Brain Regions Vulnerable to Prolonged Hypoxic-Ischemic Injury
The correct answer is D: Frontal lobes, basal ganglia, and hippocampus are particularly vulnerable to prolonged hypoxic-ischemic injury.
Primary Vulnerable Regions
The hippocampus represents one of the most consistently vulnerable structures to hypoxic-ischemic injury across all age groups:
- The hippocampus merits attention out of proportion to its size because it frequently shows anoxic-ischemic changes in elderly individuals and is critical for memory function 1
- Hippocampal injury manifests as diffuse or segmental neuron loss (particularly CA1 and prosubiculum regions) with astrocytic gliosis 1
- Bilateral hippocampal atrophy occurs following hypoxic-ischemic episodes, even when other major neurological deficits are absent 2
The basal ganglia demonstrate high metabolic vulnerability:
- Areas with highest metabolic activity, including basal ganglia and thalami, are most susceptible to hypoxic injury 3
- Abnormal cerebral findings from hypoxic-ischemic injury include damage to basal ganglia, thalamus, and cortex 1
- Immunohistochemical staining shows marked increases in neuronal nitric oxide synthase in basal ganglia following hypoxic-ischemic insults 4
Cortical Vulnerability Patterns
The frontal lobes and other cortical regions show selective vulnerability:
- Brain regions with highest metabolic activity, including perirolandic and occipital cortex, demonstrate increased susceptibility 3
- Laminar necrosis represents a distinct ischemic lesion pattern associated with severe anoxic-ischemic encephalopathy 1
- DWI lesions in cerebral cortex within the first week after cardiac arrest associate with unfavorable outcomes 1
Age-Dependent Vulnerability
The pattern of vulnerability shifts with developmental stage:
- In neonates prior to 32 weeks gestation, periventricular white matter shows selective vulnerability 4
- In the last trimester, basal ganglia become especially vulnerable to injury 4
- The "older" brain structures like hippocampus and cerebellum remain consistently vulnerable across ages 5
Clinical Significance
The brain appears to be the most vulnerable organ during profound hypoxemia, with brain malfunction as the first symptom and brain injury as the most common long-term complication in cardiac arrest survivors 1. These vulnerable regions—hippocampus, basal ganglia, and frontal/cortical areas—correspond to the cognitive and motor deficits observed following hypoxic-ischemic events 2.