Subdural Hematoma
The diagnosis is subdural hematoma. A crescent-shaped lesion on CT brain in an elderly patient who fell and presents with confusion is pathognomonic for subdural hematoma, not epidural hematoma. 1
Key Distinguishing Features
Subdural hematomas appear as crescent-shaped collections that cross cranial sutures, while epidural hematomas are lens-shaped (biconvex) and are limited by suture lines. 1 This fundamental anatomic difference makes the crescent shape diagnostic for subdural rather than epidural bleeding.
Clinical Context Supporting Subdural Hematoma
Patient Demographics
- Elderly patients are at highest risk for subdural hematomas, particularly those over 70 years of age. 2
- The combination of age, fall mechanism, and confusion is classic for chronic or acute-on-chronic subdural hematoma. 3, 4
Mechanism of Injury
- Falls in the elderly commonly cause subdural hematomas due to brain atrophy, which creates increased space for bridging veins to tear with relatively minor trauma. 2
- Subdural hematomas frequently occur after minor head trauma that patients may not even recall. 5, 4
Clinical Presentation
- Confusion and altered mental status are hallmark presentations of subdural hematoma in elderly patients, often mimicking dementia or delirium. 3, 4
- The presentation can be subtle and non-specific, ranging from cognitive decline to focal neurological deficits. 5
Why Not Epidural Hematoma
Epidural hematomas are rare in elderly patients because the dura becomes increasingly adherent to the skull with age, making dural stripping (required for epidural blood accumulation) much less likely. 1 Additionally:
- Epidural hematomas typically present with a "lucid interval" followed by rapid deterioration, not gradual confusion. 6
- They are lens-shaped (biconvex), not crescent-shaped. 1
- They are usually associated with skull fractures and middle meningeal artery injury in younger trauma patients. 6
Imaging Confirmation
Non-contrast CT head is the gold standard for diagnosing subdural hematoma, showing the characteristic crescentic fluid collection in the subdural space best appreciated on sagittal or coronal reformats. 2 The American College of Radiology confirms CT as the initial imaging modality of choice for acute head trauma. 6, 1
Critical Management Considerations
- Check for anticoagulant or antiplatelet use immediately, as these medications dramatically increase risk of hematoma expansion and are present in many elderly patients. 6, 1, 2
- Serial neurological examinations are essential to detect deterioration, with repeat CT at 24 hours especially in anticoagulated patients. 1, 7
- Surgical intervention is indicated if maximum hematoma thickness exceeds 1 cm or if the patient is symptomatic with mass effect. 2
Common Pitfall
Do not underestimate small subdural hematomas in elderly patients, particularly those on anticoagulation, as they can expand rapidly. 1 Even patients initially appearing stable may deteriorate, necessitating close observation and repeat imaging. 6, 1