Investigating Unusual Discoloration in Autopsies

During an autopsy in Germany, forensic researchers encountered an unexpected blue-green discoloration of internal organs, prompting an investigation into whether certain substances given prior to death were responsible. Their findings, published in Forensic Science, Medicine and Pathology, indicate that dyes like methylene blue and toluidine blue, as well as colorful medications or consumer products, create specific discoloration patterns. These changes might reveal important insights regarding medical treatments or substance exposure before death.

The inquiry began with a 72-year-old man’s autopsy, where the forensic team noticed that several organs turned a striking blue-green shortly after coming into contact with air. This sparked a systematic review of similar cases from their records and existing literature to uncover the underlying causes and any diagnostic significance of these unusual color changes.

Forensic pathologists possess the skills to recognize a variety of tissue abnormalities, and while color changes during autopsy are often linked to decomposition or bleeding, some instances of discoloration remain puzzling. The case in question highlighted an alarming and rapid shift in color, notably affecting the brain and heart, leading the researchers to ponder if a chemical agent was involved.

They pointed out that subtle findings—like changes in organ color—can easily be overlooked or misinterpreted, especially if they are infrequent or poorly documented. The absence of clear decomposition, paired with the unique discoloration pattern and its quick intensification during the autopsy, suggested a more particular cause.

To investigate further, the team sifted through more than 15,000 autopsy records at their institution, searching for terms like “blue-green,” “turquoise,” and “greenish” in organ appearance descriptions. This led to eleven pertinent cases, including the initial one examined.

The researchers reviewed the autopsy reports and, where possible, the patients’ hospital records. They also conducted literature searches for similar discolorations associated with known drugs or toxic substances.

Among the eleven cases, nine occurred in a hospital environment. Medical records for most of these patients provided insight into the treatments administered before death. Intravenous methylene blue was given to six patients, while two others received toluidine blue. The remaining cases likely resulted from consuming products with food-grade dyes or pigments.

Methylene blue, a synthetic dye in use for over a century, serves as a diagnostic stain in surgeries and an antidote for conditions like methemoglobinemia. It can also treat circulatory shock in intensive care scenarios. Toluidine blue, though less common, is utilized for medical imaging and tissue stains, particularly in identifying abnormal cells during biopsies.

Across the reviewed cases, distinct patterns emerged regarding organ discoloration linked to specific substances and exposure routes. Methylene blue injections mainly affected the brain and heart, whereas oral intake of dyes typically resulted in color changes in the gastrointestinal tract or urinary bladder.

In the original case, the 72-year-old had received toluidine blue during treatment for a duodenal ulcer and subsequent septic shock. His autopsy revealed pronounced blue-green discolorations in the brain, heart, and gastrointestinal tract mucous membranes. Another case involved a 30-year-old man with severe COVID-19 who showed similar coloring after receiving methylene blue for circulatory shock.

Consistent discoloration patterns were observed in cases involving methylene blue, supporting the notion that the dye, or its oxidized form, causes these changes. The researchers explained that methylene blue remains reduced in the body but oxidizes upon contact with oxygen postmortem, leading to the intensified blue-green appearance during autopsy.

Additionally, the researchers identified instances where discoloration followed the ingestion of Rohypnol®, which contains a blue dye intended to prevent misuse. In both cases, individuals attempted suicide by consuming large quantities of the drug, resulting in blue-green staining in the stomach and intestines.

A separate case involved a woman who ingested a cleaning product with Brilliant Blue FCF, displaying similar striking coloration in her urinary bladder lining, likely from the dye’s excretion through her kidneys.

These findings are in line with a previous report from 2020 in the same journal, which detailed a comparable discoloration in a different patient treated with methylene blue. That study emphasized the need to differentiate these observations from other potential discoloration causes, such as decomposition or toxic gas exposure.

This recent investigation builds upon earlier observations by identifying a broader set of analogous cases, enhancing understanding of substances that cause these effects and their specific impacts on various tissues.

While the research connected discoloration patterns to specific substances, most conclusions stemmed from visual inspections and medical record reviews. The retrospective nature of the study meant that tissue samples for toxicological confirmation were often unavailable.

In standard histology, these dyes may degrade, complicating postmortem confirmations of their presence. More advanced testing could enhance chemical verification, though such methods fell outside this study’s scope.

The rarity of systemic toluidine blue use might explain why its effects haven’t been extensively documented in similar forensic cases. As this dye might be used as a substitute for methylene blue during shortages, recognizing its potential for causing discoloration after death could gain significance in the future.

Looking ahead, the authors propose that forensic teams consider possible xenobiotic exposure when they encounter unexplained blue-green discolorations in autopsies. By integrating clinical history, medication records, and targeted toxicology tests, they can minimize misdiagnosis or unnecessary speculation.

The study, titled “Fifty shades of green and blue: autopsy findings after administration of xenobiotics,” provides a new perspective on these rare discoloration patterns and their implications.