Intracranial Hemorrhages

Intracranial hemorrhages may occur in the epidural, subdural, and subarachnoid compartments and within the brain parenchyma.

Epidural hematoma (EDH) occurs in 2% of severe head injuries. An epidural hematoma forms between the inner table of the calvarium and the dura, usually in the frontotemporal region (Fig. 12.1). It is commonly an arterial bleed that results from tearing of meningeal arteries, often of the middle meningeal artery, by a linear fracture across its cranial groove. In children, it may occur without a skull fracture. Being an arterial bleed, it has a rapidly progressing course. Brain edema, figure 12.1

Epidural hematoma. Schematic drawing shows an epidural hematoma attached to the inner table of the calvarium.

increased ICP, and cerebral herniations rapidly develop. If the blood is not evacuated, mortality is 100%.

In subdural hematoma (SDH), the hematoma forms between the inner surface of the dura and the arachnoid, generally in the fronto-parietal regions, but it may cover the entire hemisphere. It results from tearing of the veins at the point where they enter the superior sagittal sinus (bridging veins). Here, unsupported by the brain parenchyma, they are prone to tearing by motions of the brain that occur in blows to the head, falls, and traffic accidents. SDH is a common finding in physically abused children (shaken baby syndrome). Importantly, it can result from minor injuries and, in about 20% of cases, no clinical evidence of injury exists. Alcoholism, hematologic disorders, anticoagulant therapy, ventricular shunting, and old age predispose to SDH.

It is customary to distinguish acute, subacute, and chronic stages of SDH (Figs. 12.2 and 12.3). In the acute stage, days 1 to 4, the blood is partially clotted. The associated brain edema produces herniations that pose a surgical emergency. In the subacute stage, days 5 to 14, the hematoma gradually liquefies. In the chronic stage, after the second week, encapsulation begins, with fibroblast and capillary proliferation along the inner surface of the dura and proceeding toward the center. Newly formed, fragile blood vessels are the source of rebleeding into the hematoma (see Fig. 12.3).

figure 12.2

Acute subdural hematoma. A 50-year-old man became comatose 3 days after he was lightly hit on the head with a volleyball. He died 2 days later of a pontine hemorrhage (Duret hemorrhage) due to raised ICP. A. Clotted blood covers the undersurface of the left leaflet of the dura and lateral aspect of the cerebral hemisphere. B. Nonenhanced CT scan of the head from a different patient shows an acute subdural hematoma as a hyperdense, crescent-shaped lesion.

figure 12.2

Acute subdural hematoma. A 50-year-old man became comatose 3 days after he was lightly hit on the head with a volleyball. He died 2 days later of a pontine hemorrhage (Duret hemorrhage) due to raised ICP. A. Clotted blood covers the undersurface of the left leaflet of the dura and lateral aspect of the cerebral hemisphere. B. Nonenhanced CT scan of the head from a different patient shows an acute subdural hematoma as a hyperdense, crescent-shaped lesion.

figure i2.3a

Chronic subdural hematomas. A. Nonenhanced CT scan of a chronic hypodense subdural hematoma in a 63-year-old man who presented with headaches and had suffered a minor, forgotten head injury 6 weeks earlier. B. Chronic encapsulated hematoma in a 76-year-old alcoholic man. C. Granulation tissue of the capsule adheres to the inner surface of the dura (Van Gieson stain). D. Calcified subdural hematomas in a 58-year-old epileptic man.

figure i2.3b

Rebleeding within chronic subdural hematoma. A. Nonenhanced CT scan of the head of a 66-year-old severely demented man shows a small right and a large left chronic subdural hematoma with severe mass effect. B. Large amount of fresh blood has accumulated in the subdural space. C. The thick capsule of the left chronic hematoma contains fresh, partially clotted and liquefied blood. D. Marked deformation of the left hemisphere.

figure 12.4

Parenchymal hemorrhages. A. Multiple hemorrhages. The right temporal hematoma is associated with contusion. B. Solitary temporal lobe hemorrhage. Note the extensive edema, ventricular compression, and the deep groove around the hippocampus indicating hippocampal herniation.

figure 12.4

Parenchymal hemorrhages. A. Multiple hemorrhages. The right temporal hematoma is associated with contusion. B. Solitary temporal lobe hemorrhage. Note the extensive edema, ventricular compression, and the deep groove around the hippocampus indicating hippocampal herniation.

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