[Interpretation of postmortem digoxin levels: evaluating a "corrective factor" for postmortem blood digoxin concentration]

Postmortem digoxin-like immunoreactive substances (DLIS) in patients not treated with digoxin

Endogenous digoxin-like immunoreactive substances (DLIS) cross-react in immunoassays of digoxin. The postmortem rise in digoxin levels in patients treated with the drug may be due to its redistribution. It is unclear what is the contribution of DLIS to this increase and whether DLIS are present postmortem in patients not treated with digoxin. The objectives of this study were to determine whether DLIS are present after death in patients not treated with digoxin, whether a postmortem increase in DLIS is detectable and whether sampling site can affect DLIS concentrations. DLIS (measured as digoxin, TDx Abott) were determined in blood samples drawn antemortem from ICU patients; postmortem samples from femoral artery and cardiac chambers were taken at least 12 h after the death of these same patients. DLIS concentrations > or = 0.2 ng/ml were measured in 44 and 40% of patients antemortem and postmortem (femoral), respectively. No difference was found in DLIS levels between antemortem and postmortem femoral and cardiac samples. Age, ICU stay and postmortem sampling time did not affect the postmortem increase in DLIS. None of the levels was in the toxic range. DLIS may be present after death and their concentration does not increase postmortem. The interpretation of postmortem digoxin concentrations that fall in the therapeutic range should be done cautiously; such measurable levels do not necessarily indicate misuse or malicious intent even in patients who had not been treated with the drug.

Combination of fatal digoxin poisoning with endocardial fibroelastosis

This is the first report in the forensic literature of a combination of fatal digoxin poisoning with endocardial fibroelastosis (EFE). Typical morphological features of EFE as the cause of clinically diagnosed cardiomyopathy were present in the autopsy of a 3-year-old girl, including cardiac hypertrophy and marked thickening of the left-sided endocardium, consisting of numerous elastic and collagenic fibres. After exclusion of cardiac and cerebral causes of death, accidental digoxin intoxication was proved. Postmortem toxicological analyses by fluorescence polarization immunoassay (FPIA) disclosed digoxin levels of 71 micrograms/kg (femoral vein blood), 77 micrograms/kg (cardiac blood), 255 and 221 micrograms/kg (cardiac muscle of the right and left chamber), 163 micrograms/kg (psoas muscle), 91 micrograms/kg (lung), 222 micrograms/kg (liver) and 520 micrograms/kg (kidney). The results are compared with the antemortem digoxin concentration of 39 ng/ml serum. The case is discussed from its unusual morphological and toxicological aspects, with special consideration of possible medical malpractice.

Measurement of digitalis-glycoside levels in ocular tissues: a way to improve postmortem diagnosis of lethal digitalis-glycoside poisoning? I. Digoxin

Prompted by animal studies reporting the accumulation of digitalis-glycosides in ocular tissues, we investigated whether measurement of digoxin levels in human ocular tissues can improve the postmortem diagnosis of lethal digoxin intoxication. Digoxin was measured in the vitreous humor and choroid-retina of patients who had received in-patient treatment with digoxin prior to death (therapeutic group) and in a single case of suicidal intoxication. The results were compared with the digoxin levels in the femoral vein blood, myocardium, kidney and liver, and evaluated in light of the medical history of each patient. In the therapeutic group the mean digoxin level was higher in the choroid-retina than in other tissues and body fluids. The range of variation in levels in the choroid-retina following therapeutic doses was comparable to that in the other tissues. An extremely high level of digoxin was present in the choroid-retina in the case of suicidal intoxication. In all cases, levels in the vitreous humor were very low compared to those in the choroid-retina. Hence, it is unlikely that significant distortion of choroid-retinal levels occurs due to postmortem diffusion of digoxin into the vitreous body. Our results indicate that measurement of digoxin levels in the choroid-retina can aid the postmortem diagnosis of lethal digoxin intoxication.