Postoperative Intracranial Hypertension Mimicking Depressive Relapse in an Elderly Patient With Long- Standing Depression After Microvascular Decompression: A Case Report

Intracranial hypertension (ICH) typically presents with headache, nausea, and focal neurological deficits. However, atypical neuropsychiatric manifestations are not uncommon in elderly patients, especially those with preexisting psychiatric disorders. We report a 70-year-old woman with a 20-year history of well-controlled depression who underwent uneventful microvascular decompression. Postoperatively, she developed persistent low mood, reduced responsiveness, and poor appetite, which were initially attributed to environmental stress and suspected depressive relapse. Her blood pressure rose to 158/102 mmHg, while cranial CT showed no acute hemorrhage or mass effect. Lumbar puncture revealed markedly elevated intracranial pressure (350 mmH₂O). Following osmotic therapy, her headache, blood pressure, and emotional state improved dramatically without any adjustment to psychiatric medications. This case highlights that ICH can manifest primarily as neuropsychiatric deterioration in elderly patients with chronic depression. Clinicians should consider organic etiologies before attributing postoperative mood changes to psychiatric relapse alone, to avoid diagnostic delay.