Extra-axial hematomas may be localized to the epidural, subdural, and arachnoid/subarachnoid spaces (Figure 250.1). . The distinction between epidural and subdural hematomas is not always anatomically possible because both compartments may be simultaneously involved. Extra-axial hematomas are often related to trauma.

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Figure 250.1— [A] Linear palpebral echimosis. [B] brain ultrasound of the same patient: linear right occipital lobe lesion and round left occipital lesion. [C] brain CT of the same patient: right occipital subarachnoid hemorrhage and left occipital lesion subdural.

Epidural hematomas are located between the bone and the internal periosteum. They may occur in the anterior, medial, and posterior fossi, and in the spinal canal. Epidural hematomas are usually produced by trauma but the possibility of a clotting disorder should be considered. Epidural hematomas tend to produce paroxysmal clinical events, decreased limb movements (monoparesis, hemiparesis, paraparesis, upper extremity diplegia, and quadriparesis), facial weakness, or coma. The study of choice to diagnose epidural hematoma in the cranial vault is CT of the brain. The study of choice to diagnose epidural hematoma in the spinal canal is MRI of the spine. The blood in epidural hematomas does not cross the bone sutures, the inner surface the hematoma is convex, and the blood does not enter in the fissures (Figure 250.2 [A]). The convexity of the inner surface occurs because the blood pools in the center area of each bone since the periosteum is limited to each bone and is tightly attached to the bone edges. The treatment of epidural hematomas is dictated by their clinical manifestations. Drainage of the blood collection is necessary if symptoms are progressive or there are signs of impending herniation.

Subdural hematomas are localized between the periosteum and the arachnoid. Subdural hematomas are usually produced by trauma but the possibility of a clotting disorder should be considered. Subdural hematomas may be asymptomatic. Small subdural hematomas of the falx cerebri and the tentorium cerebri are frequently present after vaginal delivery in asymptomatic neonates. Most neonates with small subdural hematomas have normal neurological development. Large subdural hematomas may produce paroxysmal clinical events, decreased limb movements (monoparesis, hemiparesis, paraparesis, upper extremity diplegia, and quadriparesis), facial weakness, or coma. The study of choice to diagnose subdural hematoma in the cranial vault is CT of the brain. The study of choice to diagnose subdural hematoma in the spinal canal is MRI of the spine. The blood in subdural hematomas crosses the bone sutures (concave inner surface is convex) but does not enter into the fissures and sulci (Figure 250.2 [B]). The collection of blood is concave because it is not restricted by the individual periosteum of each bone. The treatment of subdural hematomas is dictated by the clinical manifestations. Drainage of the blood collection is necessary if symptoms are progressive or there are signs of impending herniation. Treatment of anemia and hyperbilirubinemia may be necessary. More about... 53, 286

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Figure 250.2.— [A] CT of the brain demonstrating epidural hematoma, subarachnoid hematoma, and intraparenchymal punctate hemorrhages. [B] MRI of the brain demonstrating bilateral subdural hematomas.