Iams Pediatric Care Symposium

Transcription

1 Puppy and Kitten Health Iams Pediatric Care Symposium Presented at The North American Veterinary Conference January 11, 2005 Orlando, Florida, USA

2 Reprinted in the IVIS Website with the permission of IAMS Close widow to return to IVIS Unique Challenges to Managing the Neonate and Kitten Margie Scherk, DVM, Diplomate ABVP (feline) Cats Only Veterinary Clinic Vancouver, British Columbia, Canada INTRODUCTION This paper will discuss the development of the young kitten and the problems that may be encountered that are of special importance during the first 8 weeks of life. Key points for both the veterinarian and client/breeder include the following: Daily weight measurements provide an excellent monitor of neonatal health Warm environmental temperatures are essential for neonatal kittens Failure to receive colostral antibodies may be corrected by subcutaneous or intraperitoneal administration of adult serum Kittens born to queens with type B blood must not be allowed to receive their queen s colostrum in order to prevent neonatal isoerythrolysis Critical problems of the sick neonate include hypoxia, hypothermia, hypoglycemia, sepsis, dehydration, and diarrhea Adjust antimicrobial therapy doses for the very young; reduce doses by 30 50% or lengthen dosing intervals THE FIRST 24 HOURS As soon as a kitten is born, it is groomed by the queen. She removes the birth membranes and severs the umbilical cord; she then positions herself to make her nipples accessible to the newborn. Already, the precarious risks of life have begun. Getting cold, staying wet and being exposed to the pathogens on the dam s nipples could be life-threatening. For such small creatures, thermoregulation is critical. At birth, their normal body temperature is F ( C). Kittens are unable to shiver until they are about one week old, so it is extremely important to maintain an environmental temperature directly around the kittens of 90 F (32 C) for the first week. If a kitten loses contact with the queen, he/she will crawl around in wide circles and emit distress calls. Using smell and hearing, he will attempt to locate her, as death from exposure and hypothermia is a serious risk. Grooming is critical in the development of the maternal kitten bond. Anogenital stimulation is also required to induce urination and defecation. The queen nuzzles the kittens toward her body for warmth and to her nipples for nourishment. Maternal bonding also involves nursing, purring, and responding to their calls. Nursing provides complete nutrition for the first 4 weeks of life. On average, kittens nurse for 6 to 8 hours in a 24-hour period for the first week. A common developmental abnormality, split hard palate, may make itself evident in day old neonates. Affected kittens, unable to create the necessary vacuum for suckling, will have milk dribbling from their nares and be unsuccessful at nursing: they will fail to gain weight and will cry. Nursing provides essential nutrients as well as colostral and milk immunoglobulins. Colostral immunoglobulins (IgG, IgA, and IgM) are found in equal amounts in milk as in colostrum; however, these cannot be absorbed systemically after 16 hours of life. However, milk immunoglobulins are vital in providing local, intestinal protection for several weeks. 11 Iams Pediatric Care Symposium TNAVC 2005

