CT Case 032
A 34-year-old man is brought into ED one hour after a 4m fall from a roof.
He had a brief loss of consciousness immediately following the fall, then subsequently regained consciousness.
He had a GCS of 15 on scene with the paramedics, however on ED arrival had deteriorated to GCS of 12.
Describe and interpret the CT images
CT INTERPRETATION
There is an acute (hyperdense) extra-axial haemorrhage in the left temporal region.
It has a characteristic well demarcated lens shape (also described as elliptical or biconvex). This is indicative of an extradural haematoma (EDH).
We can see that the haematoma does not cross the skull sutures. This is a typical appearance for an extradural haematoma. The dura is tightly adherent to the skull at the suture lines, preventing spread of blood beyond the suture lines.
Presence of hypodense areas within the haematoma may indicate unclotted blood from an active bleed, also called a swirl sign.
On the axial view, we can see right sided intraparenchymal haemorrhagic contusions.
On the coronal view there is an obvious depressed skull fracture of the left temporal bone with an underlying large intraparenchymal haematoma.
We can see on the bone windows that the fracture extends into the mastoid part of the left temporal region.
There is compression of the left lateral ventricle due to mass effect from the haematoma.
There is also pneumocephalus, indicating an open skull fracture.
CLINICAL CORRELATION
An EDH is a neurosurgical emergency, that requires urgent haematoma evacuation.
The most common site for EDH is underlying the temporal bone. This can be explained by the pathogenesis of EDH formation. The impact of the trauma results in fracture of the skull. The fractured bone then lacerates the underlying extradural artery (usually the middle meningeal artery). The lacerated artery bleeds, as it does so it strips the dura away from the skull, and forms an extradural haematoma. Because it is an arterial bleed it does not tamponade easily and will rapidly expand.
The squamous temporal bone is particularly thin, and it overlies the middle meningeal artery. As a result, trauma to the temporal bone is the most common site of EDH.
The classic lucid period described with EDH only occurs in about a third of patients.
This is whereby there is an initial loss of consciousness at the time of head impact, followed by a lucid period, and then drop in GCS due to expanding EDH.
Management is operative, with urgent decompression of the haematoma, with cerebral protective therapies while awaiting theatre.
References
- Nickson C. Traumatic Brain Injury (TBI) Overview. CCC
- Nickson C. Trauma! Traumatic Brain Injury. LITFL
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TOP 100 CT SERIES
Provisional fellow in emergency radiology, Liverpool hospital, Sydney. Other areas of interest include paediatric and cardiac imaging.
Emergency Medicine Education Fellow at Liverpool Hospital NSW. MBBS (Hons) Monash University. Interests in indigenous health and medical education. When not in the emergency department, can most likely be found running up some mountain training for the next ultramarathon.
Dr Leon Lam FRANZCR MBBS BSci(Med). Clinical Radiologist and Senior Staff Specialist at Liverpool Hospital, Sydney
Sydney-based Emergency Physician (MBBS, FACEM) working at Liverpool Hospital. Passionate about education, trainees and travel. Special interests include radiology, orthopaedics and trauma. Creator of the Sydney Emergency XRay interpretation day (SEXI).