[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Central nervous system](https://durgical.com/en/general-pathology/areas/cns/) › Global hypoxic-ischemic brain injury

# Global hypoxic-ischemic brain injury

- Lesion

When the whole brain loses blood or oxygen, as in cardiac arrest, the most sensitive neurons die first and border zones between arteries infarct.

Updated Nov 12, 2026

## Key points

- Most vulnerable neurons: hippocampal CA1 (Sommer sector), cerebellar Purkinje cells and cortical pyramidal cells in layers 3, 5 and 6.
- Laminar necrosis: a band of dead cortex along the middle layers from global hypoxia.
- Watershed (border zone) infarcts form between the anterior and middle cerebral artery territories, a parasagittal wedge.
- Carbon monoxide characteristically injures the globus pallidus.
- Brain death: irreversible loss of all brain function including the brainstem; at autopsy the ‘respirator brain’ is soft and autolysed.

## What it is

Global hypoxia or ischemia follows cardiac arrest, profound shock, severe hypotension, drowning, suffocation or carbon monoxide poisoning. The brain is affected unevenly: some neurons, such as CA1 pyramidal cells of the hippocampus and cerebellar Purkinje cells, are especially vulnerable, and the zones at the far ends of two arterial territories lose flow first. Severe, prolonged injury causes widespread necrosis and, if the whole brain dies while the body is ventilated, brain death.

## Step by step

- Systemic perfusion or blood oxygen falls below what the brain needs.
- Neurons with the highest activity and glutamate input fail first.
- Glutamate overload and calcium entry trigger cell death in vulnerable populations.
- If hypotension is sudden, border zones between arteries infarct.
- If restoration of flow is late, injury spreads to whole cortical layers and deep grey matter.
- Survivors may have amnesia, ataxia, seizures, a persistent vegetative state or brain death.

## Patterns of global hypoxic-ischemic injury

| Pattern | Where | Typical setting |
| --- | --- | --- |
| [Selective neuronal necrosis](https://durgical.com/en/conditions/cardiac-arrest/) | Hippocampus CA1, Purkinje cells, cortical layers | Brief cardiac arrest |
| Laminar (pseudolaminar) necrosis | Middle cortical layers, often in the depths of sulci | Prolonged hypoxia or hypotension |
| Watershed infarct | Border between anterior and middle cerebral artery territories | Sudden severe hypotension |
| [Pallidal necrosis](https://durgical.com/en/conditions/carbon-monoxide-poisoning/) | Globus pallidus | Carbon monoxide poisoning |
| [Diffuse necrosis and brain death](https://durgical.com/en/conditions/coma-and-brain-death/) | Whole brain | Prolonged arrest with later ventilation |

## Clinical notes

- Mild injury gives transient confusion; severe injury gives coma, myoclonus and poor outcome.
- Brain death is a clinical diagnosis with strict criteria; it is legally death in Colombia and most countries.

## Memory aid

In a blackout the hungriest go first: Sommer's hippocampus, Purkinje's cerebellum and the middle layers of the cortex.

## Test yourself

Think of the answer, then tap the question to see it.

## Which hippocampal region is most vulnerable to global ischemia?

The CA1 sector (Sommer sector) of pyramidal neurons.

## Where does a watershed infarct form after sudden severe hypotension?

At the border between arterial territories, classically a parasagittal strip between the anterior and middle cerebral arteries.

## Which deep grey structure is characteristically damaged by carbon monoxide?

The globus pallidus.

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## Elsewhere in DurgiPedia

- [Cerebral blood flow, brain metabolism and intracranial pressure](https://durgical.com/en/physiology/cerebral-blood-flow-brain-metabolism-and-intracranial-pressure/)

## Connections

## Related 6

- [Cerebral infarction](https://durgical.com/en/general-pathology/cerebral-infarction/)
- [How brain cells react to injury](https://durgical.com/en/general-pathology/how-brain-cells-react-to-injury/)
- [Perinatal brain injury](https://durgical.com/en/general-pathology/perinatal-brain-injury/)
- [Watershed areas and the organs most sensitive to ischemia](https://durgical.com/en/general-pathology/watershed-areas-and-the-organs-most-sensitive-to-ischemia/)
- [Hypoxia, ischemia and reperfusion injury](https://durgical.com/en/general-pathology/hypoxia-ischemia-and-reperfusion-injury/)
- [Shock: types, stages and the organs it damages](https://durgical.com/en/general-pathology/shock-types-stages-and-the-organs-it-damages/)

## Related conditions 5

- [Perinatal asphyxia and hypoxic-ischaemic encephalopathy](https://durgical.com/en/conditions/perinatal-asphyxia-and-hypoxic-ischaemic-encephalopathy/)
- [Cardiac arrest (VF, pulseless VT, asystole, PEA)](https://durgical.com/en/conditions/cardiac-arrest/)
- [Coma and brain death](https://durgical.com/en/conditions/coma-and-brain-death/)
- [Carbon monoxide poisoning](https://durgical.com/en/conditions/carbon-monoxide-poisoning/)
- [Drowning](https://durgical.com/en/conditions/drowning/)

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Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Cerebral hypoxia: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/001435.htm) (MedlinePlus, US National Library of Medicine, 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/general-pathology/global-hypoxic-ischemic-brain-injury/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/global-hypoxic-ischemic-brain-injury/