Bleeding child: diagnostic approach: SAQ

Part A (10 marks)

a) What is the most likely diagnosis, and which two features of the presentation confirm that this is a primary-hemostasis (platelet-type) rather than a coagulation-type problem? (3 marks) [1]

The most likely diagnosis is immune thrombocytopenia, suggested by the sudden onset of petechiae and bruising in an otherwise well child one to two weeks after a viral illness, with isolated severe thrombocytopenia and no blast cells on the film. The two features confirming a primary-hemostasis problem are the petechial, mucocutaneous bleeding pattern, which is immediate and superficial, and the isolated thrombocytopenia with a normal prothrombin and activated partial thromboplastin time, excluding a coagulation-factor deficiency. [1]

b) Which single investigation is essential before any corticosteroid therapy is considered, and why? (3 marks) [3]

A peripheral blood film reviewed for blast cells is essential, together with the haemoglobin and white cell count, to exclude acute lymphoblastic leukaemia. Treating suspected immune thrombocytopenia with steroids before excluding leukaemia can mask the diagnosis and delay definitive chemotherapy. The absence of additional cytopenias, blasts, hepatosplenomegaly, and lymphadenopathy supports immune thrombocytopenia, but the film must be confirmed before treatment. [3]

c) Outline the immediate management priorities for this child. (3 marks) [4]

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 kg is reserved for significant bleeding, a very low count with risk features, or an urgent need to raise the count. Avoid intramuscular injections and invasive procedures. The family must be safety-netted to present immediately with head injury, severe headache, or any significant bleeding, because intracranial haemorrhage is the catastrophic risk. [4]

d) Why is the bleeding assessment tool useful in the initial evaluation of a child with bruising, and when should it be applied? (1 mark) [1]

The bleeding assessment tool quantifies whether the bleeding is truly abnormal, separating pathological bleeding from normal childhood bruising far better than clinical impression, and it should be applied before expensive tier-two tests are ordered. [1]

Part B (10 marks)

A separate 3-year-old boy presents with a swollen, painful right knee that developed two days after a minor fall. He has had two similar episodes in the past year. His maternal uncle had bleeding problems. His platelet count is normal, prothrombin time normal, and activated partial thromboplastin time prolonged. [2]

e) What bleeding pattern does this boy show, and which phase of hemostasis has failed? (2 marks) [2]

This boy shows a coagulation-type (secondary hemostasis) pattern: a deep, delayed haemarthrosis that appeared two days after injury, with recurrence. This indicates failure of secondary hemostasis, where the fibrin mesh that should reinforce the primary platelet plug is absent, producing delayed deep bleeding into joints and muscles. [2]

f) Which factor assay is most likely to be abnormal, and what is the inheritance pattern? (3 marks) [2]

A factor VIII or factor IX assay is most likely to be abnormal, indicating haemophilia A (factor VIII) or haemophilia B (factor IX). The inheritance is X-linked recessive, which fits the male sex and the maternal family history of bleeding. Both produce an isolated prolonged activated partial thromboplastin time with a normal prothrombin time and platelet count. [2]

g) How does this boy's bleeding pattern differ from the boy in Part A, and what does that difference tell you about the failed phase of hemostasis? (3 marks) [1]

The boy in Part A has immediate, mucocutaneous, petechial bleeding (primary hemostasis), with petechiae and bruising and an isolated low platelet count, indicating failure of platelet-plug formation. This boy has delayed, deep bleeding into a joint (secondary hemostasis), with a normal platelet count and a prolonged activated partial thromboplastin time, indicating failure of fibrin-clot stabilisation. The pattern of bleeding therefore identifies which phase of hemostasis has failed before any confirmatory assay is sent. [1]

h) Name two long-term management priorities for this boy and his family after diagnosis. (2 marks) [2]

Two long-term priorities are referral to a comprehensive haemophilia service for factor replacement or prophylaxis, and family screening with genetic counselling given the X-linked inheritance and the maternal family history. A written emergency plan and education about avoiding intramuscular injections and presenting early with joint or muscle bleeds complete the long-term care. [2]