Subdural Hematoma (SDH)

= bleeding between the dura and the arachnoid membranes.
= usually from tearing of the bridging veins that drain from the surface of the brain to the dural sinuses
= arterial rupture accounts for approximately 20 to 30 percent of cases.

= Head trauma is the most common cause: motor vehicle accidents, falls, and assaults
acute traumatic SDH is highest among middle-aged men.
cerebral atrophy (the elderly, history of chronic alcohol abuse, previous traumatic brain injury) are at high risk
highest among older adults.
= use of antithrombotic agents increases the risk
= unusual causes: aneurysm, arteriovenous malformation, meningioma, dural metastases, coagulopathy, and cerebrospinal fluid hypotension.

= Acute SDH: 50% presented with coma is present from the time of injury
= Trasnsient lucid interval in up to 38% followed by a progressive neurologic decline
= Chronic SDH: insidious onset of headaches, light-headedness, cognitive impairment, apathy, somnolence, and occasionally seizures.
= Computed tomography (CT) of the head is the most widely used.
= MRI is more sensitive than CT for the detection of small SDHl, or those located adjacent to the tentorium cerebelli or interhemispheric fissure.

Depends Age and Glascos coma scale (GCS)
Head CT findings that may correlate with poor outcome:
●Hematoma thickness
●Hematoma volume
●Midline brain shift
●Reduced patency of the basal cisterns

Acute SDH
Surgical evacuation: Guidelines from an expert panel published in 2006
= clot thickness >10 mm or midline shift >5 mm, regardless of the GCS score [2].
= or GCS score decreased by ≥2 points from the time of injury to hospital admission
= or patient presents with asymmetric or fixed and dilated pupils
= intracranial pressure is consistently >20 mmHg.
Nonoperative management:
= in icu, with intracranial pressure monitoring for patients who present with coma (GCS score <9), provided they are neurologically stable
= and have clot thickness <10 mm, midline shift <5 mm
= and no pupillary abnormalities
= and no intracranial hypertension

Chronic SDH
= Urgent surgical hematoma evacuation signs attributable to brain herniation or elevated intracranial pressure, such as asymmetric or fixed and dilated pupils.
= evidence of moderate to severe cognitive impairment or progressive neurologic deterioration attributable to the chronic SDH.
= clot thickness ≥10 mm or midline shift ≥5 mm

= liquefied chronic SDH that fails to resolve spontaneously, one or more burr holes can be placed to allow drainage of the hematoma.
= A flexible catheter (Jackson-Pratt drain) is usually placed in the subdural space for several days until the drainage subsides

Reversing anticoagulation

Coexistent anticoagulation in patients with either traumatic or spontaneous SDH must be reversed before surgical intervention.
Ideally, anticoagulation should also be reversed for those patients who are managed nonoperatively. However the potential benefit of reversing anticoagulation (a reduced risk of hematoma enlargement) must be weighed against the risk of thrombosis related to the underlying need for anticoagulation in this group. As an example, in an individual with a small SDH and no signs of increased intracranial pressure who is receiving anticoagulation for a mechanical heart valve, the risk-benefit calculation may favor continued anticoagulation with close observation of neurologic status and/or reversal plus heparin bridging when the international normalized ratio (INR) is subtherapeutic.