Tag Archives: Dalmatian

Hypersensitivity Skin Disorders

Clinical hypersensitivity disorders have been classified by Gel and Coombes. The following description is simplified since in many instances complex interactions occur simultaneously. Type 1 (immediate, anaphylactic) genetically susceptible individuals inhale (absorb percutaneously?) allergens such as pollen and house dust, and produce immunoglobulin E (IgE), which fixes to tissue mast cells and blood basophils the allergen subsequently comes into contact with its specific IgE, leading to the release of vasoactive amines, which cause tissue damage examples are urticaria, angio-oedema, atopy, drug eruption and flea-bite hypersensitivity Type 2 (cytotoxic) IgG or IgM with or without complement binds to complete antigens on body tissues the antigen—antibody reaction causes cell lysis examples are pemphigus, pemphigoid, cold agglutinin disease and dnig eruption Type 3 (immune complex) circulating antigen-antibody complexes fix complement and are deposited in blood vessel walls these complexes attract neutrophils; proteolytic and hydrolytic enzymes released from the neutrophils produce tissue damage examples are systemic lupus erythematosus and bacterial hypersensitivity Type 4 (delayed) incomplete Read more […]

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 […]

Congenital Deafness

Deafness that is present at or soon after birth may have either an acquired or a hereditary etiology and may occasionally occur in any puppy whether pure bred or mixed breed. Acquired deafness may be caused by viral infections, anoxia, or the ototoxic side effects of drugs or other materials. Because dogs and cats are born deaf, deafness in a puppy or kitten is not abnormal up to a certain age. In cats the earliest discriminating hearing tests were performed at the age of 7 days. Cochlear potential measurements from a round-window electrode were found to be conclusive about the presence or absence of hearing in cats over 7 days of age (). In dogs, hearing tests were performed from the age of 4 weeks () by means of cochlear potential measurements from round-window electrodes () or brainstem auditory evoked responses (BAERs) (). Testing the Hearing of Young Puppies In our laboratory, two Irish wolfhound puppies and two beagle puppies were investigated for hearing from the third day after birth. Brain-stem auditory evoked potentials (BAERs) were recorded from surface electrodes (Dantec) on the pinnae and the skin over the parietal bone on the midline. For the recording of air-conducted BAERs, each pup was placed in a Read more […]

The Cornea

Congenital Abnormalities Comeal Opacities. The cornea of the newborn puppy or kitten is a light blue color; or at least the cornea is less clear than that of the adult. In 2 to 4 weeks, corneal clearing is sufficient to permit ophthalmoscopic examination. It is not unusual to observe multifocal or diffuse faint white opacities in the corneas of young puppies and kittens. The opacities represent superficial foci of edema, and most are self-limiting. The cause of these opacities is unknown. Therapy is not necessary unless the opacities are accompanied by a mucopurulent discharge, in which case topical ophthalmic antimicrobial preparations may be applied. Animals born with their eyelids open often have diffuse corneal edema that clears in 14 to 18 days. Because reflex lacrimation is absent at birth, the exposed cornea is subject to desiccation and infection and can be avoided by frequent application of a broad-spectrum antimicrobial ointment every 3 or 4 hours until the animal is 10 to 12 days old. Cats with lysosomal storage diseases may develop corneal opacities related to the accumulation of polysaccharides within the endothelial cells and fibroblasts of the cornea. Fine granular deposits in the corneal stroma may Read more […]

