account for about one half of all trauma deaths survivors range from baseline function to severe...
TRANSCRIPT
Head Injury
Dr Malith KumarasingheMBBS (Colombo)
Head Injuries:
Account for about one half of all trauma deaths
Survivors range from baseline function to severe morbidity
Even “minor” head injury can have severe impact
As with most trauma, broken down into blunt and penetrating
Brain anatomy
Physiology of Nervous System
Cerebral Blood Flow (CBF) = 50 – 55 ml/100g of brain tissue/minute
Main Arterial Pressure (MAP) = Diast. P + 1/3 Pulse P
Intracranial Pressure (ICP) = 10 mm Hg Cerebral Perfusion Pressure (CPP) = 50
-150 mm Hg CPP = MAP – ICP
Injuries to the Brain & Skull
Scalp injuries Skull injuries Brain injuries
Scalp Injuries
Scalp has many blood vessels so injury may bleed profusely.
Control bleeding with direct pressure. Don’t apply pressure when there is
possible skull injury.
Cephalhaematoma
It is a subperiosteal haematoma most commonly lies over one parietal bone.
It may result from difficult vacuum or forceps extraction
Management:- It usually resolves spontaneously. - Vitamin K 1 mg IM is given.
Mechanism of injury in head trauma
► Direct trauma by compression or crushing.
► Acceleration-Deceleration Injuries
when a person falls backwards onto a hard floor, the back of the person’s head hits the floor and stops. The brain, however, is still moving until it strikes the inside of the skull. If the brain gets bruised, there is bleeding, also called a hemorrhage. This bleeding
causes further damage to the brain. The skull does not need to strike an object in order for the brain to
get injured. There are many situations in motor vehicle crashes where the forces are transmitted through the brain without the skull hitting the dashboard, windshield, steering wheel or window.
Coup/Contrer-Coup Injuries: Related to acceleration-deceleration injuries (e.g injury to temporal lobe in contralateral temporal trauma)
Head Trauma
1-Skull fractures.2-Extradural ,subdural & subarachinoid.3-Cerebral contusion& intraventricular
Hge.4-Diffuse Axonal Injury (DAI).5-Related Brain edema & herniation.
Skull Fracture
► A skull fracture is a break in the skull bone and generally occurs as a result of direct impact .
► Uncomplicated skull fractures themselves rarely produce neurologic deficit, but the associated intracranial injury may have serious neurologic sequelae.
► Four major types of skull fractures may occur:
► (1) linear,► (2) depressed,► (3) diastatic, ► (4) basilar.
Linear skull fractures
Linear fractures, the most common
Involve a break in the bone but no displacement, and generally no intervention is required.
These fractures are usually the result of low-energy transfer due to blunt trauma over a wide surface area of the skull.
The fracture involves the entire thickness of the skull.
Generally, these fractures are of little clinical significance unless they involve a vascular channel, a venous sinus groove, or a suture.
Complications include epidural hematoma, venous sinus thrombosis, and suture diastasis.
Depressed skull fractures
Cech Petr
A fracture is clinically significant and requires elevation when a fragment of bone is depressed deeper than the adjacent inner table.
Depressed fractures may be closed or compound (open).
Compound fractures may be exposed when they are associated with a skin laceration or when the fracture extends into the paranasal sinuses and the middle-ear structures.
Sutures
Diastatic Skull Fracture
Diastatic fractures occur along the suture lines and usually affect newborns and infants in whom suture fusion has not yet happened. In this type of fracture, the normal suture lines are widened
Diastatic Skull Fracture
Basilar skull fractures Basilar fractures are the most serious and
involve a linear break in the bone at the base of the skull.
Most basilar fractures occur at 2 specific anatomic locations—namely, the temporal region and the occipital condylar region.
These fractures are often associated with dural tears, of which cerebrospinal fluid (CSF) rhinorrhea and otorrhea are known complications.
Basilar skull fractures
► Most basilar fractures occur at 2 specific anatomic locations — namely, the temporal region and the occipital condylar region.
Epidural Hematoma► An epidural hematoma is usually
associated with a skull fracture. It often occurs when a direct impact fractures the calvarium .
► The fractured bone lacerates a dural artery (middle meningeal artery) or a venous sinus.
► On CT, the hematoma forms a hyperdense biconvex mass. It is usually uniformly high density but may contain hypodense foci due to active bleeding.
► Comment on midline shift .
Natasha RichardsonMarch 2009
Clinical features Patients may have external evidence of head
injuries such as scalp lacerations, cephalohematoma, or contusions.
no loss of consciousness, brief loss of consciousness, or prolonged loss of consciousness.
