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Feline Paediatric Medicine
 

Feline Paediatric Medicine

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Author: Kit Sturgess

Author: Kit Sturgess
This paper was based on the FECAVA sponsored
lecture given at the PSAVA Annual Congress* Krakow
19-20th, November 2005

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    Feline Paediatric Medicine Feline Paediatric Medicine Document Transcript

    • FECAVA SPONSERED PAPER F eline paediatric medicine Kit Sturgess (1) S U M M A R Y This article aims to look at three important areas of kitten medicine; nutrition, investigation of the stunted kitten and managing the collapsed kitten. The latter two scenarios are common reasons for presenting a kitten for further veterinary advice and investigation. This paper is based on the FECAVA sponsored lecture given at the PSAVA Annual CLINICAL NUTRITION Congress* Krakow Choice of supplement – An appropriate supplement should have IN KITTENS 19-20th adequate nutritional density at the November 2005 recommended dilution (Table 2); too low Cats have unique nutritional needs. Nutritional and it is difficult for a kitten to take in problems are most likely to occur under periods sufficient volume to meet its nutritional of maximum demand such as rapid growth, needs (stomach volume approximately when any dietary deficiencies or toxicities can result in significant 70ml/kg). disease. Key areas for consideration of nutrition include – Hydration is important and concentrated formulae may – Nutritional requirements of orphan kittens predispose to dehydration. – Diets for growing kittens – Fluid requirements in neonatal kittens are up to 180ml/kg/day – Nutritional pitfalls hence frequent feeding is required to deliver an appropriate volume of fluid. Nutritional requirements of orphaned kittens Kittens can require supplementary feeding for a variety of reasons, most commonly due to Queen Bitch Cow Goat – Death of the queen during parturition – Failure of the queen’s milk supply Dry Matter % 21 22.7 13 12 – Rejection of one or more kittens by the queen Protein (%) 7.5 7.5 3.3 2.9 – Litter size is too great for the queen to supply adequate Fat (%) 8.5 9.5 3.7 3.8 nutrition Sugar (%) 4.0 3.8 5.0 4.7 – Attempts to reduce the risk of infection from a queen known Ash (%) 0.6 1.2 0.7 0.8 to be FIV or FeLV positive Calcium (mg/100g) 180 240 115 - Whilst the ideal substitute is to foster the kitten on to another Phosphorus (mg/100g) 162 180 95 - lactating queen who will accept the kitten this is rarely possible. Iron (mg/100g) 0.35 0.7 0.2.-0.6 0.3-0.4 Queen’s milk is substantially different from bovidae milk (Table Kcal/100ml 121 146 74 1) and this can not be used as a straight substitute. Home-made and commercial formulae are available (Table 2 and 3). Table 1 – Comparison of queen’s milk with other milk sources (1)Vet Freedom, Brockenhurst, Hampshire, GB - S042 7QT. E-Mail: kit.sturgess@btopenworld.com * Hosted by PSAVA(Poland) 83
    • Feline paediatric medicine – High osmolality fluids may delay gastric emptying e.g. KMR powder. – Arginine levels can be too low in some formulae and predispose to cataracts (queen’s milk arginine = 430mg/100g or 355mg/100kcal). – Taurine levels need to be sufficient (queen’s milk taurine = 10mg/100g or 8.3mg/100kcal); if the taurine content is unknown, oral supplementation can be given (Figure 2). – All home made recipes should be kept refrigerated and used within 24 hours. – Cream contains high levels of short and medium chain fatty acids and is relatively deficient in linoleic acid. – Queen’s milk is high in albumin compared to casein; however, curd can be used as this contains coagulated casein and not micelles (which are larger in bovine milk than queen’s milk and risks hard coagula forming in the stomach). – Egg whites can cause diarrhoea but are a good source of albumin. – Even the best replacers have potential problems so kittens should be weaned as early as is practicable (from 3-4 weeks). Figure 2 – Echocardiogram of a cat with dilated cardiomyopathy. Queen Recipe 1 Recipe 2 KMR powder* Cimicat* Vital Milk www.aah-pets.com www.vetbed.co.uk Royal Canin Dry Matter % 21 16.9 13.6 32.6 17.5 33.3 Protein (%) 7.5 6.25 7.1 8.9 6.4 10.3 14.5 9.5 5.9 6.4 11 5.9 Fat (%) 8.5 7.1 4.4 5.5 3.4 5.5 13.3 6.0 3.9 4.2 13 7 Sugar (%) 4.0 3.3 4.7 5.9 2.9 4.7 6.8 (5.4) 4.5 (3.6) (5.6) (6.1) (6.2) (3.3) Ash (%) 0.6 0.5 0.8 1.0 0.7 1.1 2.1 1.2 1.0 1.1 2 1.1 Calcium (mg/100g) 180 150 96.2 120 109 176 370 244 175 189 366 198 Phosphorus (mg/100g) 162 135 126 158 109 176 290 192 131 141 266 144 Iron (mg/100g) 0.35 0.29 0.6 0.75 3.5 5.6 1.3 0.8 NR NR NR NR Kcal/100ml 121 80 62 151 92 186 Volume (ml/100kcal) 83 125 161 66 108 54 Figures in italics are per 100kcal of metabolisable energy; figures in brackets are % lactulose; * - values are as fed according to manufacturers recommendations Table 2 – Comparison of queen’s milk with milk replacers Recipe 1 Recipe 2 Skimmed milk 70g One whole fresh egg 15g Low fat curd (not cottage cheese) 15g Protein supplement* 25g Lean minced beef 8g Milk, sweetened, condensed 17ml Egg yolk 3g Corn oil 7ml Vegetable oil 3g Water 250ml Lactulose 0.8g Vitamin/mineral mix 0.2g Total 100g Total 310g * Protein supplement used was ProBalance Feline (available via www.calvetsupply.com ) – analysis - 47% crude protein, 1% crude fibre and 17% crude fat. The supplement has essential vitamins and minerals, additional nutrients and digestive enzymes. Table 3 - Homemade milk substitutes for kittens 84
    • KIT STURGESS EJCAP - Vol. 16 - Issue 1 - April 2006 activity than dogs as well as lower levels of diassacharidases Feeding orphaned kittens making the feeding of a low fat diet more difficult in terms – Attention should be paid to the environment as kittens are of an alternate source of calories. unable to thermoregulate (ambient temperature 30-32oC; 3. Cats tend to be more selective eaters and therefore dietary humidity 55-60%). manipulation that results in reduced palatability such as the – Caloric need for kittens is 22-26kcal/100g (most kittens weigh addition of fibre can have a low acceptance. 100-120g at birth) 4. Carbohydrates are not the major secretagogues of insulin in – i.e. a new born kitten needs 18-23ml of queen’s milk per cats. day. 5. Cats have an essential requirement for taurine. Taurine – Weight gain of 10-15g/day is ideal. deficiency is usually associated with attempts to feed a – Feed warm formula (37.8oC) at least 4 times daily depending vegetarian/vegan diet. Taurine deficiency can lead to central on the age of the kitten. retinal degeneration, dilated cardiomyopathy and reproductive – Under feed for first feeds gradually increase to full amount failure. In the early stages these changes are reversible. over 2-3 days. 6. Cats are more sensitive to oxidants in their food which can – Feed using a nipple bottle, dosing syringe or stomach tube. cause Heinz body anaemia. Such changes have been – When using a nipple bottle, milk should slowly ooze from associated with feeding some baby foods which use onion the teat when the bottle is inverted. A drop of milk should powder as a base. be on the teat before inserting into the kitten’s mouth. The 7. Cats require a source of preformed vitamin A. milk should be allowed to flow under gravity, squeezing the 8. Cats have an essential requirement for arachidonic acid in bottle to increase the flow rate risks aspiration. their diet. – Feeding tubes are faster; a 5 FG tube should be used if the kitten is less than 300g. Measure from the nose to the last rib Vegetarian/vegan diets for kittens and insert the tube to this length. – It is not possible to formulate vegetarian/vegan diets for cats – After feeding it is vital to stimulate micturition and defecation, without careful addition of essential ingredients that are this can be done by massaging the anogenital area with usually animal derived such as taurine and arachidonic acid. moistened cotton wool. – Even when produced, balanced vegetarian/vegan diets do – Handling before feeding stimulates exercise promoting not seem to have the same health benefits as meat-based muscular and circulatory development. diets. – Kittens are particularly vulnerable to nutritional deficiencies. Diets for growing kittens Once kittens have been weaned they need to be fed a diet Feeding a raw meat diet suitable for growth. A variety of proprietary diets are available. It has been argued that raw diets are better than cooked diets Kitten diets have higher energy density, protein and vitamin for cats. No good clinical studies have been performed to address levels than adult maintenance diets. They are usually designed this point. Even raw food is not the same as a freshly killed for kitten up until 6 months of age. There are a variety of reasons rodent or bird particularly as it is likely to have been refrigerated for making a dietary change at around 6 months as this often or frozen. The greatest risk of feeding raw food is infection coincides with neutering that results in a 20-30% reduction in whether this is preformed toxins in spoiled foods, bacteria such caloric need. When feeding or formulating a kitten diet, the as Salmonella or parasites such as Toxoplasma. Appropriate unique nutritional requirements of cats should be born in mind. sourcing, storage and preparation of raw food are crucial. When Kittens have a higher caloric need than adults although the total feeding raw food, the possibility of cross contamination of volume fed can be small (Table 4). human food should also be considered. 