Clinical, Magnetic Resonance Imaging, and Histopathologic Findings in 6 Dogs with Surgically resected Extraparenchymal Spinal Cord Hematomas

Abstract

BackgroundExtraparenchymal spinal cord hematoma has been described in veterinary medicine in association with neoplasia, intervertebral disk disease, and snake envenomation. There are rare reports of spontaneous extraparenchymal spinal cord hematoma formation with no known cause in human medicine. Multiple cases of spontaneous extraparenchymal spinal cord hematoma have not been described previously in veterinary medicine.ObjectivesTo describe the signalment, clinical findings, magnetic resonance imaging (MRI) features, and surgical outcomes in histopathologically confirmed extraparenchymal spinal cord hematomas in dogs with no identified underlying etiology.AnimalsSix dogs had MRI of the spinal cord, decompressive spinal surgery, and histopathologic confirmation of extraparenchymal spinal cord hematoma not associated with an underlying cause.MethodsMulti‐institutional retrospective study.ResultsSix patients had spontaneous extraparenchymal spinal cord hematoma formation. MRI showed normal signal within the spinal cord parenchyma in all patients. All hematomas had T2‐weighted hyperintensity and the majority (5/6) had no contrast enhancement. All dogs underwent surgical decompression and most patients (5/6) returned to normal or near normal neurologic function postoperatively. Follow‐up of the patients (ranging between 921 and 1,446 days) showed no progression of neurologic clinical signs or any conditions associated with increased bleeding tendency.Conclusions and Clinical ImportanceBefore surgery and histopathology confirming extraparenchymal hematoma, the primary differential in most cases was neoplasia, based on the MRI findings. This retrospective study reminds clinicians of the importance of the combination of advanced imaging combined with histopathologic diagnosis. The prognosis for spontaneous spinal cord extraparenchymal hematoma with surgical decompression appears to be favorable in most cases.

“Acute onset tetraplegia associated with immune‐mediated thrombocytopenia and suspected secondary intraspinal hemorrhage in a dog”

“…10 Intraspinal hemorrhage has a characteristic appearance on MRI depending on its age, as reported by Braun et al 16 In the dog reported here, the presence of both T1 and T2 hyperintensity with the absence of susceptibility artifact on the T2*-weighted images and the lack of suppression on FLAIR-weighted images is most compatible with ISH in the late subacute phase, based upon human reports, 16 and is similar to prior descriptions in dogs. 15 The clinical progression described in the dog reported here, however, was more consistent with an acute process. There are additional descriptions of ISH in humans where both T1 and T2 hyperintensity are reported within the peracute and acute time frames, 17 which is consistent with the dog reported here.…”

“…There are additional descriptions of ISH in humans where both T1 and T2 hyperintensity are reported within the peracute and acute time frames, which is consistent with the dog reported here. The presumptive ISH in this case demonstrated peripheral contrast enhancement, which has previously been reported in humans and dogs . The variability of MRI findings in people with ISH and the lack of consistency among the limited reports in the veterinary literature, combined with the presence of severe thrombocytopenia and the absence of any other findings, led the authors to consider ISH secondary to ITP as the most likely diagnosis in this case .…”

“…The presumptive ISH in this case demonstrated peripheral contrast enhancement, which has previously been reported in humans and dogs. 15,17,18 The variability of MRI findings in people with ISH and the lack of consistency among the limited reports in the veterinary literature, combined with the presence of severe thrombocytopenia and the absence of any other findings, led the authors to consider ISH secondary to ITP as the most likely diagnosis in this case. 19 The additional intramedullary changes observed on MRI may represent concurrent intramedullary hemorrhage, edema, myelitis, or some combination thereof.…”

“…Extramedullary intraspinal hemorrhage has been reported to occur in dogs spontaneously or due to intervertebral disk herniation, coagulopathies, hemophilia, and snake envenomation. Intramedullary intraspinal hemorrhage has been described in dogs experiencing myelomalacia, spontaneous bleeding, or vascular malformations, causing a variety of clinical signs . Intraspinal hemorrhage has a characteristic appearance on MRI depending on its age, as reported by Braun et al In the dog reported here, the presence of both T1 and T2 hyperintensity with the absence of susceptibility artifact on the T2*‐weighted images and the lack of suppression on FLAIR‐weighted images is most compatible with ISH in the late subacute phase, based upon human reports, and is similar to prior descriptions in dogs .…”

Avaliação da citotoxicidade <i>in vitro</i> e da toxicidade aguda <i>in vivo</i> de cimentos esponjosos à base de polimetilmetacrilato e de poliuretana de mamona

“…estudaram o hematoma espinhal extra parenquimatoso espontâneo em cães e um dos métodos diagnósticos usados foi a RM, eles realizaram a RM em 6 seis cães com esse tipo de hematoma utilizando as sequências T2, T1 pré-contraste e T1 pós-contraste. Os autores observaram que os hematomas de todos os cães ficaram com alta intensidade de sinal nas imagens de T2, nas imagens de T1 sem o contraste os hematomas ficaram com baixa intensidade de sinal em 4 de 6 cães, com média intensidade de sinal em 1 cão e com alta intensidade de sinal na periferia do hematoma em 1 cão em T1 com contraste, a hemorragia ficou contrastada em apenas 1 dos seis cães (80) .…”