Where would you expect to find an intracerebral hemorrhage in a patient presenting with right-sided hemiplegia, nonoccipital headache, gaze deviation to the left, and rapid deterioration to stupor and coma?

Expected Location of Intracerebral Hemorrhage: Left Putamen

Based on the clinical presentation of right-sided hemiplegia, left gaze deviation, and rapid deterioration to coma with fixed dilated pupils, the intracerebral hemorrhage is most likely located in the left putamen.

Clinical Reasoning

Localizing the Lesion

The key localizing features point to a left-sided deep hemispheric lesion:

• Right-sided hemiplegia indicates damage to the left motor cortex or descending motor pathways (corticospinal tract), as motor fibers cross at the medullary pyramids 1

• Left gaze deviation ("eyes look toward the lesion") occurs because the frontal eye fields in the left hemisphere are damaged, removing their drive for rightward gaze. The intact right frontal eye field then drives the eyes leftward 2

• Rapid deterioration to stupor and coma within 30 minutes suggests a deep hemorrhage with mass effect causing rapid brainstem compression 1

• Fixed and dilated pupils bilaterally indicate severe brainstem compression affecting the midbrain, specifically the oculomotor nuclei and parasympathetic pathways 3, 4

• Absence of abnormal posturing despite coma suggests overwhelming brainstem dysfunction rather than isolated cortical injury 1

Why Left Putamen is Most Likely

Deep basal ganglia hemorrhages (putamen, thalamus) cause rapid deterioration due to their proximity to critical structures:

• The putamen is the most common site for hypertensive intracerebral hemorrhage 5

• Putaminal hemorrhages directly compress the internal capsule, causing contralateral hemiplegia 1

• These deep hemorrhages cause rapid mass effect with early herniation and brainstem compression, explaining the 30-minute progression to coma 1, 5

• The nonoccipital headache is consistent with supratentorial hemorrhage with increased intracranial pressure 1

Why Other Options Are Less Likely

Left parietal lobe would cause:

• Left-sided sensory loss and visual-spatial deficits more prominent than pure motor weakness 2
• Less likely to cause such rapid coma unless massive with significant mass effect 1
• Cortical hemorrhages typically have a slower progression 1

Left pons would cause:

• Bilateral motor deficits, not isolated right hemiplegia 1
• Pinpoint pupils (not fixed and dilated) due to disruption of sympathetic pathways 1
• Immediate coma at onset, not 30-minute progression 1

Right cerebellum would cause:

• Occipital headache (specifically mentioned as absent in this case) 1
• Ataxia and coordination problems rather than hemiplegia 1
• Right gaze deviation (eyes deviate away from cerebellar lesion), not left 1

Right thalamus would cause:

• Left-sided symptoms (not right hemiplegia) 1
• Wrong lateralization for the clinical presentation 1

Critical Pitfalls to Avoid

• Do not assume pupils always localize to the ipsilateral side: While typically true, bilateral fixed dilated pupils indicate severe bilateral brainstem compression from mass effect, not necessarily bilateral hemorrhages 3, 4

• Gaze deviation follows the rule: "Eyes look toward the lesion" in supratentorial strokes (away from the paralyzed side), but "eyes look away from the lesion" in pontine strokes 1

• Rapid deterioration suggests deep hemorrhage: Cortical hemorrhages typically progress more slowly unless they are massive 1, 5

• The absence of occipital headache helps exclude posterior fossa lesions (cerebellum), which characteristically cause occipital pain 1