A surgeon opens the skull and then the dura mater; removes the clot with suction or irrigation; and identifies and controls sites of bleeding. The injured vessels must be repaired. Postoperative complications can include increased intracranial pressure, brain edema, new or recurrent bleeding, infection, and seizures. In patients with a chronic subdural hematoma but no history of seizures, it is unclear whether anticonvulsants are harmful or beneficial.Those with chronic subudural haematoma (CSDH) with few or no symptoms or have high risk of complication during surgery may be treated conservatively with medications such as atorvastatin, dexamethasone, and mannitol, although supporting conservative treatment is still weak. HMG-CoA reductase inhibitor such as Atorvastatin can reduce the haematoma volume and improving neurological function in eight weeks. HMG-CoA reductase inhibitor may also reduce risk of recurrences in CSDH. Dexamethasone, when used together with surgical drainage, may reduce the recurrence rate of subdural haematoma. Even with surgical evacuation of chronic subdural haematoma, the recurrence rate is high, ranging from 7 to 20%. Prognosis
Acute subdural hematomas have one of the highest mortality rates of all head injuries, with 50 to 90 percent of cases resulting in death. About 20 to 30 percent of patients recover brain function. Additionally, chronic subdural hematomas (CSDHs) have a relatively high mortality rate (up to 16.7% in patients over the age of 65); however, they have an even higher rate of recurrence (as mentioned in the previous section).
They also occur in the posterior cranial fossa, and near the falx cerebri and tentorium cerebelli. Unlike epidural hematomas, which cannot expand past the sutures of the skull, subdural hematomas can expand along the inside of the skull, creating a concave shape that follows the curve of the brain, stopping only at 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 stages of bleeding. This may cause difficulty in distinguishing between subdural and epidural hemorrhages. A more reliable indicator of subdural hemorrhage is its involvement of a larger portion of the cerebral hemisphere. Subdural blood can also be seen as a layering density along the tentorium cerebelli. This can be a chronic, stable process, since the feeding system is low-pressure. In such cases, subtle signs of bleeding—such as effacement of sulci or medial displacement of the junction between gray matter and white matter—may be apparent. Fresh subdural bleeding is hyperdense, but becomes more hypodense over time due to dissolution of cellular elements. After 3–14 days, the bleeding becomes isodense with brain tissue and may therefore be missed. Subsequently, it will become more hypodense than brain tissue. Classification
Subdural hematomas are classified as acute, subacute, or chronic, depending on the speed of their onset.Acute bleeds often develop after high-speed acceleration or deceleration injuries. They are most severe if associated with cerebral contusions.