Perinatal brain injury

Question 1

What are the three parts of the recovery phase?

Answer 1

reperfusion 0-30min
early latent phase 30min-6hr
late secondary phase 6hr-48days

Question 2

What is Penumbra?

Answer 2

moderate ischaemic damage

Question 3

What is the only medical intervention that can treat perinatal brain damage?

Answer 3

cerebral hypothermia

33-34 degrees for 3 days

Question 4

When is the best time to treat with cerebral hypothermia?

Answer 4

Cerebral hypothermia only has efficacy if started in the latent phase. By the time reach secondary phase it’s too late.

Question 5

Can we detect injury?

Answer 5

by heart rate etc. Often by the time is is visible in brain activity etc it is too late to treat.

Question 6

What is latent phase hypo perfusion?

Answer 6

When the brain is in latent phase, the blood vessels vasoconstrict. This is possibly a protective mechanism.

Question 7

What is NIRS?

Answer 7

near infrared spectroscopy

detects failure of cerebral oxidative metabolism

Question 8

What happens with severe asphyxia?

Answer 8

There is evidence of delayed secondary impairment of cerebral oxidative metabolism

Question 9

What controls latent phase hypoperfusion?

Answer 9

the SNS

Question 10

What controls latent phase EEG?

Answer 10

controlled in part by the SNS

Question 11

Is latent phase EEG suppression protective?

Answer 11

it is partially protective. Blocking EEG leads to spikes which are damaging but these spikes can be prevented which reduces brain injury.

Question 12

What is glutatmate excitotoxicity?

Answer 12

overactivation of glutamate receptors to increase intracellular calcium and trigger cell death

Question 13

What happens to glutamate receptors during the insult?

Answer 13

energy deficit leads to failure of glutamate transporters leading to increased extracellular glutamate and over activated glutamate receptors

Question 14

What happens with glutamate after the insults?

Answer 14

The cerebral energy is normal so the glutamate levels are normal but the receptors are now hypersensitive to glutamate, so they are overactivated and there is a large influx of calcium leading to apoptosis.

Question 15

What are the characterisitcs of the latent phase?

Answer 15

recovery of cerebral oxidative metabolism
active partial inhibition of brain activity
hypoperfusion of the brain not related to blood pressure

Question 16

What do tests show during the secondary phase?

Answer 16

blood flow and oxygen are normal. There is hyperperfusion

Question 17

What is secondary oxidative metabolism failure driven by?

Answer 17

mitochondrial failure

Question 18

What is secondary phase edema?

Answer 18

Cells swell and die from the secondary oxidative metabolism failure

Question 19

What are the characteristics of the secondary phase?

Answer 19

Secondary failure of oxidative metabolism
Stereotypic evolving seizures (big seizures) Hyperaemia (increased CBF and volume)
Secondary edema – necrosis/lysis ongoing