Untersuchung zum Vorkommen idiopathischer Epilepsie beim Border Collie

Idiopathic epilepsy (IE) is a common breed-related neurological
disorder in contemporary small animal medicine. The number of
Border Collies (BCs) with epileptic seizures is increasing while
there is a lack of data of IE in this breed. Hypothesis of this
study was that IE occurs in BCs and manifests often with severe
clinical signs and poor response to medical treatment. IE was
diagnosed by recurrent seizures, normal physical, neurological and
laboratory examination. MRI and CSF analysis were requested if age
at seizure onset was < 6 months or > 5 years of age. Dogs
that failed to meet all inclusion criteria were only considered if
a first- or second-degree relative was afflicted by IE or if
seizures had occurred for at least 2 years without interictal
neurological abnormalities. Owners fulfilled a detailed
questionnaire. Subsequent phenotypic case classification was
performed by evaluation of seizure history and treatment data.
Pedigrees were sampled and matched for the appearance of common
ancestors. Ninety BCs with a reported seizure history were
collected retrospectively and prospectively. Forty-nine of them
were diagnosed with IE and were included in the present study.
Clinical manifestations were dominated by moderate (33 %) and
severe clinical courses (49 %) defined by the occurrence of cluster
seizures or status epilepticus, respectively. Pharmacoresistance
was apparent in 71 % of 24 dogs treated with ≥ 2 antiepileptic
drugs. So far, no predictors for the occurrence of
pharmacoresistance were identified in the present study. The
epilepsy remission rate was 18 %. Dogs in remission showed a
significantly higher median age at onset and a significantly lower
initial seizure frequency compared to dogs with active epilepsy (p
< 0.05). Survival time was significantly reduced in dogs aged
< 2 years at seizure onset and in dogs with severe clinical
courses (p < 0.05). Family- and pedigree analyses indicated a
strong genetic founder effect in the appearance of epilepsy,
resembling autosomal recessive inheritance. Yet, complex
inheritance could not be excluded. In conclusion, IE occurs in BCs
and is frequently associated with severe clinical signs and
pharmacoresistance. While further genetic research is required, the
results of this study suggest a substantial hereditary (disease)
component.