1. Cats have a higher protein requirement; arginine deficient diets such as some baby foods can rapidly cause hepatic Nutritional pitfalls encephalopathy. Because of their unique nutritional needs some foods are best 2. Cats have significantly lower (about 1/3rd the level) amylase avoided or given in strict moderation to kittens, these include: Physiological state Energy requirements Weight of food required g/kg body weight* (kcal / kg bodyweight) Canned diet Dry diet < 3 months (growth) 250 * 190 60 3 - 6 months (growth) 130 * 100 30 6 - 12 months 80 (neutered) -100 (entire) ** 70-90 20-25 * based on typical kitten diet - canned (130kcal/100g); dry diet (425kcal/100g) ** based on typical adult diet - canned (110kcal/100g); dry diet (400kcal/100g) Table 4 - Estimated energy requirements in healthy kittens 85
    • Feline paediatric medicine Figure 3- Radiograph showing a marked reduction in bone density in a kitten with nutritional secondary hyperparathyroidism associated with feeding an exclusive lean chicken diet. contain preformed histamine. Ingestion results in reddening of the skin, most noticeably the nose, nausea, vomiting, diarrhoea, abdominal pain and pruritus that develops within 15-60 minutes of ingestion Liver Liver contains excessively high levels of vitamin A leading to painful bone deformities which do not resolve even if the diet is corrected (Figure 4). Milk products Cats generally do love milk but they may lack the enzymes to digest it resulting in large quantities of fermentable sugars reaching the colon leading to osmotic diarrhoea. N.B. Milk is a balanced diet; calcium is NOT in excess hence milk can not be used to balance diets which have excessive phosphorus such as an all meat diet. Figure 4 – Radiograph of the stifle of a cat showing calcification Onion-based foods of the soft tissues associated with hypervitaminosis A. Cats are sensitive to oxidant intoxicants such as onions that are used as a base in some baby foods for example. Table scraps Pharmacological activity Feeding less than 10% of calories as table scraps is unlikely to Some foods have pharmacological activity e.g. chocolate but cause nutritional imbalance but can lead to obesity if not taken these are rarely consumed by kittens into account when calculating the daily ration. Feeding table scraps can lead to behavioural problems - begging, refusing to eat regular food etc. Figure 5 – Severely stunted and septic kitten (on the table) caused by an umbilical infection. This kitten did not survive. Meat and poultry Carnivores in the wild eat the majority of the carcase and not just lean meat which has excessive amounts of phosphorus relative to calcium and is deficient in sodium, iron, copper, iodine and vitamins. An all meat diet can lead to severe and potentially fatal skeletal abnormalities, nutritional secondary hyperparathyroidism (Figure 3) and joint malformations. Fish Raw fish can contain thiaminase which destroys vitamin B1 (thiamine) as well as potentially containing parasites. Excessive amounts of fish can cause a relative deficiency of vitamin E especially if the fish is packed in oil. Fish that has been improperly preserved or inadequately refrigerated, particularly the tuna and mackerel family, can 86
    • KIT STURGESS EJCAP - Vol. 16 - Issue 1 - April 2006 INVESTIGATION OF THE STUNTED KITTEN Kittens are frequently presented to veterinary surgeons because they are poorly grown (Figure 5). Based on the DAMNIT-V system, the most likely causes of stunted growth are highlighted. D Degenerative; developmental, demented (psychological) A Anomaly (congenital); allergic, autoimmune M Metabolic N Neoplastic, nutritional I Infectious; inflammatory; idiopathic; immune mediated; iatrogenic T Traumatic, toxicity V Vascular Figure 6 – An under grown kitten with an abscess on its head secondary to feline infectious peritonitis. Causes Abnormality of bone growth – Chondrodystrophy Deficient nutrient intake – Inadequate or inappropriate diet – Gastrointestinal parasitism – Persistent vomiting or regurgitation e.g. vascular ring anomaly – Maldigestion / malabsorption Increased caloric demand – Fever – Chronic infectious or inflammatory disease (Figure 6) – Major trauma – Increased caloric loss – Protein losing enteropathy – Protein losing nephropathy Figure 7 – Six month old male, Havana kitten weighing less – Urine nutrient loss e.g. juvenile onset diabetes mellitus, renal 1.7kg and showing neurological signs associated with a glycosuria portosystemic shunt. Major organ defect – Hepatic - portosystemic