How does the clinical examination localize the level of brain stem dysfunction in a comatose patient?
Location of Level of Brain stem Dysfunction
| Symptoms and Signs | Subcortical | Midbrain | Pons | Medulla |
|---|---|---|---|---|
| Consciousness | Lethargy or stupor | Coma | Coma | Coma |
| Breathing | Cheynes–Stokes | Central hyperventilation | Apneustic or cluster | Ataxic |
| Pupils | Small and reactive | Midposition and fixed (III nucleus); unilateral dilated and fixed (III nerve); large and fixed (pretectal) | Pinpoint | Midposition and fixed, often irregular in shape |
| Oculocephalic and oculovestibular responses | Present | Absent or abnormal | Absent or abnormal | Absent |
| Motor response to stimulation | Decortication | Decerebration | Decerebration or no response | No response |
