different and reference ranges for VH are not recommended for use in CSF samples. [ABSTRACT FROM AUTHOR]