Pediatric and reproductive emergency room pearls (Proceedings)

Pediatric and reproductive emergencies are common in both general practice and the emergency room setting and can be both extremely rewarding for the small animal practitioner.  This lecture will focus on evaluation, diagnosis, and treatment of both the pediatric and reproductive emergency patient.

Neonatal / pediatric emergencies

Unfortunately, just like cats are not small dogs, at times neonates and pediatrics are not just tiny adult dogs or cats either!  There are significant differences in the diagnosis, monitoring, and treatment of neonates and pediatric patients compared to adult patients.  For this reason, it is important that veterinarians become familiar with normal physical examination, hematological, biochemical, and radiographic values for this age range.

In veterinary medicine, the term neonate is typically used from birth to 2 weeks of age and the term pediatric refers to patients between 2 weeks and 6 months of age.

Neonatal / pediatric history

Common historical comments from the owners at the time of presentation include frequent crying, lack of/ineffective nursing, failure to gain weight, lethargy, and weakness.

Neonatal / pediatric examination

The neonate / pediatric examination is at times a challenge based on their small size.  A pediatric stethoscope is preferred for auscultation.  Several important differences will be emphasized as compared to adult patients. 

• The rectal temperature at birth is lower than adult patients, 95–98.6°F.  This temperature gradually increases to adult temperature (100-102.5°F) over 4 weeks.

• A physiologic heart murmur may be ausculted up until 12 weeks of age without a primary cardiac defect / concern.  If the murmur is louder than expected or persists past 12 weeks, it is important to consider congenital disease.  Other pathology that may result in a neonatal/pediatric murmur includes fever, sepsis, or anemia.

• Elevated heart rates in neonates (200 bpm in the normal neonatal puppies and 250 bpm in kittens) is common and decreases to more normal resting heart rates at approximately 4 weeks of age.  The decrease happens as parasympathetic tone increases during that time. 

• Neonatal respiratory rates are often increased as compared to adult patients.  Neonates have a smaller tidal volume and increased pulmonary interstitial fluid, thus leading to a mild increase in both respiratory rate and effort.

Neonatal / pediatric clinicopathologic data

The neonate / pediatric bloodwork results can be quite normal, but differ considerably compared to adult patients.  It is important to recognize these common differences so further testing and/or treatment is not instituted without need.

• The hematocrit (HCT) in neonatal puppies and kittens is lower than adult patients, reported to be 25-30% in the first 4 weeks of life, increasing to normal starting at 4-6 weeks of age. 

• Neonates normally have a mild increase in bilirubin (0.5mg/dl; normal adult range 0–0.4)

• Alkaline phosphatase is often markedly elevated (ALP; 3845 IU/L, normal adult range 4–107)

• γ-glutamyltransferase likewise is also quite elevated normally (GGT; 1111 IU/L, normal adult range 0–7).

• Blood urea nitrogen (BUN), creatinine, albumin, cholesterol and total protein are lower in neonates compared to adults.

• Calcium and phosphorous are higher in neonates.

• Urine is isosthenuric in neonates as they do not yet have the ability to concentrate and dilute urine.

Neonatal / pediatric imaging

Radiographically, there are several anatomical differences as compared to the adult patient.

• The thymus is located in the cranial thorax on the left side. According to Miller's Anatomy the thymus "is relatively large at birth, grows rapidly during the first few postnatal months so that it reaches its maximum development before sexual maturity, or between the fourth and fifth postnatal months, just before the shedding of the deciduous incisor teeth. The thymus begins to involute with the changing of the teeth. Although the process is rapid at first, the organ does not atrophy completely even in old age."  If this same opacity is seen in an adult patient, as compared to being normal in a neonate/pediatric patient, this would more likely represent pulmonary disease or a mediastinal mass.

• Pulmonary parenchyma has increased water content and appears more radiodense in neonates.

• Neonates have a mild increase in heart size as compared to adults.

• Neonates and pediatrics do not have prominent costochondral mineralization giving the appearance of the liver more cranial, sitting under the rib cage.

