30 de jul de 2009

Dicas essenciais para o controle da epilepsia em cães e gatos

Mônica Vicky Bahr Arias. Revista Clínica Veterinária, n.81, julho 2009
Resumo: A epilepsia é uma das alterações neurológicas mais frequentes na clínica de pequenos animais. As causas de convulsão no cão e no gato são variadas e o êxito do tratamento das desordens convulsivas se baseia no diagnóstico correto da síndrome neurológica quanto à sua origem idiopática, sintomática ou criptogênica. Aproximadamente 80% dos pacientes epilépticos tratados com anticonvulsivantes ficam livres das crises de forma permanente ou apresentam quadros de menor intensidade e frequência. As causas de falha terapêutica incluem doença progressiva, orientação inadequada do proprietário, seleção indevida de um anticonvulsivante, intolerância aos efeitos do medicamento e epilepsia resistente ao tratamento. Este artigo aborda a avaliação correta do paciente e os princípios da terapia farmacológica, com ênfase na monoterapia, para reduzir as interações e os efeitos colaterais.
Abstract: Epilepsy, one of the most common neurological disorders found in small animal practice, is characterized by the recurrence of seizures. The causes of convulsions in dogs and cats are varied and successful treatment of convulsive disorders depends on correct diagnosis. It is important to determine whether a seizure has occurred and to distinguish it from a syncopal episode, narcolepsy/cataplexy or episodic weakness. Epilepsy classification is based on its underlying etiology, including idiopathic epilepsy, symptomatic epilepsy, and probable symptomatic epilepsy. Seizures may be caused by extracranial and intracranial factors. Reactive epileptic seizures are not true epilepsy and result from an extracranial disease. Intracranial causes include neoplasia, infectious/inflammatory diseases, hydrocephalus, trauma, vascular disease, and primary epilepsy; extracranial causes include metabolic problems and toxicity. Seizure activity in young animals suggests congenital anomalies such as hepatic encephalopathy, infectious diseases, traumatic or metabolic disorders. Animals which are older than five years of age are more likely to have infectious diseases, neoplasia, degenerative diseases, trauma, metabolic disorders and acquired epilepsy. Idiopathic epilepsy may occur at any age, but it occurs most frequently in dogs or cats between six months and five years of age. Although idiopathic epilepsy in cats is an important cause of seizures, brain tumors and inflammatory diseases are more likely to cause seizures. A physical and complete neurological examination is very important in all animals with a seizure disorder. Animals with idiopathic epilepsy are expected to be neurologically normal during the inter-ictal period whereas animals with seizures from toxic, metabolic, congenital, neoplastic, and inflammatorydisorders may have neurological abnormalities between seizures. A description of an animal's seizures, their frequency and duration, and the animal's behavior between seizures may be helpful in determining the cause of a seizure disorder. Data on the environment, the nutritional status, immunizations, previous illnesses or injuries, age at onset of seizures, type and frequency of seizures provide important diagnostic information. A complete blood count, serum chemistry profile, including fasting blood glucose, calcium, BUN, albumin, total protein, cholesterol, triglycerides, urinalysis and radiographs of the thorax or abdomen should all be done for animals that have had one or more seizures. Cerebral spinal fluid analysis, electroencephalography, neuroradiography, and serum titres for infectious diseases may be helpful in determining etiology. The decision to start anti-epileptic drug therapy should be based on each individual case. Use of anti-epileptic drugs is indicated when a diagnosis of primary epilepsy is made, or when treatment of the underlying cause of the seizures in secondary epilepsy does not control seizures. General recommendations for initiating therapy include a single seizure occurring more than once every 4-6 weeks, cluster seizure activity or status epilepticus regardless of frequency. The primary goal of therapy is to balance adequate seizure control with acceptable drug adverse effects. Monotherapy is the initial goal of treating any seizuring dog or cat in order to reduce possible drug interactions and adverse effects. The most common drug used to treat seizures in veterinary medicine is phenobarbital, a relatively inexpensive, well-tolerated drug that can be administered two times per day to prevent seizures in dogs and cats. The appropriate starting dose of phenobarbital for dogs is 2.5 to 5mg/kg orally q12h. It is also the recommended first-line anticonvulsant drug in epileptic cats. Most cats can be treated with 1-2mg/kg/day. Monitoring of serum phenobarbital concentrations is important in the management of epileptic dogs treated with this drug, because seizure control in dogs and cats correlates best with serum phenobarbital concentration, not with the administered dose. The therapeutic range for serum phenobarbital concentration in dogs has been established at 15 to 45µg/mL, although concentrations above 35µg/mL are associated with an increased risk of hepatotoxicity. Dogs treated with phenobarbital should be monitored every 4-12 months with a physical examination, measurement of phenobarbital blood levels and a chemistry panel to check for signs of hepatotoxicity. Potassium bromide is used most commonly as a second anticonvulsant in dogs refractory to phenobarbital alone, or it can be used alone. As it is not metabolized in the liver, it is an ideal anticonvulsant for patients with liver disease. It is not recommended in cats due to the high prevalence of adverse respiratory problems. Diazepam, a very effective anticonvulsant; must be used primarily in emergency situations, due to its short duration of action and the fact that dogs develop tolerance to it. In refractory epileptic canine patients, other new antiepileptic drugs can be added to the standard treatment. However, pharmacokinetics and efficacy of many of these new drugs are not well known. The causes of treatment failure include the presence of progressive disease, inadequate guidance to the owner, inappropriate selection of an anticonvulsant, intolerance to effects of the drug and epilepsy resistant to treatment 4,16. This article discusses the correct assessment of the patient and the principles of pharmacological therapy, with emphasis on monotherapy to reduce interactions and side effects.
Resumen: La epilepsia es uno de los trastornos neurológicos más frecuentes en la clínica de pequeños animales. Las causas de las convulsiones en el perro y el gato son variadas y el éxito o el fracaso del tratamiento de los desórdenes convulsivos se basa en el correcto diagnóstico del síndrome epiléptico, en cuanto a su naturaleza idiopática, sintomática o criptogenética. Aproximadamente 80% de los pacientes epilépticos tratados con anticonvulsivantes quedan libres de crisis en forma permanente o presentan crisis en menor intensidad o frecuencia. Las causas de fallas terapéuticas incluyen la presencia de desórdenes subyacentes, deficiente educación al cliente, inapropiada selección del medicamento, intolerancia a los efectos del medicamento y a ataques que no responden al medicamento. En este artículo se revisan la evaluación adecuada del paciente, los principios de la farmacología antiepiléptica, con énfasis en la monoterapia para reducir las posibles interacciones farmacológicas y los efectos secundarios.
Leitura adicional

