A Brief Synopsis of AFP's "Bleeding and Bruising: A Diagnostic Work-up"

Bleeding and Bruising: A Diagnostic Work-up
Michael Ballas, MD, Wilson Care, Fort Loramie, Ohio Eric h.Kraut, MD, The Ohio State University, Columbus, Ohio
Am Fam Physician. 2008 Apr 15;77(8):1117-1124.
http://www.aafp.org/afp/2008/0415/p1117.pdf

     The differential for bleeding disorders is large. I'm going to begin by breaking down table 1 of this article. There are two types of platelet disorders. Quantitative platelet disorders are commonly due to ITP, TTP, malignancy or viral disease. The common symptoms are bleeding, bruising, petechiae, or purpura. Functional platelet disorders are due to glycoprotein disorders (Bernard-Soulier, Glanzmann) or vWD. Abnormally shaped platelets may be due to Wiskott-Aldrich syndrome or a May-Hegglin anomaly.  Patients with hemophilia will present with joint or soft tissue bleeding. Leukemia will have abnormal blood counts with an abnormal smear.  The other disorders on this chart are more obvious (alcohol, trauma, vitamin deficiency, etc).
     Prothrombin and partial thromboplastin times are helpful in determining where on the clotting cascade the problem is. For review, PT measures the extrinsic pathway (factor VII) and PTT measures the intrinsic pathway (XII, XI, IX and VIII) The common pathway which may prolong both are X, V, II and I.  So if both PT and PTT are normal, the platelets need to be checked (with an old school bleeding time or the new, more popular and less barbaric, Platelet Function Analyzer 100). Prolonged bleeding times can be due to vWD or drugs, such as aspirin. If only the PTT is abnormal, a PTT mixing study can be done. If the PTT corrects, then assays for factor VIII, IX, and XI need to be checked. If the mixing study does not correct, lupus anticoagulant or factor VIII inhibitor may be the cause. Causes also include hemophilia A or B.  A prolonged PT may be due to vitamin K deficiency or Factor VII deficiency. DIC will have prolong PT and PTT with bleeding at multiple sites. 
     A bleeding history can be quantified using a Bleeding Score System. Some patients may have never had a situation for significant bleeding to occur (no surgery, no dental procedures, etc.). Patients with a positive family history of bleeding may be at increased risk of a inherited disorder. 
     Many medications may cause bleeding, including NSAIDs, penicillins, SSRIs, TCAs. cephalosporins, and PTU (I left out the obvious ones).