shunt, glycogen storage disease (Figure 7) – Renal - dysplasia, pyelonephritis – Congenital cardiac anomaly – Lysosomal storage disease – Endocrinopathy – Hypothyroidism (Figure 8) – Hyposomatotrophism Key history – Did the queen have a normal, pregnancy and parturition? – When was the problem first noticed? – Has the kitten been slow and poorly grown since birth? Figure 8 – Hypothyroidism causing severe reduction in growth Suggests a congenital defect. rate and skeletal malformation. – Was the kitten showing normal development (i.e. indistinguishable from the other members of the litter) and Physical examination then suddenly stopped? Suggests an acquired disease. Examination of kittens can be difficult as they rarely stay still and – Are any other members of the litter similarly affected? can be aggressive if from a feral background. Neonates tend to – Have kittens in previous litters shown similar signs? show limited responses to disease, initially becoming agitated – What is the kitten’s diet, appetite and food intake? and crying, progressing to inactivity, hypothermia and loss of the – Are there signs, other than failure to grow, that indicates suckling reflex. As with all young animals, changes in their status major organ disease? can be very rapid. Weight gain can be a sensitive indicator of – Is the kitten’s body proportionate or disproportionate? developing problems and can be easily measured by the owner – Is the kitten’s body condition good or poor? (Figure 9). Failure to gain weight over any 24 hour period is worthy of further investigation. 87
    • Feline paediatric medicine Daily weight of kittens FCK Weight (grams) Age (days) Figure 9 – Growth curves for a litter of kittens, one kitten’s growth rate began to slow. A few days later this kitten developed a flat chest (Figure 12). External features – Respiration 15-35 per minute. – Body weight – Regular rhythm. – Hair coat (amount, condition, parasites, persistence of kitten – Heart murmurs may be innocent, associated with non-cardiac coat) disease (e.g. anaemia, portosystemic shunt) or associated – State of hydration with congenital cardiac disease (Table 5). – Signs of injury – Lung sounds difficult to distinguish but should be present; – Appearance of umbilicus check for symmetry or malformation of the thoracic cavity. – Discharge from nose/eyes/ears – Urine staining (patent urachus) Abdomen – Diarrhoea / rectal patency – Should feel full but not swollen or tight. – Congenital malformation – Liver and spleen not palpable. Eyes – Intestines soft, mobile and non-painful. – Kitten’s eyes open between day 5 and day 14. – Urinary bladder freely movable. – Pupillary light response is present within 24 hours of opening. – Mild cloudiness of cornea is usually evident at opening but should resolve rapidly. Figure 10 – Kitten with serous ocular discharge associated with – Swelling under the eyelids indicates pus formation (often C.felis infection. staphylococcus spp.), very rarely Chlamydophila felis (Chlamydia psittaci) (Figure 10). Ears – External auditory meatus is closed at birth and opens between 6 and 14 days; check for mites. – Middle ear infection indicated by a bulging tympanum. Mouth – Colour of mucous membrane. – Evidence of cleft palate (Figure 11). Thorax – Shape of thorax - flat chest (Figure 12), pectus excavatum – Heart rate around 200-220 beats per minute. 88
    • KIT STURGESS EJCAP - Vol. 16 - Issue 1 - April 2006 Figure 11 – Cleft palate. Figure 12 – Flat-chested kitten – this condition develops shortly after birth and particularly affects Burmese kittens. Neurological assessment – Acquired diseases tend to be infectious or toxic and therefore – Alertness other members of the litter are likely to be showing signs. – Response to stimulation – Suckle reflex Diagnostic approach – Other reflexes appropriate to age – Ensure adequate and appropriate nutrition. – Gait (walking from around 4 weeks old) – Ensure adequate worming and ectoparasite control. – Posture – Haematology, biochemistry and urinalysis to assess major – Flexor and extensor dominance appears more variable in organ disease kittens than puppies. – Include hepatic function tests (bile acids). – Retrovirus serology. Decision making – Survey radiographs - thorax, abdomen, and appendicular – Is the nutritional and caloric intake adequate? skeleton. – Is trauma a realistic possibility – if so how is it affecting – Ultrasound and echocardiography growth? – Hormonal tests – growth hormone, thyroid function – Is the problem likely to be a congenital abnormality (if so – Endoscopy and biopsy of the stomach and small intestine. which organ) or an acquired disease? – Fibroblast culture or urinalysis for lysosomal