The potential significance of elevated vitreous sodium levels at autopsy

Elevated levels of sodium that may be detected in the analysis of post-mortem fluid samples may arise from a wide variety of organic illnesses and environmental factors that have caused either water depletion or solute gain. When hypernatraemia is suspected at autopsy a careful history is required with particular emphasis on pre-existing medical conditions such as renal or gastrointestinal disease. In addition, detailed information is required on the circumstances of death, including any clinical symptoms and signs that the deceased may have manifested, or medical procedures such as dialysis, colonoscopy or intravenous fluid replacement. Reduced intake of fluid may be associated with cognitive or physical impairment or may result from environmental depletion (the latter may be a manifestation of inflicted injury). Both central and nephrogenic diabetes insipidus may result in the loss of excessive amounts of hypotonic fluid. This may also occur following diuretic use, or be due to gastroenteritis or burns. Hypernatraemia may be a marker of excessive salt/saline ingestion and/or administration and may occur accidentally or as a manifestation of child abuse. Given the range of possible etiologies, hypernatraemia may be a significant autopsy finding that requires explanation.