Tag Archives: Chow Chow

Congenital and Hereditary Disorders of the Kidney

Structural Anomalies of the Kidney RENAL AGENESIS Renal agenesis is the complete absence of one or both kidneys. Bilateral renal agenesis is fatal and is a cause of early death in puppies and kittens (). Unilateral renal agenesis is more frequendy observed in puppies and kittens than is bilateral agenesis (). Unilateral renal agenesis may affect either kidney and is usually accompanied by ipsilateral ureteral agenesis. The etiopathogenesis of renal agenesis in dogs and cats is uncertain. A familial predisposition for renal agenesis in beagles, Shetland sheepdogs, and Doberman pinschers supports a genetic basis for the anomaly (Table 17-1). Unilateral renal agenesis may remain clinically silent, provided the contralateral kidney undergoes sufficient compensatory change to maintain normal hemostasis. Clinical findings may include an inability to palpate both kidneys or to detect a kidney by ultrasonography or contrast urography. Because of close associations in the development of the urogenital system, findings of abnormal or absent vas deferens, epididymal tails, or uterine horns at the time of castration or ovariohysterectomy should arouse suspicion of concurrent unilateral renal agenesis. Because unilateral renal Read more […]

The Eyelids

Developmental Abnormalities Eyelid Agenesis. Eyelid agenesis is a congenital defect of the eyelid margin resulting in absence of varying segments of the eyelid margin, palpebral conjunctiva, and fornices. The agenesis may be unilateral or bilateral, affecting the kitten more often than the puppy. The lateral one third or two thirds of the upper eyelid margin is most frequently involved. Keratitis and ulceration result from direct contact of the cornea with facial hairs and from exposure secondary to imperfect eyelid closure. Small eyelid defects may be successfully managed with ophthalmic lubricant ointments applied three to four times a day to reduce ocular irritation or by performing an entropion procedure to evert the offending hairs. If one third of the eyelid or more is missing, a pedicle graft from the inferior temporal aspect of the lower eyelid can be transposed to the upper eyelid. Distichiasis. Distichiasis is an extra row of eyelashes (cilia) that protrudes from the orifices of the meibomian glands onto the eyelid margin. The upper, lower, or both eyelids may be involved (). Congenital distichiasis often occurs in the English bulldog, toy¬†poodle, miniature poodle, American cocker spaniel, golden retriever, Read more […]

The Lens and Vitreous

The lens develops rapidly in the early stages of embryogenesis, during which time it is nourished by the hyaloid vessel. The fully developed lens is avascular; by the second week of life, no remnants of the hyaloid system should remain. The normal lens often exhibits minor imperfections that can be easily detected with magnification in dogs and cats younger than 1 year. These include prominent anterior and posterior Y sutures and minute granules in its nucleus and cortex. A mosaic of brown pigment spots is occasionally seen on the anterior lens capsule near the center of the pupil, representing remnants of embryonic mesoderm. Disease of the vitreous would be expected to influence the lens or retina because of its attachments at the posterior lens surface and the optic disc. Congenital Abnormalities Congenital lens abnormalities include alterations in size or shape. Congenital absence of the lens (aphakia) is uncommon. In microphakia, the margin of the abnormally small lens along with elongated ciliary processes may be observed after pupillary dilation. Microphakia occurs along with other ocular defects in the Saint Bernard and beagle and in cats. Luxation of the microphakic lens may cause glaucoma. Lenticonus is a Read more […]