25 de jul de 2009

FISIOTERAPIA EM ANIMAIS DE COMPANHIA

A fisioterapia é parte importante do tratamento de pacientes com doenças neurológicas. O trabalho abaixo revisa aspectos importantes dest amodalidade terapêutica:

Reabilitação em pacientes com doenças muscoloesquléticas e espinhais

http://www.fecava.org/files/ejcap/421.pdf

23 de jul de 2009

Paraplegia aguda com perda da percepção de dor profunda em cães: revisão de literatura

Autores: Bruno Martins Araújo, Mônica Vicky Bahr Arias, Eduardo Alberto Tudury
Revista Clínica Veterinária, n.81, 2009
Resumo: A paraplegia aguda com perda da percepção de dor profunda indica lesão medular grave, capaz de lesionar fibras bastante resistentes à lesão e localizadas profundamente na medula espinhal. Várias enfermidades são consideradas no diagnóstico diferencial de cães com essa alteração, em que na maioria dos casos, a lesão ocorre por extrusão de disco intervertebral, fraturas/luxações vertebrais e embolismo fibrocartilaginoso. O diagnóstico baseia-se na resenha clínica, na anamnese, na evolução aguda dos sinais clínicos e nos resultados do exame neurológico e de exames complementares, como imagens da coluna vertebral e da medula espinhal. O tratamento deve ser direcionado na prevenção da destruição neuronal bioquímica, na descompressão da medula espinhal e/ou na estabilização da coluna vertebral. O prognóstico varia de reservado a desfavorável, dependendo da etiologia da lesão e das opções de tratamento disponíveis.
Abstract: Acute paraplegia with loss of deep pain perception (DPP) indicates severe spinal injury, capable of damaging resistant fibers that are deeply situated in the spinal cord. Several conditions are considered for the differential diagnosis of dogs with this alteration. In most cases, the lesion occurs by intervertebral disk extrusion, vertebral fractures/luxations and fibrocartilaginous embolism. The initial mechanisms of acute spinal lesion correspond to the primary injury. They occur at the moment of injury, with the partial or complete rupture of nervous tissue and the loss of medullary tissue, which are considered untreatable lesions. Afterwards, a series of vascular and metabolic alterations take place, which constitute the events referred to as secondary lesions. The diagnosis is based on patient signalment, history, on the acute evolution of clinical signs and on the results of the neurological exam and complementary exams, such as imaging of the vertebral column and the spinal cord. The treatment must be directed towards preventing biochemical neuronal destruction, with the use of neuroprotectors (substances which prevent or limit the mechanisms of secondary injury to the spinal cord). Corticosteroids have been the most frequently employed drugs in trauma and decompression of the spinal cord, both in animals and human beings. They are frequently associated with gastrointestinal complications like hemorrhage, pancreatitis, ulcers and/or gastric perforations. The medical management of the intervertebral disk disease (IVDD) with loss of DPP still consists, for some authors, in the administration of methylprednisolone sodium succinate (MPSS) during the eight hours following trauma, and in the referral for emergency decompression. Surgical treatment of these animals must be readily arranged, as it is considered a neurological emergency, and must entail: decompression of the spinal cord (hemilaminectomy or laminectomy), removal of the disk material extruded into the vertebral canal, decrease of medullary edema and ischemia, macroscopic evaluation and intraoperatory irrigation of the spinal cord. Animals that present with spinal trauma and suspected vertebral instability must be placed in a firm surface to avoid movement and additional injury to the spinal cord, while proper treatment is initiated. Hypotension must be controlled through the use of fluids, and followed by treatment with MPSS as soon as possible, within the first eight hours after trauma. Surgery is indicated for cases presenting with vertebral instability, in which animals must be evaluated through mielography or magnetic ressonance to detect evidence of spinal cord transection or extensive necrosis. If none of these alterations are present, the surgeon may perform a hemilaminectomy, to decompress (in cases where there is extradural compression) and identify a possible progressive hemorrhagic myelomalacia (PHM). If the spinal cord is intact, surgical fixation takes place. There is no specific treatment for FCE, nor is there evidence that any