Chronic Subdural Hematoma

Slow extravasation of blood into the subdural space between the dura and arachnoid membranes. Commonly seen neurosurgical condition associated with high morbidity and mortality

Primary Category
Neurocritical Care
Secondary Category


  • Slow extravasation of blood into the subdural space between the dura and arachnoid membranes
  • Commonly seen neurosurgical condition associated with high morbidity and mortality


  • Worldwide Incidence
    • 3-4/100,000/year in patients <65 years of age
    • 8-58/100,000/year in patients >65 years of age
    • 286/100,000/year in patients >80 years of age
    • May occur after weeks of minor head injury (usually >3 weeks)
  • Usually affects elderly and those on anticoagulant therapy
  • Estimated to affect 60,000 US population >65 years of age annually by 2030
  • Male to female ratio: 3:1
  • Bilateral in 20%


  • Rupture of bridging veins
  • Risk factors
    • Old age
    • Anticoagulant/antiplatelet therapy
    • Male gender
    • History of falls
    • Minor head trauma
    • Bleeding disorders
    • Seizure history
    • Alcohol use

Figure 1: Chronic Subdural Hematoma on CT

notion image
Case courtesy of UoE Radiology,, rID: 34063


  • Initial trauma to the subarachnoid space leading to acute SDH→ fibrin accumulates→ organization, dissolution of fibrin and subdural hematoma→ activate inflammatory changes lead to collagen and fibroblast formation→ subdural neomembrane formation in more than 2 weeks→ formation of weak vascular capillaries that promote subsequent chronic subdural hematoma
  • Subdural hygroma: accumulation of CSF in the subdural space→ new blood vessel formation takes place→ bleeding from these newly formed vessels lead to the development of chronic subdural hematoma

Clinical Features

  • Headache
  • Nausea/vomiting
  • Mental status changes
    • Disorientation.
    • Lethargy
    • Cognitive dysfunction (a cause of reversible dementia-like symptoms)
    • Delirium
    • Coma
  • Seizures
  • Focal neurological deficits
    • Motor weakness
    • Hemiparesis
    • Hemisensory loss
    • Speech problems
  • Difficulty walking
  • Stroke

Clinical progression

  • The early period of injury
    • Traumatic brain injury causes hematoma development, also known as “seed” for chronic SDH
  • The latent period of hematoma growth
    • Hematoma grows slowly
    • Volume expansion
    • Significant neovascularization
    • Lasts weeks to years
    • Usually asymptomatic
  • The Period of clinical appearance
    • Clinical manifestations from raised intracranial pressure by enlarging hematoma.
    • Seizures
    • Coma
    • Brain herniation

Differential Diagnosis

  • Lymphoma
  • Metastasis
  • Sarcoma
  • Infectious
    • Neurocysticercosis
    • Bacterial empyema
  • Autoimmune disorders:
    • Wegener granulomatosis
    • Rosai-Dorfmann disease
    • Polyarteritis nodosa


  • CT Scan of Head: hypodense crescent-shaped mass but can be isodense or hyperdense
  • Additional CT findings
    • Grey-white junction shifts medially
    • Convexity sulci do not extend to the inner part of the skull
  • MRI of Brain
    • May be used when alternative diagnoses are suspected


  • Focused physical examination
  • Pupillary examination and GCS assessment
  • Emergent resuscitation with assessment of airway, breathing, and circulation., followed by emergent neuroimaging (CT head without contrast)
  • Neurosurgical consultation
  • Adequate intravenous access
  • Coagulopathy correction/reversal
  • Steroids medications
  • Antiepileptic medications: Phenytoin/fosphenytoin or Levetiracetam
  • Non-operative treatment: indicated in
    • Asymptomatic patients with small hematoma
    • Moribund patients with poor baseline function
  • Indication for Surgical intervention
    • Any size that is symptomatic
    • Radiological signs of significant brain compression
    • Radiological signs of impending midline shift
    • Radiologically more than 2mm
  • Surgical Technique
    • Burr hole craniotomy
      • Most commonly used.
      • Drilling burr hole over cerebral convexity.
      • 2 burr holes 5-8cm apart are drilled.
      • Dura is entered and irrigated with normal saline.
      • Silicone drainage is placed into the subdural space and drainage is done by connecting to a drainage system.
      • Drain removed after 48 hours.
      • Done under general anesthesia.
    • Twist drill craniotomy.
      • Relatively safe and less invasive method.
      • A small craniotomy is made using a hand drill.
      • Done under local anesthesia.
      • Higher recurrence rate.
    • Craniotomy.
      • Most invasive method used in the past.
      • Used for old, organized, multiseptated SDH.
      • Large bone flap is separated followed by irrigation and evacuation of the hematoma.
      • Higher morbidity than other surgical procedures.


