CHAPTER 3 History and Physical Examination of the Neonate
In this chapter, the neonatal period is defined as the period from birth through 3 weeks of age, or when the puppy or kitten is walking and capable of spontaneous urination and defecation. Box 3-1 contains a general overview of important parameters in the physical examination of neonatal dogs and cats.
Although clients with a sick puppy or kitten often resent the time taken by a technician or veterinarian to ask historical questions, collection of a relevant history leads the veterinarian’s physical examination and any further diagnostic testing and may alter plans for therapy. If a significant number of pediatric patients are seen in a practice, it may be beneficial to use the following history questions to create a history template that can be filled out (either as a hard copy or electronically) as puppies and kittens are admitted to the practice.
Knowledge of the duration of illness helps the veterinarian differentiate acute from chronic disease and may direct the practitioner toward a specific diagnosis. It also guides interpretation of clinical signs noted on physical examination, for example, a kitten that has been ill for days and is not dehydrated is probably less severely ill than the animal that has acutely become nonresponsive.
The owner should be asked to specifically list any clinical abnormalities noted, recognizing that some, such as diarrhea, may be difficult to assess if the bitch or queen is doing a good job of cleaning the neonate. Some clinical signs indicate an emergent situation, and any puppy or kitten exhibiting these signs should be seen immediately. Such signs include the following:
Infectious diseases and parasite infestations of the neonates and diseases of the bitch are more likely to affect multiple littermates, whereas trauma, congenital disorders, and abnormalities of nursing with subsequent malnutrition are more likely to affect individual puppies or kittens.
Any fluids, supplements, antibiotics, stimulants, human or veterinary drugs of other classes, or herbal therapies and any environmental changes made to allay signs of illness should be recorded. Obtaining this information may require some probing from the technician or veterinarian, since owners may be embarrassed or apprehensive about having used medications intended for humans or other animals on neonates. Knowledge of treatments used alters the interpretation of physical examination findings and may alter treatment recommendations.
Questions should be asked about the birth of these offspring (e.g., were these puppies or kittens delivered vaginally or by cesarean section [C-section] and did dystocia occur at the time of parturition?); the dam’s current clinical condition and behavior; history of the dam’s mothering skills if she has had previous litters; and health and reproductive history of the dam, including vaccination history.
Kittens may receive as much as 25% of their maternally derived antibodies through the placenta; puppies receive 5% to 10% at best. Because of this minimal antibody transfer across the endotheliochorial placenta of bitches and queens, ingestion of colostrum is necessary for the bulk of passive transfer. Puppies and kittens should be encouraged to nurse within hours of birth. Maximal absorption of antibodies through the gastrointestinal (GI) tract occurs at about 8 hours of life, with virtually no GI uptake of antibodies by 1 day of life. In puppies, if the owner is unsure whether or not a given pup has nursed and is sure another has nursed, blood can be drawn from both and serum alkaline phosphatase (ALP) and gamma-glutamyl transpeptidase (GGT) values compared between the two. Concentrations are higher in pups that have ingested colostrum and remain high for only 1 to 2 days after ingestion. If a neonate is known not to have ingested colostrum, antibodies can be provided by administration of serum or plasma from any vaccinated adult of the same species, given orally (within the first day of life) or as subcutaneous boluses. The empirical regimen for kittens is administration of 15 ml of serum pooled from several adults (mindful of blood type to prevent neonatal isoerythrolysis), given as 3 boluses, administered at birth, and 12 and 24 hours later. The empirical regimen for puppies is administration of 10 ml/lb (22 ml/kg) of pooled adult serum; this can be given at once in large pups or split into boluses as described for kittens.
Low birth weight is correlated with poor survivability. Normal birth weight for kittens is about 100 gm (3.5 oz). Normal birth weight for puppies varies by breed, with general averages of 120 gm (4.2 oz) for toy breed pups, 250 gm (9 oz) for medium breed pups, 490 gm (17 oz) for large breed pups, and 625 gm (22 oz) for giant breed pups. Low birth weight also may be an indicator of an abnormality of the dam, for example, hypothyroidism in bitches.
