Volume 5, Case 7
Lynette L. Young, MD
Kapiolani Medical Center For Women And Children
University of Hawaiʻi John A. Burns School of Medicine
Head injuries in children are common, accounting for about 600,000 or more ED visits annually. CT is the method of choice for the evaluation of intracranial injury. It is useful in identifying epidural, subdural, subarachnoid and intracerebral hemorrhage. MRI is not generally used acutely, but it may play a role in identifying more subtle injuries. The purpose of this case is to describe the classic CT appearance of the various types of intracranial hemorrhages in children.
Since each type of intracranial hemorrhage has a different prognosis and a different management approach, it is important to be able to distinguish their appearances on CT so that they can be best described to a consulting neurosurgeon.
There is a fixed volume within the skull. Head trauma causing bleeding or swelling on one side of the tentorium leads to increased pressure in that compartment. To equalize the pressure there is a shift in volume leading to brain herniation. It is important to be able to detect early edema so that therapy may be started for increased intracranial pressure to hopefully avert herniation. Early brain edema on CT can be identified with a decrease in the size of the third ventricle and the basal cisterns. With cerebral edema there is loss of the sulci, the lateral ventricles are small, and the brain (supratentorial) is hypodense.
The different brain herniation syndromes are described in Case 6 of this volume.
Types of Intracranial Hemorrhages
1. Epidural hematoma
2. Subdural hematoma
3. Subarachnoid hematoma
4. Intracerebral hemorrhage
5. Intraventricular hemorrhage
Epidural hematomas usually result from rupture of arteries and large superficial venous sinuses. The incidence is 1% to 3% in patients hospitalized after head injury. There is an underlying fracture in 60% to 90% of the patients. The prognosis is usually better than with subdural hematomas as the calvarium absorbs some of the force. The brain is relatively spared. There is no intradural injury in about 50% of the cases. The mortality rate is 25% to 50%. The middle meningeal artery is the most commonly injured vessel, in the temporal region 70% to 75% of the time.
The epidural hematoma may subsequently lead to transtentorial herniation. The classic description of symptoms includes a brief loss of consciousness, followed by a lucid period, and then neurologic deterioration (signs and symptoms of increased intracranial pressure). These classic symptoms are present only 33% of the time. With children, the classic symptoms are rare. The extradural hemorrhage is often venous and loss of consciousness may be gradual. In 50% of the cases of epidural hematomas in children, there is no underlying skull fracture. In children 6 years and older the most common event causing an epidural hematoma is a blow to the side of the head, such as a fall off a bicycle. CT is the method of choice to evaluate an epidural hematoma. An acute epidural hematoma is described as biconvex (lentiform, elliptical, or football-shaped) in appearance. The dura is closely applied to the inner table and, as the hematoma from the bleeding expands, the dura bulges inward, giving it the biconvex or lens-shaped appearance. The dura is anchored at the suture lines so epidural hematomas generally do not cross sutures. They may extend across a venous sinus crossing the midline distinguishing it from a subdural hematoma.
The treatment for most epidural hematomas is neurosurgical evacuation.
A subdural hemorrhage may be caused from direct trauma, severe acceleration-deceleration trauma, or shaking injury. The bleeding is from tearing of the cortical bridging veins. The subdural hemorrhage may be bilateral and is frequently associated with diffuse brain injury. The functional and structural brain damage is often much more severe than the degree of bleeding. The incidence is 5% following head injury. After trauma it is 6-times more likely to have a subdural than epidural hematoma. A skull fracture is found in only about 30% of cases. The location is mostly supratentorial and along the brain convexity. Less common locations are interhemispheric, subtemporal, and tentorial.
