Chapter 242: Subdural Hematoma

PATIENT STORY

A 34-year-old driver was hit from behind at approximately 25 mph. He hit his head, but did not lose consciousness and did not seek care. Approximately 12 hours later, he developed a headache and confusion and was taken to the emergency department by a family member. He was found to have an acute subdural hematoma (Figure 242-1). He was hospitalized, and a neurosurgeon was consulted for surgical management.

INTRODUCTION

Subdural hematoma (SH) is a collection of blood between the dura and arachnoid membranes, but external to the brain. SH may be acute or chronic. While most SHs are caused by trauma, they can occur at any age, most commonly in infants (abusive or unintentional head injury) and older adults due to cerebral atrophy with traction and rupture of bridging veins. Rarely, SH may occur spontaneously, associated with a ruptured aneurysm, bleeding from intracranial tumors, or malignancy-induced coagulopathy.¹ Presentation varies widely in acute SH. While many patients are initially comatose, lucid intervals are reported in up to 38% of cases.¹ Often, symptoms may be nonspecific, such as irritability or poor feeding in infants and confusion or headaches in adults. Treatment is prompt consultation with a neurosurgeon.

EPIDEMIOLOGY

• SHs occur at all ages. In adults, SHs are more common in men than in women with a male-to-female ratio of 3:1.^1,2

• In a study of 111 asymptomatic newborns, 8% were found to have an SH; all resolved by 4 weeks without intervention.³

• Incidence of SH in infants ages 0 to 1 year in the United Kingdom was found to be 24 of 100,000.⁴

• Fewer than 1 in 100,000 adults per year have a traumatic SH.²

• SH accounts for 42 of every 100,000 adult hospitalizations.⁵

• Incidence of chronic SH is highest in the fifth through seventh decades of life.¹

• Cost is $1.6 billion per year in 2007 dollars.⁵

• Mortality rates in treated older adults are approximately 8% for patients younger than age 65 years and 33% for patients older than age 65 years.⁶

• Estimated overall mortality rate in patients with acute SH requiring surgery is 40% to 60%.⁷

ETIOLOGY AND PATHOPHYSIOLOGY

• Most SHs are caused by trauma, either accidental or intentional, from a direct injury to the head or shaking injury in an infant (shaken baby syndrome).¹

• The most common ...