Chronic Subdural Haematoma

Chronic subdural haematoma is a slowly evolving collection of liquefied blood and inflammatory fluid within the subdural space, usually developing weeks after minor trauma.

It is particularly common in:

• Older adults
• Patients with cerebral atrophy
• Anticoagulated patients
• Heavy alcohol users
• Patients receiving antiplatelet therapy

The initial haemorrhage produces an inflammatory membrane.

Fragile neocapillaries within this membrane repeatedly leak blood and plasma, allowing progressive enlargement even after the original trauma has been forgotten.

Markwalder clinical grading

A practical neurological severity classification is:

Grade 0

Neurologically normal.

Grade 1

Alert with mild symptoms such as headache, but no significant focal deficit.

Grade 2

Drowsy or disoriented with variable focal neurological deficit.

Grade 3

Stuporous with major focal deficit.

Grade 4

Comatose with severe motor response abnormalities.

The grade helps communicate severity but does not replace CT and clinical judgement.

Presentation is often gradual.

Typical features include:

• Progressive headache
• Confusion
• Cognitive decline
• Gait disturbance
• Falls
• Hemiparesis
• Dysphasia
• Drowsiness
• Seizure
• Reduced functional independence

In an older patient, chronic SDH can mimic:

• Stroke
• Dementia
• Delirium
• Parkinsonism
• Normal pressure hydrocephalus

A history of significant trauma may be absent.

Noncontrast CT: diagnostic in most patients.

The collection can be:

• Hypodense
• Isodense
• Mixed density
• Septated

Bilateral collections can produce surprisingly little midline shift despite major cerebral compression.

MRI is useful when:

• CT is equivocal
• Membranes and septations need definition
• Isodense bilateral disease is difficult to identify

Check:

• Full blood count
• Platelets
• INR
• Renal function
• Antithrombotic medication

Observation

A small minimally symptomatic chronic SDH with little mass effect can be observed with:

• Neurological follow up
• Repeat imaging
• Management of antithrombotic therapy according to thrombotic and bleeding risks

Escalate if:

• Symptoms progress
• Haematoma enlarges
• New focal deficit appears
• Consciousness deteriorates

Surgical drainage

Symptomatic chronic SDH with neurological deficit or significant mass effect is generally treated surgically.

The standard operation is burr hole evacuation with postoperative drainage.

Typical technique:

• One or two burr holes
• Open outer membrane
• Irrigate or drain liquefied haematoma
• Leave a closed subdural or subperiosteal drain

Postoperative drainage materially lowers recurrence compared with evacuation without a drain.

The drain is commonly left for approximately 24 to 48 hours, depending on output and institutional protocol.

Craniotomy

Use a larger craniotomy when:

• Haematoma is heavily organised
• Thick membranes prevent adequate drainage
• Recurrent loculated collection cannot be evacuated through burr holes
• Significant acute clot component is present

Dexamethasone

Do not use dexamethasone as routine replacement for surgical drainage in a symptomatic operable chronic SDH.

Randomised data showed worse functional outcomes, more complications and substantially more eventual surgery than initial burr hole drainage.

Routine adjunctive dexamethasone after surgery also produced fewer favourable outcomes despite a reduction in reoperation rates.

Middle meningeal artery embolisation

MMA embolisation has become an important adjunct in selected patients.

It reduces vascular supply to the inflammatory subdural membranes.

Current evidence supports MMA embolisation as an adjunct to surgical evacuation to reduce recurrence, particularly in recurrent or high recurrence risk chronic SDH.

It can also be considered as standalone therapy in carefully selected patients who require treatment but have:

• Very high operative risk
• Significant coagulopathy
• Antithrombotic treatment that cannot safely be interrupted

It is not appropriate as sole emergency therapy for a patient with rapid neurological deterioration and major mass effect requiring immediate decompression.

Anticoagulation

Reverse urgent anticoagulation when surgical decompression is required.

Restart timing should be individualised according to:

• Indication for anticoagulation
• Stroke or valve thrombosis risk
• Postoperative imaging
• Haematoma recurrence risk

Do not permanently discontinue essential anticoagulation without reassessing thromboembolic risk.