Head Injury and Chronic Subdural Haematoma

Daniel Walsh FRCS

Approximately 1.4 million people annually attend emergency departments in the United Kingdom with acute head injuries. Chronic subdural haematoma though present insidiously.

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This is a very wide ranging topic and below are only a selection of the issues that arise as part of elective practice. Please get in touch if your particular problem related to trauma of the head or face is not addressed below and we will see what we can do to help.

Brain Injury and Concussion.

Injuries to the cranium and its contents occur at all ages and their consequences are continuing to be understood. Some brain injuries constitute very time-dependent emergencies and usually present acutely throught the emergency room. Some however present are slower evolving conditions and there are elective procuedures to reconstruct or correct the cosmetic consequences of injury.

There are several patterns of brain injury occurring alone or in combination. Blood clots pressing on the surface of the brain are named for there relationship to the brain's covering, the dura. Extradural haematomas usually result from an arterial tear in the dura and have a good outlook in isolation and if treated promptly. Subdural haematomas collect beneath the dural covering and more often result from a venous tear on the surface of the brain. Traumatic subarachnoid haemorrhage is bleeding into the fluid spaces around the brain deep to its arachnoid covering and requires distinction from the similar bleeding resulting from aneurysm rupture. Contusions are bruises to the substance of the brain while diffuse axonal injury describes a microscopic injury related to shearing between the grey and white matter of the brain. All of these can occur in combination.

Post-concussive syndrome is a term used to describe residual symptoms that complicate the recovery phase of even a relatively minor brain injury. Imaging may not show any abnormality. Symptoms include:

  • Headache
  • Nausea
  • Dizziness
  • Sensitivity to light or sound
  • Disturbed sleep
  • Low mood

For most concussion will be short lived. If symptoms persist beyond three months following a head injury it is also worth checking the biochemical function of the pituitary gland. The pituitary gland produces hormones that regulate a range of metabolic functions.

Neuropsychological Consequences of Brain injury.

The cognitive consequences of brain injury are evident both in setting of major brain injuries and the chronic effect of repeated less severe injuries. This has become a challenging issue in contact sport and the long term consequences of repeated brain injury are better understood.

Cognitive problems may be informed by the physical consequences of an injury (e.g. the neuroendocrine effects of injuries to the hypothalamic-pituitary axis) and emotional or behavioural factors (e.g. post-traumatic stress disorder, breakdown of relationships or support networks). Input from a clinical psychologist can be advisable to assess and design management strategies.

Chronic Subdural Haematoma.

Chronic subdural collections pressing down on the hemispheres of the brain

Chronic subdural haematoma is one of the most common neurosurgical emergency conditions. Older people are more likely to be affected as the natural reduction in the volume of the brain later in life creates a potential space where blood can collect between the dural lining of the brain and the cortex itself. Tiny "bridging" veins that connect the brain to the dura are placed under slight tension as the brain separates from the brain surface making them more prone to shearing and tearing. Under these conditions a relatively minor blow to the head e.g. striking ones head against low beam, may go unremarked at the time although a small amount of bleeding occurs which collects in the subdural space. Because there is room to accomodate the bleeding usally there are no immediate serious consequences.

No all chronic subdural haematomas produce serious symptoms and require surgery. A proportion do however. The symptoms may include but are not limited to:

  • Headache
  • Disorientation
  • Memory impairment
  • Sensitivity to light or sound
  • Balance and co-ordination difficulty
  • Weakness and or loss of feeling on one side of the body
  • Speech impairment- slurring of speech, difficulty finding words or expressing oneself

Chronic subdural haematoma is one of the most common neurosurgical emergency conditions. Older persons are more likely to be affected as the natural reduction in the volume of the brain later in life creates a potential space where blood can collect between the dural lining of the brain and the cortex itself. Tiny "bridging" veins that connect the brain to the dura are placed under slight tension as the brain separates from the brain surface making them more prone to shearing and tearing. Under these conditions a relatively minor blow to the head e.g. striking ones head against low beam, may go unremarked at the time although a small amount of bleeding occurs which collects in the subdural space. Because there is room to accomodate the bleeding usally there are no immediate serious consequences.

Surgical Treatment of Chronic Subdural Haematoma.

Because the blood clot is usually liquid it may be released through small holes. These may be made under general or under local anaesthesia as circumstances dictate. It is our usual practice to place a drain in the subdural space for forty-eight hours after drainage in most cases. This is a proven method to reduce the risk of recurrence which is significant with chronic subdural haematoma. Rarely, if acute bleeding is encountered during surgery, a craniotomy - or door opening in the cranium- is required.

This surgery is generally safe and beneficial in appropriately selected cases even in those of more advanced age.

Middle Meningeal Artery Embolisation.

Recently endovascular embolisation of the middle meningeal artery (MMAE) within the dural leaflet has been proposed as a means to reduce the blood supply to subdural membranes and reduce the volume of subdural fluid collecting.

The precise indications remain to be established but it may offer an option for patients who suffer multiple recurrences of their collections. In an audit of our practice the represented less than 9% of patients undergoing a burrhole procedure.

MMAE has been advocated as a stand-alone treatment for smaller CSDH that might not usually require surgical evacuation or as an alternative to surgery in a symptomatic case. These indications require further exploration in a research setting and as with any intervention MMAE does brings risk of its own including a small risk of stroke.