An 83-year-old man is brought to the emergency department by his daughter due to confusion over the last 2 weeks. The patient initially became less talkative than usual before starting to confuse her with her sister. The patient also could not remember what day of the week it was and he was out of groceries and likely had been for several days when visited. While she was talking to him, he fell asleep and was difficult to rouse. The patient is unable to provide a clear history. He has a medical history of hypertension, glaucoma, and osteoarthritis in his left knee that requires him to walk with a cane. He takes hydrochlorothiazide, timolol eyedrops, and occasional acetaminophen. His temperature is 98.5° F (36.9° C), blood pressure is 122/74 mmHg, pulse is 75/min, and respirations are 14/min. The patient is lethargic but arousable, oriented only to person, and disheveled. Neurologic exam reveals intact cranial nerves, 1+ deep tendon reflexes throughout, and 4/5 strength in all extremities. There is a 3 x 5 cm green-blue area of ecchymosis on the lateral aspect of his left knee. A CT of the head without contrast is performed and shown in Figure A. Which of the following factors plays the earliest role in the progression towards this patient’s presentation?
Increased cerebrospinal fluid
Aneurysmal rupture
Cerebral atrophy
Hypertension
Cerebral atrophy
This patient is an elderly man with progressive confusion over weeks, a nonfocal neurologic exam, and a CT of the head showing a hypodense crescent, most consistent with chronic subdural hematoma (SDH). Cerebral atrophy plays the earliest role in this presentation, resulting in exposure of the bridging veins and subsequent rupture with even minor trauma.

Chronic subdural hematomas present gradually, most often with headaches, somnolence, light-headedness, cognitive impairment, and rarely, seizures. Typically, the neurologic exam is largely normal but rarely focal deficits such as contralateral hemiparesis from compression of the cortex underlying the hematoma or ipsilateral hemiparesis from the lateral displacement of the opposite cortex may occur. Chronic SDH most often occurs in the setting of cerebral atrophy related to increased age, chronic alcohol use, and prior traumatic brain injury. Exposure of the bridging veins allows even minor trauma to precipitate subdural bleeding. A non-contrast CT of the head is indicated in any elderly patient with decreased mentation and concern for chronic SDH. Since old blood appears hypodense, imaging will allow for the determination of whether the bleed is acute or chronic. Supportive care is usually sufficient for treatment but surgical evacuation of the hematoma can be considered in patients with focal deficits or an expanding hematoma.

Mehta et al. review the evidence regarding the diagnosis and management of chronic subdural hematomas in elderly patients. They discuss how crescentic layering of fluid in the subdural space on a non-contrast computed tomography scan is diagnostic of this condition. They recommend close follow-up as many patients will develop a recurrence of this condition.

Figure/Illustration A shows a non-contrast CT scan of the head with a hypodense crescent left side (red circle). This finding is consistent with a chronic subdural hematoma.

Incorrect Answers:
Answer A: Aneurysmal rupture is an extremely uncommon cause of SDH and typically causes subarachnoid hemorrhage instead. It often presents with “the worst headache of my life” or “thunderclap headache,” and would show hyperdensity in the subarachnoid space on head CT. Surgical clipping or endovascular treatment can prevent rebleeding.

Answer C: Elder abuse can be subtle and should always be considered when an elderly patient presents with confusion, bruising, or dishevelment. In children, abuse is an important cause of SDH, which may occur in the setting of “shaken baby syndrome.” However, abuse is not especially associated with chronic SDH in the elderly population, and there is another plausible reason for this patient’s presentation (trauma from a fall as evidenced by the resolving ecchymosis on his knee).

Answer D: Hypertension is a major risk factor for stroke, which typically presents with focal neurologic deficits such as hemiparesis, aphasia, or sensory loss. Although this patient does have a history of hypertension, he is normotensive in the emergency room and has non-focal neurologic decline that has been slowly progressive, which is less consistent with stroke. Furthermore, in contrast to this patient’s CT scan, acute ischemic stroke would likely present with a normal head CT and prior infarct would cause a hypodensity in the parenchyma itself. Treatment is with risk factor optimization when a patient presents outside the window for thrombolytic agents.

Answer E: Increased CSF due to poor reabsorption by arachnoid granules is the cause of normal pressure hydrocephalus (NPH). Patients typically present with the “wet, wacky, and wobbly” triad – urinary incontinence, mental status changes, and magnetic gait. Head CT would show dilated ventricles and management includes CSF shunting.

Bullet Summary:
Chronic subdural hematomas may occur in elderly patients due to cerebral atrophy and subsequent exposure of bridging veins that may tear with minor trauma.