Subdural hemorrhages have a poor prognosis with mortality rates between 60% to 90%. If the patient has surgery within 4 hours of the initial injury the mortality rate drops to 30%. The significant mortality rate is attributed to the high incidence of associated irreversible brain damage. Typically a subdural hematoma is not an isolated finding, rather it is a component of more severe head injuries. Associated conditions include focal or diffuse cerebral edema, diffuse axonal shearing, severe contusions, and epidural hematomas. The signs of a subdural hematoma usually have a slower time course compared to an epidural hematoma. The bleeding is not constrained by a tight dura and the clot has room to expand. The patients may have similar symptoms to the classic epidural history. Typically, there is history of head trauma accompanied by loss of consciousness, with some recovery but not completely back to normal. There are usually external signs of trauma and immediate loss of consciousness. The patient may have a headache, pupillary dilation, personality change, stiff neck, seizure, vomiting, irritability, and low-grade fever. Signs and symptoms of a subdural hematoma in an infant may include irritability, lethargy, a bulging fontanelle, and vomiting.
In the pediatric population an acute interhemispheric subdural hematoma is most common. This is usually due to shaking associated with child abuse (Shaken infant syndrome. See Case 1 of Volume 1, Toxic Infant With a Full Fontanelle). Subdural hematomas in the posterior fossa are rare, mostly occurring in neonates with birth trauma. A subdural hematoma should be ruled-out in an infant with seizures following a difficult delivery. With child abuse/shaken baby syndrome, children with subdural hematomas may present with coma, seizures, or other signs of increased intracranial pressure. Chronic subdural hematomas are rare in children except in abused infants from 2 to 6 months. They may present with a history of recurrent vomiting, seizures, and may have retinal hemorrhages and a tense fontanelle.
CT can identify the subdural hematomas and underlying brain injury that is commonly associated. The hematoma is described as crescent shape as it conforms to the calvarium and underlying cerebral cortex. The blood with subdural hematomas extends freely along the convexity of the brain, rather than causing a localized inward bulge like epidural hematomas (subdurals are crescent shaped, while epidurals are biconvex; ie., lentiform, football shaped). Rarely a subdural hematoma may have a atypical configuration making it indistinguishable from an epidural hematoma. This may occur with an abnormally shaped calvarium and/or loculation by fibrotic bands secondary to previous trauma or inflammation. At times, the subdural hematoma may be relatively small on CT, and there may appear to be a disproportionately large mass effect. The collection of blood is usually very extensively spread along the surface of the brain. As the hematoma ages, it becomes isodense with respect to the gray matter (7th - 21st day) and then hypodense. Contrast enhancement may be needed to delineate subacute or chronic injury on CT. Fresh blood tends to layer in the dependent portion of a subdural collection. Tentorial hematomas are hard to distinguish from subarachnoid blood layering on the tentorium. Coronal CT or MRI may be necessary for the diagnosis. Coronal CT also facilitates diagnosis of subdural hematomas located in the middle cranial fossa, subtentorial region, and vertex. The treatment for subdural hematomas is intensive medical therapy to control increased intracranial pressure, even with surgery. The patient should have neurosurgical evaluation. Surgery may not be necessary unless the hematoma is large or a significant factor in the increased intracranial pressure. Subdural taps may be done in infants.
Subarachnoid hemorrhage is the most common location for bleeding after an acute head injury. The bleeding is usually venous rather than arterial in origin. Hemorrhage into the subarachnoid space results in bloody CSF on lumbar puncture. Ruptured berry aneurysm is a classic cause of subarachnoid hemorrhage. A common cause of subarachnoid hemorrhage in pediatric patients is shaken infant syndrome (see Case 1 of Volume 1, Toxic Infant With a Full Fontanelle). While shaken infant syndrome generally results in the classic posterior interhemispheric subdural hematoma, there is hemorrhage into the subarachnoid space as well. Such infants often present appearing toxic, and a lumbar puncture done to rule out meningitis will reveal homogeneously bloody CSF.
Newborn intracranial hemorrhages associated with birth trauma are most commonly subarachnoid. The patients may present with a stiff neck and lethargy. Often, the patient may be asymptomatic. The most common symptom associated with either a subarachnoid or subdural hemorrhage in the newborn is development of seizures after 48 hours of life.