The classic lucid interval occurs in 20-50% of patients with EDH.› Initially, the concussive force that caused the head
injury results in an alteration of consciousness.› After recovering consciousness, the EDH continues
to expand until the mass effect of the hemorrhage itself results in increased intracranial pressure, a decreased level of consciousness, and a possible herniation syndrome.
severe intracranial hypertension, a Cushing response may occur.
The classic Cushing triad involves systemic hypertension, bradycardia, respiratory depression.
Treatment
treatment options for these patients are
(1) immediate surgical intervention
(2) initial, conservative, close clinical observation with possible delayed evacuation.
Subdural Hematoma Deceleration and acceleration or rotational forces that tear bridging veins can cause
an acute subdural hematoma so it occurs in cases of wide subdural space(old age &
children)
Causes of subdural are :in minimal trauma in old age, child abuse and ventricular
decompression, may occur in patients receiving anticoagulants or patients with a
coagulopathy condition.
The blood collects in the space between the arachnoid matter and the dura matter,
Because the subdural space is not limited by the cranial sutures, blood can spread
along the entire hemisphere and into the hemispheric fissure, limited only by the dural
reflections .
We have 3 major types :
Acute, subacute & chronic
Acute Subdural Hematoma
Crescent shaped; Hyperdense, may contain hypodense foci due to serum, CSF or active bleeding
► In children, subdural hematomas occurring along the posterior interhemispheric fissure and the tentorium have been described as common findings following violent nonaccidental shaking
► (ie, shaken baby syndrome) .
Clinical Features Clinical presentation depends on the
location of the lesion and the rate at which it develops.
Often, patients are rendered comatose at the time of the injury.
A subset of patients remain conscious; others deteriorate in a delayed fashion as the hematoma expands.
Treatment
significant acute traumatic subdural hematoma requires surgical treatment, temporizing medical maneuvers can be preoperatively used to decrease intracranial pressure. These measures are germane for any acute mass lesion
As with any trauma patient, resuscitation begins with the ABCs
Short-acting sedatives and paralytics should be used only when needed to facilitate adequate ventilation or when elevated intracranial pressure is suspected.
The patient should also be mildly hyperventilated
Administer anticonvulsants to prevent seizure-induced ischemia and subsequent surges in intracranial pressure.
Do not give steroids, as they have been found to be ineffective in patients with head injury.
Subacute Subdural Hematoma
► Subacute SDH may be difficult to visualize by CT because as the
hemorrhage is reabsorbed it becomes isodense to normal gray matter.
► A subacute SDH should be suspected when you identify shift of midline
structures without an obvious mass.
► Giving contrast may help in difficult cases because the interface between
the hematoma and the adjacent brain usually becomes more obvious due
to enhancement of the dura and adjacent vascular structures.
► Some of the notable characteristics of subacute SDH are:- Compressed lateral ventricle& or midline shift
- Effaced sulci .
Subacute subdural hematomas are defined arbitrarily as those that present between 4 and 21 days after injury.
Chronic Subdural Hematoma
► Chronic SDH becomes low density as the hemorrhage is further reabsorbed. It is usually uniformly low density but may be loculated. Rebleeding often occurs and causes mixed density and fluid levels.
Chronic subdural hematomas are arbitrarily defined as those hematomas presenting 21 days or more after injury.
Subarachnoid Hemorrhage ► A subarachnoid hemorrhage occurs with injury of small arteries or veins on the surface of the brain. The ruptured vessel bleeds into the space between the pia and arachnoid matter. The most common cause of subarachnoid hemorrhage is trauma .
► In the absence of significant trauma, the most common cause of subarachnoid hemorrhage is the rupture of a cerebral aneurysm.
Causes Bleeding from an arteriovenous
malformation (AVM) Bleeding disorder Bleeding from a cerebral aneurysm Head injury Unknown cause (idiopathic) Use of blood thinners
SAH classification
Subarachnoid hemorrhage (SAH) is classified according to 5 grades, as follows:
Grade I: Mild headache with or without meningeal irritation
Grade II: Severe headache and a nonfocal examination, with or without mydriasis
Grade III: Mild alteration in neurologic examination, including mental status
Grade IV: Obviously depressed level of consciousness or focal deficit
Grade V: Patient either posturing or comatose
► When traumatic, subarachnoid hemorrhage occurs most commonly over the cerebral convexities or adjacent to otherwise injured brain (i.e. adjacent to a cerebral contusion)
► If there is a large amount of SAH particularly in the basilarcisterns,sulci&fissures the physician should consider whether a ruptured aneurysm led to the subsequent trauma.
