Tag Archives: Labrador Retrievers

Congenital and Hereditary Anomalies of the Ureters

Ureteral Agenesis Ureteral agenesis is the congenital absence of one or both ureters due to incomplete ureteral bud formation. Unilateral ureteral agenesis is the most common form observed in dogs and cats and is usually accompanied by ipsilateral renal aplasia (). Ureteral Duplication Ureteral duplication is a congenital disorder involving complete or partial duplication of one ureter. This disorder has been associated with a duplexed kidney and a supernumerary kidney in dogs; ureteral duplication has not been observed in cats (). Ureteral Valves Congenital ureteral valves are persistent transverse folds of vestigial mucosa and smooth muscle fibers forming annular, semiannular, or diaphragmatic lesions in the ureter (). Semiannular ureteral valves have been described in a 6-month-old female collie with unilateral ureterectasis, hydronephrosis, and urinary incontinence (). The etiopathogenesis of urinary incontinence associated with ureteral valves in this case is uncertain. Ectopic Ureters Ureteral ectopia is a congenital anomaly in which one or both ureters terminate abnormally in the urinary bladder. Intramural ectopic ureters contact and enter the bladder wall normally but continue submucosally through the Read more […]

The Eye

The Ophthalmic Examination History A complete ophthalmic history is an essential part of every puppy’s or kitten’s examination. Owners may be asked questions regarding the animal’s signalment, history of the presenting complaint(s), and any pertinent medical or ophthalmic diseases in the animal’s family histories. Other historical information that may be included is the animal’s vaccination status, diet, environment, and exposure to other animals. Previous therapy should be identified to prevent repetition of an unsuccessful regimen. Procedure Ophthalmic examination should be performed in a quiet area. Puppies usually require only gentle but firm restraint of the head. Very young puppies cooperate nicely when held in an assistant’s arms. Kittens can also be gently restrained and are less likely to demonstrate the constant ocular motion typical of puppies. Uncooperative puppies or kittens may be placed in a towel or restraint bag. Assessment of ocular abnormalities such as orbital swelling, squinting, or ocular discharge can be done in a well-lighted room, but actual ophthalmoscopic examination should be done with the lights dimmed. A bright source of focal illumination is required; the Finoff transilluminator on Read more […]

The Globe And Orbit

Congenital Abnormalities Microphthalmos. Failure of the eye to develop to normal size is referred to as microphthalmos. Complete absence of the eye (anophthalmos) is extremely unusual in puppies and kittens. Microphthalmos is characterized by varying degrees of enophthalmos, with or without other ocular defects. Microphthalmos with multiple colobomas is an autosomal recessive trait linked to coat color in the Australian shepherd. In addition to small globes, affected dogs may have persistent pupillary membranes, cataract, equatorial staphylomas, choroidal hypoplasia, retinal dysplasia and detachment, and optic nerve hypoplasia. Vision is frequently impaired. Other breeds in which multiple ocular defects have been associated with coat color include the Great Dane, collie, Shetland sheepdog, and dachshund. Microphthalmos is also associated with inherited congenital cataracts in the miniature schnauzer, Old English sheepdog, Akita, and King Charles Cavalier spaniel. Microphthalmos occurs with retinal dysplasia in Bedlington terriers, Sealyham terriers, beagles, Labrador retrievers, and Doberman pinschers. Administration of griseofulvin to pregnant cats may produce microphthalmos in their offspring. Atypical Eye Position. 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 Retina and Optic Nerve

