Prolonged bleeding time is seen in _____________

Correct Answer: C. Von Willebrand disease

Von Willebrand disease (vWD) is the only condition among the options that prolongs bleeding time because it impairs platelet function. Bleeding time tests platelet adhesion and aggregation—specifically the ability of platelets to adhere to the subendothelium via von Willebrand factor (vWF). In vWD, deficiency or dysfunction of vWF prevents normal platelet adhesion to exposed collagen, resulting in prolonged bleeding time (typically >10 minutes). This is a qualitative platelet defect. In contrast, hemophilia A and B are coagulation factor deficiencies (Factor VIII and Factor IX, respectively) that affect the intrinsic coagulation pathway. These disorders prolong the activated partial thromboplastin time (aPTT), not bleeding time, because they do not impair platelet function or adhesion. Bleeding time remains normal in hemophilia because platelet count and function are intact. This distinction is critical in Indian clinical practice: vWD presents with mucosal bleeding (epistaxis, menorrhagia), while hemophilia presents with deep tissue and joint bleeding. The bleeding time test, though less commonly used now, remains a discriminating tool in resource-limited Indian settings and is a classic NEET PG question.

Why the other options are wrong

A. Both (b) and (c) — This is wrong because hemophilia B does not prolong bleeding time. Option (b) refers to hemophilia B, which is a Factor IX deficiency affecting the coagulation cascade, not platelet function. Only option (c)—von Willebrand disease—prolongs bleeding time. The trap here is that students may think 'both bleeding disorders' must have the same lab abnormality, but hemophilia B causes prolonged aPTT, not bleeding time. B. Hemophilia B — This is wrong because hemophilia B (Factor IX deficiency) is a coagulation disorder, not a platelet disorder. It prolongs aPTT and PT (if severe), but bleeding time remains normal because platelet adhesion and aggregation are unaffected. The NBE trap is pairing 'bleeding disorder' with 'bleeding time'—students must distinguish between coagulation defects (aPTT/PT) and platelet defects (bleeding time). D. Hemophilia A — This is wrong because hemophilia A (Factor VIII deficiency) is a coagulation factor deficiency, not a platelet dysfunction. It prolongs aPTT but leaves bleeding time normal. Both hemophilias cause deep tissue/joint bleeding due to impaired thrombin generation, not platelet adhesion failure. The cognitive trap is conflating 'bleeding disorder' with 'prolonged bleeding time'—a classic NEET PG discrimination point.

High-Yield Facts

Mnemonics

BT vs aPTT Bleeding Time = Platelet (adhesion/aggregation/count). aPTT = coagulation Factors. vWD affects platelets → BT↑. Hemophilia affects factors → aPTT↑. vWF = Glue von Willebrand Factor is the 'glue' sticking platelets to the wall. No glue → platelets can't stick → bleeding time prolonged. Hemophilia has no glue problem, so BT is normal.

NBE Trap

NBE pairs 'bleeding disorder' with 'bleeding time' to lure students into choosing hemophilia. The discriminating fact is that bleeding time tests platelet function, not coagulation factor activity—hemophilias spare platelet adhesion and thus have normal bleeding time.

Clinical Pearl

In Indian outpatient practice, a young woman with menorrhagia and normal CBC but prolonged bleeding time should raise suspicion for vWD; hemophilia A in females is rare (carrier state). This distinction guides transfusion strategy: vWD patients need cryoprecipitate or desmopressin (DDAVP); hemophilia A needs Factor VIII concentrate.

_Reference: Robbins Ch. 4 (Hemostasis & Thrombosis); Harrison Ch. 139 (Bleeding & Thrombotic Disorders)_