Category Archives: Veterinary Pediatrics

The Lymphoid System

The Lymph Nodes In dogs, the primordial structure of the largest lymph nodes is present at 35 to 38 days of gestation, and lymphocytic colonization of the nodes is prominent at 52 to 53 days of gestation (). At birth, puppies and kittens have readily recognizable lymph nodes with a loose reticular structure, low lymphocyte density, and limited organization into cortex and medulla that rapidly proliferates into cortical nodules and medullary cords. Lymph nodes and lymphatic vessels vary in location and number, but their primary function is to participate in immunologic reactions by filtering lymph and recirculating the lymphocytes (). Antigens that gain access to particular body tissues are ultimately found in lymphatic vessels that drain these tissues, making it logical that elements of the immune system are strategically positioned along lymphatic vessels. Although lymph node architecture is relatively uniform throughout the body, nodes near portals of entry of external antigens (mandibular and mesenteric lymph node areas) are often more reactive than nodes in other locations. Lymph Node Disorders As a major site of immunologic recognition, lymph nodes are expected to respond to various local and systemic inflammatory, Read more […]

Dental Disease and Care

An oral examination should be performed each time a puppy or kitten is presented. Many pathologic or potentially pathologic conditions can be detected at an early age and corrective measures taken. Introducing the pet owner to the concept of oral home care and regular professional dental prophylaxis are the two most important responsibilities of the veterinarian with regard to dental disease care and prevention. Tooth Morphology There are three types of teeth in the deciduous dentition of puppies and kittens: incisor (I), canine (C), and premolar (P); a fourth type, molar (M), is found in the permanent dentition. Each type is designed to be self-cleaning in the non-crowded scissors occlusion, when the animal eats a natural diet, that is, catches its prey. Each tooth type serves a specific function. Incisor teeth are for grooming and nibbling, canine teeth are for grasping and tearing, premolars are for shearing, and molars are for grinding. The cat, a true carnivore, has no occlusal surface on the mandibular molar. The maxillary molar is small and vestigial in the cat (). Each tooth is covered with enamel, the hardest body substance. The bulk of the tooth is dentin, a living tissue that continues to be deposited Read more […]

The Pancreas

Inflammatory Pancreatic Disease The pancreas is a unique organ possessing both exocrine (digestive) and endocrine (hormonal) functions. Inflammatory pancreatic disease affecting only the exocrine portion is extremely uncommon in young dogs and cats (). Consequently, inflammatory pancreatic disease, that is, acute pancreatitis or relapsing pancreatitis that more commonly affects older dogs and cats, has been rarely identified in dogs and cats younger than 6 months of age. The likely causes of inflammatory pancreatic disease in the young dog and cat are abdominal trauma and infectious agents. Abdominal trauma may induce pancreatitis in dogs that are traumatized by motor vehicles and in cats that have fallen or jumped from high places (high-rise syndrome) (). In addition, abdominal surgery may result in acute pancreatitis due to traumatic injury to the pancreas (spearing the pancreas with a surgical instrument) or excessive manipulation of die pancreas. Infectious agents can occasionally contribute to inflammatory pancreatic disease. Pancreatic necrosis can be found on postmortem examination of an occasional dog afflicted with canine parvovirus infection (). It is not known whether the canine parvovirus is directly Read more […]

The Urinary System

Urinary tract disorders of puppies and kittens may result from heritable (genetic) or acquired disease processes affecting differentiation and growth of the developing urinary tract or from similar processes that eventually affect the structure or function of the mature urinary system. Successful management of urinary tract disorders depends on familiarity with the structure and functions of the kidneys, ureters, urinary bladder, and urethra. Developmental Physiology Although the embryonic kidneys produce urine, maintenance of fetal homeostasis is primarily the responsibility of the placenta. Varying quantities of urine formed by the fetal kidneys pass from the developing urinary bladder through the urachus to the placenta, where unwanted waste products are absorbed by the maternal circulation and subsequently excreted in the mother’s urine (). Fetal urine also passes through the urethra into the amniotic cavity, where urine forms a major constituent of amniotic fluid. The latter part of gestation is characterized by rapid increases in nephron number and size and by maturation of glomerular and renal tubular functions (). Prenatal development of glomerular filtration and renal blood flow appears to parallel increases 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 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 […]

Acquired Disorders of the Urinary Tract

Renal Dysfunction In our experience, acquired disorders are the most common cause of renal dysfunction in puppies and kittens. Causes of acquired renal dysfunction in immature animals are similar to those encountered in adults and may include infectious, inflammatory, toxic, ischemic, or neoplastic disease processes. GLOMERULOPATHIES Like their familial and congenital counterparts, acquired glomerulopathies are characterized by morphologic and/or functional alteration of glomeruli that, if progressive, may induce subsequent changes in renal tubules, interstitium, and blood vessels resulting in chronic generalized renal dysfunction (). Acquired glomerulopathies usually develop secondary to systemic disorders in which the underlying disease processes damage not only the glomeruli but other major organs as well. Acquired glomerulopathies are infrequently encountered in young dogs and cats (). Diagnosis is based on clinical and laboratory evaluations similar to those described for familial glomerulopathies. Unlike familial disease, however, glomerulopathies acquired secondary to systemic disorders are potentially reversible. Identification and elimination of the primary disease process may halt progression of glomerular Read more […]

The Ear

Ear diseases occur at all ages in dogs and cats. The diseases seen in young dogs and cats include congenital deafness, congenital deformations of the external ear, and acute bacterial, viral, and parasitic infections. Because congenital deafness, in particular bilateral deafness, is a severe handicap to the puppy or kitten and has serious consequences for die owner who was looking forward to training the young dog, early testing of hearing in young puppies is accentuated in this post. Management of Ear Disease As for all other diseases, management of ear disease starts with the taking of the history. For young dogs and cats the history of ear disease might well be short and plainly indicative of an acute problem with a circumscribed localization. Some exceptions are generalized juvenile pyoderma, demodicosis, and, in the cat, viral infections, for in these conditions the disease of the ear may be just a part of the clinical signs. Another aspect of the history in young dogs and cats is the relation between the onset of the disease and the change of environment, separation from litter mates, and starting of solitary life under new and different circumstances. Deafness is often only recognized when the puppy or kitten Read more […]

Ear Diseases in Young Dogs and Cats

Diseases of the Pinna Congenital Deformation of the Pinna. Congenital deformation of the pinna is rare in dogs and cats, and when it occurs correction is not always needed, although faulty ear carriage may be seen as a loss of value of the dog. Veterinarians in the Netherlands do not encourage surgical intervention when the pinnae are in principle healthy, and cropping of the pinnae without medical indication is prohibited. Further information may be found elsewhere (). Inflammation. Lesions of the pinna may be part of more generalized skin disease (). They can be bacterial, fungal, parasitic, immune mediated, or vascular (drug mediated) in origin (). These disorders are not age dependent, and hence young dogs and cats are not excluded. Bacterial folliculitis of the pinna with focal areas of alopecia has been described in dogs, and dermatophytosis of the pinna with focal alopecia and extensive crusts can be found in cats (). Nonpruritic areas of alopecia in dogs should be scraped for demodectic mites. Pruritus and crusting of the pinna can be caused by Sarcoptes mites in dogs and Notoedres mites in cats (). Trauma. Trauma of the pinna can occur at any age. A tear in the pinna is usually the result of a fight 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 […]