storage disease – Is an endocrinopathy likely – kittens tend to be stunted but (Figure 13). otherwise clinically well? – Specific DNA-based genetic tests. Innocent murmurs Congenital murmur Usually I-III/VI, craniodorsal, ejection type Usually loud unless Variable with heart rate and body position – large defect Often musical – tricuspid valve dysplasia Typically diminishing with age & resolving by 16 weeks – mild semilunar valve stenosis May be associated with clinical signs – failure to grow – cyanosis, – exhaustion after brief periods of play – weakness – collapse – Source of congenital murmurs can be difficult to identify in some cats Table 5 – Characteristics of innocent cardiac murmurs and murmurs associated with congenital heart disease 89
    • Feline paediatric medicine MANAGING THE COLLAPSED History should be focused on KITTEN – Health of other members of the litter – infectious disease is likely to affect more than one kitten in the litter. – Environment to assess the likelihood of trauma or access to Neonatal responses are relatively limited and body reserves are potentially toxic compounds. low so kittens can rapidly change from being bright and well – Internal or external parasitism is very common. to collapsed and seriously ill. This section will focus on the – What parasite control has been used? initial management of the collapsed kitten including physical – Is there a possibility that the parasiticide is causing the examination, history taking, basic diagnostics and rational problem e.g. piperazine, organophosphates, permethrins? therapy. Physical examination History A thorough physical examination is essential both in order to Many of the historical questions will be similar to those for the try and achieve a diagnosis as well as identify urgent problems stunted kitten. Congenital diseases can present acutely such as that require therapy. Normal physiological values for kittens are the kitten with a cardiac defect that goes into congestive heart given in Table 6. failure or the kitten with a portosystemic shunt that becomes encephalopathic. However, in the majority of cases, trauma, Investigation of neonatal disease intoxication or infectious disease will be the most likely causes. – Routine haematology (Table 7) and biochemistry (Table 8) In such cases, the kitten will have been normally developed, can be performed from a very early age on blood obtained growing and eating well up until the very recent past. by jugular puncture (Figure 14). Parameter Kittens (mean or range) Age Rectal Heart rate Respiratory Environmental (days) temperature (bpm) rate (/min) temperature Age 0-3 days 2 weeks 4 weeks 6 weeks (oF) (oF) PCV (%) 41.7 33.6-37.0 25.7-27.3 26.2-27.9 0-7 96 ± 1.5 200-250 15-35 85-90 Haemoglobin (g/dl) 11.3 11.5-12.7 8.5-8.9 8.3-8.9 8-14 100 70-220 15-35 80 RBC (x1012/l) 5.11 5.05-5.53 4.57-4.77 5.66-6.12 15-28 - 70-220 15-35 80 MCV (fl) 81.6 65.5-69.3 52.7-55.1 44.3-46.9 29-35 Adult 70-220 15-35 70-75 MCH (pg) 24.6 22.4-23.6 18.0-19.6 14.2-15.4 >35 Adult 70-220 Adult 70 MCHC (g/dl) 27.3 33.7-35.3 32.5-33.5 31.3-32.5 WBC (x109/l) 7.55 9.1-10.2 14.1-16.5 16.1-18.8 Table 6 - Physiological values in young kittens Table 7 - Haematological values in young kittens Parameter Kitten age (weeks) 2 4 7-12 Total protein (g/l) 40-52 46-52 51-57 Albumin (g/l) 20-24 22-24 24-32 Sodium (mmol/l) - 149-153 147-152 Potassium (mmol/l) - 4.0-4.8 5.0-6.2 Chloride (mmol/l) - 120-124 113-128 Inorganic phosphate (mmol/l) - 2.0-2.4 2.5-3.1 Calcium (mmol/l) - 2.4-3.2 2.2-2.8 Urea (mmol/l) <5 <5 4.2-6.3 Creatinine (µmol/l) - 36-54 36-91 Cholesterol (mmol/l) 4.3-11.6 4.6-11.4 - ALK-P (U/l) 68-269 90-135 - ALT(U/l) 11-24 14-26 - Glucose (mmol/l) 6.08-10.32 7.92-8.96 - Bilirubin (µmol/l) 1.7-16.9 1.7-3.4 - Bile acids (µmol/l) <10 <10 - Table 8 - Serum biochemistry values in young kittens 90
    • KIT STURGESS EJCAP - Vol. 16 - Issue 1 - April 2006 Figure 13 – An under grown kitten with skeletal abnormalities Figure 14 – Jugular venipuncture in a week old kitten. associated with a lysosomal storage disease. – Many infectious diseases develop too rapidly to obtain results a lengthening of the interval between doses. quickly enough (especially bacterial culture and sensitivity or – Great care should be taken when administering broad- paired serum samples) to be of value to that individual but spectrum antimicrobials orally because of their potentially a knowledge of cause may be beneficial to the rest of the litter adverse effects on the developing gut microflora. or subsequent litters. – Subcutaneous and intramuscular absorption of drugs is slower – To minimise the amount of blood required, glucose can be and less reliable than in adults particularly