Archive Animal Disease

Red Eye   Red Eye – hyperemia of the eyelids or ocular vasculature, or hemorrhage within the eye. Active dilation of ocular vessels—in response to extraocular or intraocular inflammation or passive congestion. Hemorrhage from existing or newly formed blood vessels. ...

Rectoanal Polyps   Most rectoanal polyps are benign growths located in the distal rectum. Histopathologic evaluation typically reveals adenomas, but lesions may undergo malignant transformation.   SIGNALMENT Dog and rarely cat Middle-aged to old No breed or sex predilection   ...

Rectal Stricture Rectal Stricture – diminution in the size of the rectal or anal lumen either from cicatricial contracture or scarring as a result of wound healing or chronic inflammation or from proliferative neoplastic disease. Gastrointestinal function is compromised because ...

Vestibular Disease, Geriatric—Dogs   Vestibular Disease, Geriatric—Dogs is an acute onset non-progressive disturbance of the peripheral vestibular system in older dogs.   PATHOPHYSIOLOGY Unknown. Suspected abnormal flow of the endolymphatic fluid in the semicircular canals of the inner ear secondary ...

Renomegaly   Renomegaly – one or both kidneys are abnormally large as detected by abdominal palpation or diagnostic imaging.   PATHOPHYSIOLOGY The kidneys may become abnormally large because of abnormal cellular infiltration (e.g., inflammation, infection, and neoplasia), urinary tract obstruction, ...

Retinal Degeneration   Degeneration of the retina from any cause inherited or acquired. Inherited—generalized PRA; a group of progressive retinal diseases; may be subdivided into photoreceptor dysplasias (begin before the retina fully develops, < 12 weeks) and photoreceptor degenerations (begin after ...

Rotavirus Infections   Rotavirus Infections is a non-enveloped, double-stranded RNA virus; rota (Latin; “wheel”) for shape of the capsid; genus within the family Reoviridae; relatively resistant to environmental destruction (acid and lipid solvents); unique double capsid protects virus from inactivation ...

Rhinitis and Sinusitis Rhinitis—inflammation of nasal epithelium. Sinusitis—inflammation of paranasal sinuses. Includes frontal sinus and maxillary recess in dogs, frontal and sphenopalatine sinuses in cats. The nasal cavity communicates directly with the sinuses; thus rhinitis and sinusitis often occur together ...

Retinal Hemorrhage   Retinal Hemorrhage is focal or generalized areas of bleeding into part or all layers of the retina. May be acute or chronic.   PATHOPHYSIOLOGY Depends on cause. Trauma-induced retinal detachments—may tear retinal blood vessels. Often involved in ...

Roundworms (Ascariasis) Dogs and cats of any age may get roundworms and hookworms, but they are most vulnerable when they are very young. Ascariasis caused by Toxocara canis (dogs), T. cati (cats), and Toxascaris leonina (dogs and cats); Baylisascaris (raccoons) can infect dogs and ...