The Trachea and Major Bronchi

Cough is the most common clinical sign associated with tracheal and bronchial disease. Following a history and thorough physical examination to rule out infectious tracheobronchitis, thoracic and soft-tissue cervical radiographs may be indicated. Thoracic radiography is perhaps the single most important diagnostic test in the evaluation of the puppy or kitten that presents with cough as its primary complaint. Tracheal hypoplasia, extraluminal compressive diseases, diseases causing tracheal stenosis, intraluminal masses, and tracheal collapse may be apparent radiographically. Tracheoscopy with a small-diameter endoscope (approximately 3.5 to 5 mm in diameter or a rigid arthroscope) is useful in evaluating the trachea when obstructive or mucosal disease is suspected. It is especially useful in the diagnosis of tracheal collapse, tracheal foreign body, tracheal stenosis, parasitic tracheobronchitis, and tracheal osteochondroma. Congenital Disorders PRIMARY CILIARY DYSKINESIA Primary ciliary dyskinesia is a congenital respiratory disorder that is characterized by absent or deficient mucociliary clearance (). The ciliary dysfunction reduces mucociliary transport, which frequently leads to persistent or recurrent rhinitis, Read more […]

Cystic Endometrial Hyperplasia / Pyometra

Development Pyometra is a relatively common disorder of older intact female dogs. True incidence is not known because most bitches in the United States are spayed when they are young. Pyometra is a two-step process with initial cystic endometrial hyperplasia (CEH) followed by infection. As the name implies, CEH is a cystic thickening of the endometrium, or uterine lining (). CEH can be created experimentally by exposing uterine tissue either to estrogen or to progesterone. Cystic endometrial hyperplasia develops to a greater extent and more quickly if the uterus is first exposed to estrogen and then is exposed to progesterone. This is the normal hormonal sequence of the estrous cycle in dogs. CEH develops over time after repeated estrous cycles in the dog. There are four grades of cystic endometrial hyperplasia described by Dow: worsening in severity from type I (mild changes) to type IV (severe changes with associated inflammation and tissue destruction). As might be expected because this is a progressive disorder, mean age at diagnosis of dogs with type I CEH is younger than is mean age of dogs diagnosed with type IV CEH. By the age of 9 years, two thirds of intact bitches had some degree of cystic endometrial Read more […]

Tremor and involuntary movements

Involuntary movement disorders result in some of the most dramatic clinical presentations in veterinary medicine. Classically, these disorders are present during periods of inactivity rather than during voluntary movement. Cerebellar disease, conversely, can result in apparent involuntary abnormalities during movement. Some involuntary movements are persistent while others are episodic. Certain involuntary movements have characteristics that allow for identification of specific causes, whereas others are only a reflection of dysfunction of the nervous or musculoskeletal systems. Clinically, it is important to first identify the type of involuntary movement present. Subsequently, a more directed approach can be used to establish the cause of the movement disorder. Clinical signs Involuntary movement disorders are less well classified in animals than in humans. Terms such as tics, twitches, shivering, shuddering and fasciculation are often used to describe episodic, irregular muscle contractions. They are usually manifested through abnormal motion of the limbs, trunk or head. There are seven forms of involuntary movement. Myoclonus Myoclonus is a shock-like contraction of a muscle or muscles that tends to occur repeatedly Read more […]

Generalized Tremor Syndromes

Generalized tremors are surprisingly common in dogs (). This type of tremor can occur secondary to intoxications, drug therapies, congenital myelin abnormalities, storage diseases, encephalitis, or may arise without a definable cause. Degenerative diseases Lysosomal storage diseases Lysosomal storage diseases of the nervous system may have tremor as a presenting abnormality. Examples include globoid cell leucodystrophy, mannosidosis and gangliosidosis. The numerous storage diseases and their associated characteristic clinical signs have been described elsewhere (). Clinical signs: These diseases are often breed-related () with clinical signs first appearing in animals <1 year of age, but they can occur at any age. Many of these diseases involve the cerebellum and are associated with intention tremors. Pathogenesis: Accumulation of metabolic byproducts within neurons or the surrounding neuropil usually results from an inherited deficiency of a specific catabolic enzyme. The accumulation causes dysfunction of the cells and regions of the nervous system affected. Diagnosis: Ante-mortem testing for many of these diseases often results in negative or normal findings. CSF analysis is often normal, although Read more […]