Tapetal coloration of the fundus of the puppy and kitten is usually gray or blue at 6 to 8 weeks of age, gradually acquiring its adult coloration by 4 to 7 months of age when the tapetum matures. Myelination of the optic disc may also be incomplete in the puppy and kitten, giving the impression of a small, well-defined nerve head that takes on a more fluffy appearance as adult myelination occurs.Both congenital and acquired disorders of the retina and optic nerve are recognized in the young dog and cat. These may be inherited, as with collie eye anomaly, or secondary to postnatal influences, as occurs with canine distemper-induced retinitis. Congenital abnormalities can be diagnosed as early as 6 weeks of age, when the posterior segment is clearly observed. The more common congenital abnormalities of the canine fundus are summarized in Table Congenital Abnormalities of the Canine Fundus. Acquired abnormalities develop with advancing age and in this discussion are limited to those in dogs and cats younger than 6 months of age. Table Congenital Abnormalities of the Canine Fundus (diagnosed as early as 6-8 wk of age). DISORDER BREED CHARACTERISTIC FEATURES Collie eye anomaly Collie, Shetland sheepdog, Read more […]

Age-related tissue changes that may affect anaesthesia or surgery

Age-related changes that may affect anaesthesia or surgery include: Nervous System Cardiovascular system Respiratory system Renal Liver Endocrine Obesity Nervous system Central nervous system Reduced functional tissue in the CNS is probably one of the factors that reduces the anaesthetic dose needed in older patients. Old patients often have sluggish, impaired or absent reflex responses (e.g. pupillary light reflex) which may complicate monitoring during anaesthesia. Loss of function of the special senses such as sight and hearing may lead to apprehension in strange environments (especially in cats), and sometimes sedation is needed to reduce preoperative stress which otherwise can significantly increase sympathetic simulation. Geriatric animals have reduced ability to generate body temperature and are susceptible to develop hypothermia, particularly during prolonged surgery or the postoperative recovery period. In this context it is important to remember that core body temperature may differ from peripheral measurements, and the use of oesophageal thermometers or infra-red thermometers (applied in the aural canal) may be preferable to rectal temperature recording. Peripheral nervous Read more […]

Viral infections

Canine and feline viral enteritis are usually diagnosed in younger unvaccinated animals. The animal’s age, history, clinical signs and haematological findings are important in ranking a viral aetiology as a likely cause of the animal’s diarrhoea. Canine parvovirus Dogs are susceptible to infection by two types of parvovirus. Canine parvovirus-1 (CPV-1) is a relatively non-pathogenic virus that is occasionally associated with myocarditis, pneumonitis and gastroenteritis in very young puppies. Canine parvovirus-2 (CPV-2) causes classic parvovirus enteritis 5-12 days after infection via the faecal-oral route. CPV-2b is a more recently recognized mutated form of CPV-2, which may be more pathogenic in some dogs. Dobermanns, Rottweilers, Pit Bull Terriers and Labrador Retrievers appear more susceptible than other breeds. The virus replicates in the intestinal crypts and causes severe villous blunting, diarrhoea, vomiting and subsequent bacterial translocation. Presenting complaints can vary from lethargy and anorexia, to vomiting with or without blood. Diarrhoea can” be absent In the early stages of infection and usually occurs 24-48 hours after onset of vomiting. The diarrhoea can often be profuse and haemorrhagic. Read more […]

Pregnancy

Physiology and Endocrinology The eggs released by the bitch are fertilized in the uterine tubes and move into the uterus 8 to 9 days after ovulation. The conceptus implants and the placenta begin to be formed 16 to 18 days after ovulation. High concentrations of progesterone must be present throughout pregnancy. Progesterone during pregnancy decreases uterine contractility; stimulates secretions of the endometrial glands, which presumably provide nutrients to maintain the conceptus before implantation; and stimulates mammary development. Prolactin concentrations begin to rise at midgestation. Concentration of relaxin, released from the placenta, also rises beginning at midgestation (). The body of the bitch responds to the presence of the enlarged uterus and developing fetuses with processes designed to maintain function in the bitch while promoting development and growth of the puppies. Physiologic changes in the bitch that occur during normal pregnancy include the following: • Increased heart rate • Increased packed cell volume (% of the blood made up of red blood cells) • Increased oxygen consumption • Slower gastric emptying time • Increased blood flow to the kidney Superfecundation 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 […]