Extradural (epidural) haematoma: causes, warning signs and treatment

The brain is covered by three protective layers called meninges, the outermost of which is the dura. An extradural haematoma is a collection of blood that builds up between the dura and the inside of the skull. A private hospital group describes it as blood collecting and clotting between the inner surface of the skull and the firm covering of the brain, usually caused by a head injury or skull fracture.

It is different from a subdural haematoma, which is bleeding underneath the dura inside the brain. The NHS describes subdural haematoma as bleeding inside the brain, usually caused by a head injury, that can be very serious and usually has to be treated with surgery.

Extradural haematoma can also occur in the spinal canal. Patient.info explains that spinal extradural haemorrhage may follow the trauma of epidural anaesthesia or lumbar puncture, and when spontaneous there is usually a coagulation or platelet defect. This guide concentrates on the skull.

According to Patient.info, which publishes professional reference articles written by UK doctors, an extradural haematoma is most often due to a fractured temporal or parietal bone that damages the middle meningeal artery or vein, so blood collects between the dura and skull. It is typically caused by trauma to the temple just beside the eye, though it may also follow a tear in the dural venous sinuses.

It occurs in about 2% of all head injuries. Males outnumber females by 4 to 1. It is rare in small children because of the plasticity of the skull and less common over the age of 60 because the dura is tightly adherent. Patient.info notes that children are less likely than adults to have an associated skull fracture.

Prevention centres on avoiding head injury. Patient.info mentions helmets for cyclists and for sports such as skateboarding and snowboarding, and notes that alcohol is often a contributing factor, whether through drink-driving or binge drinking followed by falls or fighting.

Patient.info says there is usually a history of trauma and a head injury that causes loss of consciousness. Classically this is followed by a lucid interval, a period during which the person seems well, after which they deteriorate. However, this classical presentation occurs in less than a third of cases, so the absence of a lucid interval does not rule it out. Bleeding at the back of the skull can cause very rapid deterioration, measured in minutes.

Changes that should be looked for after a serious head injury include headache, nausea or vomiting, seizures, a slow heartbeat with raised blood pressure (a sign of raised pressure inside the skull), clear fluid from the ears or nose, drowsiness or falling level of consciousness, unequal pupils and weakness of the limbs.

The NHS head injury advice lists when to call 999 after a head injury: if someone has been knocked out and has not woken up, cannot stay awake or keep their eyes open, has a fit, has fallen from a height of more than 1 metre or 5 stairs, has problems with vision or hearing, has clear fluid coming from the ears or nose, has new numbness or weakness, has problems with walking, balance, understanding, speaking or writing, or has hit their head at speed. It advises not driving to A&E, because the 999 call handler can give advice.

Patient.info says that in a patient with a serious head injury, CT scanning gives much more information than plain X-ray, which may only show a skull fracture. A CT scan may show a haematoma or air pockets, and if the person deteriorates the CT must be repeated. MRI gives very good images but may not be suitable for someone in an unstable condition. Blood tests, including clotting studies where a bleeding problem is suspected, are advised, and a lumbar puncture should be avoided, especially if raised pressure has not been excluded.

Doctors also need to assess the neck. Patient.info notes that people with extradural haematoma may also have a traumatic cervical spine injury, so the neck is treated with great care until injury has been excluded. People with a head injury are often intoxicated, which can make it hard to know whether any drop in consciousness is due to bleeding or to alcohol or drugs.

Initial management follows trauma principles. Patient.info describes securing the airway, breathing and circulation first, a full trauma assessment because other injuries are common, and intravenous fluids if needed. Further treatment depends on the person's condition.

• Patient.info reports Brain Trauma Foundation criteria that patients who are not comatose with an extradural haematoma under 30 cm³ in volume, under 15 mm thick and causing under 5 mm midline shift may be managed conservatively, while a volume above 30 cm³ should have surgical evacuation regardless of coma score.

• A private hospital group describes craniotomy for extradural haematoma as carried out under general anaesthetic, with the surgeon making a temporary window in the skull and removing the clot using suction and washing out, before replacing the bone.

• Extradural haematomas are usually treated urgently in major trauma centres, according to the same private hospital group.

Patient.info says prognosis after surgical evacuation is generally excellent. Those who are alert on admission rarely die, while a low Glasgow Coma Scale score worsens the outlook. The overall mortality rate is about 30%. Outcome is improved by expeditious treatment, and factors that increase the risk of poor outcome include older age, larger haematoma volume, temporal location, rapid clinical progression, pupil abnormalities and raised intracranial pressure.

Complications can include neurological deficits, which can be temporary or permanent, and post-traumatic seizures that may develop 1 to 3 months after injury. Delayed effects include post-concussion syndrome with headaches, dizziness, restlessness, emotional lability, poor concentration and fatigue.

The NHS says people recovering from a serious head bleed may need rehabilitation support such as physiotherapy, occupational therapy and speech and language therapy; its subdural haematoma guidance describes these services, and the same approach applies in practice after any brain bleed.

Because an extradural haematoma is an emergency, it is dealt with through 999, the emergency department and regional neurosurgical centres on the NHS, with CT scanning and surgery provided free at the point of use. Rehabilitation after discharge is arranged through NHS neurorehabilitation and community services.

Private hospitals do not usually receive acute head injuries. A private provider describing this surgery says that extradural haematomas are occasionally slow to develop with fewer effects on the patient and may sometimes be treated in private hospitals, but the large majority are managed urgently in trauma centres.