NEONATOLOGY

1. NEONATOLOGY

2. Prepartum evaluation • Evaluation should include assessment of the placenta, repro system and fetal fluids • Transrectal palpation • Transrectal and transabdominal ultrasound • After 6 months of gestation use both types of ultrasound • Do not do vaginal or speculum exam (increased risk of infection)

3. Readiness for birth • Hard to determine therefore induction is not recommended • Udder development • W/in last months of gestation • Secretion thin watery and clear then start to increase in opacity d/t increasing calcium levels • Pulmonary maturity • Amniotic fluid lecithin/sphyngomyelin rations are not predictive in the foal • Abdominocentesis has a high risk of abortion • Interfere if there is persistent fetal tachycardia

4. Specific fetal evaluation • Fetal HR from 65-115 bpm (episodic bradycardia/tachycardia occurs) • Persistent tachycardia is a sign of fetal distress

5. Postpartum evaluation • Should be standing by 2 hours • Should start nursing no later than the first 3 hours • All of the meconium should be passed by 36-48 hours • First urination at 8.5 hours (longer for fillies) • Temp: 99-102 F • Resp: 60-80 breaths/min decreases to 30 breaths/min w/in first hour

6. Postpartum evaluation • CV system • 40-80 beats/ min immediately after birth • Increases to 120-150 beats/ min for several hours • Stabilizes to 80-100 beats/ min w/in first week • L to R PDA may be normal in the first 24-48 hours; the foal may then close the PDA (if it reopens the foal may have oxygen tension problems) • Nervous system • Immature cerebellum when born • May note excessive jerky movements • Usually goes away within the first few months

7. Meconium Impaction • MOST FREQUENT CAUSE OF COLIC IN THE NEONATAL FOAL • Time period: usually within first 24 hours (can be a couple days later if it’s a high impaction) • Etiology: high (large colon) or low (small colon) • CS: similar to adult colic • Tx • Enema’s: mild soapy solution or acetylcystein diluted in water with bicarb • Mineral oil by NG tube • IV fluids

8. Ruptured Bladder • Colic starts 24-72 hours after birth • Signalment: male foals more commonly • Risk factors • Difficult births • Umbilical/urachal infections • CS • Similar to meconium impaction • Straining posturing to urinate • Pathophysiology • Rupture due to excessive pressure on a full bladder (during travel through the pelvic canal)

9. Ruptured Bladder • Dx • Serum chemistries: hyponatremia/chloremia, hyperkalemia; BUN and Cr elevated • Abdominal ultrasound: peritoneal effusion • Contrast cystogram of the bladder (see the hole) • Abdominocentesis: elevated Cr, infuse bladder with methylene blue and check color of fluid via abdominocentesis

10. Ruptured Bladder • Tx • Medical emergency (not a surgical emergency) • Stabilize patient prior to sx • Drain abdomen to remove K • Fluids (avoid K containing fluids) • Sx repair of the bladder

11. Uroabdomen • Indistinguishable from ruptured bladder • D/t leakage from the urachus near or at the attachment to the bladder • Develops in foals with sepsis and urachal infections

12. GI Ulceration • Occurs due to stress or NSAID toxicity • Up to 50% of foals develop GIT ulcers within the first 3-4 months • Lesions in the squamous mucosa are due to gastric acidity issues • Lesions in the glandular mucosa is due to mucosal protection issues • CS: similar to meconium impaction • Typically CS at 24-72 hours of age • Colic- dorsal recumbency • Ptyalism • Most have lesions in the non glandular portion but <5% show CS

13. GI Ulceration • Dx • CS • Endoscopy • Fecal occult blood, gastric content blood • Tx • H2 blockers: cimetidine, ranitidine, famotidine • Omeprazole: complete blockage of acid secretion but not yet approved for foals < 30 days old

14. UlcersAdults vs foals

15. The Sick Foal • Premature: foal of gestational age less than 320 days • Dysmature: foal born at >325 days but displaying characteristics of immaturity or being undersized • Small for gestational age • Intrauterine growth retardation: neonate having suffered arrested, altered or slowed development due to some derangement in intrauterine environment

16. Prematurity • Physical characteristics • Decreased suckle reflex • Short, silky coat • Hyperextension of the fetlocks • Floppy ears • Labored respirations (atypical) • Metabolic and lab characteristics • Temp fluctuations • Leukopenia w Neut:Lympho ratio close to 1 • Low resting cortisol • Abnormal cortisol stimulation: poor response to ACTH

17. Prematurity • Dx • Hx, PE, complete lab evaluation • Neuro evaluation: weak and quiet, sleep more • Cuboidal bone ossification index • 1- some cuboidal bones show no evidence of ossification • 2- all cuboidal bones show some ossification • 3- cuboidal bones small and rounded- larger joint spaces • 4- normal ossification • Therapy: • Nursing care • Immunologic support: colostrum, Ig administration

18. Failure of Passive Transfer • PFPT = Serum IgG<800 • Total FPT = Serum IgG<200 • Predisposing factors • PREMATURITY is the #1 risk factor • Mare factors: poor quality (primiparous), loss prior to birth • Foal factors: poor ingestion, GIT absorption problems

19. Colostrum • Epitheliochorial placentation in the horse allows for no transfer of Ig’s in utero • Colostrum provides • Ig’s, energy requirements, growth factors, leukocytes, laxatives, various factors which enhance the intestinal absorption of the colostrum • How is it produced • Serum Ig’s get extracted and concentrated in the mammary gland. • Usually in last month of gestation the mare is vaccinated to increase levels of Ig’s in colostrum • Good quality IgG content >3000 mg/dl (SG > 1.060)

20. Immunological Asssessment of the foal • Test the foal no later than 12 hours post birth • Should have at least 800 mg/dl • Single radial immunodiffusion “gold standard” • Expensive, results take 24 houss • ELISA (CITE test) • Rapid, easily acts as its own control • Snap test available

21. Treatment of FPT • If <12 hours: administer colostrum • If between 12-24 hours • <400: good colostrum or plasma transfusion • >400: good colostrum • If greater than 24 hours: plasma transfusion, use commercially available frozen plasma

22. Neonatal Septicemia • FPT IS THE MAJOR PREDISPOSING FACTOR • Etiology: E.coli, klebsiella, actinobacillus equuli • CS: pyrexia rare; typically normothermic • Dx • Positive blood culture (takes about 72 hours to get results) • Should recommend 3 cultures but 92% will be positive on the first culture • 60-81% of confirmed septic foals have positive blood cultures

23. Neonatal Septicemia • Dx • In utero acquired infection • Increased fibrinogen • Neutrophilia • Elevated creatinine • Neonatal foal Sepsis score • Pertinent historical and physical exam findings w CBC and chemistry results (showing organ dysfunction) -> predicts the likelihood of sepsis • Score of >12 correctly predicts sepsis 93% of the time

24. Neonatal Septicemia • Tx • Antimicrobials • Penicillin and amikacin • Not per os administration • If CNS (septic meningitis) change to 3rd gen cephalosporins, cefataxime, moxalactam) • Immunological support: • Commercial plasma and endoserum • Supportive therapy • Anti-inflammtories, anti-ulcer meds • Fluid therapy: D5W, LRS

25. Neonatal Septicemia • Complications and Sequelae • Chronic pneumonia (50%) • Ileus, enteritis, colitis, diarrhea (38%) • Joint ill: occurs later after the septicemia seems like it has a good resolution, tx: repeated flushing of joints • Patent urachus or uroabdomen • Septic meningitis: depressed, altered mentation, head pressing, seizures