3 important that the serum is nonhemolyzed. Collect blood into sterile clotting tubes (without additives), clot for 20 minutes at room temperature and then harvest the serum, being careful to avoid red blood cells. Each donor cat can provide maximally 60 ml whole blood or 30 ml of serum; thus each donor cat can provide serum for two kittens. 3 Studies looking at the availability of equine IgG have been disappointing. 4 The serum may be administered immediately or stored refrigerated for a few days. Should extra serum be available, it may be frozen as IgG is stable for up to one year. Administration to tiny neonatal kittens should be divided into 2 3 doses so that the 15 ml is given SC or IP every 12 hours over a 36 hour period. Oral absorption of immunoglobulins is limited after hours. 3 If a queen is not producing adequate milk for any reason, including dystocia or cesarean-section, metoclopramide (0.2 to 0.4 mg/kg PO q 8 hours) may be used to stimulate prolactin release, thereby increasing milk production. For the short term, the kittens may need to be supplemented with milk replacer as well as nursing. Two conditions are important relative to colostral availability and absorption. These are failure of passive transfer (FTP) of maternal antibodies and neonatal isoerythrolysis (NI). Failure of Passive Transfer of Maternal Antibodies (FTP) Kittens are born without detectable levels of serum IgG. 1 Maternal antibodies provide essential immunity against many infectious agents to which kittens are commonly exposed and 95% of antibodies are acquired by the kittens from colostrum. For example, within 24 hours, a kitten s titer against feline panleukopenia virus reaches 72% of the queen s serum titer. 2 Inadequate maternal antibody protection may occur as a result of the inability to nurse, orphaning, low immunoglobulin levels in the queen, and/or poor colostrum quality or quantity. 3 Failure of passive transfer should be presumed if kittens have been orphaned or have not nursed within the first 16 hours. While immunodiffusion tests may be performed to determine the concentration of IgG, the test turnaround time is too long for a fragile neonate. Neonatal kittens may develop sepsis and die within hours of showing clinical signs. FTP may be treated by administering feline serum intraperitoneally (IP) or subcutaneously (SC) and will effectively correct IgG deficiency in kittens less than 24 hours of age. Serum donors should be healthy, vaccinated, retrovirus negative adults. Use blood type A cats to avoid fatal mismatches. Sterile collection of 30 ml of whole blood provides the therapeutic dose of 15 ml of serum. It is very Neonatal Isoerythrolysis (NI) Cats have three blood types. The most frequent type is A, B is uncommon, and AB is rare. Cats with type B blood have vigorous anti-a antibodies. Because kittens are not exposed to their mother s alloantibodies in utero, they are born healthy and usually start off nursing well. In a situation in which type A kittens are born to a type B mother, the kittens will develop hemolytic anemia within hours or days after absorbing colostral anti-a antibodies. They stop nursing, pass dark red-brown urine (hemoglobinuria), become anemic, icteric, and depressed. If they live beyond three days, they may develop necrosis of the tail-tip, however, the majority of kittens with NI fail to thrive and subsequently die. If it is known or suspected that one is dealing with a type B queen, the kittens should be removed from the dam for the first 72 hours to prevent them from exposure to anti- A antibodies. They may be nursed by a surrogate type A queen or fed with milk replacer. After this time, they may be put back on their dam. Failure of passive transfer should be taken into consideration and SC or IP serum from an adult type A donor should be given as discussed in the preceding section. 5 Ideally, the blood type of the queen and the kittens should be known. Kittens may be typed using blood from the umbilical cord; alternately, this blood can be crossmatched against the dam s serum. Kittens with type B blood can be returned to nurse from their type B mother immediately. Prevention of NI is the goal, as even with early diagnosis and supportive care (blood transfusions, etc), the prognosis is guarded. In the United States, the highest frequency of type B cats was reported in the Devon Rex, British Shorthair, Cornish Rex, Scottish Fold, Sphinx, Somali, Birman, Japanese Bobtail, and Persians. However, there are marked differences in the blood type distributions in various regions of the world and even within some countries. 6 Thus, because we cannot assume that queens are type A, blood typing cats who are to be used for breeding will help prevent this problem. Iams Pediatric Care Symposium TNAVC

4 NOTES THE FIRST WEEK If a queen is healthy and adequately nourished, the nutritional needs of the kittens should be completely met for the first three to four weeks of life. Kittens need kcal/100 gram body weight/day for the first three months of life. Provided they receive these calories, they should gain 10 15g/day. The exception to this is the normal loss of weight that occurs within the first 24 hours after birth; this should not exceed 10% of birth weight. Daily body weight measurement is a simple way to monitor basic health in neonatal kittens. Along with failure to gain weight at a normal rate, other simple signs that should be a cause for concern are inactivity and incessant crying. Kittens will normally sleep 90% of the time. Hypothermia along with hypoglycemia should be ruled out before looking for more complicated diagnoses. As kittens explore around their nest over the first days and weeks of life, they respond to odors, temperature, and pain. They call for their dam not only at frequencies audible to the human ear, but also at an ultrasonic range, which the queen responds to in kind, as well as by rescuing the kitten. THE FIRST EIGHT WEEKS Kittens are introduced to solid food by the queen from about 4 weeks of age onward. She does this by bringing them killed prey initially and then live prey as they get older as a means of teaching them how to hunt and kill. At this age their digestive tracts are ready for solid food, so gradual introduction of a softened kitten food, mixed with kitten milk replacer or water into a thick gruel consistency is warranted after 4 weeks. By 8 weeks of age and g in weight, most kittens will be completely weaned from the queen s milk. Body temperature in a 4-week-old kitten is 100 F (37.8 C) and the environment directly around them should be maintained at F ( C). Normal behavior evolves and develops during the first weeks of age through play with littermates, interactions with the dam and other adult cats and interactions with humans. 13 Iams Pediatric Care Symposium TNAVC 2005

