hemorrhage
Summary
Hemorrhage is the escape of blood from blood vessels, classified as external (visible) or internal (concealed). It can be arterial (bright red, pulsatile), venous (dark red, steady flow), or capillary (oozing). Severity ranges from minor bleeding to life-threatening exsanguination requiring immediate intervention.
Detail
Hemorrhage occurs when blood vessel integrity is compromised due to trauma, disease, or coagulopathy. Pathophysiologically, bleeding triggers hemostatic mechanisms including vasoconstriction, platelet aggregation, and coagulation cascade activation. Clinical presentation depends on location, rate, and volume of blood loss. Acute hemorrhage >15-20% blood volume causes hypovolemic shock with tachycardia, hypotension, and decreased perfusion. Chronic bleeding may present as anemia with fatigue and pallor. Major causes include trauma, GI bleeding (peptic ulcers, varices, malignancy), obstetric complications, coagulation disorders, and vascular malformations. Management involves controlling the source (pressure, surgery, endoscopy), fluid resuscitation, and blood products as needed. Laboratory findings include decreased hemoglobin/hematocrit, and coagulation studies help identify underlying disorders.
Sources
- Robbins & Cotran Pathologic Basis of Disease
- Harrison's Principles of Internal Medicine
- First Aid for the USMLE Step 1
- Emergency Medicine: Clinical Essentials
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