• Neonates and pediatric patients have decreased abdominal detail due to lack of fat as well as a normal, small volume abdominal effusion

Neonatal / pediatric venous access and alternatives

Intravenous (IV) access is the preferred route for fluid and medication administration and when possible, should be performed.  In the event an IV catheter cannot be placed, placement of an intraosseous catheter is a reasonable alternative. Fluid or drugs administered by this route are rapidly absorbed into the circulatory system. The most common sites for intraosseous access include the trochanteric fossa of the femur, the greater tubercle of the humerus, the wing of the ilium and crest of the tibia. The author's preferred site for IO catheter placement is the proximal femur. The author commonly uses an 18–22 gauge hypodermic needle.   Similar to an IV catheter, an IO catheter can should be placed in an area that is prepared in a sterile manner.  When placing an IO catheter, the needle inserted into the bone parallel to the long axis of the bone.  Following placement, the clinician should gently aspirate, then flush with saline to assure patency.  The catheter is secured with a bandage, suture, or tape preparation. Intravenous access should be attempted as soon as possible following IO catheter placement, ideally within 2 hours to reduce the risk of complications from the IO catheter such as infection, inflammation, or even fracture.

Neonatal / pediatric fluid therapy

Neonates have a higher percentage of total body water, a greater surface area to body weight ratio, a higher metabolic rate, more permeable skin, decreased renal concentrating ability, and decreased body fat as compared to adults.  For these reasons, neonates have higher fluid requirements and must be treated accordingly. 

• Shock boluses of isotonic crystalloids are slightly higher in neonates, 30–40 mL/kg in puppies and 20–30 mL/kg in kittens as compared to adults. 

• Maintenance rates of isotonic crystalloids are also slightly higher, reported to be  80–100 mL/kg/day. 

It is important to keep the fluids warm due to the concern for hypothermic changes with large volume of potentially cool fluids in neonates and pediatrics.

Neonatal / pediatric supplementation

Hypoglycemia is common in these patients due to a combination of factors including inefficient hepatic gluconeogenesis, decreased liver glycogen stores, decreased intake, and loss of glucose in the urine as urinary glucose reabsorption does not normalize until approximately 3 weeks in puppies. Gastrointestinal losses such as vomiting, diarrhea, as well as lack of intake also can exacerbate hypoglycemia in neonates.

Critically ill neonates may require a dextrose bolus of 12.5% dextrose IV or IO (0.1 to 0.2 mL/100 g), followed by a constant-rate infusion of 1% to 5% dextrose in a balanced electrolyte solution to prevent rebound hypoglycemia.

Neonatal / pediatric temperature regulation

Neonates have a greater surface area-to-volume ratio, impaired shivering reflex and decreased vasoconstrictive ability as compared to adults and for this reason have an increased risk for hypothermia. Hypothermic patients should be rewarmed accordingly.

Neonatal / pediatric nutrition

If there is a concern for insufficient nutrition, often nursing from the bitch or queen, nutritional supplementation is recommended via alternatives such as bottle-feeding and tube feeding. Tube feeding is performed using a small suction catheter or a 5-Fr red rubber catheter for neonates under 300grams and an 8–10 Fr for larger neonates.  It is important to confirm proper placement prior to milk administration due to the risk for placement in the trachea and subsequent pneumonitis or pneumonia.  Puppies are expected to double their weight within 10 days of birth and gain 5–10%/day. Nursing kittens should also double their weight within the first 10 days of life and normal kittens gain 10–15 g/day.

Postpartum emergencies

Dystocia

Dystocia is defined as the inability to expel fetus from the uterus and birth canal at the expected time of parturition.  This is an emergency that requires immediate attention to reduce both the risk of morbidity and mortality to the mother and fetus.  Common causes for dystocia include a pelvic obstruction, an oversized fetus, fetal malpresentation, or fetal death.  If possible, an attempt should be made to manually remove the fetus if protruding from the vaginal vault.  This is performed with a water-based sterile lubricant and gentle traction wearing sterile gloves.  Instruments that may injure the mother or fetus should be avoided if possible.

For patients with dystocia it is also important to correct any fluid, electrolyte, calcium, and glucose imbalances. Oxytocin is commonly used, but important to understand the risks and why dosing currently is likely far less than what veterinarians used years ago.  Excess dosing of oxytocin can lead to tetanic and unproductive uterine contractions, placental separation and fetal hypoxia. It is also important to identify obstructive dystocia, closed cervix, fetal distress, placental separation, uterine disease, an/or uterine rupture prior to administration of oxytocin.  If ruled out, oxytocin can be considered at 1–5 IU SC or IM repeating in 20-30 minutes if ineffective. Calcium gluconate 10% as well as dextrose supplementation can also be considered if electrolyte support is a concern.