5 Congenital Problems Many congenital problems have been reported in the cat. A comprehensive discussion of this topic exceeds the scope of this article and the author respectfully refers the interested reader to Hoskins 1995 article 7 or Murtaugh s chapter, 8 both of which provide an extensive list. Normal Development 9 In cats, like other vertebrates, the tactile system is the first sensory system to develop during gestation. The vestibular righting reflex develops by about day 54 of gestation. After birth, the sensory world of the kitten is dominated by thermal, tactile, and olfactory stimuli. Olfaction is essential in directing the newborn toward milk and mother; this system is fully mature by about three weeks of age. Auditory and visual systems develop later. The ears are small and flat at birth; responses to sound are noted by 5 days of age with orientation to sounds occurring by about 2 weeks of age. Hearing is well developed by one month of age. Kittens eyes open between 7 10 days of age, although there are individual variations to either extreme. The eyes open independent of each other over a period of a few days. Guided behavior develops over the next few weeks so that by 3 to 4 weeks, a kitten is able to use visual cues to locate and navigate towards his/her mother. The palpebral reflex is present before the eyes are CARE OF THE ORPHAN KITTEN Care of orphaned kittens is time-consuming, but rewarding! Correct failure of passive transfer (FTP) if suspected Feed 4 6 times per day Insure adequate environmental warmth Maintain a sanitary environment Stimulate urination and defecation by anogenital stimulation with warm wet cotton ball or cloth after each feeding for the first days of life Weigh each kitten once a day on a kitchen or postage scale Milk replacer requires 7.5% protein and 4.5% fat, which is considerably higher than cow s milk. Commercial kitten milk replacer is better than homemade formula. Formula should be warmed before feeding and refrigerated between feedings. The caloric requirement of a newborn is 420 kcal/kg initially, declining gradually to 275 kcal/kg by 5 6 weeks of age. Diarrhea may be a result of overfeeding completely open. The corneal reflex is noted as soon as the eyes are open. The body-righting reaction is present at birth and continues to mature for 4 weeks. The air-righting reaction does not begin to develop until after 4 weeks of age. Nonvisual placing response occurs first in the forelimbs (by about 5 days of age); hindlimb proprioception and placing develops around 2 weeks of age. Rudimentary walking begins at about 3 weeks of age prior to which time they waddle in a slow and cumbersome fashion. By 5 7 weeks, they master running but balance and coordination are still developing so they are not able to turn quickly or walk along narrow surfaces until about 10 weeks of age. Motor and behavioral development occur simultaneously. During the period between 3 and 8 weeks, the young kitten is very impressionable. One should take advantage of this by exposing kittens to a wide variety of people, animals, and environments under favorable circumstances. Introducing them to a variety of foods (flavor, shape, texture, consistency) as they are being weaned will discourage food fixations and fussy eaters from developing. CLINICAL EVALUATION OF THE NEONATE AND YOUNG KITTEN 8,10 If presented with a neonate or young kitten, in addition to a comprehensive physical examination, the following should be considered: Examine young kittens on a warm surface and in a warm environment, F (28 30 C). It is beneficial to use warm towels on a table or lap and a heat lamp to warm the air immediately around them. Body weight at birth is ideally g with a steady gain of g/day. By 2 weeks of age, they should weigh double their birth weight. Thereafter, kittens should gain 1 lb (0.5kg)/month until 4 5 months when the discrepancy between the male and female growth rate becomes marked. Kittens should be weighed once a day. Body temperature at birth is F ( C); by four weeks of age their temperature is 100 F (37.8 C). Check the umbilicus for abdominal wall disruption, inflammation or infection. The cord will normally dry up and fall off by three days of age. Check the shape of the head looking for hydrocephalus; look at the face for harelip or malocclusion; open the mouth to check for cleft palate. Stenotic nares may be present; to check for airflow, hold a glass slide or a small mirror under the nose to see if the surface fogs under both nostrils. Head and facial abnormalities are more common in brachycephalic breeds and Burmese. The Burmese breed has also had problems with cyclopia. Hydration may be assessed by mucus membrane moisture and urine production since in the young kitten, skin elasticity is a poor gauge. Iams Pediatric Care Symposium TNAVC

