Subdural haematoma Flashcards
What is a subdural haematoma?
collection of venous blood accumulating in the potential space between the dura mater and arachnoid mater
In which patients do subdural haemorhhages typically occur?
elderly patients following minor trauma
What is the aetiology of subdural haematomas?
minor trauma results in shearing forces that tear bridging veins between the cortex and dura mater
What are 4 risk factors for subdural haemorrhage?
- Advancing age (>65)
- Bleeding disorders or anticoagulant therapy
- Chronic alcohol use
- Recent trauma
What are the 3 classes that subdural haemorrhage can be grouped into?
- Acute
- Subacute
- Chronic
Within what time frame does chronic SDH occur?
>3 weeks
Within what time frame does sub-acute SDH occur?
3 days to 3 weeks
Within what time frame does acute subdural haematoma occur?
<3 days
What is an acute subdural haematoma?
collection of fresh blood within the subdural space, most commonly caused by high impact trauma
What is often associated with acute subdural haematoma and why?
other underlying brain injuries, because it is associated with high-impact injuries
What is the presentation of acute subdural haematoma?
spectrum of severity depending on size/ associated injuries; ranges from incidental finding in trauma to severe coma and coning due to herniation
What is the first line investigation for subdural haematoma?
CT imaging
What is the finding of subdural haematoma on CT?
crescenteric collection (banana), hyperdense compared with brain, not limited by suture lines
How does CT scan appearance of SDH vary depending on hyperacute vs acute vs subacute vs chronic phase?
- hyperacute (<1 hr): clot may appear as relatively isodense with underlying cerebral oedema
- acute (<3 days): crescent shaped homogeneous hyperdense extra-axial collection over affected hemisphere
- sub-acute (3 days to 3 weeks): organisation of clot, density falls so appears more isodense. mass effect, sulcal effacement
- chronic (>3 weeks): haematoma becomes hypodense relatie to adjance cortex
In what proportion of adults are SDH bilateral?
15%
In what proportion of children are SDH bilateral?
80%
How often do patients present in the hyper-acute (<1 hour) phase of SDH?
rarely
What can aid identification of the SDH in the sub-acute phase (3 days to 3 weeks) when the density of the close is more isodense?
contrast-enhanced CT or MRI
How can small or incidental acute subdurals be managed?
observed conservatively
What is the management of larger acute subdural haemorrhages?
surgical: monitoring of ICP, decompressive craniectomy
What is a chronic subdural haematoma?
collection of blood within the subdural space that has been present for weeks to months
How do chronic subdural haemorrhages typically form?
rupture of small bridging veins wihtin the subdural space causes slow bleeding - elderly and alcoholic patients particularly at risk of subdural haematomas due to atrophy and therefore taut or fragile bridging veins
Which patients are at particular risk of chronic subdural haemorrhage and why?
Elderly and alcoholic patients are particularly at risk of subdural haematomas since they have brain atrophy and therefore fragile or taut bridging veins
What is the typical presentation of a chronic subdural haematoma?
several week to month progressive history of either confusion, reduced consciousness or neurological deficit
In what syndrome can infants be affected by subdural haemorrhage? Why does this occur?
shaken baby syndrome - due to fragile bridging veins which can rupture
How does the appearance of acute vs chronic subdural haemorrhages vary?
will appear hypodense i.e. dark in chronic, white in acute i.e. hyperdense
What is the management of small or incidental subdural haematomas?
conservatively, with hope will dissolve with time
What is the management of chronic subdural with confusion or neurological deficit?
surgical decompression with burr holes
