hematoma

A hematoma is a localized collection of blood outside blood vessels, typically confined by surrounding tissues after rupture of a vessel. It results from injury or pathology that allows blood to leak into tissue, a body cavity, or potential space, forming a clot that may expand or resolve over time.

Hematomas are categorized by location. Extracranial examples include subcutaneous hematomas (bruises) and muscular hematomas. Intracranial hematomas include epidural, subdural, subarachnoid, and intracerebral types. Other organ-specific hematomas occur in the liver, spleen, kidneys, or pelvis, each with distinct clinical implications.

Causes include trauma, surgical or procedural injury, anticoagulant or antiplatelet therapy, coagulopathies, vascular malformations, tumors, and spontaneous rupture of fragile vessels. Risk factors include advanced age, hypertension, liver disease, alcohol use, and excessive anticoagulation. In children, birth or accidental injuries can produce hematomas; in newborns, intracranial bleeds may occur with difficult delivery.

Symptoms vary with location. Superficial hematomas cause swelling, tenderness, and color changes. Large muscular hematomas may impair function. Intracranial hematomas can cause headache, nausea, confusion, focal neurological deficits, or loss of consciousness and require urgent assessment. Diagnosis relies on imaging: CT is first-line for suspected intracranial bleeding; MRI or ultrasound may be used for other sites. Laboratory tests assess bleeding risk and anemia.

Management depends on size, location, and stability. Small, nonexpanding hematomas may be observed; larger or expanding ones often require drainage or surgical evacuation. Reversal of anticoagulation, correction of coagulopathy, and treatment of underlying causes are important. Prognosis varies with location and timeliness of treatment.