Chronic Subdural Hematoma

KEY FACTS

TERMINOLOGY

• Chronic subdural hematoma (cSDH)

• Chronic (> 3 weeks to months) subdural blood products

○ Mixed chronic and acute hemorrhage is common

IMAGING

• Crescent-shaped extraaxial collection

○ Spreads diffusely over affected hemisphere

○ Surrounded by enhancing membranes

○ Often septated, loculated, with fluid-fluid levels

○ Recurrent, mixed-age hemorrhage is common and raises

suspicion of nonaccidental trauma in children

• Imaging recommendations

○ NECT is good initial screen

○ Use wide window settings (150-200 HU)

○ MR better demonstrates cSDH

TOP DIFFERENTIAL DIAGNOSES

• Subdural hygroma

• Subdural effusion

• Subdural empyema

PATHOLOGY

• Serosanguineous fluid

• Encapsulated by granulation tissue: "Neomembranes" with

fragile capillaries

• 5% multiloculated with fluid-blood density levels

CLINICAL ISSUES

• Treatment

○ Surgical drainage with resection of membranes

• Older age, brain atrophy are contributory factors in

conversion of traumatic SDH into cSDH

• Recurrence risk varies with type

○ Separated SDH has highest risk

○ Large > small preoperative collections

○ Residual postoperative volume > 80 mL

(Left) Axial graphic depicts

pathology of classic chronic

subdural hematoma (SDH)

with the formation of thin

internal ﬈, thicker external

﬇ membranes. Note the

stretched bridging veins ſt

crossing the SDH, top-tobottom gradation of fluid

from serosanguinous to more

proteinaceous contents.

(Right) Axial NECT depicts

chronic SDH (cSDH) as

crescentic hypodense

extraaxial fluid collection ſt

over the left hemisphere.

Stretched cortical veins ﬇ are

faintly visible as they cross the

SDH.

(Left) Axial graphic depicts

"mixed" subdural hematoma.

Numerous loculations ﬉ that

contain hemorrhages of

multiple ages are present.

Note the fluid-fluid levels with

mixed acute, subacute blood

ſt. Rehemorrhage into

preexisting subacute &/or

cSDH is common. (Right) Axial

NECT shows classic left-sided

"mixed" SDH ﬇. Note the

multiple loculations and fluidfluid levels ſt formed by

acute rehemorrhage into

preexisting loculated cSDH.

Brain: Pathology-Based Diagnoses: Malformations,

Trauma, and Stroke

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