Risk factors, treatment, and outcome in dogs and cats with subdural hematoma and hemispheric collapse after ventriculoperitoneal shunting of congenital internal hydrocephalus.

BACKGROUND: Overshunting and hemispheric collapse are well-known complications after ventriculoperitoneal shunt (VPS) implantation. Risk factors that predispose to overshunting, treatment options, and prognosis after therapeutic intervention have not been described. HYPOTHESIS/OBJECTIVES: To identify preoperative risk factors for overshunting, the effect of surgical decompression, and their outcomes. ANIMALS: Seventy-five dogs and 7 cats. METHODS: Retrospective case cohort study. Age, breed, sex, body weight, number of dilated ventricles, ventricle brain ratio, intraventricular pressure, and implanted pressure valve systems were evaluated as possible risk factors. RESULTS: Overshunting had a prevalence of 18% (Cl 95% 9.9-26.66). An increase of 0.05 in VBR increased the risk of overshunting by OR 2.23 (Cl 95% 1.4-3.5; P = .001). Biventricular hydrocephalus had the highest risk for overshunting compared to a tri- (OR 2.48 with Cl 95% 0.5-11.1) or tetraventricular hydrocephalus (OR 11.6 with Cl 95% 1.7-81.1; P = .05). There was no influence regarding the use of gravitational vs differential pressure valves (P > .78). Overshunting resulted in hemispheric collapse, subdural hemorrhage, and peracute deterioration of neurological status in 15 animals. Subdural hematoma was removed in 8 dogs and 2 cats with prompt postoperative improvement of clinical signs. CONCLUSIONS AND CLINICAL IMPORTANCE: Biventricular hydrocephalus and increased VBR indicate a higher risk for overshunting. The use of differential valves with gravitational units has no influence on occurrence of overshunting related complications and outcomes. Decompressive surgery provides a favorable treatment option for hemispheric collapse and has a good outcome.

Impaired cerebrospinal fluid transport due to idiopathic subdural hematoma in pig: an unusual case.

BACKGROUND: We report the effects of the presentation of an idiopathic subdural hematoma (SDH) in an adult domestic pig on the glymphatic system, a brain-wide solute clearance system. This accidental finding is based on our recently published study that described this system for the first time in large mammals. Our current results define the need to investigate cerebrovascular pathologies that could compromise glymphatic function in gyrencephalic animal models as a tool to bridge rodent and human glymphatic studies. CASE PRESENTATION: The pig underwent intracisternal infusion of a fluorescent tracer under general anesthesia to delineate cerebrospinal fluid (CSF) pathways, and was euthanized at the end of 3 h of tracer circulation. During brain isolation, a hematoma measuring approximately 15 × 35 mm in size beneath the dura was evident overlying fronto-parietal brain surface. Interestingly, CSF tracer distribution was markedly reduced on dorsal, lateral and ventral surfaces of the brain when compared with a control pig that was infused with the same tracer. Furthermore, regional distribution of tracer along the interhemispheric fissure, lateral fissure and hippocampus was 4-5-fold reduced in comparison with a control pig. Microscopically, glial-fibrillary acidic protein and aquaporin-4 water channel immunoreactivities were altered in the SDH pig brain. CONCLUSIONS: This is the first case of impaired glymphatic pathway due to an idiopathic SDH in a pig. Potential etiology could involve an acceleration-deceleration injury inflicted prior to arrival at our housing facility (e.g., during animal transportation) leading to disruption of bridging veins along the superior sagittal sinus and impairing CSF pathways in the whole brain. This accidental finding of globally impaired glymphatic function sheds light on a novel consequence of SDH, which may play a role in the enhanced cognitive decline seen in elderly presenting with chronic SDH.

Hemorrhagic Myelomalacia in a Bichon Frise Following Lumbar Spinal Tap-A Case Report.