Noncontrast CT will detect up to 90% of all subarachnoid bleeds within the first 24 hours regardless of etiology. The initial CT should be done without contrast as contrast may obscure the presence of subarachnoid blood. Subarachnoid hemorrhage is commonly seen in the basilar cisterns of patients following head trauma. The basilar cisterns may appear denser or isodense to brain due to hemorrhage. Blood may accumulate in the cortical sulci making them more dense than the underlying cerebral cortex. The suprasellar cistern should be examined carefully as small amounts of blood may collect around the skull base. The falx and tentorium appear hyperdense on CT with subarachnoid hemorrhage. The falx borders may be irregular or scalloped from blood entering into neighboring sulci. The pseudodelta sign occurs when blood outlines the border of the dependent portion of the superior sagittal sinus. On CT, subarachnoid hemorrhage may have a similar appearance with pronounced cerebral edema. With cerebral edema, the brain is hypodense and the normal falx may appear to have increased density. The cerebral tissue is usually of normal density with subarachnoid bleeding, and the dense falx should be examined closely for a scalloped appearance due to blood. The treatment of subarachnoid hemorrhage is often medical rather than surgical.
Intracerebral hematomas occur 1% to 2% of the time following head injury requiring hospitalization. The most common locations are the anterior portion of the temporal lobe and the posterior portion of the frontal lobe. The mortality rate is 55%. The brain substance may become necrotic and the temporal lobe may become edematous and herniate through the tentorium. Intracerebral hematomas are uncommon in children. Blood in the parenchyma is usually the result of severe focal injury or penetrating trauma. The prognosis is poor, with a high risk of developing increased intracranial pressure and cerebral herniation or severe neurologic compromise. A delayed traumatic intracerebral hematoma may develop 48 hours to 72 hours after an injury. The initial CT scan may show an area of cerebral contusion. If the patient suddenly deteriorates neurologically, a repeat CT scan should be done. The intracerebral hematoma may be surgically drained. These patients are followed closely in the ICU usually with fluids at 2/3 maintenance.
Intraventricular hemorrhage has an incidence of 3% to 35% of patients with head injury. The most common etiology is the rupture of subependymal veins. This is due usually to rotational forces. Injury to the corpus callosum commonly occurs. Intraventricular hemorrhage is usually caused by extension of an intraparenchymal bleed if the corpus callosum is not injured. The blood is most commonly in the lateral ventricles. Rare causes of cerebrovascular disease in children may predispose one to acute intraventricular hemorrhage.
Review the following CT scan images. Each is an example of a type of intracranial hemorrhage. Click on each letter and review the interpretations below.
This CT shows a right frontal epidural hematoma. There is the classic biconvex (lentiform or football) shaped appearance with the dura bulging inward.
Case B
This is a 2-year old male who fell from a couch to the tile floor. There is no history of loss of consciousness. The CT shows a right parietal epidural hematoma. The hematoma is biconvex or lens-shape in appearance. There is a midline shift to the left.
Case C
[C1 below]
[C2 below]
This is a 9-month old female with history of closed head trauma the day prior. She presented with increasing lethargy, emesis, and a right sided scalp hematoma.
[C1] The CT scan reveals a right temporo-parietal epidural hematoma with considerable shift of the midline structures from right to left. There is a non-depressed right parietal skull fracture overlying the epidural hematoma. There is compression of the right lateral ventricle.
[C2] These are lower cuts (from lowest to highest cuts:
Left upper: Five-pointed star of the suprasellar cistern is fairly well preserved. Fourth ventricle posterior to this.
Right upper: Six-pointed star of the suprasellar cistern is shown. The right uncus is pushing into the suprasellar cistern (early uncal herniation). Fourth ventricle posterior to this.
Left lower: Quadrigeminal cistern is compressed. Right lateral ventricle compressed. Midline shift to the left.
Right lower: The right epidural hematoma is visible. The ipsilateral ventricle is compressed. Midline shift to the left.
Case D
This is a 7-year old male with history of hemophilia. This CT shows a subdural hematoma over the left parietal and occipital lobes causing a moderate mass effect and slight deviation of the midline. This hematoma follows along the convexity of the brain (crescent shaped). The suprasellar cistern is fairly well preserved. The quadrigeminal cistern is within normal limits.
The following views are shown (highest to lowest):
Left upper: Left subdural hematoma with overlying soft tissue swelling. Ipsilateral ventricular compression. Midline shift to right.
Right upper: Quadrigeminal cistern size within normal limits.
Left lower: Six-sided star of the suprasellar cistern fairly well preserved. Compression of the quadrigeminal cistern.
