Abstract
Intraparenchymal hemorrhage (IPH) and subdural hematoma (SDH) are well-recognized separate clinical entities. We present a case of spontaneous bilateral SDHs identified during the resolution phase of a hypertensive IPH in a 73-year-old male. The patient initially presented unconscious with an acute right-sided thalamoganglionic IPH confirmed via non-contrast brain computed tomography scan. Conservative management led to neurological improvement, but routine follow-up imaging at eight weeks unexpectedly demonstrated bilateral SDHs without clinical deterioration. Further imaging at 14 weeks indicated progressive enlargement of the right-sided SDH. Extensive diagnostic evaluations, including magnetic resonance imaging and magnetic resonance venography, identified no underlying vascular or structural abnormalities, besides ruling out other predisposing factors such as coagulation disorders, preceding trauma, or brain atrophy. We hypothesize that intracranial pressure fluctuations during the resolution of IPH contribute to the formation of spontaneous SDH. This case highlights a potential cause of unexplained SDH in the context of a resolving IPH, underscoring the knowledge gap in pathophysiology and its underlying mechanisms.