Medical imaging in Bothrops lanceolatus envenomation: a retrospective series from Martinique

In the lush, humid forests of Martinique, a small but formidable pit viper known as Bothrops lanceolatus makes its home. This snake is the only venomous species on the island, and its bite triggers a unique and dangerous reaction in the human body. Unlike many other snakebites that primarily cause bleeding or tissue destruction, the venom of this specific viper often turns the body's own clotting system against the victim. Instead of bleeding out, the blood begins to form dangerous clots inside the vessels, which can travel to the brain, heart, or lungs and cause strokes, heart attacks, or blockages. For decades, doctors have relied on observing the patient's symptoms—such as swelling, pain, and changes in consciousness—to judge how severe a bite is and to decide when to administer the life-saving antivenom. However, because these internal clots can form without obvious external signs, there has been a lingering question about whether modern medical imaging tools, like scanners and ultrasound machines, could help doctors see these hidden dangers earlier and more accurately.

A team of researchers at the University Hospital of Martinique set out to answer this question by looking back at the medical records of nearly four hundred patients treated for this specific snakebite over a fourteen-year period. They wanted to understand how often doctors used imaging technology and whether those images actually changed how they treated the patients. The study focused on a specific window of time, from 2011 to 2024, a period that also saw the introduction of a specialized antivenom called Bothrofav, which has significantly improved survival rates. The researchers gathered data on every patient who arrived at the hospital, noting their age, the severity of their bite based on a standard clinical scale, and whether they underwent any scans. They then compared the patients who received imaging against those who did not, looking for patterns in how the technology was used and what it revealed.

The results showed that while the vast majority of snakebite cases are mild and do not require advanced scanning, imaging becomes a critical tool when the situation is serious. Out of the 389 patients, only about one in five underwent any form of medical imaging. However, this number was not distributed evenly. The researchers found that imaging was rarely used for mild cases but was far more common for patients with severe symptoms. When patients were in shock, fell into a coma, or showed signs of severe infection, doctors were much more likely to order a scan. The data confirmed a strong link between the severity of the bite and the decision to use technology; those with the most dangerous grades of envenomation were significantly more likely to be scanned than those with minor injuries.

The scans themselves revealed specific, life-threatening problems that would have been difficult to diagnose with a physical exam alone. In a small number of cases, the imaging confirmed that the venom had caused blood clots to form in critical areas. The researchers documented eleven distinct clotting events in six different patients. These included clots that blocked blood flow to the brain, causing strokes; clots that lodged in the heart muscle, causing inflammation; and clots that traveled to the lungs, causing pulmonary embolisms. The study highlighted that different types of machines were best for different jobs. For example, ultrasound was excellent for spotting clots in the legs and arms, while a specialized type of scan called a CT angiography was essential for finding clots in the chest and lungs. For brain and heart issues, magnetic resonance imaging provided the clearest picture of the damage.

One of the most striking findings was the specific pattern of brain injury associated with this snake. The researchers noted that when strokes occurred, they frequently appeared in a particular area of the brain near the back, a region supplied by a specific artery. This consistent pattern suggests that the venom targets this area in a predictable way. The study also found that imaging helped doctors decide when to give more antivenom. In several cases where patients had compartment syndrome—a condition where swelling cuts off blood flow to a limb—ultrasound helped confirm the diagnosis, leading to surgical intervention or additional doses of the antidote. The data showed that patients who received imaging were more likely to be admitted to the hospital and the intensive care unit, reflecting the fact that these scans were reserved for the most critical cases.

Despite these clear benefits, the authors emphasize that medical imaging is a helper, not a replacement, for clinical judgment. The primary way to manage a snakebite remains a careful physical examination and the rapid administration of antivenom. Imaging is not needed for every patient, especially those with mild bites, but it serves as a vital safety net for the most severe cases. It allows doctors to confirm hidden complications like internal clots or tissue death that might otherwise go unnoticed until it is too late. The study concludes that while the management of snakebites is rooted in clinical observation, the judicious use of tools like ultrasound, CT, and MRI provides a necessary layer of clarity. By integrating these images into the treatment plan, doctors can better assess the true severity of the bite, confirm dangerous complications, and tailor their therapy to save lives, particularly in a region where this specific, clot-forming snake is a constant presence.