Radiation-Induced Cerebral Micro bleeds

Abstract

A 29 year-old Thai female presented with a right-sided headache for 3 days prior to hospital admission. The patient complained of severe pain and upon examination, pain was found to be localized only on the right parietal area. Initially diagnosed as a migraine headache, the pain gradually improved with simple analgesics. She had neither history of head trauma, hypertension, diabetes, psychiatric problems, nor family history of Alzheimer's disease. Seven years earlier at the age of 22 years, the patient presented with progressive headaches with nausea and vomiting followed by generalized tonic clonic seizures. The neurological examination at that time showed bilateral papilledema. Initial computed tomography (CT) scan (Figure 1) of the brain revealed a pineal region tumor with obstructive hydrocephalus. However, magnetic resonance imaging (MRI) of the brain was not performed at the initial diagnosis. Right occipital transtentorial craniectomy with near total tumor removal and ventriculo peritoneal shunt placement were performed. The pathological finding of the tumor was reported to be pineal parenchymal tumor grade III/IV based on the currently proposed system or pineal parenchymal tumor of intermediate differentiation (gr III or IV) according to WHO classification [1,2]. She received 30 Fractions of whole brain irradiation with 6 cycles of chemotherapy (cyclophosphamide and vincristine). The radiation dose ranged from 42 to 90 cGy per dose of each radiation site (total dose 36 Gy of whole brain irradiation with booster at tumor base up to 54 Gy). She received her first MRI 5 months after the last dose of radiation which showed only a few cerebral micro bleeds (CMBs) in the subcortical white matter of the left cerebral hemisphere. Magnetic resonance angiography (MRA) of the brain was normal and there was no evidence of cerebral infarction. Serial MRI of the brain was performed at 5 years after the cranial radiation and showed a markedly increase in number of CMBs ( At the last presentation, both her general physical and neurological examinations were normal. MRI of the brain demonstrated sub-acute brain infarction at the head and body of the right caudate nucleus and globus palledus. There was also a small focal sub-acute hemorrhage at deep white matter of the right parietal lobe. An interval increase in number of micro hemorrhages in subcortical and deep white matters of the cerebral and cerebellar hemispheres and brain stem were noted. MRA of the brain revealed a mild irregular luminal narrowing at distal M1 segment of the right MCA.