Equine Neonatology 1 + 2 Y3 Flashcards
When is a foal classed as premature?
A foal born at a gestational age of < 320 days that displays immature physical characteristics
When is a foal classed as dysmature?
A full-term foal that displays immature physical characteristics
- Full term average 340 d
Name 4 characteristics of prematurity/dysmaturity
Low birth weight
Short, silky hair coat
Floppy ears
Domed head
Describe the neonate immune system
Foals are immunocompetant at birth
Competent specific & non-specific immune system
But immunologically naïve
Autogenous IgG adult levels by 4 months of age
Which cells are responsible for colostrum absorption?
Enterocytes
Describe the features of enterocytes
- Specialist enterocytes absorb the immunoglobulins by pinocytosis
- These cells have a lifespan of a maximum of twenty-four hours
- Maximum absorption occurs within eight hours of life
When are the IgG levels considered to be normal?
Normal transfer > 8 g/l
When are the IgG levels indicating FPT?
FPT IgG < 4 g/l
PFPT IgG 4-8 g/l
List the predisposing factors for failure of passive transfer
- Premature lactation: twinning, placentitis
- Inadequate colostrum production: severe illness, premature foaling
- Failure to ingest an adequate volume of colostrum: weak foal, foal rejection
- Failure to absorb colostrum: premature foals and/or foals with concurrent illnesses
When does the greatest absorption of IgG occur?
Within the first 6 hours of life
When can IgG levels be read?
Peak IgG 18 hours
Best time to test?
- Before 18 hours so the enterocytes haven’t closed and colostrum can still be administered if the levels of IgG are low
- Around 12 hours
How can failure of passive transfer be treated?
To treat or not in an otherwise normal foal?
If delay in suck is obvious, give colostrum
Always treat sick foals
> 12-24 hours need plasma from the mare
What is the main risk of treating FPT?
Septicaemia
What are the main risk factors for neonatal illnesses?
- Health of the dam during gestation
- Gestational and foaling environment
- Ease of delivery
- Foal’s gestational age at birth
- Placental abnormalities
- Adequacy of placental transfer of maternal immunoglobulin
What is the normal time for the suck reflex in a newborn foal?
20 minutes
How long should it take for a foal to stand and suck?
Stand in 1 hour, suck within 2
What is meconium?
Dark brown pellets or paste all passed within 24 hours
How long should it take a foal to urinate?
Dilute and large volumes first passed by six hours (colts) or ten hours (fillies)
What is the average weight of a thoroughbred foal?
45-55kg
How much weight should a foal gain per day?
0.5-1.5kg per day
What is the normal temp of a foal?
37.2 - 38.9oC
38.5 is the maximum for an adult horse
What is the heart rate of a foal?
Birth: 40 - 80 bpm
First week: 60 - 100 bpm
What is the normal respiratory rate of a foal?
45 to 60 brpm
7 days of age - 35 to 50 brpm
Describe the basic intensive medical therapy required for a sick foal?
- Fluids
- Antibiotics
- Immunoglobulin (plasma or hyperimmune serum)
- Anti-inflammatory
- Circulatory support
- Antiulcer meds
- Respiratory stimulants E.g. caffiene
- Diuretics if persistent oliguria: Furosemide or mannitol (usually reflects CO)
Which anti-inflammatory is given to foals with septicaemia?
Flunixin 0.5 - 1 mg/kg bid
Name 2 anti-ulcer medications
Sucralfate
Omeprazole
How should a foal be fed?
Need 20% BWT in milk/day – 10L minimum split into 2 hourly or more frequent feeds
Care re reflux, air, aspiration
How should a foal undergoing intensive nursing care be monitored?
- Repeat clinical examinations frequently
- Fluids ins and outs (esp. urine output)
- Laboratory - Electrolytes, foal profile, urine SpG
- Radiography
- Ultrasonography
- Blood pressure
- Arterial blood gasses
- Cardiac output
Which antibiotics can be used in foals?
