Section 1: Trauma Flashcards
1
Q
Types of Skull Fractures
A
- Linear
- Sharp lucent line
- Can be extensive and widespread
- Depressed
- Focal
- Inwardly displaced fragments
- Often lacerates dura-arachnoid
- Elevated
- Rare
- Fragmented rotated outward
- Diastatic
- Typically associated with severe trauma
- Usually caused by linear fracture that extends into suture
- Widens, spreads apart suture or synchondrosis
- ”Growing”
- Rare
- Usually in young children
- Fracture lacerates dura-arachnoid
- Brain/arachnoid herniates through torn dura
- Trapped tissue prevents bone healing
- CT: Rounded edges, scalloped margins of skull
- MR: CSF ± brain
2
Q
Types of Scalp Lacerations
A
- Lacerations
- ± Foreign bodies
- Cephalohematoma
- Usually infants
- Subperiosteal
- Small, unilateral (limited by sutures)
- Subgaleal hematoma
- Between galea, periosteum of skull
- Circumferential, not limited by sutures
- Can be very large, life-threatening
3
Q
Classic Acute Epidural Hematoma
- Terminology
- Etiology
- Pathology
- Clinical
- Imaging
A
- Terminology
- EDH = blood between skull, dura
- Etiology
- Associated skull fracture in 90-95%
- Arterial 90%
- Most often middle meningeal artery
- Venous 10%
- Pathology
- Unilateral, supratentorial (> 90%)
- Dura stripped away from skull → biconvex hematoma
- Usually does not cross sutures (exception = children, 10%)
- Does cross sites of dural attachment
- Clinical
- Rare (1-4% of head trauma)
- Older children, and young adults most common
- M:F = 4:1
- Classic “lucid interval” in only 50%
- Delayed deterioration common
- Low mortality if recognized, treated
- Small EDHs
- If minimal mass, no “swirl sign” is often managed conservatively
- Imaging
- Hyperdense lens-shaped
- “Swirl sign” (hypodensity) = rapid bleeding
4
Q
Venous Epidural Hematomas
Tell me a little about them?
Subtypes?
A
- Not all EDHs are the same!
- Different etiologies in different anatomic locations
- Prognosis and treatment vary.
- Venous EDHs = 10% of all EDHs
- Skull fracture crosses dural venous sinus
- Can cross sutures, dural attachments
- Skull fracture crosses dural venous sinus
- Often subtle, easily overlooked
- Coronal, sagittal reformatted images key to diagnosis
- Subtypes
- Vertex EDH
- Anterior temporal EDH
- Clival EDH
5
Q
Vertex EDH
A
- Venous epidural hematoma subtype
- Skull fracture crosses superior sagittal sinus (SSS)
- SSS can be lacerated, compressed, thrombosed
- Hematoma under low pressure develops gradually
- Slow onset of symptoms
- May become large, cause significant mass effect
6
Q
Anterior Temporal EDH
A
- Venous epidural hematoma subtype
- Sphenoid wing or zygomaticomaxillary fracture
- Injures sphenoparietal venous sinus
- Hematoma accumulates at anterior tip of middle cranial fossa
- Limited anatomically (laterally by sphenotemporal suture, medially by orbital fissure)
- Benign clinical course
7
Q
Clival EDH
A
- Venous epidural hematoma subtype
- Most common = child with neck injury
- May cause multiple cranial neuropathies (CN VI most common)
- Hyperdense collection under clival dura
- Limited by tight attachment of dura to basisphenoid, tectorial membrane
- Usually benign course, resolves spontaneously
8
Q
Acute SDH (aSDH)
A
- Second most common traumatic extraaxial hemorrhage
- Acute SDH > > epidural hematoma
- Crescentic collection of blood between dura, arachnoid
- Supratentorial (95%), bilateral (15%)
- SDHs cross sutures
- SDHs do not cross dural attachments
- CT
- Hyperdense (60%)
- Mixed (40%)
- Isodense acute SDH rare (anemia, coagulopathy, CSF mixture)
9
Q
Subacute SDH (sSDH)
A
- Clot organizes, lysis, forms “neomembranes”
- CT
- Density decreases 1-2 HU/day
- Isodense with cortex in 7-10 days
- Look for displaced “dots” of CSF under SDH
- Gray-white interface “buckled” inward
- Displaced cortical veins seen on CECT
- MR
- Signal varies with clot age
- T2* (GRE, SWI) shows “blooming”
- T1 C+ shows clot inside enhancing membranes
10
Q
Chronic/Mixed SDH (s/mSDH)
A
- Serosanguineous fluid
- Hypodense on NECT
- Rehemorrhage (5-10%)
- Loculated blood “pockets” with fluid-fluid levels common
- Differential diagnosis of uncomplicated cSDH
- Subdural hygroma (arachnoid tear → subdural CSF)
- Subdural effusion (clear fluid accumulates after meningitis)
- Subdural empyema (pus)
11
Q
Traumatic Subarachnoid Hemorrhage (tSAH)
A
- Most common traumatic extraaxial hemorrhage
- tSAH >> aneurysmal SAH
- Adjacent to cortic contusions
- Superficial sulci > basal cisters
12
Q
Cerebral Contusions
A
- Most common intraaxial injury
- Brain impacts skull and/or dura
- Causes “brain bruises” in gyral crests
- Usually multiple, often bilateral
- Anteroinferior frontal, temporal lobes most common sites
- Imaging
- Superficial petechial, focal hemorrhage
- Edema, hemorrhage more apparent with time
- T2* (GRE, SWI) most sensitive imaging
13
Q
Diffuse Axonal Injury (DAI)
A
- Second most common intraaxial injury
- Spares cortex, involves subcortical/deep WM
- Imaging
- GCS low; initial imaging often minimally abnormal
- Subcortical, deep petechial hemorrhages (“tip of the iceberg”)
- T2* (GRE, SWI) most sensitive technique
14
Q
Diffuse Vascular Injury
A
- Rare, usually fatal
- High-speed, high-impact MVCs
- May represent extreme end of DAI spectrum
- Imaging
- CT shows diffuse brain swelling
- T2 and FLAIR show a few scattered hyperintensities
- SWI shows innumerable linear hypointensities
15
Q
Subcortical Injury
A
- Basically really bad shear-strain injuries
- “The deeper the injury, the worse it is”
- Basal ganglia, thalami, midbrain, pons
- Hemorrhages, axonal injury, brain tears
- Gross intraventricular hemorrhage common
