CASE
A 65-year-old white male presented to the emergency department (ED) with sudden onset of confusion and visual disturbances. While in the ED, he lost consciousness. No tonic-clonic activity was apparent; but a seizure was suspected, and the patient was given lorazepam (Ativan) 6 mg IV. Nevertheless, he progressively became less responsive, and a neurology consult was ordered.
Physical evaluation During the
examination, the patient's eyes were
open, with forced gaze to the right and upward and horizontal nystagmus; visual stimulus drew no response. Pupils were 3 mm in diameter and nonreactive. The patient gave no verbal response to pain. Initially he moved only the left upper extremity (UE), but during the latter part of the examination, he was able to move the right UE as well. Both lower extremities moved in response to tactile stimuli. There was no obvious facial asymmetry. By the time the examination neared its conclusion, the forced gaze to the right had resolved. The patient was lying with eyes closed, but he would open them partially when called and almost completely in response to painful stimuli. There was minimal spontaneous movement of all extremities and mild pain in both UEs—clinical findings which suggested that seizure activity was ending. After the examination, the patient received a 1,000-mg loading dose of fosphenytoin. An urgent bedside EEG showed recurrent epileptiform activity in the left temporal lobe region (around T5). Initial CT demonstrated periventricular small vessel ischemic changes with no acute infarction or hemorrhage.
History The patient's medical history included metastatic prostate carcinoma with prior radiotherapy to the left inguinal area and chemotherapy, right lung pulmonary embolus (PE), and deep vein thrombosis (DVT) in the right common and superficial femoral veins. His outpatient medications included dalteparin sodium, dexamethasone, fentanyl, goserelin acetate, gabapentin, lorazepam, pegfilgrastim, ondansetron, and mometasone. Family and social history were unremarkable.
Approximately 75 minutes after undergoing EEG in the ED, the patient was reexamined in the ICU. He was found to be awake, restless, and confused but not agitated. Extraocular movements were full. He did not speak. Good motion was observed in all four extremities, including purposive movements in both upper extremities. The patient was admitted to an acute medical floor for further evaluation and treatment of new-onset seizures and started on phenytoin 400 mg daily. Differential diagnosis at this point included possible metastasis from prostatic carcinoma, left frontal ischemia, and cerebral microbleed (CMB).
Imaging Conventional MRI of the brain and MRI with gradient-recalled-echo (GRE) T2-weighted images were ordered. On conventional MRI, multifocal, intra-axial, small deposits of hemosiderin were observed primarily at the gray/white matter interface (Figure 1). The GRE T2-weighted images (Figure 2) showed several small, hypointense lesions in both the infra- and supratentorial regions (including the gray/white matter junction); similar moderate-sized lesions were seen in the left parietal and right frontal regions. What is the likely diagnosis?