Clinical Features
main symptom is a severe headache that starts suddenly and is often worse near the back of the head.
Patients often describe it as the "worst headache ever" and unlike any other type of headache pain. The headache may start after a popping or snapping feeling in the head.
Decreased consciousness and alertness Eye discomfort in bright light (photophobia) Mood and personality changes, including
confusion and irritability Muscle aches (especially neck pain and
shoulder pain) Nausea and vomiting Numbness in part of the body Seizure Stiff neck Vision problems, including double vision,
blind spots, or temporary vision loss in one eye
Treatment Strict Bed rest Surgery could be considered in:
Remove large collections of blood or relieve pressure on the brain if the hemorrhage is due to an injury
Repair the aneurysm if the hemorrhage is due to an aneurysm rupture
Craniotomy (cutting a hole in the skull) and aneurysm clipping -- to close the aneurysm
Endovascular coiling -- placing coils in the aneurysm to reduce the risk of further bleeding
Cerebral Contusion ► Brain contusions commonly are identified in patients with
traumatic brain injury (TBI) .► The second mechanism is related to countercoup
acceleration or deceleration ,which causes the brain to strike the skull. In an event in which the head is in motion, cortical injury occurs adjacent to the floor of the anterior or posterior cranial fossa, the sphenoid wing, the petrous ridge, the convexity of the skull, and the falx or tentorium. The inferior frontal and temporal lobes are particularly vulnerable
► Cerebral contusions are the most common primary intra-axial injury. They often occur when the brain impacts an osseous ridge or a dural fold. The foci of punctate hemorrhage or edema are located along gyral crests. The following are common locations:- Temporal lobe - anterior tip, inferior surface, sylvian region- Frontal lobe - anterior pole, inferior surface- Dorsolateral midbrain- Inferior cerebellum
► On CT, cerebral contusion appears as an ill-defined hypodense area mixed with foci of hemorrhage. Adjacent subarachnoid hemorrhage is common. After 24-48 hours, hemorrhagic transformation or coalescence of petechial hemorrhages into a rounded hematoma is common
► CT scans often demonstrate progression over time in the size and number of contusions and the amount of hemorrhage within the contusions
► MRI findings typically demonstrate the lesions from the onset of injury, but many facilities cannot perform MRI on an emergent basis
► On MRI, contusions are isointense to hyperintense on T1-weighted and hyperintense on T2-weighted image& The signal intensity is increased in the affected region on DWIs .
Diffuse Axonal Injury ► Diffuse axonal injury is often referred to as "shear
injury". It is the most common cause of significant morbidity in CNS trauma. Fifty percent of all primary intra-axial injuries are diffuse axonal injuries .
► When shearing forces occur in areas of greater density differential, the axons suffer trauma; this results in edema and in axoplasmic leakage (which is most severe during the first 2 weeks following injury). The exact location of the shear-strain injury depends on the plane of rotation
► Immediate loss of consciousness is typical of these injuries .
› The true extent of axonal injury typically is worse than that visualized using current imaging techniques The CT of a patient with diffuse axonal injury may be normal despite the patient's presentation with a profound neurological deficit .
► With CT, diffuse axonal injury may appear as ill-defined areas of high density or hemorrhage in characteristic locations.
► One or more small intraparenchymal (petechial) hemorrhages less than 2 cm in diameter, located in the cerebral hemispheres at the grey white interface as well as corpus callosum &brainstem.
► One may also observe small focal areas of low density on CT scans; these correspond to areas of edema
► Stage I - This involves the parasagittal regions of the frontal lobes, the periventricular temporal lobes, and, less likely, the parietal and occipital lobes, internal and external capsules, and cerebellum.
Stage II - This involves the corpus callosum in addition to the white-matter areas of stage I. Most commonly, the posterior body and splenium are involved; however, the process is believed to advance anteriorly with increasing severity of disease. Both sides of the corpus callosum may be involved; however, involvement more frequently is unilateral and may be hemorrhagic. The involvement of the corpus callosum carries a poorer prognosis
Stage III - This involves the areas associated with stage II, with the addition of brainstem involvement. A predilection exists for the superior cerebellar peduncles, medial lemnisci, and corticospinal tracts .
Intraventricular Hemorrhage
► Traumatic intraventricular hemorrhage is associated with diffuse axonal injury, deep gray matter injury, and brainstem contusion. An isolated intraventricular hemorrhage may be due to rupture of subependymal veins .
Cerebral Edema► Severe brain
edema or a large intracranial hemorrhage may cause downward brain displacement and coning, which is usually fatal
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