Animal Behavior for Shelter Veterinarians and Staff. Группа авторов
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4.6.2.2 Seizures
Generalized seizures in dogs and cats are characterized by the animal falling into a laterally recumbent position with limbs rigid and paddling. They may or may not evacuate their bladder or bowels, they may vocalize, and they will usually fail to respond if spoken to or touched. Focal seizures, however, are involuntary movements that may be localized to a single limb or part of the face. The animal experiencing a focal seizure may be somewhat responsive to other stimuli, but an aura and pre‐ and postictal phases may be present. These types of seizures can result in unusual behavioral presentations and can be difficult to diagnose.
Focal seizures may be divided into motor and sensory‐type seizures. While motor seizures involve involuntary movement of one part of the body, sensory focal seizures may result in abnormal sensations such as tingling, pain, or visual hallucinations. Fly‐biting or fly‐snapping behaviors in some dogs may occur as a result of focal seizures with visual hallucinations. However, evidence linking these and similar behaviors to gastrointestinal distress confirms the possibility of multiple etiologies that can be associated with this non‐specific behavioral sign (Frank 2012; Mills et al. 2020). Complex focal seizures (formerly known as psychomotor seizures) are focal seizures with alterations in awareness. Affected dogs may exhibit repetitive motor activities such as head pressing, vocalizing, or aimless walking or running (Berendt and Gram 1999). In some cases, complex focal seizures manifest as impaired consciousness and bizarre behavior, such as unprovoked aggression or extreme, irrational fear (Dodman et al. 1992, 1996).
Seizures are just one type of involuntary movement disorder in dogs and cats. Other forms of involuntary movements can occur and will need to be differentiated from seizures and primary behavioral disorders. Movements seen during periods of inactivity can be confirmed as movement disorders rather than behavioral disorders. However, involuntary movement disorders such as those associated with cerebellar diseases will occur during periods of activity. Some metabolic diseases and peripheral nervous system and musculoskeletal disorders may also result in involuntary movements. Involuntary movements limited to facial or head movements are likely to be caused by a seizure disorder.
4.6.2.2.1 Cats
Cats with acute onset of partial seizure involving orofacial movements, such as salivation, facial twitching, lip smacking, chewing, licking, or swallowing, along with other behavioral changes, such as sitting and staring while motionless and/or acting confused, have been diagnosed with a form of hippocampal necrosis (Pakozdy et al. 2011). The majority of these cats exhibited other neurological abnormalities on their first presentation. Seizures in cats may also be associated with metabolic disease such as diabetes mellitus, hepatic encephalopathy, neoplasia, or meningoencephalitis (Barnes et al. 2004).
4.6.2.3 Toxicosis
Toxins may lead to personality changes in animals. Animals that have been intoxicated may present with central nervous system signs such as ataxia, stupor, seizures, or death. When signs are acute, a history of exposure is usually present. Shelter staff will be unlikely to encounter these scenarios since once the animal is in the shelter, opportunities to access toxic substances will be limited.
4.6.2.4 Degenerative Conditions
Most degenerative conditions of the neurologic system are heritable and will appear within the first few weeks to months of life. They include such conditions as cerebellar abiotrophy and lysosomal storage diseases.
Cerebellar abiotrophy can be minimal to rapidly progressive and varies to some degree by the breed affected. The condition has been reported in many breeds, including the Kerry blue terrier, rough‐coated collie, beagle, Samoyed, Irish setter, Gordon setter, Airedale, Finnish harrier, Bernese mountain dog, Labrador and golden retriever, cocker spaniel, cairn terrier, and Great Dane. Most puppies will be normal at birth. At two to nine weeks of age, they begin to show signs of cerebellar damage, including ataxia, intention tremors, swaying, hypermetria, a head tilt, and a broad‐based stance. At the extreme, pups may demonstrate opisthotonos with extensor rigidity of the forelimbs and flexed hindlimbs, the typical decerebellate posture. While the age of onset is prior to four months in most cases, some animals may not show signs of disease until two to two‐and‐a‐half years of age. In some cases where the disease progression is minimal or very slow, some animals can learn to compensate for their disabilities. Cerebellar abiotrophy can develop in the cat but has been less well documented. A single case report has described adult‐onset cerebellar cortical abiotrophy with retinal degeneration in a domestic shorthaired cat (Joseph 2011). If observed and examined carefully, the clinical signs associated with cerebellar degeneration should be readily differentiated from primary behavioral problems.
Lysosomal storage diseases are relatively rare genetic defects that are characterized by progressive neuronal degeneration. They are most likely to occur in purebred animals with a history of inbreeding in the affected line. Animals born with lysosomal storage diseases are normal at birth, with clinical signs usually developing during the first year of life. Neuronal ceroid lipofuscinosis is one of the storage diseases that can appear in adult animals. Case reports of dachshunds with this condition have reported dogs developing the signs at three, five, and seven years of age (Cummings and de LaHunta 1977; Vandevelde and Fatzer 1980). Early signs may include ataxia, disorientation, weakness, and behavioral changes, but, with time, affected individuals will suffer vision loss, progressive motor and cognitive decline, and seizures.
4.6.2.5 Inflammatory Conditions
Clinical signs will vary with the site of the brain inflammation and may be acute or chronic. A progressive, acute disease process is most typical. Neurological deficits seen with inflammation may be diffuse, focal, or multifocal. Encephalitis or parenchymal central nervous inflammation may present with depression, stupor, coma, or other types of altered consciousness. Blindness, ataxia, seizures, and other behavioral changes may also be seen. Box 4.3 lists some of the more common infectious and parasitic causes of central nervous system signs in dogs and cats.
4.6.3 Urogenital Disorders
Inappropriate elimination is a common behavioral complaint for pet owners, but it is also often a primary sign of a medical condition. Distinguishing the two and/or recognizing when a medical condition exists at the same time as learned behavior (or a failure of house training) can be challenging but will be critical to solving the problem. Box 4.4 lists some of the more common reasons for dogs and cats to soil the house with urine. Regardless of the species, the first challenge is to observe the animal and attempt to determine if it has voluntary control over urination some of the time, all of the time, or none of the time, as this will help narrow down the list of differential diagnoses.
Box 4.3 Infectious and Parasitic Causes of Central Nervous System Signs in Dogs and Cats
Feline infectious peritonitis
Feline leukemia virus
Toxoplasmosis
Canine distemper virus
Rabies
Fungal infections
Protozoal infections
Encephalitozoon cuniculi
Parasite migrations
Dirofilariasis
Ascarid larval migrans
Cuterebriasis
4.6.3.1 Urinary Incontinence
Incontinence is the failure of voluntary control