# von Willebrand Disease > von Willebrand disease for NEET-SS Haematology: subtypes 1, 2A-2N and 3, RCo-to-antigen ratio, desmopressin response, the type 2B trap and Heyde syndrome. - Canonical URL: https://prepelephant.com/topics/neet-ss/clinical-haematology/von-willebrand-dm - Exam / course: NEET-SS · Subject: Clinical Haematology - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "von Willebrand Disease", PrepElephant, https://prepelephant.com/topics/neet-ss/clinical-haematology/von-willebrand-dm ## Direct answer Menorrhagia since menarche, dental extraction ooze and easy bruising with a normal platelet count and a variably prolonged APTT — that constellation makes von Willebrand disease the commonest inherited bleeding disorder, with type 1 accounting for about three-quarters. Diagnosis rests on a panel read intelligently: von Willebrand factor antigen, its activity (ristocetin cofactor or GPIbM-based), factor VIII and, when needed, multimers — interpreted against blood group, because group O alone lowers the level by a quarter to a third. Most patients respond to desmopressin; type 3 and non-responders need plasma-derived, factor-VIII-containing von Willebrand concentrate, and type 2B is the subtype in which desmopressin actively harms. ## What you must remember - Von Willebrand factor has two jobs — platelet adhesion through GPIb and factor VIII carriage — hence a platelet-type bleeding history sits alongside a prolonged APTT with low factor VIII. - Type 1 (about 75%, autosomal dominant, partial deficiency) and type 3 (autosomal recessive, virtually absent factor with factor VIII under 1 IU/dL and haemophilia-severe bleeding) are quantitative; type 2 subtypes are qualitative. - Type 2 subtypes: 2A loses high-molecular-weight multimers; 2B binds platelets too avidly, causing thrombocytopenia that worsens after desmopressin; 2M has low function with normal multimers; 2N cannot carry factor VIII and mimics mild haemophilia A in both sexes. - An activity-to-antigen ratio below about 0.6 separates type 2 from type 1; multimer analysis then resolves 2A, 2B and 2M. - Diagnostic thresholds: repeated levels below 30 IU/dL support disease; 30-50 IU/dL is "low von Willebrand factor", managed on the bleeding phenotype. - Desmopressin 0.3 μg/kg after a documented test dose; hyponatraemia is the harm, so restrict fluids for 24 hours, and tachyphylaxis limits repeated dosing to 24-48 hours apart. - Pregnancy raises the factor two- to three-fold by term, masking type 1 — while type 2B may first appear as new "ITP", and levels fall abruptly postpartum, stacking the risk of secondary postpartum haemorrhage. - Acquired von Willebrand disease: aortic stenosis with gastrointestinal angiodysplasia (Heyde syndrome), lymphoproliferative disorders, hypothyroidism, myeloma and Wilms tumour in children. ## Reading the panel on real patients A 26-year-old with menorrhagia, haemoglobin 9, APTT mildly prolonged and platelets 280 has antigen 22 IU/dL, activity 20 and factor VIII 28 — ratio near 0.9, everything low together: type 1. A desmopressin test dose lifting activity above 50 IU/dL predicts safe cover for her dental extraction, with tranexamic acid and hormonal control of the menorrhagia alongside. Contrast a second patient: antigen 35, activity 12 — ratio 0.34 — and platelets 90. The low ratio declares type 2, and the thrombocytopenia convicts type 2B, where desmopressin would strip platelets further; she receives a von Willebrand-containing concentrate for procedures instead. Every panel is repeated when the patient is well and unstressed, because illness, exercise and the post-acute phase all perturb levels — a single normal value during an acute episode excludes nothing. ## How the exam frames it The classic stem is the child with recurrent bruising and platelets of 80, labelled immune thrombocytopenia and given steroids that do nothing: a von Willebrand panel with a low activity-to-antigen ratio and thrombocytopenia that worsens on desmopressin unmasks type 2B. The second favourite is the "girl with low factor VIII" — if antigen is normal but factor VIII sits at 10-20% and her father is similarly affected, the answer is type 2N, not a haemophilia carrier, because 2N is autosomal. The third is interpretation discipline: blood group O, recent exercise, stress, pregnancy and oestrogen all shift levels, so the diagnosis demands consistently low values on repeat testing rather than one isolated number. ## Frequently asked questions ### Which subtype of von Willebrand disease worsens with desmopressin? Type 2B. Its gain-of-function factor binds platelets more avidly as levels rise, deepening the thrombocytopenia — concentrate therapy is used instead. ### Why is the APTT prolonged in von Willebrand disease? Von Willebrand factor carries factor VIII in the circulation; when it is absent or defective, factor VIII falls and the APTT lengthens. The prothrombin time stays normal. ### Which test separates type 1 from type 2? The activity-to-antigen ratio: below about 0.6 indicates qualitative type 2 disease; in type 1 antigen and activity fall together. Multimer analysis subclassifies the type 2 variants. ### Which subtype mimics mild haemophilia A? Type 2N, the factor VIII-binding defect. Normal antigen with low factor VIII in an autosomal (father-to-child) pattern distinguishes it from X-linked haemophilia carriage. ### What is the treatment for type 3 disease? Plasma-derived von Willebrand factor concentrate containing factor VIII, given for prophylaxis or bleeding; desmopressin is useless when the factor is virtually absent. ### What is Heyde syndrome? Aortic stenosis with acquired type 2A-like von Willebrand disease and bleeding from gastrointestinal angiodysplasia — high shear strips the high-molecular-weight multimers. Valve replacement corrects it.