if the kitten is estimated on a glucometer and 0.5ml EDTA tubes used dehydrated. making a total bleed of 1.5ml in the smallest of kittens – Antimicrobials administered to the dam do not reach sufficient for most tests to be carried out. therapeutic concentrations in the milk. – Ensuring adequate nutritional support either by naso- Blood volume in cats is estimated at 75ml/kg. A week-old oesophageal or gastric intubation is a vital part of therapy kitten will weigh around 200g and have 15ml of blood particularly in the face of sepsis. – Radiographs can be difficult to evaluate in young kittens as mineralization of the skeleton is poor and the film can be Figure 15 – Fluid warmer that can be attached to the giving set easily over exposed. Reducing the kV to half that used for line. an adult of similar body thickness should produce radiographs that will provide valuable diagnostic information. – Faecal examinations can be easily performed and are of particular value where protozoan parasites are suspected. Despite aggressive therapy, acutely sick kittens will die and it is important to try and encourage the owner to allow a post mortem examination. Maximum information can be obtained if the carcass is fresh. If a post-mortem can not immediately be performed, the body should be stored in the fridge and not the freezer. A systematic approach should be adopted and all details should be recorded including sex, colour, body weight, amount of body fat, presence of ingesta in the stomach, faeces in the colon and urine in the bladder. Consideration affecting the treatment of neonatal disease Special consideration needs to be given when giving drugs or fluids to paediatric patients as they have an immature metabolism, small total body weight but relatively high body surface area. Drugs – Absorption, distribution, metabolism and excretion of drugs can be significantly different from adults. – Few drugs have had dose rates calculated for use in young kittens. – Generally, an increase in the initial dose (/kg) is required with 91
    • Feline paediatric medicine Fluid therapy Intravenous Fluid requirements (/kg) are higher in neonates than adults BUT – 23g or 25g catheter can be placed in the cephalic vein of total volumes are low. Young kittens have immature kidneys and many small kittens. lack the ability to concentrate their urine in the face of – Larger catheters can be placed in the jugular vein but this can dehydration and therefore will become dehydrated very quickly be difficult in kittens that are dehydrated. Placing a jugular especially if there is increased fluid loss such as vomiting or catheter may required sedation/anaesthesia and cut down. diarrhoea. The benefits of jugular access have to be balanced with the – Maintenance fluid requirements of very young kittens (less risks of placement. than 2 weeks) are around 180ml/kg/day. By weaning fluid – The kitten’s short legs can make the catheter very positional requirements are around 120ml/kg/day. Adult maintenance and flow difficult to maintain in gravity fed fluid systems. requirements (50ml/kg/day) are appropriate in kittens over Forced flow in the absence of syringe or fluid pumps can be 6 months old. achieved using – Battery operated, fixed-rate (0.5 or 1.0ml/hr), single use Example fluid reservoirs (Figure 16). A week old kitten weighing 200g will therefore require 36ml – Spring-driven, refillable, syringe pumps, flow rate variation of fluid at maintenance over 24 hours i.e. 1.5ml per hour. is limited and achieved using variable diameter tubing Even using a paediatric giving set, this is equivalent to 1 drop connected to the patient. every 40 seconds. – Single patient use, refillable balloon infusion devices that Increased fluid rates are necessary if the kitten is dehydrated use the elastic recoil of the balloon to push the fluid. Flow or has increased fluid loss (diarrhoea or vomiting). Fluid rate variation is limited and achieved using variable should be given at approximately 4ml/kg per episode of diameter tubing connected to the patient. vomiting or diarrhoea Intraperitoneal If the kitten is 8% dehydrated and having episodes of – This route is not ideal as absorption can be relatively slow vomiting and diarrhoea every 4 hours then especially in the face of hypovolaemia and is poorly suited – Maintenance at 1.5ml/hr to long-term fluid therapy. However, in the hypovolaemic, Fluid deficit is 16ml – replace 50% in the first 6 hours (= collapsed kitten this may be the fastest way of delivering 1.3ml/hr) and the remainder over 18 hours (= 0.5 ml/hr) therapy in the short term. – Increased need associated with GIT signs is 24ml/kg/day – The risks of puncturing viscera are low. = 5ml/day = 0.2ml/hr – Aseptic technique is mandatory. Fluid rate for first 6 hours is then 3ml/hour (1 drop per 20 – Daily fluid requirements should be calculated and the volume seconds) reducing to 2.2ml/hour (1 drop every 27 seconds) divided to be given 2-3 times daily. These calculations are approximations and it is vital that the state of hydration and urine output is Intraosseus monitored. – Useful where venous access not possible due to vein size or hypotension causing the veins to collapse. – The cortical bone is sufficiently soft in kittens such that a – Syringe pumps can be of great value and are significantly hypodermic needle (18-19g) can be used. cheaper than fluid pumps; otherwise a burette with a – The area should be surgically prepared and the needle placed paediatric giving set (60 drops per ml) will ensure that the in either the proximal tibia or proximal femur. Only one kitten is not over-hydrated. attempt should be made at each site since, if the bone cortex – Kittens will tend to become acidotic associated with many disease states but reduced hepatic function can mean that Figure 16 – Mechanical, low they are less able to metabolise lactate into bicarbonate. flow rate devices (available – For most kittens Ringers solution is appropriate. If the from Mila International: kitten is significantly acidotic, bicarbonate can be given www.milaint.com). separately at 1mmol/kg over 20 minutes. – Glucose can be replaced using a 5% dextrose solution mixed 50:50 with lactated ringers or by giving 1-2ml of 10-25% glucose i/v to profoundly depressed kittens. Methods of drug and fluid administration Kittens are particularly prone to hypothermia so fluids should be warmed before administration. Because the rate of administration of fluids is slow, warming the whole bag of fluid is not effective. Fluid needs to be warmed as it passes through the giving set using a proprietary fluid warmer (Figure 15), heated pads or warm water that is regularly replaced. 92
    • KIT STURGESS EJCAP - Vol. 16 - Issue 1 - April 2006 is already punctured, it will result in fluid leaking out. – Inadequate colostrum – Fluids, drugs or whole blood can be given at the same rates – Low birth weight as for i/v therapy. – Trauma – Neonatal isoerythrolysis Neonatal isoerythrolysis – Infectious disease Blood group A kittens are at risk of neonatal isoerythrolysis if they are born to a B group queen. B group cats have naturally Key history occurring, high affinity, anti-A antibodies that are passed to the – Breeding history of household. kitten in the colostrum resulting in immune-mediated haemolytic – Disease status of household. anaemia. – Individual breeding history of queen. – Number of kittens born alive and dead. Clinical signs – Health of queen now and during pregnancy. Kittens start to fade when they are a few days of age. Owners – Status of other litter members. first notice discoloration of the urine due to haemoglobinuria. – Status of other kittens in the household. Kittens will become jaundiced. Tail and ear tip necrosis will also – Recent arrivals / showing / mating. occur. – Pattern of illness to-date. – Health parameters noted by breeder e.g. weight gain. Blood group distribution by breed in the UK – Hygiene, worming, vaccination and flea control regimes. NB – blood group distribution in other areas of Europe may be – Has the kitten ever appeared normal? different from this – Did the kitten ever suckle normally? Breeds with no type B cats – Has supplementary feeding been provided (risk aspiration)? – Siamese, Burmese, Tonkinese, Oriental short hair, Ocicat – Blood group of queen and stud cat (if known). Breeds with <5% type B cats – DSH, DLH, Maine Coon, Norwegian Forest Cat Investigation Breeds with 10-20% type B cats A full physical examination should be performed including a – Abyssinian, Birman, Himalayan/Persians, Scottish fold ear, neurologic assessment for alertness, suckle reflex, response to Somali, Sphinx noxious stimuli and reflex responses (not fully developed until Breeds with >20% type B cats 12 weeks). – British and exotic short hairs, Cornish and Devon rex Decision making Therapy – Level of problem - household, litter or individual. Aggressive therapy needs to be given at an early stage and blood – Congenital vs. hereditary? transfusion with group A blood is necessary. Mortality rates can – Infectious vs. anatomic? be high. – Likelihood of trauma? – Possibility of neonatal isoerythrolysis? Prevention Subsequent matings of the queen should with a B group stud Diagnostic investigation cat. If this is not possible then the kittens should be blood – Routine haematology and biochemistry grouped (jugular sample or umbilical blood) at birth before they – Faecal and