Pontine Hemorrhage Pupil Findings
The classic pupillary finding in pontine hemorrhage is bilateral pinpoint pupils (1-2mm) that are reactive to light, though this reactivity may only be visible with magnification. 1
Primary Pupillary Presentations
The pupillary abnormalities in pontine hemorrhage vary based on hemorrhage size and severity:
Small to Moderate Hemorrhages (≤20mm transaxial diameter)
- Pinpoint pupils (miotic) are the hallmark finding, typically bilateral and symmetric 1
- These pupils remain reactive to light, though the response may be sluggish and require magnification to detect 1
- Normal pupillary function suggests better prognosis when combined with mild consciousness disturbance 1
Large or Massive Hemorrhages (>20mm transaxial diameter)
- Bilaterally dilated pupils indicate severe pontine damage and carry extremely poor prognosis 1
- Anisocoria (asymmetric pupils) can occur with asymmetric hemorrhage extension 1
- Absent pupillary light reflex is an independent predictor of 30-day mortality (P = 0.0003) 2
Prognostic Significance
Pupillary abnormalities are critical prognostic indicators in pontine hemorrhage:
- Absence of pupillary light reflex is one of three independent mortality predictors in acute primary pontine hemorrhage, along with Glasgow Coma Scale ≤6 and blood glucose ≥180 mg/dL 2
- In patients with small hematomas (≤20mm), pupillary abnormalities at onset specifically correlate with poor outcome 3
- Patients with normal pupils combined with no or mild consciousness disturbance have good prognosis 1
- Those with dilated, pinpoint, or anisocoric pupils combined with coma within 2 hours of onset have poor prognosis 1
Clinical Assessment Context
When evaluating pupils in suspected pontine hemorrhage:
- Pupillary examination should be part of urgent neurological evaluation including Glasgow Coma Scale motor score 4
- Document pupillary size, symmetry, and light reactivity in both bright and dim illumination 4
- Pupillary findings must be interpreted alongside consciousness level, hematoma size on CT, and presence of hydrocephalus 5, 3
- Coma on admission remains the strongest single predictor of mortality (P = 0.038 on multivariate analysis), but pupillary abnormalities provide crucial additional prognostic information 5