Epidural hematoma

epidural hematoma

1. EPIDURAL HAEM A T OMA

2. EPIDURAL HAEMATOMA It is a collection of blood between the potential space that exists between the inner table of skull and the dura (periosteal layer). Extension of hematoma usually is limited by the suture lines owing to the light attachment of the dura at these locations (continuation of periosteal layer of the dura with the pericranium at the sutures)

3. The person may have varying degrees of symptoms associated with the severity of the head injury. The following are the most common symptoms of a head injury. However, each individual may experience symptoms differently. With this type of moderate to severe head injury, immediate medical attention is required. Symptoms may include: confusion loss of consciousness blurred vision severe headache vomiting loss of short-term memory, such as difficulty remembering the events that lead right up to and through the traumatic event slurred speech difficult walking dizziness weakness in one side or area of the body sweating pale skin color seizures behavior changes including irritability blood or clear fluid draining from the ears or nose one pupil (dark area in the center of the eye) looks larger than the other eye deep cut or laceration in the scalp open wound in the head foreign object penetrating the head

4. Pathophysiology It results from brief linear contact force to the calvarium that causes seperation of the periosteal dura from the bone and disruption of interposed vessels due to sheering stress Skull # are found in 85% - 95 % of adult cases Chronic or delayed manifestation may occur when the venous sources are involved The haematoma arises from injury to the middle meningeal artery in over half of the patients ,from the middle meningeal vein in one third and from diploic veins or torn dural venous sinus from the remainder .

5. The temporoparietal region and middle menigeal artery are most commonly involved 66% Anterior ethemoidal arteries may be involved in frontal injuries ,the transverse or sigmoid sinus in occipital injuries and superior saggital sinus in trauma to the vertex . Posterior fossa EDH occur in 5 % of all cases of EDH

6. Lucid interval An epidural hemorrhage is often characterized by the following sequence of events: Blunt trauma/ a blow to the head, followed by: 1) Initial confusion, decreased consciousness, or loss of consciousness 2) A “lucid interval” (20-50%): a brief period of full conciousness/restored mental status. The patient seems back to his/her “normal self.” 3) Change in mental status +/- unstable vital signs (blood pressure, heart rate): the patient becomes confused, somnolent (sleepy), may have neurologic signs such as hemiparesis, one dilated pupil, may become comatose.

7. Diagnosis The diagnosis of EDH must be considered when the plain skull xrays show a fracture and it must be clinically corelated If the clinical condition of the patient permits and a non contrast computed tomogram is possible,it must be done urgently The classic CT appearance is seen in 84 % of the cases and shows hyperdense ,biconvex The derivation of the ABC /2 formula is as follows: The volume of an ellipsoid is 4/3π( A /2)( B /2)( C /2), where A , B , and C are the three diameters. If π is estimated to be 3, then the volume of an ellipsoid becomes ABC /2.

8. Generally EDH is confined within the sutures but this may not be the case everytime ,occasionally ,air may be seen within the haematoma due to an associated internal or external compound fracture of the skull. MRI can also be done but it is in no way superior to CT and also time consuming . INFRARED SPECTROSCOPY which can be used with reasonable sensitivity and specificity for detection of intracranial lesions in a short time .and could be informative when the patient is herniating and urgent surgical intervention is required Cervical spine evaluation is usually necessary because of the risk of neck injury associated with EDH .

9. MANAGEMENT LAB INVESTIGATIONS 1. CBC with platelets :to monitor for infection and asseses haematocrit and platelets for furthur haemorrhagic risk 2.PROTHROMBIN TIME /ACTIVATED PARTIAL THROMBOPLASTIN TIME (aPTT) :to identify bleeding diasthesis 3. SERUM CHEMISTRY including electrolytes,blood urea nitrogen ,creatinine and glucose :to characterize metabolic deaarangement that may complicate the clinical course Toxicology screen and serum alcohol level :to identify associated cause of head trauma and establish need for survelliance with regard to withdrawl symptoms Type and hold an appropriate amount of blood : to prepare for necessary transfusion needed due to blood loss or anaemia

10. Management of EDH is most of the time surgical but in few selected patients ,non surgical management may be attempted ,these are : A. Small EDH less than equal to 1 cm B. subacute or chronic EDH C.minimal neurological signs and symptom s these patients are closely observed and surgery is undertaken if no evidence of progressive improvement is noted. In 50 % of the cases ,there is transient increase in size between day5 – 16 and it is that time where non surgical patients need special attention .surgery should be done for most posterior fossa EDHs

11. In a rapidly deteriorating patient with suspected EDH ,a CT scan is inapropriate .the clinical triad of : Altered mental status Unilateral pupillary dilatation with loss of light reflex Co n t r al a t e r al hemiparesis Is often due to upper brainstem compression by uncal herniation which in majority of the trauma cases is due to EDH .in such patients exploratory burr holes are indicated

12. MRI MRI can clearly demonstrate the displaced dura which appears as a hypointense line on T1 and T2 sequences which is helpful in distinguishing it from subdural haematoma. Acute EDH appears isointense on T1 and shows variable intensities from hypo- to hyperintense on a T2 sequence. Early subacute EDH appears hypointense on T2 while late subacute and chronic EDH are hyperintense on both T1 and T2 sequences. Intravenous contrast may demonstrate displaced or occluded venous sinus in case of venous origin of EDH.

13. Differential diagnosis With large haematomas, there is rarely significant confusion as to the correct diagnosis. In smaller lesions, especially when there is associated parenchymal injury (e.g. cerebral contusions , traumatic subarachnoid blood , concurrent subdural haematoma ) the diagnosis can be more challenging. Differential considerations include: subdural haemorrhage (SDH) can cross sutures usually sickle shaped limited by dural reflections usually in older patients or in young patients with significant other closed head injuries meningioma may be hyperdense enhances with contrast usually remote from fracture (e.g. parafalcine) •

14. Mechanism of action Mannitol exerts its ICP-lowering effects via two mechanisms—an immediate effect because of plasma expansion and a slightly delayed effect related to its osmotic action. The early plasma expansion reduces blood viscosity and this in turn improves regional cerebral microvascular flow and oxygenation. It also increases intravascular volume and therefore cardiac output. Together, these effects result in an increase in regional cerebral blood flow and compensatory cerebral vasoconstriction in brain regions where autoregulation is intact, resulting in a reduction in ICP.

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