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Biomedical subjects

M L Harrington

Publications and source records attributed to M L Harrington.

12 recordsLinked to original sources

Clinical signs associated with brain tumors in dogs: 97 cases (1992-1997).

OBJECTIVE: To determine the prevalence of various clinical signs in dogs with brain tumors. DESIGN: Retrospective study. ANIMALS: 97 dogs with brain tumors. PROCEDURE: Medical records were reviewed for signalment, tumor type and location, and clinical signs. RESULTS: 33 breeds were represented; Golden Retrievers were most commonly affected. Most dogs were older (median age, 9 years); 95% of dogs were > or = 5 years old. Seventy-six percent of dogs had tumors in the supratentorial region. Seizures were the most common clinical sign at initial examination, with lower prevalence for circling, ataxia, and head tilt. Meningioma was the most common tumor. CONCLUSIONS AND CLINICAL RELEVANCE: Brain tumors develop most often in dogs > or = 5 years old and are uncommon in dogs < 5 years old. Seizures are a common clinical sign, and a brain tumor should be considered in dogs that have their first seizure after they are 4 years old.

Age Factors

Suspected herbicide toxicosis in a dog.

An 8-year-old 38-kg spayed female Golden Retriever was admitted for vomiting, signs of abdominal pain on palpation, ataxia, anorexia, and generalized weakness of 2 days' duration. Ten hours prior to onset of clinical signs, the dog was found standing in and drinking from large pools of an accidentally spilled herbicide that contained an octanoic acid ester of bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) and an isooctyl ester of (2-methyl-4-chloro) phenoxyacetic acid (MCPA). Appendicular muscles were firm on palpation and persistent muscle contraction (myotonia > 1 minute duration) was found on muscle percussion, using a reflex hammer. Electrical activity indicative of myotonia was identified on electromyographic evaluation. With supportive treatment, the dog eventually recovered from suspected MCPA toxicosis. Although rare, MCPA toxicosis should be considered as a cause of acquired myotonia in dogs.

2-Methyl-4-chlorophenoxyacetic Acid

Intracranial tumors.

Intracranial tumors in dogs are relatively common but are less common in cats. Features of various tumors are described. The antemortem diagnosis is based on demonstrating the mass with advanced imaging. Tumor type, however, can only be diagnosed by histological confirmation. Diagnosis and treatment options are discussed.

Animals

Surgical treatments for seizure. Adaptability for dogs.

Surgical treatments are often used for human epileptics who are refractory to more conventional anticonvulsant therapies. The goals of surgery are to decrease seizure morbidity or, ideally, bring about a cure to the seizure disorder. As a sizable subpopulation of dogs with seizures are also refractory to currently available anticonvulsant therapies, consideration has been given to evaluating alternative treatments for seizures in dogs. This article discusses the adaptability of surgical treatments used in humans for use in seizure control in affected dogs.

Animals

Hydrocephalus.

Hydrocephalus may be an acquired or congenital condition. Clinical signs often reflect the level of brain involvement. In young dogs, the presence of a dome-shaped head and/or persistent fontanel are suggestive of hydrocephalus. Ventriculoperitoneal shunting is often used for definitive treatment of hydrocephalus.

Animals

Effect of craniectomy/durotomy alone and in combination with hyperventilation, diuretics, and corticosteroids on intracranial pressure in clinically normal dogs.

OBJECTIVE: To determine the effect of craniectomy and durotomy on intracranial pressure (ICP) in clinically normal dogs. DESIGN: Two-part study (experiments A and B) involving craniectomy and durotomy, with and without treatments to lower ICP. ANIMALS: Six (experiment A) and 7 (experiment B) healthy dogs. PROCEDURE: In experiment A, craniectomy was performed in combination with durotomy, diuretic administration, methylprednisolone sodium succinate administration, and hyperventilation, and effect of these manipulations on ICP was determined. In experiment B, dogs had only craniectomy and durotomy without associated ICP-lowering treatments. During both experiments, ICP was monitored throughout the surgical procedure with a fiber optic ICP monitoring device. RESULTS: Intracranial pressure decreased after the combination of craniectomy, durotomy, and other ICP-lowering treatments in dogs of experiment A. Similar magnitude of decrease in ICP was observed in dogs of experiment B after craniectomy and durotomy. CONCLUSIONS: Comparison of these experiments indicate that surgical removal of overlying skull and incision of the dura mater can significantly decrease ICP in clinically normal dogs. CLINICAL RELEVANCE: Craniectomy and durotomy may be useful as an adjunct treatment for increased ICP.

Adrenal Cortex Hormones

Effect of craniectomy, durotomy, and wound closure on intracranial pressure in healthy cats.