6 NOTES Eyes and ears remain closed/down until 3 16 days of age. Divergent strabismus is normal until about 8 weeks of age. Subtle cloudiness of the anterior chamber is normal until 3 months of age. The blue-grey iris coloration changes to the adult coloration by 4 weeks of age. Once the eyes are open, check for abnormalities including misplaced cilia, iris colobomas, persistent pupillary membranes. Cataracts and retinal dysplasia occur rarely. Upper respiratory problems commonly affect kittens. In the very young, however, they can be extremely debilitating and prevent the kitten from nursing due to nasal congestion, or can result in blindness if a septic conjunctivitis occurs while the eyelids are still closed. In that situation, the eyelids should be gently but firmly pried open as soon as the lid separation is obvious to allow the debris to be flushed with a saline solution and to administer ophthalmic antibiotics every 2 4 hours. Warmed subcutaneous fluid therapy and nutritional support along with humidification to loosen the nasal secretions are essential. While not routinely recommended in older kittens and cats, young kittens with debilitating respiratory viral infections should be treated with antimicrobial therapy because they are more susceptible to bacterial complications. Antimicrobial therapy must be tailored to the developmental age as well as the size of the kitten. This is discussed later in this article. Assess each limb for symmetry with the contralateral limb. Assess the conformation of the thorax by palpating the ribcage, assessing its shape and by feeling the sternum to check for abnormalities. Heart murmurs are the most common cardiac abnormality ausculted in kittens. Many are benign functional murmurs, however, patent ductus arteriosis, ventricular septal defects, aortic stenosis and tetralogy of Fallot have all been reported. Should any functional murmur persist, it may be a reflection of altered viscosity (anemia, hypoproteinemia) or infection; these warrant further diagnostic evaluation including echocardiography. Abdominal palpation will help assess the presence of 15 Iams Pediatric Care Symposium TNAVC 2005

7 both kidneys, abdominal fluid, and thickening (infiltration/inflammation) of the intestinal loops. In a very young kitten, because defecation is not observed (the queen removes all feces), it is advisable to check that the anus is present and that there is a patent opening. External genitalia should be evaluated to determine if both testicles have descended in the male. Descent of both testicles may occur as late as six weeks of age; if they are not present by 16 weeks, cryptorchidism should be suspected. Looking at the perineal region allows one to detect scrotal fluid in a sick kitten. When present, this may be a reflection of feline infectious peritonitis (FIP). Lymph nodes may all be evaluated just as in the older kitten and adult cat. THE SICK NEONATE 8 Survivability of newborn kittens is inversely related to birth weight. Survival of taurine-deficient kittens is poor. Sick kittens are inactive, inappetant, and vocalize a great deal. They will die quickly if they do not receive prompt medical care. Critical problems of the sick neonate include hypoxia, hypothermia, hypoglycemia, sepsis, dehydration, and diarrhea. Kittens need two to three times the glucose/kg compared to adult cats. Initially, an anorectic or inappetant kitten should be given 1 2 ml of 5 10% warmed dextrose per os every hour while hypothermia and rehydration are achieved. In comatose kittens, a 50% dextrose solution can be rubbed on their oral mucous membranes, administered intravenously or gently administered per rectum. Oxygen must be included in treatment of the very young because of immature respiratory and impaired hemoglobin function. Rehydration with warmed lactated ringers solution should ideally be given via the intravenous or intraosseous route. Because of their tiny size or for initial correction of hypovolemia, another method is to administer 3.5ml/100g body weight subcutaneously every 15 minutes. By giving small volumes at regular frequencies, overhydration can be avoided. This treatment frequency can stop once increased urine production is observed. Do not feed milk replacer to a hypothermic kitten; doing so will result in diarrhea from impaired digestive function. FADING KITTEN SYNDROME Fading kittens are those who either are small and who are ineffectual nursers or who are born looking well and acting normally but become unthrifty after a few weeks of age. Numerous etiologies have been proposed and implicated. These include exposure to infectious agents (respiratory viruses, FIP, FeLV, Streptococcus canis), genetics, nutrition (taurine deficiency), thymic atrophy, toxic chemicals, and poor husbandry. Catteries involved have had cats with mild respiratory disease, endometritis, FIP, cardiomyopathy. Differential diagnoses should include trauma during or subsequent to birth, fatal congenital defects, lactation failure, hypothermia, hypoglycemia, acidosis, bacterial septicemia, viral infections, toxoplasmosis, and endoparasitism. 9 DIAGNOSTICS IN THE YOUNG KITTEN In order to minimize over-sampling, small volumes of blood should be used. Collection of blood should be limited to a maximum of 0.5 ml of blood within the first week of life. (A 100 g kitten may have a total blood volume of 6 ml.) Using this blood, a packed cell volume, total solids (microhematocrit tube), white blood cell and differential count (Unopette and blood film), blood glucose, and urea may be determined. 10 From two to eight weeks of age, a normal physiologic anemia exists such that at 1 2 weeks normal packed cell volume (PCV) is 31 39%; at 2 4 weeks, 25 28%; at 4 6 weeks, 26 29%; and at 6 8 weeks, 29 31%. 11 The initially higher PCV is a result of the higher mean corpuscular volume (MCV) of fetal cells. Nucleated red cells are also an expected finding in the first few days of life. The most important causes of marked anemia in kittens are NI or trauma. Sepsis may not affect the PCV. Neonatal kittens have poor granulocyte reserves, and are therefore especially at risk if they become septic. Low neutrophil counts should be taken seriously and monitored carefully for impending sepsis. Hypoglycemia is a serious but correctable problem in young kittens. They are prone to hypoglycemia because of high metabolic rate, low fat reserves, and sparse hepatic glycogen reserves. Glucometers tend to report lower values than chemistry analyzers. Causes for hypoglycemia include poor nursing, hypothermia, and sepsis. Treatment for hypoglycemia is essential and is discussed earlier in this article. Urea levels are slightly higher than in adults for the first few days of life, then decline to normal or lower values. Dehydration and renal failure are causes for increased urea in kittens, just as they are in adults. Alkaline phosphatase and phosphorus levels are increased as in other juveniles. Iams Pediatric Care Symposium TNAVC

