A patient who has been irradiated for a head and neck cancer may develop a cognitive decline. Abayomi identified risk factors for its occurrence. The author is from the Medical College of Virginia Hospitals.
Proposed mechanism: radiation-induced vascular damage in the temporal lobe affecting the medial temporal lobe memory centers (hippocampus, parahippocampal cortex, perirhinal cortex, enterorhinal cortex).
Sites at increased risk:
(1) nasopharynx
(2) paranasal sinus
(3) parotid gland
(4) pituitary adenoma
(5) tumors of the auditory canal
Cognitive impairment may be accompanied by other neurologic findings (headache, dizziness, confusion, etc).
Interventions to reduce risk:
(1) modify radiation delivery (intensity-modulated, 3-D conformal) so that delivery to the medial temporal lobe is reduced
(2) address risk factors for atherosclerosis (smoking, hypertension, hyperlipidemia, obesity, diabetes)
Differential diagnosis:
(1) concurrent cause of dementia
(2) depression
(3) chemotherapy effect