urinalysis are allowed to suckle and A or AB group kittens given A group – Bacterial culture colostrum (usually requires fostering onto an A group queen) – Serology or milk replacer until after gut closure (24 hours). In kittens – A positive FIV test can not be interpreted in a neonate given milk replacer, the lack of colostrum will, however, make because of passive transfer of antibodies from the queen. them vulnerable to other infectious diseases. This risk can be A kitten born to an FIV antibody negative queen is highly reduced by feeding 1-3ml of serum from a type A cat. unlikely to have FIV. Ideally queens and stud cats should be blood typed prior to – Imaging studies mating. – Biopsy / post mortem Fading kittens Blood transfusions Definition Kittens can survive with a very low haematocrit and can present These are typically kittens born apparently healthy that either with a PCV as low as 6-8%. These kittens are very vulnerable to fail to suckle (or lose their suckle reflex) and die with no organ- stress and need to be handled carefully and pre-oxygenated specific clinical signs. Fading kittens may occur as single cases; before attempting to take blood or place an i/v line. Where affect multiple or all kittens in the litter. severe anaemia is suspected, a small amount of blood is required to blood type the kitten and measure their PCV. If the kitten is Common causes symptomatic or has a PCV of less than 12%, blood transfusion – Congenital abnormality is appropriate and can be very rewarding. Only small volumes – Exposure to teratogens in utero of blood are required but can result in dramatic clinical – Inadequate nutrition improvement. 93
    • Feline paediatric medicine Blood volume required REFERENCES AND FURTHER Example A 200g kitten (7 day old) presents with a PCV of 8%. READING A group matched blood donor is available whose PCV is 30%. HOSGOOD (G.), HOSKINS (J.D.) (1998) - Small Animal Paediatric Target PCV is 25% for the kitten Medicine and Surgery, Butterworth Heinemann, Oxford. Volume required = IHLE (S.L.) (2005) - Failure to Grow in Textbook of Veterinary Desired PCV (L/L) – Actual PCV (L/L) x 100 x bodyweight (kg) Internal Medicine [6th edition]; Ettinger, S.J. & Feldman, E.C. eds. PCV of donor (L/L) Elsevier Saunders, Missouri, pg. 80-82. JACOBS (R.N.), PAPICH (M.G.) (2000) - in Kirk’s Current Veterinary = 0.25 – 0.08 x 100 x 0.2 = 11ml Therapy XIII; Bonugura, J. ed. W.B.Saunders, Philadelphia, pg. 1211-1212. 0.30 KIRK (C.A.), DEBRAEKELEER, (J.), ARMSTRONG (P.J.) (2000) - Normal Cats in Small Animal Clinical Nutrition [4th edition]; Hand, M.S., Thatcher, C.D., Remillard, R.L. & Roudebush, P. eds. Blood collection Walsworth Publishing Company, Missouri, pg. 329-334. Blood can be collected in 10-20ml syringes pre wetted with acid STURGESS (C.P.) - (1998) Infectious Disease Of Neonates, Young citrate dextrose solution (1ml/10ml of blood collected) via a 21g Puppies & Kittens in BSAVA Manual of Small Animal butterfly catheter placed in the jugular vein of a donor cat. In Reproduction & Periparturient Care, pg.159-166. some cases mild sedation of the donor [e.g. ketamine (5mg/kg) STURGESS (C.P.) (2003) - Feline Internal Medicine, Blackwells, and midazolam (0.25mg/kg)] may be necessary. Alpha2- Oxford, pg 27-28, 35-36, 313-319. adrenergic agonists such as medetomidine should be avoided due to their hypotensive effects making venipuncture difficult. Donor cats should be clinically healthy, less than 8 years old and ideally have been tested negative for FeLV, FIV and FIA (feline infectious anaemia). Performing the transfusion Blood should be administered via an intravenous or intraosseus route using a T-connector or low volume extension tubing (2- 3ml) to minimise dead space. Blood should be given at an initial transfusion rate of half maintenance for the first half hour in the non-emergency situation. In reality, for most kittens this means a bolus of 0.5 ml and waiting for half an hour to see whether there is an adverse reaction. Thereafter blood can be given at twice maintenance. In an emergency, blood can be given at shock rates (70ml/kg/hour) – for the kitten in the example above, this means giving the 11ml needed over about 45 minutes. CONCLUSIONS Kitten medicine is a truly challenging but very rewarding area for the veterinarian. The small size of the patient, speed with which they deteriorate and lack of localising clinical signs makes investigation and treatment difficult. The value of success, however, is great in the hope that your patient will survive and enjoy the next 15 year or so of life. ACKNOWLEDGMENTS Professor T.J. Gruffydd-Jones for Figures 8 and 11 Dr D. Gunn-Moore for Figures 6 and 13 Mrs R. Giles for Figure 1 94