Puppies and kittens may lose a small amount of weight in the first 24 hours of life because they dehydrate slightly and defecate for the first time. Puppies and kittens should gain weight daily, doubling birth weight by 7 to 10 days of age. It has been demonstrated that those pups that lose more than 10% of their birth weight within the first 2 days of life were much less likely to survive to weaning than those that maintain or gain weight in that time. It is recommended that all neonates be weighed at birth, at 12 and 24 hours of life, and daily thereafter, with good records maintained to document changes in body weight. Any loss of weight after 1 day of age should be a signal to have that neonate seen by a veterinarian; weight loss may precede onset of recognizable signs of disease by as much as 16 hours.
Body weight can be used to estimate age of healthy kittens. Most kittens gain weight in a fairly linear fashion so that they weigh about 1 lb at 1 month of age, about 2 lb at 2 months, and so on until reaching adult weight at about 6 months of age.
|Event||Age at occurrence|
|Umbilical cord dries and falls off||2-3 days|
|Eyelids open||5-14 days|
|External ear canals open||6-14 days|
|Extensor dominance||5 days|
|Capable of crawling||7-14 days|
|Capable of walking, urinating, and defecating spontaneously||14-21 days|
|Hematocrit/RBC number stabilize near that of adult||8 weeks|
|Renal function nears that of adult||8 weeks|
|Hepatic function nears that of adult||4-5 months|
RBC, Red blood cell.
Human neonates are scored for various viability measures at birth. The scoring system used was developed by Virginia Apgar, MD, and bears her name. A similar scoring system has been proposed for neonatal dogs and cats (Table 3-2). At present, there are no studies correlating viability scores at birth with morbidity or mortality in puppies or kittens. This system may be most useful as a way of consistently reevaluating an ill puppy or kitten during hospitalization or if they are presented repeatedly. This system provides an objective measure for the medical record for this individual and may be used to guide urgency of diagnostics or alterations in treatment by the veterinary staff.
Body temperature should be measured using a rectal thermometer. It has been demonstrated that rectal thermometry is a more accurate reflection of core body temperature than any other method in adult dogs, and there is no reason to believe that this is not also true in pediatric dogs and cats.
Normal rectal body temperature in the first week of life is considerably lower than in normal adult dogs or cats. Neonatal puppies and kittens do not generate heat by movement and do not have an active shiver reflex until about 6 days of age, relying on brown fat for thermogenesis and on the environment. In the first week of life, normal body temperature is 94.5° to 97.5° F (35° to 36° C). In the second and third weeks of life, before the puppy or kitten is actively crawling and walking consistently, normal body temperature ranges from 98.6° to 100.0° F (37.0° to 38.2° C). Body temperature less than 94.0° F (34.4° C) is associated with GI stasis.
Hydration status can be difficult to assess in neonatal puppies and kittens. Skin turgor or tenting is not as accurate an indicator of hydration status in pediatric animals as it is in adult animals because neonates have less subcutaneous fat. Well-hydrated puppies and kittens with light pigmentation normally have fairly deep pink coloration of the ventrum, muzzle, and oral mucous membranes (Figure 3-1). There is deepening to dark pink or red with dehydration, but this is a very subjective measure. Oral and ocular mucous membranes may be dry in dehydrated animals. Caution should be used when assessing oral mucous membranes in animals that have recently nursed; milk on the mucous membranes will make them feel slick, artifactually suggesting normal hydration. Normal urine in neonatal animals is very dilute with no discernible color. Stimulation of urination by gentle manipulation of the genitalia with a moistened cotton ball allows one to assess color of urine; any yellow color suggests dehydration is present. Packed cell volume (PCV) cannot be used as a measure of hydration in neonatal puppies and kittens because there is variation in the number of red blood cells (RBCs) passed through the placenta and umbilicus at the time of parturition and because there is a normal decline in PCV with age until it stabilizes at about 8 weeks of age.