Bleeding that is spontaneous, excessive, or delayed in onset following tissue injury results from a localized pathologic process or a disorder of the hemostatic process, involving a complex interplay among vascular integrity, platelet number and function, coagulation factors, and fibrinolysis. This topic review will discuss the diagnostic approach to the patient with abnormal bleeding.
Congenital and acquired disorders of platelet function, as well as the hemostatic process and associated disorders, are discussed separately.
The clinical evaluation of a patient with a bleeding disorder begins with a careful history. Patients with inherited hemostatic disorders may report little bleeding, while others without inherited or acquired hemostatic abnormalities may report exaggerated tendencies to bleed [1,2]. Given the variability in patients' perceptions of bleeding, as well as the lack of a uniform clinical measure of bleeding severity , a dialogue between the patient and physician is essential for the consideration of a bleeding diathesis. A careful assessment of the presenting complaint can provide important clues as to where a defect might reside in the hemostatic process and whether the defect is inherited or acquired, providing a rational approach to laboratory investigation (table 1). Use of a standardized bleeding assessment tool may help in the prospective evaluation of patients referred for hemostatic evaluation [4,5].
Bleeding history — Patients with a suspected bleeding disorder should be questioned about past bleeding problems, a history of iron-responsive anemia, bleeding outcomes following surgical procedures and tooth extractions, history of transfusion, character of menses, and dietary habits or antibiotic use which might predispose to vitamin K deficiency. The patient should also be questioned concerning the presence of thyroid, liver, and kidney disease. Complaints such as hematuria, melena, and menorrhagia are often less helpful, since structural causes are more commonly responsible than a bleeding diathesis.