McMaster University hematologist finds different limb loss syndromes

How people can develop limb gangrene and lose fingers and feet has baffled doctors for centuries.

Now a McMaster University hematologist has identified different limb loss syndromes along with explanations for what is happening and what can be done about it.

In a review published today by the New England Journal of Medicine, Dr. Ted Warkentin says these rare but devastating conditions can be the result of microthrombosis, or blood clots in the smallest blood vessels. He has identified various causes such as septic shock, some cancers, and side effects of certain blood thinners.

"This is a new idea, but important because these conditions can be devastating. Some of the athletes of the current Parapan Am Games are disabled because of these medical conditions," said Warkentin, a professor of medicine and of pathology and molecular medicine for the Michael G. DeGroote School of Medicine at McMaster. He is also a hematologist for Hamilton Health Sciences.

He looked into the syndrome called "symmetric peripheral gangrene" which can kill the extremities, including both the feet and hands, and sometimes other areas such as nose or ears. These patients often have underlying septic shock caused by blood poisoning, but it is failure of the liver to produce factors that protect the small blood vessels, such as "protein C," that has been identified as a risk factor for the limb gangrene.

The treatment for symmetric peripheral gangrene is the blood thinner, heparin, as well as replacement of the missing protective factors through use of blood plasma.

Warkentin also looked into the syndrome of "venous limb gangrene," which is the rare situation of limb loss that occurs in a patient with blood clots in a larger limb vein (called "deep vein thrombosis" or DVT). Here, he identified side effects of blood thinners, such as heparin and warfarin, as well as advanced cancer, as possible causes. These patients were also found to have critically low levels of protein C.

"By closely examining this group of rare and poorly understood syndromes, we can identify certain unifying themes, and get closer to having a rational approach to treating these conditions," said Warkentin.