A 3 year old male child presents to the Emergency Department with his foster father.  The child had a recent upper respiratory tract infection 19 days ago and now has a 2 day history of bruising. The child has not had nose bleeding. There is no past history of bleeding nor bruising. 

On exam, the child looks well, actively running around the room.  Vitals as listed. 

Head and neck exams are normal.  There are no adventitious breath sounds.  Cardiac exam reveals a grade 2/6 soft vibratory systolic ejection murmur.  The skin exam shows 1 mm diameter, non-blanching, red spots scattered diffusely and small bruises over the arms and legs.  There is no adenopathy, no hepatosplenomegaly and all joints are normal. 

Lab work 

CBC -  WBC 8.9 x109/L (Normal range: 6-14 10E9/L)

Hemoglobin 116 g/L (Normal range: 100-150 g/L)

Platelets 8 x 109/L.  (Normal range: 150-400 10E9/L)

INR 1.1  (Normal range: 0.9-1.1)

PTT 25 seconds. (Normal range: 27.0-37.0 seconds)

What is the most likely etiology of the child’s bruises?

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Dr. Susan Bannister


Dr. Marc Zucker



Dr. Karen Forbes