A 68-year-old man with chronic alcoholism presents with insidious onset of confusion and gait disturbance over 3 weeks. CT head shows a crescent-shaped hypodense collection over the cerebral convexity. What is the most common cause of this type of intracranial hematoma in elderly patients?

## Subdural Hematoma in Elderly: Epidemiology and Mechanism **Key Point:** Chronic subdural hematoma (cSDH) in elderly patients is classically caused by minor or trivial head trauma that the patient may not even recall — a hallmark feature distinguishing it from acute SDH. ### Why Minor Trauma in Elderly? Elderly patients have: - Brain atrophy with increased subdural space - Fragile bridging veins that tear easily with minimal trauma - Coagulopathy (anticoagulant use, liver disease from alcohol) - Increased fall risk The trivial nature of the inciting injury is so characteristic that **absence of a remembered head injury does NOT rule out cSDH** — in fact, many elderly patients cannot recall the event. ### Clinical Presentation Timeline | Feature | Acute SDH | Chronic SDH | |---------|-----------|-------------| | **Onset** | Hours to days | 2–3 weeks or longer | | **Trauma severity** | Severe, high-impact | Minor or trivial (often forgotten) | | **Typical patient** | Young, high-energy injury | Elderly, alcoholic, anticoagulated | | **CT appearance** | Hyperdense crescent | Hypodense crescent (fluid-like) | | **Mechanism** | Tearing of cortical vessels | Tearing of bridging veins | **Clinical Pearl:** The insidious presentation (3 weeks of confusion + gait disturbance) is pathognomonic for chronic SDH. The crescent-shaped hypodense collection is the radiological hallmark. **High-Yield:** In any elderly patient with dementia-like symptoms, gait disturbance, or personality change over weeks, always think cSDH — it is a treatable cause of reversible cognitive decline. ### Why Not the Other Options? - **Severe head trauma:** Would cause acute SDH (hyperdense, immediate presentation), not chronic SDH with 3-week insidious course. - **Acute SDH from falls:** Presents acutely (hours to days), not over 3 weeks. - **Ruptured aneurysm:** Causes subarachnoid hemorrhage (blood in subarachnoid space, thunderclap headache), not subdural hematoma. **Mnemonic:** **CASH** = **C**hronic SDH in **A**lcoholics and **S**eniors from **H**ead trauma (trivial).