An 88 year old woman is brought to the A&E by her family. She admitted to falling 2 days ago, when trying to change a light bulb, but did not seek medical assistance. Since the fall, she has become increasingly confused, wincing as though in pain. She has an extensive past medical history, including hypertension, type 2 diabetes and a previous ischaemic stroke.

Upon examination, the patient is disoriented and lethargic. Neurological examination shows weakness in her right arm and leg, along with a noticeable drift when attempting to lift her right arm. She is apyrexial. A CT head scan shows a left-sided crescent-shaped hyperdensity.

Which of the following is the most likely diagnosis?

Options:
explanation: This vignette describes a case of subdural haematoma, with symptoms developing after a fall. In contrast, meningitis is typically caused by infectious agents such as bacteria or viruses rather than trauma. Meningitis can develop over time, but it typically presents with more acute symptoms, including fever, severe headache, neck stiffness, and altered mental status. Notably, this patient is apyrexial. Meningitis-related abnormalities on imaging might involve contrast enhancement in the meninges or signs of brain inflammation, but not typically evidence of haemorrhage.
name: Meningitis
label: e
answer: no
explanation: This is the correct answer. The patient's history of a fall, gradual onset of symptoms, confusion, neurological deficits, as well as the crescent-shaped hyperdensity on the CT scan are consistent with a subdural haematoma. A subdural haematoma is a collection of blood accumulating between the arachnoid mater and the dura mater. Over time this can increase intracranial pressure, leading to neurological deficits such as muscle weakness on the contralateral side of the haematoma, and altered mental status. It is particularly prevalent in the elderly, as ageing can reduce brain mass, which may lead to stretching and thinning of bridging veins that connect the brain's surface to the dura. These veins are more prone to tearing when subjected to trauma.
name: Subdural haematoma
label: a
answer: yes
explanation: This vignette describes a case of subdural haematoma, with symptoms worsening over several days. In contrast, ischaemic strokes typically have a sudden and rapid onset of symptoms. Ischaemic strokes usually present with areas of hypodensity on imaging due to the loss of blood flow to affected brain tissue, not hyperdensity as in this vignette. Moreover, ischaemic strokes are not directly caused by head trauma and are instead caused by the occlusion of blood vessels supplying the brain.
name: Ischaemic stroke
label: c
answer: no
explanation: This vignette describes a case of subdural haematoma. Epidural haematomas typically result from head trauma. Although the patient had a fall, the neurological deficits show a gradual progression. By contrast, epidural haematomas tend to have a more rapid and sudden onset of symptoms following the initial injury. Furthermore, epidural haematomas typically present as biconvex or lens-shaped hyperdensity on imaging. In this case, the crescent-shaped hyperdensity is more suggestive of a subdural haematoma.
name: Epidural haematoma
label: b
answer: no
explanation: This vignette describes a case of subdural haematoma, with symptoms worsening in the days following a trauma. In contrast, subarachnoid haemorrhage classically presents with a sudden and severe 'thunderclap' headache at the onset of bleeding, often described as 'the worst headache of my life'. CT scans normally show hyperdense signals in the subarachnoid space.
name: Subarachnoid haemorrhage
label: d
answer: no

Correct answer: a