Chronic subdural hematoma

Ravindra Kumar Garg MD (Dr. Garg of King George's Medical University in Lucknow, India, has no relevant financial relationships to disclose.)
Steven R Levine MD, editor. (

Dr. Levine of the SUNY Health Science Center at Brooklyn has no relevant financial relationships to disclose.

Originally released October 1, 1998; last updated March 11, 2020; expires March 11, 2023


Chronic subdural hematoma is one of the most frequent neurosurgical conditions. It is frequently encountered in elderly people (usually, after minor head trauma) and in patients on long-term anticoagulation and long-term hemodialysis. Bilateral chronic subdural hematoma tends to occur more frequently in patients with anticoagulant or antiplatelet therapy. Innate immune responses play an important role in the pathogenesis of chronic subdural hematoma. The most frequent presenting symptoms are headache, cognitive decline, and focal neurologic deficit. Cognitive decline includes confusional state, psychomotor slowing, gait abnormalities, and subacute dementia. Chronic subdural hematomas often present with atypical and unusual manifestations and can be difficult to diagnose. A high index of suspicion is needed to make the early diagnosis. Patients require surgical hematoma evacuation. The common surgical procedures for chronic subdural hematoma include twist drill craniostomy, burr hole evacuation, or craniotomy. Endoscopic hematoma evacuation is a safe and effective alternative for clot removal in the elderly. Tranexamic acid, angiotensin-converting enzyme inhibitors, mannitol, a platelet-activating factor receptor antagonist, and atorvastatin are tried medical treatment options for chronic subdural hematoma. Dexamethasone usage may not be of help in reducing the chances of recurrence. A combination of atorvastatin with low-dose corticosteroids may be beneficial in improving neurologic function. Embolization of the middle meningeal artery has emerged as an effective treatment modality for new or recurrent chronic subdural hematoma. In this article, the author discusses the pathophysiology, clinical presentation, impact on outcome, and available treatments for chronic subdural hematoma.

Key points


• Almost all chronic subdural hematomas result from modest cranial trauma.


• The most frequent presenting symptoms are headache, cognitive decline, gait abnormalities, and hemiparesis.


• A high index of suspicion is important for diagnosis.


• The outcome is generally favorable with neurosurgical evacuation of hematoma.


• However, the incidence of recurrent hematoma varies from 3.7% to 30% after surgery.

Historical note and terminology

In 1657 Wepfer described the presence of a "bloody cyst" in the subdural space of an elderly man postmortem who had developed an aphasia and hemiplegia. Morgagni discussed a similar patient in 1747, and in 1857 Virchow described a case of pachymeningitis hemorrhagica interna, which he attributed to inflammation (Virchow 1857). The association between pachymeningitis hemorrhagica interna and chronic traumatic subdural hematomas, however, did not become generally recognized until the early 20th century. Trotter in 1914 and Putnam and Cushing in 1925 described the pathology and surgical treatment of chronic traumatic subdural hematomas (Trotter 1914; Putnam and Cushing 1925). Limited trephination for drainage of chronic subdural hematoma was commonly employed in the 18th century (Hill 1772), and by the 1930s burr hole drainage was the operation of choice (Fleming and Jones 1932). Closed drainage through a small twist drill hole was reported to carry a lower risk of hematoma recurrence (Tabaddor and Shulman 1977). The evolution of surgical techniques is summarized by Weigel and colleagues (Weigel et al 2004). Naffziger described subacute and chronic subdural fluid collections in which blood was absent or minimal (Naffziger 1924). He termed these collections “subdural hygromas,” and attributed their formation to cerebrospinal fluid leaking through an arachnoid tear.

Traumatic subdural hematomas are divided into acute, subacute, and chronic types. Acute subdural hematomas are those that are clinically evident within 72 hours of accumulation, whereas chronic subdural hematomas are those hematomas present over 20 days. Subdural hematomas detected between 3 days and 3 weeks after trauma are considered "subacute," but these lesions usually behave clinically as either an acute or a chronic subdural hematoma.

CT scan of chronic subdural hematoma Image: Chronic subdural hematoma (CT)
CT of acute subdural hematoma Image: Acute subdural hematoma (CT)
CT of left-sided chronic subdural hematoma Image: Left-sided chronic subdural hematoma (CT)

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