Managing the sick neonate (Proceedings)

Objectives

• To recognize the signs of specific illnesses and disease in the sick neonate.

• To review treatment and prevention of common neonatal diseases.

General Key Points

• Although suffering from a variety of different diseases, many sick neonates present with similar clinical signs. Therefore initial treatment should be directed toward those disease processes with a fair to good prognosis, especially when a specific diagnosis cannot be ascertained. Environmental problems, poor mothering or husbandry and bacterial infectious processes carry a more favorable prognosis than viral infections or genetic defects.

• Weakness, anorexia, constant vocalizing or crying, abdominal distention or pain, poor weight gain, poor nursing, restlessness and isolation are the most common clinical signs of illness in the neonate.

Neonatal Mortality

• Common causes of neonatal mortality include congenital abnormalities, teratogens, nutritional deficiencies, trauma, poor husbandry, infection, "low birth weight" and neonatal isoerythrolysis.

• "Normal" mortality rates have been reported as ranging from 15% to 30 or even 40% during the first 12 weeks.

• Normal mortality rates are best evaluated in consideration of the breed, kennel, cattery or breeders historical losses.

• A specific cause of many neonatal deaths is not ascertained, due to a variety of limiting factors.

• The majority of puppy and kitten losses occur either in-utero, at birth (stillborn) or within the first 2 weeks of life.

Presentation of the Neonate

• Neonates may be presented for examination for a number of different reasons. Routine tail docking or dewclaw removal, post-partum check-ups or "clean out" shots, poor weight gain, death of a littermate or clinical signs of illness in the animal.

• Many sick neonates are NOT presented to veterinarians at all (or until death is almost imminent.) Lack of proper understanding of the signs of illness, poor management, financial limitations, the lack of an emotional bond with the newborns, fear of being labeled a "backyard breeder" or even a poor relationship with the veterinarian can delay or prevent the presentation of neonates for treatment.

• Reception and lay staff must be trained to properly handle phone consultations with owners and the emergency presentation of sick newborn animals. Specifically the "to who, with what, where, when and how" of delivering a sick neonate, littermates and dam should be included in all clinic protocols.

Examination of the Bitch or Queen

• A thorough examination of the dam may provide valuable information in diagnosis the neonate's illness. Obtain a thorough and accurate history of the pregnancy, delivery and subsequent care of litter.

• The presence of clinical or subclinical mastitis, metritis, agalactia, eclampsia or sepsis in the dam can contribute to neonatal illness.

• The dams overall condition and nutritional state should be assessed.

• Her reproductive history as well as that of the breed and kennel/cattery should be obtained.

• Littermates should be screened for early signs of disease.

Specific Diseases or Syndromes

1. Fading Puppy/Kitten Syndrome

• The syndrome known as "fading" in puppies or kittens is probably formed by grouping together deaths due to otherwise poorly defined etiologies. The diagnosis is usually applied to those that are born weak and fail to thrive or those that are born apparently strong but weaken and die in the first 7-10 days.

• Possible causes include maternal neglect or trauma, environmental problems, poor colostral intake or inadequate milk production, septicemia, congenital defects including inborn errors of metabolism and neonatal isoerythrolysis in kittens.

• Other theories have indicated possible thymic or thyroid dysfunctions and abnormal surfactant production as potential causes of the syndrome.

2. Toxic Milk Syndrome

• Another ill-defined syndrome used to describe poor-doing puppies and kittens that persistently vocalize, bloat, and display abdominal pain or discomfort. Has commonly been blamed on uterine disorders in the dam. However, it has been reported in formula fed neonates as well.

• Maybe associated with delayed GI transit, ileus and gastric overdistention brought on by hypothermia or hypoglycemia.

• Definitive diagnosis is problematic, toxic milk syndrome is usually suspected when poor doing puppies improve when removed from suckling on their dam.

3. Neonatal Isoerythrolysis

• Infrequent among domestic cats, more common in purebreds. Studies of percentage A vs. B blood types have been done in many feline breeds and should be consulted for risk within a specific breed.

• Cats have alloantibodies against other blood type antigens. These antibodies are transferred in the colostrum. These antibodies are not produced by internal mechanisms until 6-10 weeks of age. Blood type A cats generally have very low anti-B antibody titers, but cats with blood type B will have high anti-A titers by 3-4 months of age. This antibody production does not require any previous exposure or pregnancy.

• Kittens of type A or AB blood born to type B dam may be affected. Antibodies acquired in colostrum will bind and lyse their own red blood cells.