- Aminoglycosides
- Care in very young foals -nephrotoxicity
- Used in conjunction with gram positive cover - Penicillins and other beta-lactams
- Ceftiofur (high, frequent doses e.g. 5 mg/kg, QID compared to adults 2mg/kg S or BID)
- Cefquinome 1mg/kg
Describe the respiratory support that can be given to foals
- Postural: Moving the foal from lateral to sternal recumbency is one of the most important things that you can do to improve respiratory function
- Intranasal oxygen
- Mechanical ventilation
- Drugs (bronchodilators, central stimulants)
What is the most important differential in the sick foal?
Septicaemia
What are the risk factors for septicaemia?
FPT
Hygiene
Stress
Poor management
Disease
Pathogen virulence
Name some common pathogens involved in septicaemia
E coli, Actinobacillus, Salmonella spp., Proteus, Klebsiella, other gram negative spp.
Beta-haemolytic Strepococcus, Staphylococcus, Clostridia
Mixed infections possible
How do septicaemic organisms enter the foal?
Openings - umbilicus?
Open gut
Inhalation
In utero
What are the clinical signs of septicaemia?
- Off suck
- Lethargic
- Increase RR and effort
- Acute severe lameness
- Discharger or swelling of umbilicus
- Inconsistent fever
- Congested, dark mm or petechial haemorrhages
- Hypopyon: inflammation of the anterior chamber of the eye
- Diarrhoea
- Meningitis
Describe SIRS (septic shock)
- Vasoactive inflammatory mediators lead to vasodilation
- Increased metabolic rate and oxygen consumption
- Cardiac output is increased initially (hyperdynamic phase)
- Microvascular permeability leads to volume maldistribution
- Increased cardiac output can no longer be maintained (hypodynamic phase)
How is a blood culture used to identify sepsis?
- Obtain blood in sterile manner
- Prior antibiotic administration reduces likelihood of positive culture
- Antibiotic sensitivity
- Delay before results available
- Provides information on pathogens in your area
How can umbilical US help diagnose sepsis?
If the umbilical artery is larger than 1cm then it means its infected
Hyperechoic arteries
What are the DDx for a foal with respiratory signs?
- Neonatal septicaemia (bacterial pneumonia)
- Viral pneumonia
- Meconium aspiration
- Aspiration pneumonia
- Haemothorax and pneumothorax
- Respiratory distress syndrome
- Pulmonary hypertension
- Central respiratory depression
What does SCID stand for?
Severe compromised immunodeficiency
Describe the main features of SCID
- Failure to produce functional B and T lymphocytes
- Autosomal recessive in Arabians and part breds
- Normal at birth disease begins at 1 to 2 months of age
- Lethal
How is SCID diagnosed?
- Appropriate clinical signs
- Persistent lymphopaenia < 1x 109/L
- Confirmation by post mortem - gross and histopathological - hypoplasia in lymph nodes, thymus and spleen
Perinatal asphyxia syndrome is also known as?
Dummy foal syndrome
Hypoxic-Ischemic Encephalopathy
What is perinatal asphyxia syndrome?
Ischaemia, oedema and reperfusion injury to foal’s brain, kidneys, intestine and other organs due to lack of oxygen
What does PAS present?
May not be apparent until the foal is 12-24 hours old
What is the main sign of PAS?
Hypoxic encephalopathy
What are the mild CS of PAS?
Unable to attach to mare, poor suck reflex
What are the moderate CS of PAS?
Aimless wandering
Abnormal phonation (barkers)
Blind
What are the severe CS of PAS?
Seizures, coma
How is PAS managed/treated?
Antibiotics (short term), nutrition, care of eyes, stop damage to self
Control of seizures = Diazepam, phenobarbital
How does a ruptured bladder occur?
Usually excessive pressure during parturition on a distended bladder
Also could be a congenital defect
How does a ruptured bladder present?
- Most common in colts and signs are normally present within the first 2-3 days of life
- Dysuria esp. stranguria
- Frequent attempts to urinate with only small amounts voided
- Depression and abdominal distension may be more apparent after 2 days
Describe the biochemical changes seen with a ruptured bladder
Post-renal azotaemia with hyponatraemia, hypochloraemia and hyperkalaemia
Equilibration of urine in the abdominal cavity with serum electrolytes
How else can a ruptured bladder be diagnosed?