  • Recurrence
  • Seizures
  • Subdural empyema
  • Intracerebral hemorrhage
  • Epidural hematoma
  • Pneumocephalus
  • Intracerebral abscess
  • Meningitis


  • Good clinical outcome after surgery in 80-90% of patients
  • Death rate: 0.5-4.3%
  • Recurrence rate nearly 70%
  • 10-20% of recurring cases require repeated surgical management


  • Asghar M, Adhiyaman V, Greenway MW, Bhowmick BK, Bates A. Chronic subdural haematoma in the elderly: a North Wales experience. J R Soc Med 2002;95:290–292.
  • Bourgeois P, Sleiman M, Louis E, et al. Chronic subdural hematoma in patients over 80 years of age [in French]. Neurochirurgie 1999;45:124–128.
  • Cousseau DH, Echevarria Martin G, Gaspari M, Gonorazky SE. Chronic and subacute subdural haematoma: an epidemiological study in a captive population [in Spanish]. Rev Neurol 2001;32:821–824.
  • Adhiyaman V, Asghar M, Ganeshram KN, Bhowmick BK. Chronic subdural haematoma in the elderly. Postgrad Med J 2002;78:71–5.
  • Santarius T, Kirkpatrick PJ, Ganesan D, Chia HL, Jalloh I, Smielewski P. Use of drains versus no drains after burr-hole evacuation of chronic subdural haematoma: a randomised controlled trial. Lancet (London, England) 2009;374:1067–73.
  • Asghar M, Adhiyaman V, Greenway M, Bhowmick BK, Bates A. Chronic subdural haematoma in the elderly—a North Wales experience. Journal of the royal society of medicine. 2002;95(6):290-2.
  • Miranda LB, Braxton E, Hobbs J, Quigley MR. Chronic subdural hematoma in the elderly: not a benign disease: clinical article. Journal of neurosurgery. 2011;114(1):72-6.
  • Kolias AG, Chari A, Santarius T, et al. Chronic subdural haematoma: modern management and emerging therapies. Nat Rev Neurol 2014;10(10):570–8.
  • Adhiyaman V, Asghar M, Ganeshram KN, et al. Chronic subdural haematoma in the elderly. Postgrad Med J 2002;78(916):71–5.
  • Mori K, Maeda M. Surgical treatment of chronic subdural hematoma in 500 consecutive cases: clinical characteristics, surgical outcome, complications, and recurrence rate. Neurol Med Chir (Tokyo) 2001;41(8):371–81.
  • Gelabert-Gonza´lez M, Iglesias-Pais M, Garcı´a-Allut A, et al. Chronic subdural haematoma: surgical treatment and outcome in 1000 cases. Clin Neurol Neurosurg 2005;107(3):223–9.
  • Ivamoto HS, Lemos HP, Atallah AN. Surgical treatments for chronic subdural hematomas: a comprehensive systematic review. World Neurosurg 2016; 86:399–418.
  • Iliescu IA, Constantinescu AI. Clinical evolutional aspects of chronic subdural haematomas - literature review. J Med Life 2015;8(Spec Issue):26–33.
  • Sambasivan M. An overview of chronic subdural hematoma: experience with 2300 cases. Surg Neurol 1997;47(5):418–22.
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Manish KC

Written by

Manish KC

ECFMG Certified Physician, Clinical Research Coordinator at the Division of Gastroenterology, Hepatology, and Nutrition at the University of Louisville, Remote Researcher at the Larkin Health System, Miami, Florida

Junaid Siddiquie, MD, MRCP

Center for Neuro-Restoration at Cleveland Clinic Main Campus

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