A 10-year-old spayed female Bichon Frise presented to the neurology service for back pain and pelvic limb weakness for approximately 2 months duration. Neurologic examination revealed T3-L3 and L4-S3 myelopathies with multifocal spinal pain. Magnetic resonance imaging of the vertebral column revealed multiple mild disc protrusions but no obvious cause for the neurologic deficits. Attempts to collect cerebrospinal fluid from the lumbar spine and cerebellomedullary cistern were unsuccessful. Following anesthesia, the dog was noted to be paraplegic with flaccid pelvic limb muscle tone and absent nociception. Repeat magnetic resonance imaging the following day revealed suspect hemorrhage ventral to the spinal cord cranial to the site of the lumbar spinal tap. Exploratory hemilaminectomy revealed purplish discoloration of the dura. Durotomy was performed and severe myelomalacia of the spinal cord was noted. To the author's knowledge, this is the first reported case of myelomalacia suspected secondary to lumbar spinal tap in a dog.

Endothelin-1 Immunoreactivity and its Association with Intramedullary Hemorrhage and Myelomalacia in Naturally Occurring Disk Extrusion in Dogs.

BACKGROUND: The pathophysiology of ascending/descending myelomalacia (ADMM) after canine intervertebral disk (IVD) extrusion remains poorly understood. Vasoactive molecules might contribute. HYPOTHESIS/OBJECTIVES: To investigate the immunoreactivity of endothelin-1 (ET-1) in the uninjured and injured spinal cord of dogs and its potential association with intramedullary hemorrhage and extension of myelomalacia. ANIMALS: Eleven normal control and 34 dogs with thoracolumbar IVD extrusion. METHODS: Spinal cord tissue of dogs retrospectively selected from our histopathologic database was examined histologically at the level of the extrusion (center) and in segments remote from the center. Endothelin-1 immunoreactivity was examined immunohistochemically and by in situ hybridization. Associations between the immunoreactivity for ET-1 and the severity of intramedullary hemorrhage or the extension of myelomalacia were examined. RESULTS: Endothelin-1 was expressed by astrocytes, macrophages, and neurons and only rarely by endothelial cells in all dogs. At the center, ET-1 immunoreactivity was significantly higher in astrocytes (median score 4.02) and lower in neurons (3.21) than in control dogs (3.0 and 4.54) (P < .001; P = .004) irrespective of the grade of hemorrhage or myelomalacia. In both astrocytes and neurons, there was a higher ET-1 immunoreactivity in spinal cord regions remote from the center (4.58 and 4.15) than in the center itself (P = .013; P = .001). ET-1 mRNA was present in nearly all neurons with variable intensity, but not in astrocytes. CONCLUSION AND CLINICAL IMPORTANCE: Enhanced ET-1 immunoreactivity over multiple spinal cord segments after IVD extrusion might play a role in the pathogenesis of ADMM. More effective quantitative techniques are required.

Spinal cord injury secondary to electrocution in a dog.

A 13-year-old, female spayed, crossbreed dog of 32 kg was presented for evaluation of peracute onset of non-ambulatory tetraparesis after chewing an electrical wire. Neurological examination was consistent with a C1-C5 myelopathy. Magnetic resonance imaging revealed a focal intramedullary lesion over the C2-C3 vertebral bodies, which was confirmed to be an acute focal necrotising poliomyelopathy with subarachnoid and subdural haemorrhages on postmortem examination. This report describes the clinical, imaging and histopathological findings of this unusual type of spinal cord injury, and the effects of electrocution in the central nervous system of dogs.

Intracranial trauma in a dog due to being "swung" at birth.

A male Labrador Retriever neonate presented for evaluation 8 hours after birth because of the onset of generalized seizure activity. The neonate was one of 8 puppies delivered over a 19-hour period to a 4-year-old female Labrador Retriever at an assistance dog breeding colony. Uterine and fetal heart monitoring were performed during the first and second stages of labor; secondary uterine inertia was diagnosed 10 hours after the onset of stage-1 labor. In addition to standard medical therapy, manual assistance was provided for the delivery of all but the second puppy (feathering, pulling, elevating forequarters, abdominal compression). The puppy presented was the third puppy born. At birth, resuscitation efforts were instituted because of a lack of spontaneous breathing and bradycardia. In an effort to remove amniotic fluid from the airways, the puppy was "swung" by an experienced attendee in an arch from mid-abdomen height to knee height while cradled in both hands with the head stabilized. Initial evaluation of the puppy revealed normal blood glucose and no ultrasonographic evidence of hydrocephalus. Because of continued seizure activity, euthanasia and necropsy were elected. At necropsy, there was gross evidence of subdural hematoma formation. Subsequent histopathology of the brain, liver, lung, spleen, small intestine, colon, and kidney revealed subdural and intracerebral hemorrhage. Findings were consistent with high-velocity deceleration trauma ("shaken baby syndrome"). Traditional neonatal resuscitation via "swinging" is a dangerous and potentially lethal practice capable of inducing significant brain trauma in the canine neonate.

