Head Trauma

Head injuries range from fractures of the skull to bleeding around the brain. The approach to diagnosis and treatment is determined by the type of injury and by the neurological condition of the patient.

Skull Fracture

Skull fractures are common after head injury. They are usually not accompanied by serious brain injury. Since every patient with a skull fracture carries a risk of bleeding, close observation is required.

1. Linear fractures. Detected on plain radiographs and/or computed tomography (CT). Observation is required because of the risk of bleeding; simple fractures require no treatment.
2. Depressed fractures. A portion of the skull is driven inward toward the brain. Bone fragments depressed by more than the thickness of the skull must be elevated surgically. Treatment is directed primarily at the underlying brain injury.
3. Compound depressed fractures. A depressed fracture with a breach of the skin. Nervous tissue or cerebrospinal fluid may escape through the open wound. This is an emergency: the bone fragments must be removed surgically and the coverings of the brain repaired.
4. Skull base fractures. These are often not visible on plain radiographs. The diagnosis is made from physical signs such as leakage of cerebrospinal fluid from the nose (rhinorrhea) or the ear (otorrhea), and by computed tomography. Repair of the skull base may be necessary.

Acute Subdural Hematoma

An acute subdural hematoma is a collection of blood between the surface of the brain and the dura, its outer covering, usually caused by the stretching and tearing of vessels on the surface of the brain.

Traumatic acute subdural hematomas are among the most lethal of all head injuries. They occur in 10–20% of cases of traumatic brain injury and account for 30% of fatal injuries.

Diagnosis and Treatment

• Computed tomography is the investigation of choice.
• Most patients are found to have a low Glasgow Coma Scale (GCS) score on examination at admission.
• Hematomas measuring 1 cm or more at their widest point require emergency surgery. Smaller hematomas may be observed closely. All patients require monitoring in an intensive care unit.
• Once the blood has been evacuated through a craniotomy, the bone flap may where necessary be stored in the abdomen or the thigh.

Outcome

• Recovery after brain injury varies greatly from patient to patient.
• Mortality ranges between 50% and 90%.
• In a small proportion of patients, brain function recovers completely or in part.
• Seizures after hemorrhage are common.
• Patients who reach hospital early, younger adults, those with a high Glasgow Coma Score, those in whom brain stem reflexes are preserved, and those without serious brain injury have been found more likely to benefit from treatment.

Chronic Subdural Hematoma

Chronic subdural hematoma is the term given to long-standing bleeding between the brain and the dura. Atrophy of the brain places the bridging veins lying between the brain and its coverings under tension, and injury causes these vessels to bleed.

More than half of patients do not recall the causative event. This is because even a relatively trivial injury, such as a minor knock to the head, may give rise to such slow bleeding. The signs appear weeks or months after the injury. The blood is firmer at the outset and becomes liquid over time.

Other risk factors include the use of alcohol, seizures, and the use of anticoagulant and/or antiplatelet medication.

The commonest symptom is headache. Others include drowsiness, difficulty with memory, confusion, lethargy, nausea, vomiting, disturbance of vision and seizures. Patients with a large hematoma may show weakness of varying degree and alteration of consciousness.

Diagnosis and Treatment

• Computed tomography and magnetic resonance imaging are used in diagnosis. Chronic subdural hematomas vary in density and may extend over a large part of the surface of the brain.
• Patients who have symptoms, who have signs on neurological examination, or who have a large collection of blood should be treated surgically.
• At operation one or two burr holes are made in the skull, the blood is evacuated and a drain is placed.

Outcome

• In 80–90% of patients, brain function improves considerably after drainage.

Extradural Hematoma

An extradural (epidural) hematoma is bleeding between the skull and the dura. It is usually accompanied by a skull fracture, the bleeding arising from a vessel damaged by the fracture.

It occurs about half as often as subdural hematoma and usually in younger adults. It is four times more common in men than in women, and is rarely encountered before the age of two or after the age of sixty.

Its classical features include headache, vomiting, loss of consciousness, seizures, impairment of neural function, a rise in blood pressure and difficulty breathing.

Diagnosis and Treatment

• Computed tomography is classically used in diagnosis.
• Magnetic resonance imaging is a further option. Computed tomography is quicker, however, and so is the method more widely used in assessing patients after trauma.
• Small hematomas that are not compressing the brain may be observed and may resolve without surgery.
• An operation is usually required where the hematoma measures more than 1 cm at its widest point.
• Treatment consists in the surgical evacuation of the blood together with control of the bleeding, so that the hematoma does not re-form.

Outcome

• The most important determinants of outcome are the Glasgow Coma Score at admission, the pupillary response, the neurological examination and the CT findings.
• A favorable outcome is obtained after surgery in approximately 90% of patients whose neurological condition is good.
• Intracranial injuries associated with the trauma, such as cerebral contusions, adversely affect the outcome.
• Early diagnosis and emergency surgery improve the prospect of recovery in patients with a severe extradural hematoma.