Hematoma

Hematoma is a localized collection of blood within tissues resulting from vessel rupture due to trauma or coagulation disorders. The extravasated blood forms a cavity filled with either liquid or clotted blood.

In everyday language, small subcutaneous hematomas are commonly referred to as bruises or contusions. However, in medical terminology, a hematoma implies a larger blood accumulation that may compress surrounding tissues and organs.

Etiology and pathophysiology

The most common cause of hematoma is trauma (contusion, impact injuries, fracture), which leads to disruption of the vessel wall. Less frequently, hematomas occur spontaneously secondary to disorders that impair blood clotting (e.g., hemophilia) or increase vascular fragility.

The extravasated blood gradually coagulates. Over time, hemoglobin within the hematoma undergoes a series of biochemical transformations, explaining the characteristic color changes from bluish-purple to greenish and yellow — commonly referred to as the blooming bruise. Small hematomas typically resolve completely, while larger ones may become encapsulated or develop secondary infection (suppuration).

Clinical Significance

Clinical manifestations depend on the size and location of the hematoma. Superficial hematomas cause localized pain, edema, skin discoloration, and swelling. Deep hematomas, particularly intracranial ones, are life-threatening due to brain compression.

Based on anatomical location, hematomas are classified as:

• Subcutaneous and intramuscular hematomas. The most common types.
• Subdural and epidural hematomas. Intracranial blood accumulations requiring urgent neurosurgical intervention.
• Retrobulbar hematoma. An accumulation of blood behind the eyeball.

Superficial hematomas are easily diagnosed with simple methods (e.g., physical examination). Deep or internal hematomas, however, may require imaging, including ultrasound (US), computed tomography (CT), or magnetic resonance imaging (MRI). Treatment of small hematomas is conservative and includes rest, cold application, and pressure dressing. Large hematomas or those compressing vital organs require surgery, in which the lesion is incised to evacuate the accumulated blood.