Читать книгу Canine and Feline Epilepsy - Luisa De Risio - Страница 74

Luisa De Risio Neurology/Neurosurgery Unit, Centre for Small Animal Studies, Animal Health Trust, Newmarket, UK

Reactive seizures are the reaction of a normal brain to a systemic metabolic, nutritional or exogenous toxic disorder (Podell, 1995). Reported prevalence of reactive seizures in dogs and cats varies among studies ranging from 7 to 32% in dogs and from 4 to 28% in cats (Bateman and Parent, 1999; Platt and Haag, 2002; Rusbridge, 2005; Pákozdy et al., 2008, 2010; Zimmermann et al., 2009; Brauer et al., 2011; Steinmetz et al., 2013) (see Chapters 7 and 8). In a recent study the most frequent cause of reactive seizures were intoxications (37/96, 39% of dogs) and hypoglycaemia (31/96, 32% of dogs) (see Fig. 7.2, Chapter 7); 49% (47/96) of dogs had generalized tonic-clonic seizures with loss of consciousness and 41% (39/96) of dogs were presented in status epilepticus (Brauer et al., 2011). Dogs with reactive seizures caused by exogenous toxicity have a significantly higher risk to develop status epilepticus, particularly as first manifestation of a seizure disorder, than dogs with other seizure aetiologies (Zimmermann et al., 2009). In cats with reactive seizures and structural epilepsy, status epilepticus is significantly more common than in cats with idiopathic epilepsy (see Schriefl et al., 2008; Pákozdy et al., 2010; Chapter 3).

Clinical presentation in animals with systemic metabolic, nutritional and toxic disorders is variable depending on the underlying aetiology. Toxic disorders generally have an acute (less than 24 h) onset and neurological signs may be preceded or accompanied by gastrointestinal, cardiovascular or respiratory signs. However, chronic lead intoxication may result in recurrent seizures. Metabolic and nutritional disorders can present with an acute, subacute, or chronic onset and may be progressive or relapsing remitting. The neurological examination generally reveals diffuse, bilateral and often symmetrical neurological deficits, however seizures can sometimes be the only neurological abnormality. Diagnostic investigations (see Chapter 10) are aimed at identifying the underlying aetiology of the seizures and, if present, of the other clinical signs. Treatment is aimed at the underlying aetiology and seizure control with anti-epileptic medications (AEMs).

This chapter describes disorders commonly resulting in reactive seizures. For detailed information on specific AEMs, as well as management of cluster seizures and status epilepticus, the reader is referred to Chapters 12 to 24.