Disease of the equine neonate pt 2 Flashcards
Terms widely used for newborn foals with neurological signs of non-infectious nature
- Neonatal maladjustment syndrome (NMS)
- Dummy foal syndrome
- Neonatal encephalopathy (NE)
Neonatal Maladjustment Syndrome
- do we have good mechanistic info?
- Foal-specific mechanistic information is lacking – most extrapolated from other species
Terms widely used for newborn foals with neurological signs of non-infectious nature
<><><> - We often assume that foals with signs of disorientation / recumbency (of neurological nature) in the immediate post-partum period have a similar underlying pathophysiology.
- Many processes can alter neuronal function and treatment could be different.
Neonatal Maladjustment Syndrome
- common outcome?
- Most NMS foals recover with supportive care and without CNS sequelae
connection between neurosteroid levels and dummy foal syndrome? and sick foals?
- there are neurosteroids produced in normal foals in utero, which have some inhibitory effects on consciousness, gut motility, suck reflex, and movement
- these are normally degraded at birth, but in dummy foals (and sick foals) levels tend to be higher in neonates than for healthy foals
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Progestogens remain elevated in sicker (septic) foals
Neonatal encephalopathy (NE) is a broad term used for:
foals (and infants) that develop non-infectious neurologic signs in the immediate postpartum period.
Controversies about equine NE and neonatal maladjustment syndrome (NMS) relate to:
- the lack of pathophysiologic information and target-specific therapies
- most mechanistic explanations extrapolated from other species.
Neonatal Maladjustment Syndrome
- is it a single clinical condition? what do we base our understanding on?
Based on clinical history, clinical signs, postmortem findings, and recent association of NE with neuroactive steroids, it is likely that NE represents different syndromes with shared clinical features.
probably the main contributors to NE:
- Ischemia/hypoxia and endocrine/paracrine imbalances
Foals with NE can have abnormalities in:
other organs that may go unnoticed
connection between progesterone levels in sick foals and outcomes, and dummy foals
Critically ill foals with high progesterone concentrations have more severe disease and are more likely to die than those with normal progesterone concentrations
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Progestogens tend to be higher in “dummy foals”
hypoxia vs ischemia
Hypoxia
* Low oxygen tension
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Ischemia
* Decreased delivery to tissues
* Anaerobic metabolism
pathogenesis of hypoxic ischemic encephalopathy
hypoxemia
> systemic hypotension
> regional hypoxia-ischemia
> ionic shifts and depolarization, energy failure
> neurotransmitter release increased, Ca++ activated, phospholipid degradation, increased free radicals, lipid peroxidation…
> disrupted cell memnranes and metabolic machinery
> seizures, status epilepticus
> blodd-brain barrier disruption, brain edema
NMS can impact what organs?
Multi-organ condition
* Central nervous system
* Renal
* Gastrointestinal
* Respiratory
* Cardiovascular
* Etc…
NMS neurological signs
- Hyperesthesia
- Aimless wandering
- Lack of recognition of dam
- Spastic gait
- Ataxia
- Loss of suckle, decreased tongue tone
- Abnormal sounds (“Barking”)
- Dysphagia
<><><> - Cortical blindness
- Variable pupil size
- Nystagmus, abnormal eye position
- Head pressing
- Irregular respiration
- Depression, stupor
- Seizures
NMS non-neuro clinical signs
Organ dysfunction:
* Respiratory effort and/or rate
* Respiratory distress
* Poor urine output
* Edema
* Icterus
* Diarrhea
* Gastric reflux
* Colic
NMS Dx
- Clinical signs
- CSF analysis
- Rule out other differentials
<><> - Assessment of other organ function
- CBC and biochemistry
- Arterial blood gases
- Thoracic radiographs
Ddx for NMS
- Septicemia
- Metabolic
- Meningitis
- Congenital malformations, etc.
NMS: Treatment
Control seizure activity
* Diazepam
* Phenobarbital
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Reduce CNS edema
* Furosemide
* Mannitol (avoid if hemorrhage suspected)
* Hypertonic saline
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Judicious fluid therapy
* Avoid volume overload
* Maintain normal blood glucose
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Hypothermia (33o-33.5oC for 72h)
* slow and controlled rewarming
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Oxygenation
* Intranasal
* Ventilation
* Standing or sternal recumbency!!!
* Respiratory stimulants (caffeine)
* Improve oxygen delivery to tissues
* Prevent reestablishment of fetal circulation
* Prevent decreased surfactant production
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Squeeze = foal hugging
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Restore renal function
* Judicious fluid therapy
* Monitor output
* Diuresis
* Dopamine, dobutamine
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Restore gastrointestinal function
* Nasogastric reflux
* Nutritional support
* Enema
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* Anti-inflammatories (?)
* Nursing care
what is the purpose of foal hugging for NMS? what is it?
squeeze procedure eg. with rope for maladjusted foal, for 20 min
> arousal increased when released from squeeze
> consciousness, suckling from mare
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- theory is this works via stimulating birth, cause release of norepinephrine, decrease neurosteroids…
how to control seizure activity in NMS foal
- Diazepam
- Phenobarbital
how to reduce CNS edema in NMS foal
- Furosemide
- Mannitol (avoid if hemorrhage suspected)
- Hypertonic saline
purpose of oxygenation for NMS syndrome?
how can we do it?
- Improve oxygen delivery to tissues
- Prevent reestablishment of fetal circulation
- Prevent decreased surfactant production
<><><> - Intranasal
- Ventilation
- Standing or sternal recumbency!!!
- Respiratory stimulants (caffeine)
how to restore renal function in NMS foal?
- Judicious fluid therapy
- Monitor output
- Diuresis
- Dopamine, dobutamine
how to restore GI function in NMS foal?
- Nasogastric reflux
- Nutritional support
- Enema
hypothermia for newborns with NMS / hypoxic- ischemic encephalopathy?
- cooling seems to be an effective treatment in humans
NMS prognosis? what can affect this?
- Impossible to initially predict the outcome of a dummy foal!
- > 70% recover
- Monitor for 2o complications that
could affect prognosis - Anticipate and prevent!
number one differential for sepsis?
dummy foal
- and vise versa
- possible to have both conditions
Most common cause of colic in neonates.
Meconium Impaction
after what time period since parturition should we consider meconium impaction
If meconium has not been passed within 12-24 hours, should consider meconium impaction.
meconium impaction prognosis
Usually resolves with medical intervention.
meconium impaction categories
primary
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secondary
* Dehydration
* Ileus
* Poor intake
meconium impaction clinical signs
- Depression
- Poor nursing
- Straining to defecate
- Repeated posturing
- Abdominal distension
- Intestinal tympany
- Owner has not seen feces yet
meconium impaction Dx
- Digital rectal examination
- Abdominal radiographs
- Abdominal ultrasonography
Meconium Impaction: Treatment
- Routine enemas.
- Intravenous fluids.
- Acetylcysteine (Mucomyst) enema.
<><> - Surgery: Exploratory laparotomy
meconium impaction pain management
Sedatives and analgesics
* Butorphanol
* Xylazine
* Daizepam
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NSAIDs
* Flunixin meglumine
* Ketoprofen