• Signs range from poor-doing or slow weight gain to severe anemia, nephropathy, DIC and organ failure.

• Kittens are born apparently healthy and die or fail to thrive very soon after nursing.

• Kittens born to type B queens, bred with type A studs, should be removed from the queen immediately at birth. They are then either hand fed milk replacer or fostered on a lactating type A queen for the first 24-48 hours of life.

• Avoiding the mating of type B females to type A males can prevent neonatal isoerythrolysis.

4. Feline Viral Disease

• Feline leukemia may be transmitted to kittens by nursing or other contact with affected animals. May cause thymic atrophy and secondary sepsis in young kittens.

• Upper respiratory viruses can affect young kittens with typical symptoms of conjunctivitis, sneezing, oculonasal discharge and respiratory distress.

• Feline Infectious Peritonitis (FIP) or Corona virus infections are rarely described in young kittens.

• Exposure to the Panleukopenia virus in utero can cause cerebellar hypoplasia. Susceptible neonates that become infected after birth may display vomiting, diarrhea, leukopenia and death.

5. Canine Herpes Virus

• A common ubiquitous respiratory virus, part of the Kennel Cough complex.

• Reported to cause abortion, resorption and stillbirth of puppies.

• Infection most serious for neonates if acquired in late gestation or the first 3 weeks of life. Most common cause of viral infection in neonatal puppies.

• Causes severe hemorrhages in multiple organs. Clinical signs include depression, persistent crying, hypothermia, abdominal pain, bloating, shallow respiration, weakness and death in 6-24 hours.

• Pathognomonic lesions are speckled hemorrhages on surface of kidneys and occasionally the liver at necropsy.

• Suggested treatments involve warming body temperature of puppies above 100 ? F to slow viral replication, hyper-immune serum supplementation and antiviral drugs.

6. Other Canine Viral

• Canine Parvo Virus can cause myocarditis in the infant period, usually between 3-6 weeks of age. Maternally transferred antibodies protect most neonates.

• Canine distemper and ICH (CAV-2) viral infections are rare in the neonatal period.

• Canine corona virus and other enteric viruses may cause diarrhea in neonates.

• Minute Virus of Canines (CPV type I) can cause acute respiratory distress, diarrhea and death in first weeks of life. This infection is rarely reported and diagnosis is difficult.

7. Bacterial Septicemia

• Multiple bacterial species implicated. Gram negatives most commonly. Causative organisms can sometimes be cultured from dam's vaginal secretions.

• Sources of infection include the gastrointestinal tract, umbilicus (most common), respiratory or urinary infection and skin wounds.

• Inadequate colostral intake or stress predisposes to infection.

• Clinical signs may vary but often include vomiting, diarrhea with red inflamed anus, persistent vocalization, weakness, abdominal pain, fever, dehydration and sloughing of skin on extremities. Other clinical signs may be displayed, such as hematuria, omphalitis, respiratory distress or conjunctivitis; depending on the organ systems involved.

• Presumptive diagnosis can be made by clinical signs, hypoglycemia, neutrophilia with left shift, or a neutropenia resulting from severe sepsis. Definitive diagnosis is made by blood or urine culture. Most commonly diagnosed at necropsy.

• Treatment of septicemia requires fluid therapy with glucose supplementation, oxygen therapy, and antibiotics. Penicillin and cephalosporins are empirically used until culture and sensitivity results can be obtained.

8. Management Issues

• Environmental stresses such as overcrowding, excessive noise, heat, cold, drafts, humidity and poor sanitation will affect survival.

• Indicators of poor mothering include inadequate lactation, cannibalism or trauma to the neonate.

• Poor nutrition, excess stress, genetics and other factors may contribute to mothering issues.

9. Premature Puppies or Kittens

• One of the most common causes is premature cesarean section.

• Low birth weight, lack of hair on face and extremities, poor suckling and possible surfactant failure.

• The dam may display poor milk production, agalactia and reduced mothering instincts.

• Require supplemental feeding, preferably tube feeding, proper temperature and humidity to maintain health.

• Some authors recommend Vitamin K supplementation.

10. Anasarca (Walrus) puppies

• Fetal anasarca. Cause is unknown but hypothyroidism, cardiac defects and an undetermined genetic defect have been hypothesized.

• Most common in brachycephalic breeds; bulldogs and pugs.

• Treatment has been described using furosemide and potassium supplementation. (Hoskins) Success rate with such treatment has not been reported and may be unrewarding.

