Bleeding child: diagnostic approach: Case

Case discussion

Diagnosis and immediate assessment

This boy presents the classic picture of acute immune thrombocytopenia: sudden petechiae and bruising in an afebrile, otherwise well preschool child, one to two weeks after a viral illness, with isolated severe thrombocytopenia and a normal prothrombin and activated partial thromboplastin time. The bleeding pattern is primary-hemostasis (platelet-type): immediate, mucocutaneous, and petechial. The first step is to confirm the diagnosis and exclude its dangerous mimic, acute lymphoblastic leukaemia, before any treatment that could mask it. [1]

Excluding leukaemia before treatment

The blood film is the single most important test here. The absence of blast cells, the normal haemoglobin and white cell count, the absence of additional cytopenias, and the well appearance all support immune thrombocytopenia over leukaemia. Large platelets on the film reflect young, reactive platelets, consistent with peripheral destruction rather than marrow failure. Before any corticosteroid is given, the film must be reviewed, because treating leukaemia with steroids can mask the diagnosis and delay definitive chemotherapy. The absence of hepatosplenomegaly and lymphadenopathy further supports the benign diagnosis. [3]

Pathophysiology

Immune thrombocytopenia is an antibody-mediated destruction of platelets, often triggered by a recent viral infection that generates antibodies that cross-react with platelet surface glycoproteins. The platelets are opsonised and cleared by splenic macrophages, producing isolated severe thrombocytopenia. The bone marrow is normal or shows increased megakaryocytes, which is why the film shows large, young platelets. The bleeding pattern is purely primary-hemostasis, because the coagulation factors are intact, which is why the prothrombin and activated partial thromboplastin times are normal. [1]

Management

A well child with immune thrombocytopenia and only skin bleeding can be observed with a clear safety-net and early review, because most acute immune thrombocytopenia resolves spontaneously. Treatment with corticosteroids or intravenous immunoglobulin at 0.8 to 1 g per kilogram is reserved for significant bleeding, a very low count with risk features, or an urgent need to raise the count, such as before surgery. Avoid intramuscular injections and invasive procedures, because the count is very low and the child could bleed. The catastrophic risk is intracranial haemorrhage, which is rare, so the family must be safety-netted to present immediately with head injury, severe headache, or any significant bleeding. [4]

Pitfalls and safeguarding

Two pitfalls deserve emphasis. First, platelet transfusion is reserved for life-threatening bleeding in immune thrombocytopenia, because transfused platelets are rapidly destroyed by the same antibody. Second, although this child's bruising is explained by thrombocytopenia, bruising in a non-mobile infant or patterned, multi-site bruising must always prompt a concurrent safeguarding assessment, because a bleeding disorder and non-accidental injury can coexist. In this well, mobile preschool child with a consistent history and a single diagnosis, non-accidental injury is less likely, but the pattern of bruising and the history should always be reviewed. [1]

Disposition and follow-up

This boy can be managed as an outpatient with a clear safety-net and early review, because he is well and has only skin bleeding. The family is taught to recognise the features of dangerous bleeding and to present immediately with head injury or severe bleeding. The platelet count is rechecked within a few days and at intervals until it recovers, and most acute immune thrombocytopenia resolves within six months. Haematology referral is arranged, and chronic or persistent disease is managed with haematology input. The prognosis is excellent, with spontaneous resolution in the majority and a low risk of serious bleeding once the family is safety-netted. [3]