The color changes of the organs can reveal precious information to the forensic doctors. But not all have a pathological meaning: some are the direct result of substances administered to patients before their death.
When the brain turns blue: a medical-legal mystery finally elucidated
In this study published in theInternational Journal of Legal Medicinethe researchers analyzed cases of autopsies with unusual blue colors of the brain and other organs. This rare phenomenon had been reported sporadically in the scientific literature.
The team describes several examples: in some cases, Only the brain sported an intense bluish shade, in others, heart, stomach, lungs Or the oral mucosa had a similar coloring. The authors note: “The blue-purple coloring was clearly visible on the surface of the brain and persisted after the cuts “ (International Journal of Legal Medicine2024).
© Forensic Science, Medicine and Pathology
The difference between the surface and the interior of the brain
Interior coating of the heart, intense and dark blue-green
To understand this oddity, scientists have crossed the toxicological, histological and pharmacological data of each case. Result: a culprit was essential.
The blue of methylene, main suspect … but not solely responsible
In the majority of cases studied, the deceased had received methylene blue Shortly before their death. This substance is used in medicine to treat the methemoglobinemia (an alteration of hemoglobin preventing transport of oxygen), certain drug poisoning, complicated urinary tract infections, as well as in certain surgical contexts for its antiseptic and diagnostic coloring properties.
According to researchers: “Methylene blue is a cationic compound that is distributed throughout the body, with a particular affinity for tissues rich in water and lipids“.
The path of administration strongly influences the distribution of coloring. When it is intravenous injectedit quickly diffuses in the highly vascularized organs such as the brain, the heart or the kidneys. In ingestion oral in the form of tabletsthe concentration is often higher in the stomach, the intestine and the liver, which explains the predominant coloring of these tissues in certain cases.
The study stresses that other compounds, although much more rarely encountered, can cause similar blue or greenish coloring:
- Indigo Carmine (dye used for certain medical explorations);
- Brilliant Blue FCF (food coloring);
- Certain drugs with a phenothiazine structure;
- Copper or other metals in particular cases of intoxication;
- Flunitrazepam (Rohypnol)a powerful sedative, some metabolites of which can induce changes in tissue.
These substances, such as methylene blue, can be fixed permanently in the tissues, sometimes until visible several days after death.
An index for autopsy … without proof of direct toxicity
For forensic doctors, this coloring is not only a curiosity: it can guide the survey on administered treatments and the cause of death. “”The recognition of this phenomenon is important to avoid erroneous interpretations during the autopsy “insist the authors.
On the other hand, nothing indicates that this shade has a direct deleterious effect on the organs: methylene blue acts above all as a visual marker of his passage, and not as a lesion. Researchers highlight, however, that in certain contexts, the molecule can have significant side effects, especially in high doses or in fragile patients.
This rare phenomenon recalls that each detail observed during an autopsy-even an unexpected color-can help resolve the medical and medico-legal puzzle surrounding a death.