Non-traumatic subdural hygroma

Subdural hygroma consists of a cerebrospinal fluid-like subdural fluid collection with a low oncotic pressure in comparison with venous blood. Its etiology and pathophysiology, which may be different from other subdural fluid collections, are reviewed. We report the clinical history of a 80-year-old woman with a bilateral frontal subdural hygroma. Serial CT-scanning demonstrated a rapid increase in volume after two years of slow evolution. In our patient dehydration may have been the triggering factor. The course of non-traumatic subdural hygroma is not well known. This report illustrates that subdural hygroma can have a dramatic evolution and that therapeutic decisions in these patients should be based on repeated CT-scans.