Intention tremors due to cerebellar disorders

Tremors that occur when an animal intends to move in a goal-orientated activity are most often the result of cerebellar disease (). Degenerative diseases Cerebellar cortical degeneration Cerebellar cortical degeneration, also termed cerebellar abiotrophy, is usually an inherited disease in dogs () with few reports in cats. Primary cerebellar cortical degeneration refers to degeneration and loss of Purkinje cells, molecular cells and granule cells. Clinical signs: These diseases are recognized syndromes in American Staffordshire Terriers, American Pit Bull Terriers, Kerry Blue Terriers, Gordon Setters, Rough-coated Collies, Border Collies, Brittany Spaniels, Bullmastiffs, Old English Sheepdogs and occur rarely in Samoyeds, Airedales, Finnish Harriers, Labrador Retrievers, Golden Retrievers, Beagles, Cocker Spaniels, Cairn Terriers, Great Danes, Scottish Terriers and others (). Clinical signs usually begin between 3 and 12 months of age. However, a subset of adult onset diseases occur with signs starting from 2-8 years of age in the Brittany Spaniel (), Gordon Setter (), Old English Sheepdog (), American Staffordshire Terrier () and Scottish Terrier (). Other signs of cerebellar disease that accompany cerebellar Read more […]

Aggressive Behavior

Characteristics of Dogs That Bite: Age and Sex The etiology of aggressive behavior presents considerable variation from dog to dog. Aggressive behavior is most frequently exhibited by socially mature and intact male dogs (), but young puppies can have serious precocious aggression problems, as well. Mugford (1984) reported that among 50 English cocker spaniels the mean average age of dogs with dominance-related aggression was 7.4 months (range, 3 to 24 months). In another group of golden retrievers treated by Mugford (1987), 24 with aggression problems averaged 2.9 years of age (range, 0.7 to 8.0 years). Of the 24 dogs treated by Mugford, 19 were males, two of which had been castrated. Beaver (1983) found that of 120 dogs with aggression problems (various diagnoses) the mean age was 3 years (range, 9 weeks to 11 years). She reported that 60.1% of the dogs were intact males (14% castrated), with 15.4% intact females (10.5% spayed). Wright (1985) found that the average age of dogs involved in severe attacks was 3 years (range, 0.67 to 10.5 years). All 16 dogs were males. These statistics suggest that considerable variation exists with respect to the time of onset associated with aggression problems. Although most dogs Read more […]

The faults and defects of the breeds: Non-Sporting Dogs

American Eskimo Dogs Hip dysplasia Bichons Frises Patella luxation Boston Terriers Neoplasias; Patella luxation, either medial or lateral; Swimmers syndrome, the inability to stand at four to six weeks; Vertebral abnormalities Bulldogs Spina bifida, caused by ununited neural arches; Neoplausa; Swimmers syndrome, the inability to stand at four to six weeks; Hip dysplasia; Elbow dysplasia; Flaccid shoulder joints; Thyroid disorders; Vertebral abnormalites Chinese Shar-Peis Patella luxation; Hip dysplasia; Elbow dysplasia; Swollen hock syndrome Chow Chows Hip dysplasia; Elbow dysplasia Dalmatians Muscular dystrophy Finnish Spitz Patella luxation French Bulldogs Hemivertebrae, which is the asymmetric abnormal development of vertebrae, resulting in scoliosis and crowding of one half of the body, producing a wedge-shape. It often results in neonatal death or spinal cord compression in older puppies. Keeshonds Thyroid and other endocrine disorders, primary hyperparathyroidism in older dogs; Patella luxation; Hip dysplasia; Neoplasias Lhasa Apsos Patella luxation, either medial or lateral; Hip dysplasia Poodles (Miniature) Dwarfism; Hypoplasia of dens; Atypical pannus; Patella luxation; Shoulder luxation; Read more […]