GOOD MORNING

SUBDURAL HEMATOMA

CONTENTS• Introduction• Classification• Signs & Symptoms• Causes• Pathophysiology• Diagnosis• Treatment• Craniotomy• Complications

INTRODUCTION

• A subdural hematoma , also known as a subdural hemorrhage (SDH), is a type of hematoma, a form of traumatic brain injury in which blood gathers within the outermost meningeal layer, between the dura matter, which adheres to the skull, and the arachnoid mater enveloping the brain.

• Usually results from tears in bridging veins that cross the subdural space.

• subdural hemorrhages may cause an increase in intracranial pressure (ICP), which can cause compression of and damage to delicate brain tissue. Subdural hematomas are often life-threatening when acute, but chronic subdural hematomas are usually not deadly if treated.

• In contrast, epidural hematomas are usually caused by tears in arteries, resulting in a buildup of blood between the dura and the skull.

CLASSIFICATION

CLASSIFICATION

• Subdural hematomas are divided into

(depending on their speed of onset ) acute chronic,

ACUTE SDH

• Acute subdural hematomas that are due to trauma are the lethal of all head injuries and have a high mortality rate if they are not rapidly treated with surgical decompression.

Etiology of acute SDH

Head traumaCoagulopathy or medical anticoagulation (eg,

warfarin [Coumadin], heparin, hemophilia, liver disease, thrombocytopenia)

Nontraumatic intracranial hemorrhage due to cerebral aneurysm, arteriovenous malformation, or tumor (meningioma or dural metastases)

Postsurgical (craniotomy, CSF shunting)

Intracranial hypotension (eg, after lumbar puncture, lumbar CSF leak, lumboperitoneal shunt, spinal epidural anesthesia

Child abuse or shaken baby syndrome (in the pediatric age group)

Spontaneous or unknown (rare)

• Acute bleeds develop after high speed acceleration or deceleration injuries and are increasingly severe with larger hematomas.

• They are most severe if associated with cerebral contusions.

• Though much faster than chronic subdural bleeds, acute subdural bleeding is usually venous and therefore slower than the usually arterial bleeding of an epidural hemorrhage.

• Acute subdural bleeds have a high mortality rate, higher even than diffuse brain injuries, because the force (acceleration/deceleration) required to cause them cause other severe injuries as well.

• The mortality rate associated with acute subdural hematoma is around 60 to 80%.

CHRONIC SDH Chronic subdural bleeds develop over the period

of days to weeks, often after minor head trauma. They may not be discovered until they present

clinically months or years after a head injury. The bleeding from a chronic bleed is slow,

probably from repeated minor bleeds, and usually stops by itself.

Since these bleeds progress slowly, they present the chance of being stopped before they cause significant damage.

Etiology of Chronic SDH

Head trauma (may be relatively mild, eg, in older individuals with cerebral atrophy)

Acute SDH, with or without surgical intervention

Spontaneous or idiopathic

Small chronic subdural hematomas, those less than a centimeter wide, have much better outcomes than acute subdural bleeds.

Only 22% of patients with chronic subdural bleeds had outcomes worse than "good" or "complete recovery".

Chronic subdural hematomas are common in the elderly.

SIGNS &

SYMPTOMS

Symptoms of subdural hemorrhage have a slower onset than those of epidural hemorrhages because the lower pressure veins bleed more slowly than arteries.

Therefore, signs and symptoms may show up in minutes, if not immediately but can be delayed as much as 2 weeks

Signs and Symptoms of subdural hematoma can include any combination of the following:

• Loss of consciousness or fluctuating levels of consciousness

• Irritability• Seizures• Pain• Numbness• Headache (either constant or fluctuating)• Dizziness• Disorientation• Amnesia• Weakness or lethargy

• Nausea or vomiting• Loss of appetite• Personality changes• Inability to speak or slurred speech• Ataxia, or difficulty walking• Altered breathing patterns• Hearing loss or hearing ringing (tinnitus)• Blurred Vision• Deviated gaze, or abnormal movement of the

eyes

CAUSES

• Subdural hematomas are most often caused by head injury, when rapidly changing velocities within the skull may stretch and tear small bridging veins.

• Subdural hemorrhages generally result from shearing injuries due to various rotational or linear forces.

• Subdural hemorrhage is a classic finding in shaken baby syndrome which show shearing forces

• Subdural hematoma is also commonly seen in the elderly and in alcoholics, who have evidence of cerebral atrophy. Cerebral atrophy increases the length the bridging veins have to traverse between the two meningeal layers, hence increasing the likelihood of shearing forces causing a tear

• It is also more common in patients on anticoagulants, especially aspirin and warfarin. Patients on these medications can have a subdural hematoma with a minor injury.

• A further cause can be a reduction in cerebral spinal fluid pressure which can create a low pressure in the dura and so cause rupture of the blood vessels.

PATHOPHYSIOLOGY

PATHOPHYSIOLOGY• Collected blood from the subdural bleed may

draw in water due to osmosis, causing it to expand, which may compress brain tissue and cause new bleeds by tearing other blood vessels.