8 A urine sample may be obtained by stimulating the anogenital region with a warm moist cotton ball. By 4 weeks of age, urine specific gravity is ; full concentrating ability (usg 1.080) is reached by 8 weeks. Microbiologic and cytologic samples should be collected from umbilical discharge, purulent nasal discharge or persistent diarrhea. Necropsies are recommended when kittens die, in order to guide therapy for the rest of the litter. NOTES THERAPY IN THE YOUNG KITTEN Because renal and hepatic functions are incompletely developed in the very young kitten, adjustments to dose and frequency of medications must be considered. In addition, fluid compartment distribution differs, body fat and protein levels are lower than in the mature cat, and the blood brain barrier are not mature at birth. Neonatal glomerular filtration rate and renal tubular function are approximately one-fourth to one-third of that of an adult cat. Kitten urine is normally very dilute; fluid requirements are 200 ml/kg/day. Because of their small size, both physically and physiologically, a kitten that becomes ill can deteriorate and dehydrate quickly. 8 In general, one can use adult dose regimes after 4 weeks of age and certainly after 8 weeks of age. In younger individuals, however, one must reduce the dose or lengthen the dose interval. No simple formulae exist for this, but a gross rule of thumb is to reduce adult doses by 30 50%. Because neonates are susceptible to life-threatening sepsis, one must be prepared to use antibiotics. Drugs which should be avoided in the very young include tetracyclines, sulfonamides, aminoglycosides, chloramphenicol, and nitrofurantoin due to reduced ability to excrete these agents. Drugs which interfere with hemoglobin oxidation can be detrimental in the young, thus oxidant drugs such as sulfonamides, nitrofurantoin, acetylsalicylic acid, and phenothiazines should not be used. Intravenous and intraosseus routes are preferred because oral, subcutaneous and intramuscular absorption are less reliable. Secondhand treatment via the queen s milk is not adequate as milk levels reach only 1 2% of the maternal plasma level. REFERENCES 1. Levy JK, Crawford, C, Collante, WR. Use of adult cat serum to correct failure of passive transfer in kittens. J Am Vet Med Assoc 2001; 219: Casal ML, Jezyk PF, Giger U. Transfer of colostral antibodies from queens to their kittens. Am J Vet Res 1996; 57: Levy JK. In-clinic treatment of failure of passive transfer in kittens, in Proceedings. Waltham Feline Medicine Symposium Crawford PC, Hanel RM, Levy JK. Evaluation of treatment of colostrums-deprived kittens with equine IgG. Am J Vet Res 2003; 64: Hoskins JD. Small Animal Pediatric Medicine, in Proceedings. Tufts Animal Expo Iams Pediatric Care Symposium TNAVC 2005

9 6. Giger U. Blood typing and crossmatching to ensure compatible transfusions. In: Bonagura JD, ed. Kirk s Current Veterinary Therapy XIII Small Animal Practice. Philadelphia: W.B. Saunders, 2000; Hoskins JD. Congenital defects of cats. Compend Contin Educ Pract Vet 1995; 17: Murtaugh RJ. Pediatrics: the kitten from birth to eight weeks. In: Sherding RG, ed. The Cat: Diseases and Clinical Management, 2nd ed. New York, NY: Churchill Livingstone, 1994; Bateson P. Behavioural development in the cat. In: Turner DC, Bateson P, eds. The Domestic Cat: the Biology of Its Behaviour. 2nd ed. Cambridge, UK: Cambridge University Press, 2000; Hoskins JD, ed. Veterinary Pediatrics: Dogs and Cats from Birth to Six Months, 3rd ed. Philadelphia: WB Saunders Co, Abrams-Ogg ACG. Neonatal and pediatric diagnostic evaluation, in Proceedings. Western Veterinary Conference Iams Pediatric Care Symposium TNAVC