11. Ophthalmia Neonatorum

• Infection beneath the unopened lids producing swelling and purulent discharge.

• Staphylococcus sp. is usual pathogen.

• Eyelids must be separated gently by applying moist warm compress along with gentle traction using blunt probe to pry lids apart.

• Treated with application of an antibiotic ophthalmic ointment after opening and cleansing the conjunctival sac.

12. Parasitic Disease

• Feline toxoplasmosis be acquired in utero, the parasite can cause fever, pneumonia, diarrhea, depression, and neurological abnormalities. The prognosis is poor.

• Roundworms (Toxocara and Toxascaris sp.) and hookworms (Ansylostoma sp.) may infect puppies and kittens at a young age. For hookworms, the major route of transmission to puppies is transmammary, however for roundworms both transplacental and transmammary transmission occurs. Many puppies are born with ascarid infections. Roundworm infection of kittens prior to birth does not occur, but transmission via the milk does. The migrating and early intestinal stages of these worms can cause severe, even fatal, disease in the first few weeks of life. Patent infections can occur by 3 weeks of age in puppies and 6 weeks of age in kittens.

• Strategic deworming of the dam in late pregnancy into the post-partum period can prevent neonatal infections. Fenbendazole in the preferred drug and is usually started at day 40 of gestation and continued until 14 days post partum.

• Coccidia and giardia are other frequent causes of pediatric diarrhea. Treatment is usually rewarding.

Treatment of the Sick Neonate

Initial approach to treatment is supportive and empirical in most critically ill neonates. Primary care is usually directed at these areas of concern; temperature regulation, hydration, nutrition, drug and oxygen therapy.

1. The 4-H's

Hypothermia

• Neonates do not possess a mature shivering reflex or vasoconstriction ability needed for thermoregulation. They are also normally hypothermic compared to adults.

• External heat source must be supplied for puppies or kittens removed from their dam or queen.

• Incubators should provide an ambient temperature of 85°F to 90°F and humidity of 55-65%.

• Hypothermic neonates exhibit respiratory depression, bradycardia and reduced gastrointestinal motility.

• Warming should be done S L O W L Y (over 30 or more minutes) to reduce the possibility of heat stress, dehydration, peripheral vasodilation and shock.

• Administration of warmed IV or intraosseous fluids or even a warm enema should be considered.

Hypoglycemia

• Neonates have minimal glycogen storage capacity and decreased hepatic function. Glucose levels lower than 50 mg/dl are considered significant.

• Hypoglycemia may be indicated by weakness, bradycardia, crying, hypothermia or convulsions.

• Glucose can be provided orally or along with fluids in dehydrated hypothermic animals.

• Avoid hypertonic solutions subcutaneously.

• Avoid food intake until patient is normothermic and rehydrated.

Hypoxemia

• Cyanotic or dyspnic neonates should receive oxygen supplementation.

• Intranasal administration by nasal catheter is best.

• Oxygen can also be administered in cages, incubators, boxes or tanks.

Hypovolemia

• Dry, pale oral mucous membranes, decreased CRT and concentrated (visibly yellow) urine indicate dehydration.

• Skin turgor is not an accurate predictor of dehydration. The skin of ventral abdomen may appear wrinkled with severe dehydration. A deepened red color of the skin of the abdomen and muzzle may also indicate dehydration.

• Warmed intravenous fluids can be given at a rate of 1 ml/ 30 grams of body weight in the first 5-10 minutes. Once CRT and mucous membrane color improve the rate is then lowered to a maintenance level of 60-90 ml/ lb/day.

• Preferred route of fluid administration depends on severity of dehydration.

• Hyperimmune serum can be administered by subcutaneous or intraperitoneal routes to provide antibodies for neonates with poor colostral intake or infections.

2. Antibiotics

• Collect feces, urine, blood or exudates for culture and sensitivity first.

• Begin empirical treatment immediately unless bacterial infection can be ruled out.

• Adjust dosage and interval as indicated in neonate.

3. Fluid therapy

• Route of administration depends on severity of condition and dehydration.

• Intraosseous route should be considered in severely ill animals.

• Use warm balanced electrolyte solutions supplemented with glucose and potassium as indicated by signs and laboratory findings.

• Fluid requirements are higher than adults, reported maintenance rates range from 60-180 ml/kg/day. Overhydration can lead to pulmonary edema and must be avoided. Careful monitoring of fluid administration is therefore a necessity.

• Supplemental milk should NOT be provided to ill animals until hypothermia and hypovolemia have been corrected.

