ABSTRACT
A mortality event caused by exposure to the carbamate insecticide methomyl was diagnosed in several hundred pigeons fed treated corn kernels in a city park. A cholinesterase inhibitor insecticide was initially suspected based on clinical signs and a significant inhibition (P < 0.05) of brain cholinesterase (ChE) activity compared with normal values for the species. However, brain ChE activity was within the normal range in birds subsequently submitted in an advanced stage of autolysis. Two groups of 10 healthy pigeons were allocated into a control group and an experimental group, which was offered corn samples retrieved from the incident site. Within minutes of ingesting the contaminated corn, the birds became immobile, had transient wing fluttering, and developed profuse salivation immediately followed by death. Plasma ChE activity at death had declined by more than 95% of preexposure levels (0.04 +/- 0.02 vs. 1.56 +/- 0.23 micromol/min per milliliter). Brain activity in the sagittal brain sections that were immediately frozen after death was inhibited by > or =50% of control birds (13.5 +/- 2.2 vs. 27.5 +/- 1.8 micromol/min per gram). However, the sagittal sections left for 1.5 days at ambient temperature of 25 degrees C had normal or higher activity, an effect that was attributed to a combination of spontaneous reactivation and dehydration. After incubation of both plasma and brain homogenates for 1 hr at 37 degrees C, ChE activity recovered by 2- and 1.46-fold, respectively. An organophosphorus and carbamate screen conducted by 2 independent laboratories identified and quantified methomyl in treated kernels at 400 ppm. These results indicate that spontaneous reactivation and dehydration can mask previous reductions in ChE activity.
Subject(s)
Bird Diseases/chemically induced , Brain/metabolism , Cholinesterases/blood , Cholinesterases/metabolism , Columbidae , Methomyl/toxicity , Animals , Insecticides/toxicityABSTRACT
La hidrocefalia es una acumulación excesiva de liquido cefalorraquídeo (LCR) en el sistema ventricular cerebral como consecuencia de una causa primaria. Esta enfermedad puede ser adquirida o congénita, manifestándose con signos clínicos de enfermedad neurológica. Este artículo presenta una revisión sobre la fisiopatología, diagnóstico y tratamiento médico quirúrgico de la hidrocefalia en un paciente canino atendido en el Centro de Medicina Veterinaria y de Zootecnia del CES (Medellín, Colombia). En el paciente se realizó una derivación ventrículo peritoneal como tratamiento quirúrgico de la enfermedad; la cirugía se llevó a cabo sin complicaciones y se obtuvo una recuperación satisfactoria con reversión progresiva de la sintomatología clínica. La derivación ventrículo peritoneal como opción quirúrgica para el tratamiento de la hidrocefalia en caninos se convierte entonces en una herramienta valiosa para el médico veterinario, la cual le permite establecer un pronóstico más esperanzador respecto a la longevidad y calidad de vida del paciente.
Hydrocephalus is an excessive accumulation of cerebrospinal fluid (CSF) in the cerebral ventricular system of the brain as a result of a primary cause. This disease can be acquired or congenital, pronouncing itself with clinical signs of neurological disease. This article presents a clinical case with a detailed description of the physiopathology, diagnosis and surgical treatment of hydrocephalus in a canine patient that was attended at the Centro de Medicina Veterinaria y Zootecnia CES (Medellín, Colombia). In this patient a ventricle to peritoneal derivation was practiced as a surgical treatment of the disease; the surgery was carried out without complications and a satisfactory recovery with progressive reversion of the clinical symptomatology was obtained. The ventricle to peritoneal derivation is a surgical option for the treatment of hydrocephalus in canine that becomes a valuable tool for veterinarians, which allows them to establish a more hopeful prognosis regarding longevity and quality of life of the patient.