LOCAL EDEMA AND HEMORRHAGE CAUSED BY Crotalus durissus terrificus ENVENOMING EVALUATED BY MAGNETIC RESONANCE IMAGING (MRI)

Abstract

The objective of this study was to detect the presence of local edema and hemorrhage caused by Crotalus durissus terrificus envenoming using magnetic resonance imaging (MRI). Six patients bitten by Crotalus durissus terrificus snakes were treated at the Emergency Unit and Tropical Diseases Unit of Botucatu School of Medicine, UNESP, São Paulo State, Brazil. After receiving specific serotherapy, the patients were submitted to MR of the bite site. Post contrast T1 and T2 spin-echo MRI were obtained revealing the following lesions: edema associated with hemorrhage in subcutaneous and muscular tissue (n=3), edema in subcutaneous tissue (n=2), and perimuscular hemorrhage (n=1). In this study, MR demonstrated a local effect of Crotalus durissus terrificus envenoming in inducing edema and hemorrhage, mainly in muscular tissues and perimuscular areas. These results indicate that Crotalus durissus terrificus venom cause a local muscular tissue damage in human envenoming represented by edema and hemorrhage

Spin Echo Magnetic Resonance Imaging

“…Edema presents as a hypointense signal on pre-contrast T1 time and enhanced on pre-contrast T1 time and hyperintense on T2 time. Lesions identified as haemorrhagic lesions present a hypersignal on pre-and post-contrast T1 and T2 times [21,22,23].…”

“…The edema corresponds to an increase of water content into the extracellular space and/or into the intracellular compartment. T2-weighted sequences are the main time interval that detects this increase in the form of an intense area of hypersignal in [21,22,23].…”

“…In haemorrhagic lesions or in the presence of degradation components of blood in any tissue often give the hyperintense signal on T1 and T2. They are a consequence of a local vascular injury [22,23]. Tissue lesion and inflammatory processes related to the musculoskeletal system cause changes in the relaxation times T1 and T2 and reflects the signal intensity.…”

“…Tissue lesion and inflammatory processes related to the musculoskeletal system cause changes in the relaxation times T1 and T2 and reflects the signal intensity. The inflammatory processes increase the signal intensity on T2-weighted images and the swelling causes an increase of water in the tissues that determines the signal changes observed [22]. Bleeding observed in subcutaneous and muscle tissues is generally different from that resulting from the degradation process known in the pathologies of the central nervous system.…”