The Anterior Uvea

The irides of the puppy and kitten are often a different color than those of the adult. The blue-gray iris of puppies and kittens usually changes to the adult coloration within a few weeks. Iris color is ultimately related to the degree of stromal pigmentation and is influenced by coat color. Congenital Abnormalities Persistent Pupillary Membranes. Persistent pupillary membranes are strands of tissue that arise from the anterior iris surface and represent remnants of an embryonic vascular system. The persistent pupillary membranes may be confined to the iris surface or may extend from the iris to the cornea or lens (). Persistent pupillary membranes are inherited in the basenji. Iris Cysts. Iris cysts are floating, fluid-filled vesicles that arise from the posterior iris epithelium and are usually found in the anterior chamber. Iris cysts may be unilateral or bilateral and singular or multiple in number. Pupillary Abnormalities. A notch-like defect (coloboma) is occasionally seen in the ventronasal pupillary border of young dogs and cats, resulting in a keyhole-shaped pupil. An eccentric pupil (corectopia) may accompany multiple ocular defects, as occurs in the Australian shepherd. Eccentric pupils are usually 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 […]

The Upper Airway: Nasal Cavity, Paranasal Sinus, Nasopharyngeal, Pharyngeal, and Laryngeal Diseases

Sneezing and nasal discharge are the most common clinical signs of nasal cavity disease. Owners of puppies or kittens that are quickly cleaned by their mother or that are fastidious about licking any appearing discharge may overlook a nasal discharge. Viral disease or environmental irritants usually cause a serous or mucoid discharge; bacterial disease causes a purulent or mucopurulent discharge. Sneezing is usually prominent in acute disease but wanes with chronicity. Acute viral diseases sometimes cause enough destruction of the nasal epithelium to obliterate the sneeze reflex, despite the presence of nasal discharge and other upper respiratory signs. Less common signs of nasal disease include stertorous breathing, pawing or rubbing at the nose or mouth, facial pain, facial deformity, ocular discharge, exophthalmos, or fetid breath. Because clinical signs related to the nose and sinuses can be manifestations of oral, pharyngeal, airway, and pulmonary disease, these areas should be carefully inspected. Evaluation of the nasal cavity should include oral and dental examination, radiographs of the nasal cavity, rhinoscopy, and visual examination of the nasopharynx and internal nares (). Pharyngeal and laryngeal disease 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 […]

Membranous Labyrinth

The ectodermally derived membranous labyrinth consists of four fluid-filled compartments, all of which communicate. These compartments are contained within the components of the bony labyrinth and include the saccule and utriculus within the bony vestibule connected by the utriculosaccular duct, the three semicircular ducts within the bony semicircular canals that connect to the utriculus and a cochlear duct within the bony cochlea that is connected to the saccule by the ductus reuniens. The endolymphatic duct is an extension from the utriculosaccular duct through the bony vestibular aqueduct to the intracranial dura where the duct expands into a endolymphatic sac. The endolymph contained within the membranous labyrinth is thought to be derived from the blood vessels and epithelium of the stria vascularis along the peripheral wall of the cochlear duct and is absorbed back into the blood through the blood vessels surrounding the endolymphatic sac. The three semicircular ducts are the anterior (vertical), posterior (vertical), and lateral (horizontal). Each semicircular duct is oriented at right angles to the others. Thus rotation of the head around any plane causes endolymph to flow within one or more of the ducts. Each Read more […]

Paraparesis: Anomalous diseases

Dermoid sinus Clinical signs: Dermoid sinuses more often occur in the cervical region but can involve the thoracolumbar region (). Neurological examination is normal in the non-communicating form but neurological signs may occur if the sinus communicates with the dura or becomes infected (). Neurological signs reflect the neuroanatomical localization of the sinus. Close inspection of the hair on the midline may reveal abnormal placement. Pathogenesis: Dermoid sinus is an inherited neural tube defect in the Rhodesian Ridgeback () but has also been reported in other breeds (). The defect results from incomplete separation of the skin and neural tube during embryonic development (). The sinus often extends from the skin to the supraspinous ligament as a closed sac filled with keratin debris. Communication with the subarachnoid space can predispose to meningomyelitis. Diagnosis: Diagnosis is based on physical examination; radiography can be used to evaluate the extent of the sinus. Contrast radiography, using a non-ionic contrast medium (e.g. iohexol), determines whether the tract is closed and non-communicating or open and communicating with the spinal canal. Myelography determines the amount of spinal cord displacement. Read more […]