Right lower: Six-sided star of the suprasellar cistern. Fourth ventricle located posterior to the suprasellar cistern.
Case E
This is a 4-month old with suspected shaken baby syndrome. The CT shows frontal subacute (or chronic) subdural effusions with an acute right temporo-parietal subdural hematoma. There is probably a small amount of blood in the interhemispheric fissure posteriorly. The posterior interhemispheric subdural hematoma is felt to be indicative of shaken baby syndrome unless other explanations of severe trauma can account for the findings.
Case F
This is an 8-month old male who fell down 6 stairs while in a walker. He had a brief loss of consciousness and an episode of emesis. There is a focal extra-axial (probably epidural, possibly subdural) hematoma over the right frontal and parietal cortex with minimal mass effect. There is no fracture.
Case G
This is a 21-month old female admitted to the PICU. There is history of previous injuries including a left clavicle fracture and greenstick fracture of the distal portion of the shaft of the left radius and ulna. The CT shows an acute subdural hematoma in the right fronto-temporal region. There is compression of the right lateral ventricle with shift of the midline structures from right to left. This hematoma is crescent shaped as classically described with subdural hematomas.
Case H
[H1 below]
[H2 below]
This is a 14-month old male with history of a closed head injury. He clinically is bradycardic and has dilated pupils.
[H1] These CT cuts (without contrast) show hypodensity of the cerebral hemispheres with loss of white-gray matter differentiation suggesting cerebral edema. The ventricles are slit-like and the subarachnoid spaces are obliterated, suggesting cerebral edema and ICP elevation. There is blood in the interhemispheric regions, posteriorly and anteriorly.
[H2] There is subarachnoid hemorrhage in the basal cisterns (suprasellar cistern and quadrigeminal cistern), posterior fossa, and interhemispheric fissure. The suprasellar cistern and the quadrigeminal cisterns are obliterated, indicating severe intracranial hypertension.
Case I
This is a 6-year old male with a closed head injury. He collided with a moving while van riding his bicycle without a helmet. There is a small amount of blood in the occipital horns of the lateral ventricles. There is a moderate amount of subarachnoid hemorrhage in the posterior fossa which is more extensive on the left. There is a small amount of subarachnoid or subdural hemorrhage in the posterior interhemispheric fissure. The left image shows the six-sided star of the suprasellar cistern which is well preserved. The center image shows a well preserved quadrigeminal cistern.
Case J
This is a 7-year old female involved in a motor vehicle accident. There is extensive subarachnoid hemorrhage with a mild degree of lateral and third ventricular dilation. Blood/CSF levels are visible in the occipital horns of the lateral ventricles. The left image shows a moderate amount of blood in the fourth ventricle (This may look like the quadrigeminal cistern, but it is too low. The quadrigeminal cistern is visible in cuts above the suprasellar cistern, not below the suprasellar cistern). The center image shows blood in the five-pointed star of the suprasellar cistern. The right view shows blood in the posterior interhemispheric space.
Case K
This is a 3-week old dropped three feet by an older sister. The patient "stopped breathing" on impact and was cyanotic. There is a questionable history of seizure activity. The CT shows a small amount of blood on the surface of the brain in both parietal regions and in the posterior interhemispheric fissure. The blood is probably both subarachnoid and subdural in location. The findings are suspicious for shaken baby syndrome.
Case L
Severe bilateral intraventricular hemorrhage. The left image shows an obliterated suprasellar cistern. The center image shows an obliterated (or blood filled) quadrigeminal cistern. The right view shows ventricular dilatation.
Case M
There is a left subdural hematoma. There is soft tissue swelling noted over the left scalp. There is a midline shift to the right. There is compression of the ipsilateral lateral ventricle and dilatation of the contralateral lateral ventricle. The left image shows an obliterated suprasellar cistern. The center image shows a severely compressed quadrigeminal cistern that is pushed posteriorly. The right image shows probable subfalcine herniation (herniation under the falx, refer to Case 6 of this volume).
Case N
Severe bilateral intraventricular hemorrhage. The left image shows obliterated suprasellar and quadrigeminal cisterns (or blood filled).
References