Pediatric Bleeding Disorders: Evaluation and Approach

How normal clotting works

Hemostasis depends on four cooperating players: an intact vessel wall, platelets that plug the initial defect, the coagulation cascade that generates a stable fibrin clot, and fibrinolysis that later dissolves it. A problem anywhere along that chain can tip a child toward bleeding. Conceptually, bleeding results from too little procoagulant activity, too few or poorly functioning platelets, a fragile vessel wall, or excessive clot breakdown — while the mirror-image derangements push toward thrombosis.

The history does most of the work

A careful history frequently points to the diagnosis before any test is sent. Work through a few axes:

• Spontaneous vs. induced — does bleeding follow trauma or surgery, or happen out of the blue?
• Congenital vs. acquired — lifelong pattern, or a new change?
• Nature and site — where and what kind of bleeding?
• Hemostatic challenges — how did the child do with circumcision, dental extractions, or surgery?
• Mucosal clues — recurrent epistaxis, or menorrhagia in an adolescent.
• Family history — hemophilia A and B are X-linked recessive (affected maternal uncles); von Willebrand disease is usually autosomal dominant. Bear in mind that girls can be affected by hemophilia through Turner syndrome, extreme lyonization, or a carrier–patient union.

Physical examination

Look for signs that reframe "just bruising" as something systemic: pallor (anemia), hepatosplenomegaly or lymphadenopathy (suggesting malignancy or infiltration), hemarthrosis (factor deficiency), and any sign of intracranial hemorrhage. The distribution and depth of bleeding on exam should be matched against the history's pattern.

Laboratory workup

Screening tests

• CBC with peripheral smear and platelet count
• Platelet function analyzer (PFA); bleeding time is largely abandoned
• PT and aPTT

The PT/aPTT pattern narrows the field quickly. A prolonged aPTT should be worked up with a mixing study to separate a factor deficiency (corrects) from an inhibitor such as a lupus anticoagulant (does not correct) — the latter is often self-limited and, despite the name, is not usually associated with bleeding.

Confirmatory tests

• Specific factor assays (VIII, IX, and others)
• VWD panel: VWF antigen, VWF activity (ristocetin cofactor), and multimer analysis; platelet aggregation studies
• Fibrinogen, fibrin split products, D-dimer, and smear review (for DIC/microangiopathy)
• Genetic studies and bone marrow examination when indicated

Reading the platelets: size and turnover

Platelet indices add diagnostic information the raw count misses. Mean platelet volume (MPV, normally ~7–11 fL) reflects platelet age — freshly released platelets are larger. The immature platelet fraction (IPF, ~1–7%) is a reticulocyte-equivalent for platelets, reflecting the rate of production.

Schistocytes (fragmented red cells, normal <~0.5%) on the smear signal a microangiopathy — TTP, HUS, or DIC — or a mechanical cause such as a prosthetic valve; in TTP, serial schistocyte counts track with LDH.

Why the IPF matters at the bedside

In a consumptive or post-viral thrombocytopenia, the IPF rises one to two days before the platelet count recovers. A rising IPF at the nadir signals that the marrow is already responding — which can spare a stable, non-bleeding child an unnecessary platelet transfusion.

Worked examples

Differential diagnosis

The causes of abnormal bleeding and thrombocytopenia in children span several categories:

Retinal hemorrhages deserve special mention: they accompany the majority of abusive head trauma, but also occur with hematologic disease, CNS vascular malformations, infection, and — transiently — after normal delivery. The finding is a prompt for careful evaluation, not a diagnosis on its own.

Bleeding in the newborn

Neonatal thrombocytopenia

Causes cluster into immune (maternal ITP or SLE; neonatal alloimmune thrombocytopenia, in which a well mother and infant have an isolated low count with a real risk of intracranial hemorrhage), infectious/consumptive (sepsis with DIC, congenital infections), and congenital/syndromic (TAR syndrome, Wiskott–Aldrich, Kasabach–Merritt, congenital leukemia).

Vitamin K deficiency bleeding (VKDB)

Formerly called hemorrhagic disease of the newborn, classic VKDB affects primarily breastfed infants and presents with bleeding in the first days to weeks of life — ecchymoses, GI or pulmonary hemorrhage, and, uncommonly but catastrophically, intracranial hemorrhage. Newborns are at risk because of poor placental transfer and stores, an immature liver, minimal gut-flora synthesis, and low vitamin K content in breast milk — which is exactly why routine vitamin K prophylaxis at birth matters.

Hereditary bleeding disorders

• Hemophilia A and B — X-linked deficiencies of factor VIII or IX.
• Von Willebrand disease — the most common inherited bleeding disorder (roughly 1% of the population), typically autosomal dominant, with mucocutaneous bleeding.
• Factor XIII deficiency — classically delayed bleeding from the umbilical stump, with normal routine coagulation screens.
• Rare factor deficiencies — including factors VII, X, and XIII.

Management principles

Procedures

Plan ahead. For dental extraction or surgery in a child with a factor deficiency, correct to an appropriate level beforehand (often ≥50%, depending on the procedure). DDAVP is an option for mild hemophilia A and some VWD; antifibrinolytics such as epsilon-aminocaproic acid (Amicar) or tranexamic acid help with mucosal procedures.