4. Vitamin K

• Vitamin K is recommended for any sick or hemorrhaging neonate less than 2 days old.

• Low thrombin levels predispose to hemorrhage.

5. Oral Nutrition

• Tube feeding can be instituted once the critical neonate has been rehydrated, become normoglycemic and normothermic and regained an acceptable level of activity with normal muscle tone. Breeders can be encouraged to institute tube feeding early in the course of disease when neonates first display any signs of poor-doing.

• Dosage of commercial milk replacer is adjusted according to age and weight of the neonate.

• Reported dose for commercial puppy milk replacer is 60cc/lb/day divided every two hours in the first week. The dose is adjusted according to age and weight gained. Usually 70 cc/lb/day in the second week, 80 cc/lb/day in the third week and 90-100 cc/lb/day in the fourth week of life. Most puppies and kittens can be weaned onto solid food after the third week.

6. Colostrum Replacement

• Puppies and kittens should be observed for adequate nursing and colostral intake in the first 24-48 hours. When inadequate intake is suspected antibodies can be supplied by subcutaneous administration of serum from well-immunized and immunocompetent donors. (Kennel dog or cat; or pooled samples are excellent sources).

• Suggested dosage is 6-12 ml serum SQ q 12 hrs for up to 3 doses.

Prognosis

The prognosis for survival is better with conditions that are more amenable to treatment. Environmental conditions such as poor mothering and temperature abnormalities carry a good prognosis if properly addressed. Bacterial infections carry a fair prognosis. Viral infections carry a poor to grave prognosis and often affect the entire litter. Prognosis with congenital abnormalities will vary from good to grave depending upon the system involved and the affect of the defect on the overall health of the neonate.

Monitoring Treatment

Serial assessment of physical examination findings, weight gain, mentation, temperature, urine output, blood glucose, chest auscultation, PCV and other applicable testing should be employed. The major goals when treating neonates include temperature maintenance, hydration control, nutrition and weight gain and stimulation of urination and defecation. In critical patients the focus should be on the 4 H's.

Summary

• Sick neonates may quickly succumb to a variety of environmental, husbandry, infectious, traumatic and congenital problems.

• Prompt recognition of the ill or fading neonate, immediate application of appropriate treatment modalities and management of the unique issues affecting ill neonates can often lead to positive and rewarding outcomes.

References

Boothe DM, Tannert K. Special considerations for drug and fluid therapy in the pediatric patient. Comp Cont Ed Pract Vet; 1992; 14: 313-329.

Freshman JL. Practical Care of the neonatal kitten and puppy. Veterinary Information Network, Inc 2002.

Freshman JL. Puppy Neonatology, in Proceedings. Western Veterinary Conference 2002.

Haskins ME, Casal ML. Interpreting Gross Necropsy Observations in Neonatal and Pediatric Kittens. In: August JR, ed. Consultations in Feline Internal Medicine 3rd Ed. Philadelphia: WB Saunders Co, 1997; 587-594.

Hoskins, JD(ed). Veterinary Pediatrics, Dogs and Cats from Birth to Six months, 3rd Ed. Philadelphia, W.B. Saunders, 2001.

Johnston SD, Root Kustritz MV, Olsen PNS. The Neonate- from Birth to Weaning. In Canine and Feline Theriogenology, 1st edition. Philadelphia, W. B. Saunders, 2001;146-167

Lawler, DF, Chandler ML. Indications and techniques for tube feeding puppies. Can Prac 1992; 17:20-23.

Lawler DF, Care and Diseases of Neonatal Puppies and Kittens. In: Kirk RW ed. Current Veterinary Therapy: Small Animal Practice X. Philadelphia: WB Saunders Co, 1989; 1325-1334.

Lee JA, Critical Care of the Neonate, in Proceedings of the Annual Conference , Society for Theriogenology, 2004: 326-333.

Macintire DK. Pediatric Intensive Care, in Vet Clin North Am [Small Anim Pract] 1999; 29: 971-988.

McMichael M, Dhupa N. Pediatric Critical Care Medicine: Specific Syndromes. Compend Cont Ed Pract Vet 2000;22:353-360.

Poffenbarger EM, Olson ON, Ralston SL, et al. Canine Neonatology.Part II.Disorders of the Neonate. Comp Cont Ed Pract Vet 1991; 139: 25-37

Root Kustritz MV, Common Disorders of the Small Animal Neonate, in Proceedings of the Annual Conference, Society for Theriogenology, 2004; 316-326 .