Uterine prolapse

Uterine prolapse may be seen during birthing or commonly within 48 hours following birthing when the cervix is open.  Due to the risk of infection, trauma and necrosis, immediate therapy is warranted. If appreciated early in the process, digital manipulation can be attempted, replacing the uterus while the patient is under general anesthesia.  If not found immediately, uterine tissue swelling prevents successful digital manipulation and additional therapy may be needed.  Hyperosmotic fluids such as 50% dextrose or mannitol may decrease tissue swelling and assist with replacement.  In more severe cases, an episiotomy or abdominal surgery are needed to manually reduce the prolapse. If infection or necrosis is identified, ovariohysterectomy is indicated.

Retained placenta

Placentas should pass within 15 minutes of each puppy or kitten. Retained placentas carry the risk for metritis.  Clinical signs of a retained placenta and subsequent metritis include a foul smelling discharge, fever, vomiting, anorexia, and lethargy.  While an astute owner may report the failure of the placenta to pass, this can also be confirmed via ultrasound. Treatment with antibiotics, oxytocin, or PGF2a can be considered.

Metritis

Clinical signs of metritis include anorexia, depression, lethargy, fever, and foul smelling vaginal discharge. Diagnosis of metritis is based not only on history and examination findings, but often confirmed via abdominal ultrasound. Additional diagnostic findings that can aid in the diagnosis include a complete blood count (leukocytosis with left shift) as well as a deep vaginal swab for culture and sensitivity. 

Hypocalcemia

Commonly referred to as eclampsia, hypocalcemia is a fairly common condition in bitches, notably small breed patients, 2–3 weeks after delivery. It is uncommon in cats, but can occur. Signs of hypocalcemia include tremors, panting, stiffness, pacing, salivation and restlessness. As it progresses the patient may exhibit worsening signs including tetany, hyperthermia, tachycardia, and seizure behavior. The treatment of choice is 10% calcium gluconate; administered slowly with the patient monitored on ECG.  The dose range is 0.22-0.44mg/kg administered slowly IV until signs improve. Other signs such as dehydration or hypoglycemia should be treated accordingly. Oral calcium treatment (500 mg TID per 20 lbs) as well as vitamin D (10,000-25,000 IU) should be continued throughout the rest of lactation with the recommendation of removing the puppies from the bitch and supplemented with milk replacer, at minimum for 12-24.

Mastitis

Mastitis is the term documenting inflammation of the mammary gland, commonly associated with infection. The most common bacteria isolated include Staphylococcus sp. and Streptococcus sp. Clinical signs may be localized to one gland or throughout multiple glands.  The glands affected are often warm to the touch, painful, firm, and erythematous. Diagnosis is based on clinical signs, history, cytology of milk confirms, and ideally culture and sensitivity. Broad spectrum antibiotics that achieve good concentration in milk (cephalexin or clavamox).

References

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Davidson AP. Obstetrical monitoring in dogs. Vet Med 2003;6: 508.

Davidson AP. Dystocia management. In: JD Bonagura, ed. Kirk's Veterinary Therapy XIV. WB Saunders Co, Philadelphia, PA, in press.

Davidson A. Postpartum disorders in the bitch, queen & neonates. Western Veterinary Conference 2008.

Feldman EC, Nelson RW. Periparturient diseases. In: Veterinary Reproduction and Endocrinology. Philadelphia, WB Saunders, 1996.

Johnston SD, Root Kustritz MV, Olson PNS. The neonate - from birth to weaning. In: Johnston SD, Root Kustritz MV, Olson PNS, eds. Canine and Feline Theriogenology, 1st edition. Philadelphia: WB Saunders; 2001:146–167.

Johnston SD, Root Kustritz MV, Olson PN. Canine and Feline Theriogenology. Philadelphia: WB Saunders Co, 2001

Macintire DK. Reproductive emergencies, Atlantic Coast Veterinary Conference 2006

Smith FO. Postpartum diseases. Vet Clin North Am Small Anim Pract. 1986;16(3):521-524

Wallace MS. Management of parturition and problems of the periparturient period of dogs and cats. Sem Vet Med Surg (Small Anim) 1994;9(1).