Delayed acute subdural hematoma (DASH) is a subdural hematoma which is detected later. An initial computed tomography (CT) does not reveal any intracranial hemorrhage at all.

Delayed posttraumatic acute subdural hematoma which happens more than a week with a rapid progress after mild traumatic brain injury and causes death of patient is rarely reported ¹⁾.

Few patients of DASH after mild traumatic brain injury associated with percutaneous coronary intervention (PCI) have been published.

The patients included two men and two women, aged 65 to 86 years, who presented to the emergency department after mild TBI between January 2002 and June 2004. All were treated with chronic anticoagulation or anti-aggregation therapy. They deteriorated owing to DASH from 9 hours to 3 days after TBI. Three of the four patients underwent craniotomy for evacuation of their hematomas. One patient, who suffered only focal neurological deficit, was treated conservatively, and her hematoma gradually resolved. Two patients died and two reached Glasgow Outcome Scores of 3 and 4 after extended inpatient rehabilitation.

A suspicion of DASH should be raised in elderly, anticoagulated, mild TBI patients, including those who present to the emergency department with Glasgow Coma Scores of 15 and normal computed tomographic scans after injury. Based on our experience, we recommend that elderly, anticoagulated mild TBI patients should be admitted for 24 to 48 hours of observation after injury ²⁾.

A 63-year-old woman presented with cardiac pulmonary arrest due to acute myocardial infarction and lethal arrhythmia. She had hit her head on the road. The initial CT did not reveal any hemorrhage in the intra-cranium. She fully recovered after PCI. However, 1 hour after PCI, she lost consciousness and immediate CT showed acute subdural hematoma and subarachnoid hemorrhage. The period from losing consciousness to brain herniation presenting as anisocoria was very short-only 30 minutes in our patient. Although emergent evacuation of hematoma and external decompression were performed, the patient died 1 day after the operation.

The authors encountered a patient of DASH after PCI that resulted in death. Clinicians should be aware that subdural hemorrhage can occur after PCI if no hemorrhage is noted in the initial head CT, and the operation should be performed as soon as possible when the consciousness level decreases ³⁾.

Matsuda W, Sugimoto K, Sato N, Watanabe T, Fujimoto A, Matsumura A. Delayed onset of posttraumatic acute subdural hematoma after mild head injury with normal computed tomography: a case report and brief review. J Trauma. 2008 Aug;65(2):461-3. doi: 10.1097/01.ta.0000202465.13784.2a. PubMed PMID: 18288015 ⁴⁾.