Glossary of Neuro - Head Trauma
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- Trauma is the leading cause of mortality and morbidity in people aged _______
- 1-40 and in more than half of them head injury is a significant contributing factor
- GCS score -- 3 factors
- eye opening, best verbal response, best motor response
- max and min GCS scores
- max 15
- 4 Signs of Basal skull fracture:
- Raccoon's eyes (periorbital ecchymoses)
Battle's sign (postauricular ecchymoses)
CSF leakage from nose or ear
- Most common focal intracerebral lesion in patient with severe brain injury
- Acute subdural hematoma
- what is an acute subdural hematoma?
- tearing of the bridging veins between the cerebral cortex and the venous sinuses --> subdural hematomas that can occur spontaneously or with mild trauma, especially in the elderly
- Epidural hematoma is usually from..?
- epidural <-- a skull fracture that lacerates the middle meningeal artery --> and accumulation of blood between the dura and the skull
- Classic presentation of an epidural hematoma?
- a brief loss of consciousness followed by a lucid interval for several hours and then deterioration in the level of consciousness, with hemiparesis on the siden opposite the hematoma as well as ispilateral pupillary dilation
- What do epidural hematomas look like on CT scan?
- hyperdense with a biconvex (crescent moon) shape.
- Immediate treatement for epidural hematomas?
- emergency surgery. Mortality is relatively low (5-10%) provided that the hematoma is diagnosed and treated with surgical drainage within a few hours
- Mortality and morbidity for epidurals?
- relatively low - 5-10% provided hematoma is dx and tx with surgical drainage in a few hours
- What do contusions and intracerebral hematomas looks like on head CT
- high-density areas on head CT, representing brusies of the brain parenchyma.
- Where do contusions and intracerebral hematomas occur?
- typically where areas of sudden deceleration of the head causes the brain to impact on bony prominences. The majority occur in the inferior frontal or temporal lobes
- 2 types of contusions?
- Coup - directly below site of impact
contrecoup - abnormalities located on opposite side of brain as it is thrust against the skull
- Tx for contusions and intracerebral hematomas
- tx is typically following clinically and with follow-up head CT scans.
Surgery is reserved for patients with significant mass effect and clinical deterioration
- Subarachnoid Hemorrhage
- -bleeding into the subarachnoid space.
Head trauma is the most common cause of SAH.
- Management of patients with SAH
- monitoring for cerebral vasospasm, increased intracranial pressure, and acute hydrocephalus
- Diffuse axonal injury/ Diffuse axonal shearing is caused by
- rotation acceleration and deceleration of the head.
It is most commonly seen in motor vehicle accidents.
It is also the most common presumed cause of coma in patients with closed head injury in the absence of cerebral hemorrhage of other space occupying lesion on head CT scan.
- Diffuse axonal injury is characterized by:
- gross and microscopic axonal changes in the cerebral white matter and small hermorrhagic lesiions of the corpus collosum and brainstem (Duret Hemorrhages)
- A mass lesion of tumor or blood will cause the ICP to rise after which compensatory mechanisms?
- decreased CSF and venous blood in skull
- 4 herniation syndromes
- Uncal (Tentorial) Herniation
Central (transtentorial) Herniation
- Cause of Uncal (tentorial) herniation:
- mass lesion of the middle cranial fossa
- Where is the uncus?
- the uncus is the inferomedial portion of the temporal lobe
- Where does the uncus herniate?
- downward into the posterior fossa between the rostral brainstem and the tentorium cerebelli.
- Symptomes of Uncal (tentorial) herniation
- Typically the 3rd cranial nerve is entrapped --> unilateral dilated pupil.
As the herniation progresses hemiparesis and alteration of consciousness can occur. With eventual brainstem signs and changes in respiratory patterns. Eventually in can lead to death
- Cause of Cingulate Herniation?
- A mass lesion, usually in the frontal lobes --> displacement of the cingulate gyrus across the falx cerebri in the frontal midline.
- Symptoms of Cingulate Herniation?
- There are no specific signs or symptoms of Cingulate Herniation but it can frequently be seen on CT scan
- Cause of Central (transtentorial) herniation
- a large supratentorial mass pushes the diencephalon and midbrain through the tentorial opening
- Symptoms of Central (transtentorial) herniation
- altered consciousness, bilateral small reactive pupils, and decorticate posturing followed by decerebrate posturing.
Decorticate, or flexor, posturing - present with the arms flexed, or bent inward on the chest, the hands are clenched into fists, and the legs extended.
Decerebrate, or extensor, posturing - the arms are extended by the sides, the head is arched back, and the legs are extended
Cheyne-Stokes respirations (crescendo-decrescendo pattern followed by respiratory pause) can be seen.
- Cause of Tonsillar herniation
- posterior fossa mass --> herniation of the cerebellar tonsils through the foramen magnum.
Cerebellar tonsils then compress the medulla --> respiratory arrest. Usually fatal
- 1st thing to do if herniation or increased ICP is suspected?
- get a CT
- After CT, if herniation or increased ICP is suspected, what should you do?
- 1) elevate head of the pts bed 30 degrees in order to dispace CSF
2) Hyperventilate pt to achieve a PCO2 between 25 and 30 mmHg, which --> cerebral vasoconstriction an a reduction of intracranial volume which --> decreased ICP
3) Mannitol is an osmotic diuretic that temporarily decreases intracranial volume and pressure
4) Loop diuretics (furosemide) can cause diuresis.
Treat the underlying condtion
ie. surgical drainage or shunt for large parenchymal hemorrhage or epidural hematoma
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