Traumatic Haemorrhage

Abstract

Computed tomography (CT) is the key tool to diagnose intracranial haemorrhage following craniocerebral trauma. MRI provides additional information in cases when this seems appropriate such as a more detailed clarification of traumatic neurological disabilities, differentiation between oedema and ischaemia or imaging of shear damage to the neuronal fibre pathways.

Most common is subarachnoid haemorrhage (SAH), followed by subdural (SDH) and epidural haemorrhage (EDH). Besides trauma, SAH may also emerge spontaneously due to rupture of an aneurysm, most likely at the Willis circle. In contrast to spontaneous subarachnoidal bleeding, traumatic SAH does not normally occur at the Sylvian fissure or the basal cisterns, but rather at the cortical, surface sulci and in the interhemispheric gap. As a consequence, the distribution pattern may cause clarification by CT angiography. Subdural haematomas are common concomitant injuries of craniocerebral trauma, especially within elderly patients. They impress computer tomographically as falciform hyperdense bleeding, which can spread along the interhemispheric gap or the falx cerebri and are, therefore, able to cross the adhesion points of the dura and calotte, in contrast to epidural haematomas. Because of their mostly venous origin, neurologic symptoms are commonly subacute. Despite the very early stage of SDH up to 1 h, SDH loses density with time but may show several bleeding events, making it variable in density, especially in CT follow-ups. Epidural haematomas are rather rare, but often dramatic consequences of craniocerebral trauma are associated with skull fractures in up to 90% of cases. They emerge especially temporally at the coup site and are mostly of arterial origin with subsequent secondary complications, such as mass effects. In acute diagnostics, the CT shows a biconvex and hyperdense bleeding, which does not cross the sutures. EDHs with surgical decompression in time have a good outcome, which is why quick and correct diagnosis is of extraordinary importance. A clinically symptom-free interval between the time of injury and the start of mass effects can aggravate diagnosis.

Contusions are one of the most common complications of SHT and occur when the gyri collide with the cranial calotte or dura mater. They manifest themselves as multiple hyperdense lesions with perifocal oedema, preferably at the frontobase and in the temporal lobe, and are often associated with other intracranial haemorrhages, especially SAB. Their peculiarity is that they tend to haemorrhagic progression in up to 50% of cases. Contrast extravasation can predict this. According to this background, control CTs play an important role and can be prognostically decisive. An intravenous administration of KM should be weighed up accordingly in follow-up examinations.

Diffuse axonal damage occurs primarily on the basis of high-speed trauma with associated rapid head rotation. The axonal integrity is destroyed. Since a haemorrhagic component is often absent or can be extremely discreet, the detection with CT is often not possible, and instead, MRI is the imaging method of choice. DAI lesions are most frequently found in descending order at the medullary cortex border, the corpus callosum and in the brainstem. DAI is associated with a very unfavourable prognosis, especially in severe SHT, and is a frequent cause of persistent disabilities up to maximum forms such as apallic syndrome.

At present, however, there is still no clear evidence of an increase in risk of patients under anticoagulation after mild craniocerebral trauma, especially for the endpoint of compulsory therapy, if the data situation is unsatisfactory. For a final evaluation, a significantly more mature study situation on patients under anticoagulation with mild SHT is required. This should only be possible with very large numbers of patients in a multicentre approach.

In order to be able to cope with the presumably increasing incidence of SHT with increasing age in the future, a continuous reduction in the radiation exposure of the CT and a better availability of the MRT will be necessary. Further positive effects may arise from the establishment of dual-energy CT in SHT diagnostics. It is possible that the virtual native representation will help in the assessment of the course after KM administration. In addition, it may even be possible to identify active bleeding components in haematomas.