From the Guidelines
Bleeding disorders with no PT/PTT changes can be caused by several conditions, including von Willebrand disease, platelet disorders, factor XIII deficiency, and vascular disorders, which require specialized testing and treatment beyond routine coagulation tests. These conditions can present with mucocutaneous bleeding, delayed bleeding, and poor wound healing, despite normal PT/PTT values. According to the study by 1, von Willebrand disease and factor XIII deficiency are not reliably detected by PT/PTT screening tests, and mild deficiencies in factor VIII or factor IX may not cause abnormalities in the aPTT but can still result in significant bleeding.
The diagnosis of these conditions requires specialized testing, including platelet function assays, von Willebrand factor antigen and activity levels, factor XIII assays, and bleeding time tests. As recommended by 1, flow cytometry screening should be carried out on resting platelets using antibodies against specific glycoproteins, and second-step tests may include light transmission aggregometry with an expanded agonist panel and measurement of serum TxB2.
Treatment varies by condition, and DDAVP (desmopressin) at 0.3 mcg/kg is recommended for vWD Type 1, while platelet transfusions and specific factor concentrates may be necessary for other conditions. Antifibrinolytics like tranexamic acid (10-15 mg/kg TID) can be used as adjunctive therapy for mucosal bleeding. It is essential to consult with a pediatric hematologist for accurate diagnosis and treatment of these conditions, as individual patient characteristics can affect the results of diagnostic tests.
Some key conditions to consider include:
- von Willebrand disease
- Platelet disorders, such as immune thrombocytopenic purpura and qualitative platelet function disorders
- Factor XIII deficiency
- Vascular disorders, such as hereditary hemorrhagic telangiectasia and Ehlers-Danlos syndrome
- Mild hemophilia A or B, which may present with normal screening tests despite clinical bleeding.
In clinical practice, it is crucial to prioritize the diagnosis and treatment of these conditions to prevent significant bleeding and improve patient outcomes, as highlighted by the study 1.
From the Research
Bleeding Disorders with No PT/PTT Changes
Bleeding disorders can be complex and varied, making diagnosis and management challenging 2. Some bleeding disorders, such as von Willebrand disease (VWD) and platelet disorders, do not present with changes in prothrombin time (PT) or partial thromboplastin time (PTT).
Types of Bleeding Disorders
- Von Willebrand Disease (VWD): a common inherited bleeding disorder characterized by a deficiency or dysfunction of von Willebrand factor (VWF) 2, 3.
- Platelet-Type Von Willebrand Disease (PT-VWD): a rare autosomal dominant bleeding disorder caused by gain-of-function mutations in the platelet GP1BA gene, leading to platelet hyperresponsiveness 4, 5, 6.
Characteristics of PT-VWD
- Clinical Presentation: mild to moderate mucocutaneous bleeding, which can worsen during pregnancy or with antiplatelet drugs 5, 6.
- Laboratory Features: low VWF:ristocetin cofactor, low or normal VWF:antigen, and enhanced ristocetin-induced platelet agglutination (RIPA) 5, 6.
- Diagnosis: simplified RIPA mixing assays, cryoprecipitate challenge, flow cytometry, and genetic testing to identify mutations in the GP1BA gene 4, 6.