- US confirms large amount of fluid in the abdomen
- Compare creatinine conc of the peritoneal fluid to that of serum and if > 2:1 confirms diagnosis
- May see calcium carbonate crystals in peritoneal fluid
- Check if increased inflammation in abdomen - rarely see in uncomplicated cases
How is a ruptured bladder treated?
Emergency surgery is usually not required - often best to manage medically first
Good out come (>80%) with surgery if performed on a stabilised foal
What are the DDx for a foal with colic?
- Meconium impaction – most common
- Ruptured bladder/uroperitoneum
- Overfeeding/lactose intolerance
- Distension associated with diarrhoea
- Gastric ulcers
- SI/LI obstruction
- Congenital abnormalities
What are the DDx for foal anaemia?
- Blood loss – low protein E.g. umbilical artery or post natal haemorrhage from trauma, injury
- Haemolysis – normal protein e.g. esp. neonatal isoerythrolysis
How does neonatal isoerythrolysis present?
Haemolytic anaemia from 24hr
How is neonatal isoerythrolysis diagnosed?
- Confirm by detecting Ab on red cells (Coombs test)
- Supported by demonstrating red cell antibodies in colostrum using agglutination or haemolytic assays
How is neonatal isoerythrolysis treated?
PCV > 15% remove source till safe and limit movement and stress (including handling)
<15% blood transfusion - Ensure compatible!
Supportive care for sick foal = antibiotics, anti-ulcer meds, monitor fluids, glucose, nursing
What are the DDx for neonatal foal diarrhoea?
- Foal heat diarrhoea at about 7 days old
- Neonatal septicaemia/infectious diarrhoea (E.coli, Salmonella, other G negs, Clostridia)
What are the clinical signs of foal heat diarrhoea?
Mild, self-limiting diarrhoea
Foal generally remains bright and sucking
How is foal heat diarrhoea treated?
Nothing
Intestinal protectants e.g. kaolin, bisthmus subsalicylate
Probiotics
Prognosis = good
How does Clostridial D+ present?
- Severe, peracute, frequently fatal
- Necrotising - foul smelling faeces
- Seen in individual septicaemic foals and also as outbreaks
- Severe gas distension and colic
- Contagious - ISOLATE
How is Clostridial D+ diagnosed?
Culture – normal flora so interpretation difficult
ELISA or PCR (for toxins: CPE, β2, Toxin A)
Gas in or on the mucosa on ultrasound
How is Clostridial D+ treated?
Metronidazole or penicillin
What are the DDx for diarrhoea in foals 10d +?
- Rota virus
- Other viruses (coronavirus, adenovirus, parvovirus)
- Crytosporidium parvum
- Rhodococcus equi
- Lawsonia intracellularis
How does Rotavirus affect foals?
1 - 4 weeks of age
Highly infectious - occurs in outbreaks
How is rotavirus diagnosed?
Electron microscopy
ELISA - kits available for use in practice labs
How does Rhodococcus equi cause D+?
Excreted in dams’ faeces, builds up on pasture in warm, dry conditions, ingested, colonizes white blood cells, abscessation
- Enteric infection: persistent diarrhoea, fever
- Intra-abdominal abscess: fever, colic
- Less common that respiratory forms
How is rotavirus treated?
Passive immunisation
Supportive therapy
What is the causative agent of Equine Proliferative Enteropathy?
Lawsonia intracellularis
What are the clinical signs of equine proliferative enteropathy?
- Weight loss oedema, lethargy depression weakness
- Diarrhoea, mild colic, episodic pyrexia less common
- 3 – 11 months of age less commonly older
How is equine proliferative enteropathy diagnosed?
Dx ultrasonography
Hypoproteinaemia
PCR of faeces and serology (both only moderate sensitivity)
How is equine proliferative enteropathy treated?
e.g. Erythromycin/rifampin
Oxytetracycline
Should see rapid response