Subdural hematoma of the brainstem in a dog: magnetic resonance findings and treatment.

An 8-year-old, spayed female Dalmatian with a history of seizures was evaluated for cervical pain and bilateral scleral hemorrhages. Diagnostic evaluations revealed a mass displacing the ventral brainstem on magnetic resonance imaging (MRI). The mass was surgically removed and histologically confirmed to be a hematoma. The dog's neurological signs resolved completely after surgery. Although extradural, subdural, subarachnoid, and intraparenchymal hemorrhages have been reported in dogs and cats, this is the first known report of a subdural hematoma of the ventral brainstem in a dog. On the basis of the history and the appearance of the subdural hematoma on MRI, a traumatic event during the seizure episodes was considered the most likely cause of the subdural hematoma in this case.

Effect of perfluorocarbons on brain oxygenation and ischemic damage in an acute subdural hematoma model in rats.

OBJECT: This study was conducted to determine whether perfluorocarbons (PFCs) improve brain oxygenation and reduce ischemic brain damage in an acute subdural hematoma (SDH) model in rats. METHODS: Forty adult male Sprague-Dawley rats were allocated to four groups: (1) controls, acute SDH treated with saline and 30% O2; (2) 30-PFC group, acute SDH treated with PFC infusion in 30% O2; (3) 100-O2 group, acute SDH treated with 100% O2; and (4) 100-PFC group, acute SDH treated with PFC plus 100% O2. Ten minutes after the induction of acute SDH, a single dose of PFC was infused and 30% or 100% O2 was administered simultaneously. Four hours later, half of the rats were killed by perfusion for histological study to assess the extent of ischemic brain damage. The other half were used to measure brain tissue oxygen tension (PO2). The volume of ischemic brain damage was 162.4 +/- 7.6 mm3 in controls, 165.3 +/- 11.3 mm3 in the 30-PFC group, 153.4 +/- 17.3 mm3 in the 100-O2 group, and 95.9 +/- 12.8 mm3 in the 100-PFC group (41% reduction compared with controls, p = 0.002). Baseline brain tissue PO2 values were approximately 20 mm Hg, and after induction of acute SDH, PO2 rapidly decreased and remained at 1 to 2 mm Hg. Treatment with either PFC or 100% O2 improved brain tissue PO2, with final values of 5.14 and 7.02 mm Hg, respectively. Infusion of PFC with 100% O2 improved brain tissue PO2 the most, with a final value of 15.16 mm Hg. CONCLUSIONS: Data from the current study demonstrated that PFC infusion along with 100% O2 can significantly improve brain oxygenation and reduce ischemic brain damage in acute SDH.

Intradural vasculitis and hemorrhage in full sibling Welsh springer spaniels.

Two, full sibling, Welsh springer spaniel presented at 8 and 18 mo of age with rapidly progressive ataxia, recumbency, and pyrexia. The spinal cord contained extensive subdural hemorrhage and, in 1 dog, suppurative and necrotizing arteritis in the dura. The findings suggest a familial form of canine juvenile polyarteritis syndrome.

Subdural hematoma in a dog.

A traumatic subacute subdural hematoma in a dog was diagnosed by computed tomography and treated successfully by craniectomy and surgical drainage.

Meningeal haemorrhage and congestion associated with the perinatal mortality of foals.

A high frequency of meningeal lesions was found at autopsy in foals dying perinatally. Such lesions are considered an index of injury to the fetal central nervous system, from trauma and/or hypoxia during birth. Their incidence in the sample examined (26 foals) is similar to that observed in the perinatal mortality of lambs and calves.