treatment possesses more value than the general nursing care for patients that remain recumbent. The prognosis varies from guarded to unfavorable, depending on the etiology of the lesion and on the available treatment options. In IVDD, the main factor to be considered is the presence or absence of DPP. Among dogs without DPP, the main parameters to be evaluated are speed of occurrence and duration of analgesia, and the recovery time frame to pain perception. Animals which have lost deep pain perception after suffering exogenous vertebral trauma usually present an unfavorable prognosis for recovery, because in this type of injury, the lack of nociception is frequently associated with the transection of the spinal cord or to the rapid onset of PHM. For dogs suffering medullary infarction due to FCE, prognosis in terms of recovery of function is very unpredictable, reflecting the varying severity of the characteristic lesion of this disease. It is important to point out that some animals manage to regain the ability to walk without recovering DPP. In these animals, the occurrence of involuntary motor activity may indicate the development of spinal cord reflex walk, which originates from the mechanism of neural plasticity and the formation of local circuits 53. Paraplegic animals need intensive nursing care during their recovery period or during their entire life (in cases where there isirreparable spinal cord injury). Attention must be given to the emptying of the bladder and intestines, by means of abdominal massage or urinary catheter, and the use of an appropriate diet; to the prevention of skin sores and decubitus ulcers, by constantly cleaning the skin of urine and feces and changing position every four hours; to the treatment of trauma related wounds (usually in case of car accidents) and to the use of passive and active physical therapy, to avoid muscle atrophy and contracture and loss of articular and neuromuscular function.
Resumen: La paraplejia aguda con pérdida de la percepción del dolor profundo indica lesión medular severa, capaz de lesionar fibras muy resistentes a lesiones y situadas profundamente en la médula espinal. Varias enfermedades deben ser consideradas en el diagnóstico diferencial de esta alteración, que en la mayoría de los casos, tienen lesiones por extrusión del disco intervertebral, fracturas / dislocaciones vertebrales o embolismo fibrocartilaginoso. El diagnóstico se basa en la reseña, la anamnesis, los signos clínicos agudos, los resultados del examen neurológico y pruebas adicionales como la obtención de imágenes de la columna vertebral y médula espinal. El tratamiento debe ser dirigido a la prevención de la destrucción neuronal bioquímica, la descompresión de la médula espinal y/o en la estabilización de la columna vertebral. El pronóstico varía de reservado a desfavorable, dependiendo de la etiología de las lesiones y las opciones de los tratamientos disponibles.
Links relacionados:

21 de jul de 2009

Cirurgia da coluna - disco intervertebral

O autor Pierre Méheust apresenta uma revisão sobre técnicas cirúrgicas e indicações:

http://files.meetup.com/545346/Article%20on%20invertebral%20disk%20surgery%20from%20Veterinary%20Focus.pdf

Modificação da técnica de abordagem ventral à articulação atlantoxial sem a secção do músculo esternotireóideo.

Cienc. Rural [online]. 2009, vol.39, n.4, pp. 1227-1230.

O objetivo deste trabalho foi apresentar uma variação na técnica de acesso ventral à articulação atlantoaxial para tratamento da instabilidade atlantoaxial sem a secção do músculo esternotireóideo. Foram utilizados 15 cães, pesando entre oito e 12kg, sem raça definida, independente do sexo, distribuídos aleatoriamente em três grupos iguais de acordo com o período pós-operatório (PO) denominados de I (30dias), II (60 dias) e III (90 dias) para avaliações clínicas diárias. A articulação atlantoaxial foi submetida à artrodese por meio do acesso ventral utilizando pinos de Steinmann associados à resina acrílica autopolimerizável. O acesso e a exposição da articulação atlantoaxial sem a secção do músculo esternotireóideo foram realizados sem complicações ou limitações adicionais. Nenhum cão desta pesquisa apresentou tosse, dispnéia, regurgitação, paralisia laríngea ou Síndrome de Horner. Pode-se concluir que a secção do músculo esternotireóideo é um procedimento desnecessário e que não interfere na exposição da articulação atlantoaxial e na realização da artrodese em cães por meio do acesso ventral.
Palavras-chave : artrodese atlantoaxial; neurologia; cão.