Somnolence Syndrome

**Semantic type:** Disease or Syndrome

**Definition:** An uncommon subacute encephalopathy seen following cranial irradiation for cerebral neoplasms. Clinical signs manifest several weeks after treatment and include drowsiness, fatigue, lethargy and slowed mental processing. Clinical course is usually benign, self-limited and independent of radiotherapy dose.

**Synonyms:** - somnolence syndrome