Porencephaly and cortical dysplasia as cause of seizures in a dog

Abstract

BackgroundSeizures are a common problem in small animal neurology and it may be related to underlying diseases. Porencephaly is an extremely rare disorder, and in Veterinary Medicine it affects more often ruminants, with only few reports in dogs.Case presentationA one-year-old intact male Shih-Tzu dog was referred to Veterinary University Hospital with history of abnormal gait and generalized tonic-clonic seizures. Signs included hypermetria, abnormal nystagmus and increased myotatic reflexes. At necropsy, during the brain analysis, a cleft was observed in the left parietal and occipital lobes, creating a communication between the subarachnoid space and the left lateral ventricle, consistent with porencephaly; and also a focal atrophy of the caudal paravermal and vermal portions of the cerebellum. Furthermore, the histological examination showed cortical and cerebellar neuronal dysplasia.ConclusionsReports of seizures due to porencephaly are rare in dogs. In this case, the dog presented a group of brain abnormalities which per se or in assemblage could result in seizure manifestation.

Cranial cavity filled with cerebrospinal fluid in an otter (Lontra longicaudis) - case report

“…Clinical signs in animals with porencephaly may be absent at birth and develop after several years (Machado, 2012). Reported clinical signs include seizures, pleurothotonus, and behaviour changes, such as aggressiveness (Cubas et al, 2014).…”

“…Cystic intracranial malformations filled with cerebrospinal fluid (CSF) are occasionally reported in domestic animals and should be considered as a possible cause of seizures, blindness, ataxia, and other neurologic issues (Lee et al, 2009;Mackillop, 2011;Davies et al, 2012;Machado, 2012;Schmidt et al, 2012;Hori et al, 2015). Similar conditions are rarely described in wild animals, but there are reports of cerebral malformation with similar macroscopic characteristics in primates (Hirowatari et al, 2012) and a fennec fox (Yamazaki et al, 2016).…”

Porencephaly in a fennec fox (<i>Vulpes zerda</i>)

“…In humans, porencephaly commonly manifests in infants as a congenital disorder [4], but in animals, it often occurs in livestock (e.g., cattle, sheep and goats) where prenatal virus infections may represent a predisposing factor [3, 5, 6, 12, 16]. In dogs and cats, porencephaly occurs sporadically, and the cause remains unknown [1, 2, 9, 10, 11, 17]. …”

“…Remarkably, this fennec did not show any signs of seizure or neurologic manifestation over the course of his life, and these results indicated that the animal was well-adapted. In canine, brain anomalies like porencephaly have been shown to have some correlation with seizures [2, 10, 15], giving us reason to believe that this may be an asymptomatic case of the abnormality.…”

“…In humans, virus infection or vascular insufficiency has been implicated as major causes of secondary porencephaly. While a mutation in the procollagen type IV α 1 gene (Col4a1) was reported in mice with porencephaly [4], a similar genetic correlation has not been noted in other animals [10]. In many humans and animals, the actual cause is unclear; therefore, a study of a large number of cases is useful for elucidation of the cause of porencephaly.…”