hematomas

A hematoma is a localized collection of blood outside a blood vessel, usually resulting from rupture of a vessel and leakage into surrounding tissue where it clots. Hematomas differ from ecchymosis (a bruise) in that they form a defined mass and may persist or enlarge over time.

Hematomas are described by location. Subcutaneous hematomas form under the skin after minor trauma and often present as a swollen, discolored area. Intramuscular hematomas occur within muscle tissue and can cause pain and weakness. Retroperitoneal hematomas develop in the retroperitoneal space and can be life-threatening due to hidden blood loss. Intracranial hematomas include epidural, subdural, and intracerebral types, each with distinct patterns of bleeding and clinical consequences. Hematomas can also occur in joints (intra-articular) or other organs or tissues, such as subperiosteal hematomas.

Causes include direct trauma, surgical or diagnostic procedures, and spontaneous bleeding due to coagulopathy, thrombocytopenia, liver disease, or the use of anticoagulants or antiplatelet drugs. Risk factors include advanced age, hypertension, vascular fragility, and certain medical conditions.

Diagnosis relies on history, physical examination, and imaging. Ultrasound is useful for soft-tissue hematomas; computed tomography is the primary tool for acute intracranial hematomas; magnetic resonance imaging provides detailed brain imaging when needed. Laboratory tests may assess coagulation status and bleeding risk.

Management depends on size, location, and progression. Small, nonexpanding hematomas often resolve without intervention. Larger or expanding hematomas may require drainage or surgical evacuation. Intracranial hematomas require urgent neurosurgical evaluation and management, including reversal of anticoagulation when appropriate, supportive care, and treatment of the underlying cause. Prognosis varies with location and promptness of treatment.