• In some subdural bleeds, the arachnoid layer of the meninges is torn, and cerebrospinal fluid (CSF) and blood both expand in the intracranial space, increasing pressure

• Substances that cause vasoconstriction may be released from the collected material in a subdural hematoma, causing further ischemia under the site by restricting blood flow to the brain.

• When the brain is denied adequate blood flow, a biochemical cascade known as the ischemic cascade is unleashed, and may ultimately lead to brain cell death.

DIAGNOSIS

A subdural hematoma demonstrated by CT.

• Subdural hematomas occur most often around the tops and sides of the frontal and parietal lobes.They also occur in the posterior cranial fossa, and near the falx cerebri and tentorium cerebelli.

• Unlike EDH, subdural hematomas can expand along the inside of the skull, creating a concave shape that follows the curve of the brain, stopping only at the dural reflections like the tentorium cerebelli and falx cerebri

• On a CT scan, subdural hematomas are classically crescent-shaped, with a concave surface away from the skull. However, they can have a convex appearance, especially in the early stage of bleeding.

• A more reliable indicator of subdural hemorrhage is its involvement of a larger portion of the cerebral hemisphere since it can cross suture lines, unlike an epidural hemorrhage

• Subdural blood can also be seen as a layering density along the tentorium cerebelli.

• In chronic bleed, subtle signs of bleeding such as effacement of sulci or medial displacement of the junction between gray matter and white matter may be apparent.

• A chronic bleed can be the same density as brain tissue (called isodense to brain), meaning that it will show up on CT scan as the same shade as brain tissue, potentially obscuring the finding.

TREATMENT

• Treatment of a subdural hematoma depends on its size and rate of growth.

• Some small subdural hematomas can be managed by careful monitoring until the body heals itself.

• Other small subdural hematomas can be managed by inserting a

temporary small catheter

through a hole drilled

through the skull and

sucking out the hematoma;

this procedure can be done

at the bedside.

• Large or symptomatic hematomas require a craniotomy, the surgical opening of the skull. It involves opening the dura, removal of the blood clot with suction or irrigation, and identifying and controling sites of bleeding.

CRANIOTOMY

• Craniotomy is any bony opening that is cut into the skull. A section of skull, called a bone flap, is removed to access the brain underneath.

• There are many types of craniotomies, which are named according to the area of skull to be removed .

• Typically the bone flap is replaced. If the bone flap is not replaced, the procedure is called a craniectomy

Craniotomies are often named for the bone being removed. Some common craniotomies include frontotemporal, parietal, temporal, and suboccipital

• Craniotomies are also named according to their size and complexity.

• Small dime-sized craniotomies are called burr holes or keyhole craniotomies.

• Sometimes stereotactic frames, image-guided computer systems, or endoscopes are used to precisely direct instruments through these small holes.

insert a shunt into the ventricles to drain cerebrospinal fluid (hydrocephalus)

insert a deep brain stimulator to treat Parkinson Disease

insert an intracranial pressure (ICP) monitor remove a small sample of abnormal tissue

(needle biopsy)drain a blood clot (stereotactic hematoma

aspiration)insert an endoscope to remove small tumors and

clip aneurysms

Burr holes or keyhole craniotomies are used for minimally invasive procedures to:

Large or complex craniotomies are used to:

remove or treat large brain tumors, aneurysms, or AVMs

treat the brain following a skull fracture or injury (e.g., gunshot wound)

remove tumors that invade the bony skull

CRANIOTOMY PROCEDURE

The patient’s head is placed in a three-pin Mayfield skull clamp. The clamp attaches to the operative table and holds the head absolutely still during delicate brain surgery. The skin incision is usually made behind the hairline (dashed line).

A craniotomy is cut with a special saw called a craniotome. The bone flap is removed to reveal the protective covering of the brain called the dura.

The dura is opened and folded back to expose the brain.

The bone flap is replaced and secured to the skull with tiny plates and screws.

Postoperative complications include increased intracranial pressure brain edema new or recurrent bleeding infection and seizure

Specific complications related to a craniotomy may include:

stroke

seizures

swelling of the brain, which may require a second craniotomy

nerve damage, which may cause muscle paralysis or weakness

CSF leak, which may require repair

loss of mental functions

permanent brain damage with associated disabilities

DISCUSSION

EPIDURAL HAEMORRHAGE SUBDURAL HAEMORRHAGE

1. It is hematoma between inner periosteum of cranium and duramater.

2.Mostly due to bleed from artery especially middle meningeal.

3. Commonly associated with laceration & fracture of overlying

cranial vault.

4.On CT: seen as biconvex hyperdense area pushing the brain

tissue away.

1. It occurs between the dura matter, which adheres to the skull, and the

arachnoid mater enveloping the brain.

2. due to tearing of bridging veins of brain.

3. Not always associated with fracture of cranial bones, may show blunt

trauma.

4. On CT: follows the anatomy of cerebral hemisphere & is seen

concave away from skull/ crescent shaped.

Retrograde amnesia?• It is a form of amnesia where one is

unable to recall events that occurred before the development of the amnesia.

It results from injury to brain regions associated with declarative memory; the temporal lobes & especially hippocamppus.

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