Hidrocefalia congênita em cães Hydrocephalus Congenital in Dogs

Background: Hydrocephalus is a condition characterized by increased cerebrospinal fluid volume, with progressive dilatation of the ventricular system, with subsequent destruction and atrophy of the brain parenchyma. The congenital form is the most observed in the first months of life and occurs more frequently in small breed dogs. Because of the importance of this disease in the differential diagnosis in young dogs with signs cortical thalamus and the lack of national literature on the subject, the objective of this report was to present ten cases of congenital hydrocephalus in dogs and information about the race, sex, age, neurological signs, the findings of complementary tests and response to therapy. Cases: Ten dogs were referred to the Veterinary Medical Teaching Hospital of the UFSM, being three mixed breed dogs, two Lhasa apso, two Dachshunds, one Poodle, one English Bulldog and one Yorkshire terrier, aged between one month and one year and six months, seven females and three males. In all cases, the owners reported during anamnesis, altered level of consciousness (drowsiness or hallucination) and behavior and learning difficulties. For anatomical location of the lesion was performed complete neurological examination. As complementary tests were requested hemogram and serum biochemistry. In some individuals was performed analysis of cerebrospinal fluid by puncturing the lower back. transcranial ultrasound examination was performed only in five dogs. Opposite the historical, clinical, neurological and laboratory test findings, the diagnosis was congenital hydrocephalus. After the diagnosis, seven dogs were subjected to treatment with corticosteroids and three dogs were euthanized at the option of the owner. Of the seven treated dogs, none had a satisfactory clinical improvement during long time. Five dogs died during clinical treatment and were not subject to the necropsy by the lack of notification by the owners. Discussion: Congenital hydrocephalus is diagnosed more frequently than acquired in routine clinical small animal. In addition, young animals are the most affected by the primary hydrocephalus. The mean age of the dogs of this report was four months. Only one dog was over one year old, but the history, the onset of clinical signs was at six months of age. As for breed all were predisposed breeds and crossbred dogs were small, as described in the literature. Due to accumulation of cerebrospinal fluid in the ventricular system, clinical signs occur by compression of adjacent brain parenchyma. The clinical signs in dogs found in this study were changes in behavior and level of consciousness, characterized by drowsiness and/or hallucinations (100%), skull increased volume (80%), bilateral lateral ventral strabismus (60%), seizures (30%), non ambulatory tetraparesis (20%), walking in circles (20%) and head turn (10%). As the evolution of clinical signs, although some patients may remain stable for some time, clinical signs are generally progressive. In nine dogs of this study the signs were progressive. Medical therapy includes general supportive care and medication to reduce the production of cerebrospinal fluid and hence reduce intracranial pressure. Various medications are used for this purpose, such as corticosteroids, diuretics and blockers carbonic anhydrase. In this study, the protocol was instituted therapy with prednisolone at the dose of 0.5 mg kg (body weight) oral, every 24 h for 14 days. Three dogs had mild clinical improvement in the first week of therapy, however, subsequently had worsening of neurological signs. The study has as clinical relevance, the importance of congenital hydrocephalus in the differential diagnosis of young dogs with neurological signs of cortical thalamus, and the effective ultrasound examination to conclude the diagnosis. The prognosis is poor in patients undergoing medical treatment with corticosteroids.