Dummy Foal and NMS

Question 1

what terms are used for Dummy foals with perinatal asphyxia syndrome (PAS)

Answer 1

Perinatal Asphyxia Syndrome (PAS)

Neonatal Encephalopathy (NE)

Hypoxic Ischemic Encephalopathy/Syndrome (HIE/HIS)

Dummy Foal

Wanderer

Barker Foal

Others

Question 2

what is PAS

Answer 2

perinatal asphyxia syndrome

Hypoxia of tissues occurring during parturition

Dystocia

Premature placental separation

C section

Question 3

what are the most sensitive organs to PAS

Answer 3

Brain

• Hypoxic ischemic encephalopathy (HIE)

GI

Kidney

Question 4

what are the pathophysiology of PAS

Answer 4

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)

Question 5

what are the signs of PAS

Answer 5

Behavioural change

Altered mentation

Loss of suckle/dysphagia

Seizures

Ileus or diarrhea

Renal failure

Can reflect hypoxic injury to any body system

Question 6

how is PAS treated

Answer 6

Depends on severity

Supportive care

Maintain tissue perfusion:

• Normotensive, normovolemic
• Or potentially vasopressors

Oxygen therapy

Manage seizure activity

Manage organ damage

Therapeutic hypothermia?

Question 7

what is the prognosis of PAS

Answer 7

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

Question 8

what is the difference between PAS and neonatal maladjustment syndrome

Answer 8

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

Question 9

what is the pathophysiology of NMS

Answer 9

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

Question 10

how is NMS treated

Answer 10

Stimulates stage 2 labour

• Compression of the thorax
• Madigan foal squeeze
• Thought to reset neurotransmitters
• Supportive care

Question 11

when is the madigan squeeze contraindicated

Answer 11

For foals with NMS:

NOT for hypoxia related ‘dummy foals’

Contraindicated in:

Systemically sick foals

Respiratory disease

Rib fractures