Dummy Foal and NMS Flashcards
what terms are used for Dummy foals with perinatal asphyxia syndrome (PAS)
Perinatal Asphyxia Syndrome (PAS)
Neonatal Encephalopathy (NE)
Hypoxic Ischemic Encephalopathy/Syndrome (HIE/HIS)
Dummy Foal
Wanderer
Barker Foal
Others
what is PAS
perinatal asphyxia syndrome
Hypoxia of tissues occurring during parturition
Dystocia
Premature placental separation
C section
what are the most sensitive organs to PAS
Brain
- Hypoxic ischemic encephalopathy (HIE)
GI
Kidney
what are the pathophysiology of PAS
Reduced oxygen delivery to neuronal cells
Other places as well
Initial phase: energy failure due to oxygen and glucose depletion
- Depletion of ATP, failure of membrane pump — cell swelling and lysis
- Glutamate accumulation in extracellular space
Delayed phase: hyperemia and cytotoxic edema
- Ca enters cells (glutamate receptor/NDMA)
- Ca leads to activation of enzymes
- Foals can deteriorate significantly in the delayed phase (48hrs after birth)
what are the signs of PAS
Behavioural change
Altered mentation
Loss of suckle/dysphagia
Seizures
Ileus or diarrhea
Renal failure
Can reflect hypoxic injury to any body system
how is PAS treated
Depends on severity
Supportive care
Maintain tissue perfusion:
- Normotensive, normovolemic
- Or potentially vasopressors
Oxygen therapy
Manage seizure activity
Manage organ damage
Therapeutic hypothermia?
what is the prognosis of PAS
Good:
Up to 8-% survival and achieve athletic function
Foals that exhibit seizure activity within the first 24 hours have poorer outcomes
Secondary sepsis significantly reduces prognosis
what is the difference between PAS and neonatal maladjustment syndrome
These foals are also referred to as ‘Dummy foals’. But they are actually different
NMS has very different pathophysiology, and so therefore different treatment options
However clinically the two look very similar, and in the past there was confusion as to how to separate the conditions
Foals which appear to be dummy foals but have no history of hypoxic event
Often the opposite — foals delivered very fast
what is the pathophysiology of NMS
Normal in utero unconsciousness
- Maintained by adenosine, progesterone and related to neurosteroids (allopregnanolone and pregnanolone)
This must rapidly transition to autonomous activity at birth
Pressure of the birth canal during stage 2 labour might play a role in neonatal transition from neuroinhibition to neuroactivation
Foals with NMS have persistence of neurosteroids
History usually includes a rapid birth
how is NMS treated
Stimulates stage 2 labour
- Compression of the thorax
- Madigan foal squeeze
- Thought to reset neurotransmitters
- Supportive care
when is the madigan squeeze contraindicated
For foals with NMS:
NOT for hypoxia related ‘dummy foals’
Contraindicated in:
Systemically sick foals
Respiratory disease
Rib fractures