OBJECTIVES: To establish intracranial pressure (ICP) measurements in healthy cats under isoflurane anesthesia, using a fiberoptic monitoring system; to assess brain lesions associated with such monitoring; and to determine whether decompressive intracranial surgery decreases ICP in healthy cats. ANIMALS: 6 healthy cats. PROCEDURE: Craniectomy and durotomy were performed, and the effect of these procedures on ICP was determined. ICP was monitored by use of a fiberoptic monitoring system. Gross and microscopic evaluations of brain tissues were performed after data collection. RESULTS: ICP decreased significantly after craniotomy and durotomy. After wound closure, ICP remained significantly reduced relative to initial pressures. However, postsurgical pressures were significantly increased, compared with those associated with ICP after durotomy. Gross and histologic abnormalities associated with placement of the ICP monitoring cable included mild focal acute hemorrhage and mechanical cortical disruption. CONCLUSIONS: Craniectomy and durotomy significantly decreased ICP in healthy cats. ICP increased after wound closure, but remained significantly lower than initial pressures. CLINICAL RELEVANCE: Craniectomy and durotomy may be used to decrease ICP in cats.

Animals

Pathologic effects in brain after intracranial pressure monitoring in clinically normal dogs, using a fiberoptic monitoring system.

During 2 separate studies, intracranial pressure (ICP) was measured in 13 healthy dogs (group A, n = 7; group B, n = 6), using a fiberoptic monitoring system implanted surgically in the right superficial cerebral cortex. Average ICP was measured for 15 minutes after a 15-minute postimplantation period of equilibration. Intracranial pressure was measured in group-A dogs at 2.0 and 1.3% end-tidal isoflurane concentrations. Mean +/- 1 SD ICP in group-A dogs at 2.0 and 1.3% end-tidal isoflurane concentrations was 11 +/- 2 and 11 +/- 3 mm of Hg, respectively. Dogs of group A were euthanatized immediately after measurements were obtained. Mean ICP +/- 1 SD in group-B dogs was 11 +/- 3 mm of Hg. After monitoring, but prior to euthanasia, group-B dogs underwent callosotomy, and were maintained for 30 days after surgery. The brain was removed from all dogs, formalin fixed, and examined grossly and microscopically for lesions associated with fiberoptic cable implantation. Variable degrees of hemorrhage and mechanical brain damage were seen focally around the catheter site in all brains from group-A dogs, especially when the cable entered through a sulcus. In 1 dog, local vacuolation was seen in the brain immediately adjacent to the tract associated with implantation of the fiberoptic catheter. In all other dogs, the additional cortex was histologically normal. Histologic lesions associated with cable implantation were not observed in group-B dogs.

Animals

Clinical effects of longitudinal division of the corpus callosum in normal dogs.

Longitudinal division of the corpus callosum was performed in six normal beagles to determine surgical morbidity. The corpus callosum was divided sagittally on the midline and the effect on neurological function was determined. Five of six dogs were clinically normal within 14 days or less after surgery. One dog had persistent but improving clinical signs consistent with a forebrain disturbance at 30 days after surgery. Overall, minimal morbidity and no mortality was associated with this surgical procedure. Further study is indicated to determine the efficacy of this surgical treatment for seizure control in dogs with idiopathic epilepsy.

Animals

Acute, unilateral transverse sinus occlusion during craniectomy in seven dogs with space-occupying intracranial disease.

OBJECTIVE: The purpose of this study was to determine the effect of acute, unilateral transverse sinus occlusion on intracranial pressure (ICP) and postoperative mortality in dogs with structural intracranial disease. STUDY DESIGN: Affected dogs had a single transverse sinus occluded during craniectomy for intracranial mass biopsy or removal. ANIMALS: Seven dogs with space-occupying intracranial disease in the cerebellopontine angle area. METHODS: The ipsilateral transverse sinus was permanently occluded during the surgical approach to the intracranial lesion to increase surgical exposure by allowing a caudal lateral rostrotentorial craniectomy to be combined with a suboccipital craniectomy. In five dogs, intracranial pressure was monitored during surgery using a fiberoptic intracranial pressure monitoring device. RESULTS: Initial ICP varied among dogs, ranging from 7 to 21 mm Hg. Intracranial pressure, however, decreased in all dogs after craniectomy and durotomy (P < .05). No increase in intracranial pressure occurred after transverse sinus occlusion (P = .42). All dogs survived the surgical procedure. CONCLUSIONS: Acute, unilateral transverse sinus occlusion during craniectomy in dogs with space-occupying intracranial lesions did not result in significant increases in ICP or intraoperative mortality. CLINICAL RELEVANCE: Acute, unilateral transverse sinus occlusion during craniectomy can be used to increased surgical exposure to the caudal fossa of the brain without increased risk of increasing ICP.

Animals

Realignment of a seventh lumbar vertebral fracture/luxation using a Senn retractor in two puppies.

Two puppies, each with fractures of the seventh lumbar (L7) vertebra, had their vertebral canals aligned surgically with the aid of a Senn retractor. The retractor was used to provide leverage during vertebral manipulations. Surgical fixation was achieved using Steinmann pins and polymethylmethacrylate. Both puppies were improved immediately after surgery and were clinically normal six months after surgery.

Animals