Serum biochemical markers in drowning: diagnostic efficacy of Strontium and other trace elements.

The aim of our study was to analyse several serum biochemical markers in order to evaluate the discriminant capacity of trace elements individually and jointly in drowning (seawater drowning and freshwater drowning) and their correlation with age, sex, postmortem interval, time in water and concentrations of the trace elements in the drowning medium. Sixty-seven cases of drowning (53 seawater drownings (SWD); 14 freshwater drownings (FWD) and 73 control cases (other asphyxias, n=44, and other causes of death, n=29) were selected according to the scene, cause and circumstances of death, together with autopsy findings. Serum strontium (Sr), magnesium (Mg), sodium (Na), chloride (Cl), calcium (Ca), iron (Fe), urea, creatinine (Cr) and cardiac Troponine T (cTn-T) were measured in the left ventricle (Lv), right ventricle (Rv) and peripheral blood. Lv-Rv differences for each marker and Sr, Mg, Na, Cl, Ca and Fe concentrations in the drowning medium were determinated. Mean concentrations of Sr, Cl and Mg in both ventricles and peripheral serum and Lv-Rv differences and Ca Lv and Na Rv were significantly higher in cases of drowning than for other causes of death. In SWD, Sr, Mg, Ca, Na and Cl were significantly higher in Lv than in Rv as a result of aspirating water. In contrast, haemodilution is evident from the significantly higher levels of Fe and urea in Rv than in Lv in cases of SWD, and from the higher Mg and Cr levels in Rv in FWD. In the case of SWD, serum levels of Sr are confirmed as the best parameter for diagnosis, although other trace elements may also be useful, such as the serum concentrations of Mg and Cl. In the case of FWD, the joint determination of Sr and other biochemical markers, especially Fe, may increase correct diagnosis.