Hemostasis in the healthy patient is achieved in two stages. Primary hemostasis involves vasospasm and platelet activation while secondary hemostasis involves coagulation and fibrinolysis. Disorders of primary hemostasis generally result in excessive, superficial mucocutaneous bleeding after minor cuts. Disorders of secondary hemostasis generally result in delayed, internal bleeding out of proportion to blunt trauma. Combined disorders, such as disseminated intravascular coagulation (DIC), can result in both mucocutaneous bleeding and bleeding into deep spaces simultaneously. A careful history and physical examination can help guide laboratory work-up down the appropriate path.
It is important to elicit what “abnormal bleeding” means to the patient, as there is wide variability in patient perceptions of bleeding. Some patients with hemostatic disorders will report little to no bleeding, while others with normal hemostasis will report an excessive tendency to bleed. A basic bleeding history should include the location (superficial vs deep), prior response to insult (surgical procedure, tooth extraction, significant injury), menstrual history, history of iron deficiency anemia (IDA), childhood and family history (positive in inherited diathesis), predisposing conditions (liver, thyroid, renal disease), medication use (ethanol, warfarin, salicylates, nonsteroidal anti-inflammatory drugs [NSAIDs], selective serotonin reuptake inhibitors [SSRIs], and antibiotics), and herbal supplement use (omega-3 fatty acids, vitamin E, ginseng, ginkgo biloba, ginger, garlic). Complaints such as hematemesis, hematuria, melena, and hematochezia can be misleading because they are often due to structural disease and do not necessarily indicate a hemostatic disorder.
An emergency department (ED) physical should quickly assess hemodynamic status (blood pressure, heart rate) and cardiovascular state (look for flow murmurs and pulse quality). The physical should then focus on sources of pathologic bleeding. Bleeding due to a platelet disorder (primary hemostasis) will result in petechiae, nonpalpable ecchymoses, or epistaxis. These can be identified with a complete skin survey and oropharyngeal examination. Bleeding due to coagulation disorders will result in palpable ecchymoses, soft tissue hematomas, or hemarthroses. These can be identified by a joint and soft tissue survey for swelling, discoloration, or asymmetry. A fecal occult blood test and dipstick urinalysis may also be done to evaluate for gastrointestinal (GI) or genitourinary bleeding.
The three most common screening tests in a bleeding patient are platelet count, prothrombin time (PT), and activated partial thromboplastin time (aPTT). This routine work-up, when combined with a thorough history and physical, is often sufficient for diagnosis (Table 41–1). If need be, there are a multitude of specific tests that can confirm the diagnosis (Table 41–2).
Table 41–1.Basic hemostatic tests. ||Download (.pdf) Table 41–1. Basic hemostatic tests.
|Laboratory Test ||Normal Range ||Study Comments |
|Platelet count ||150,000–400,000 platelets/μL ||Surgical and traumatic bleeding can occur with platelet counts <50,000/μL ...|