A really well looking preschooler has been referred to the ED because of petechiae and bruising. The mom has consulted Dr. Google and is worried that her son has leukemia. He had a cold last week that he recovered from, and has not had any recent fevers, weight loss, bone pain, pallor or any other complaints for that matter. He is a very active child, and has been known to get bruises on his legs from “diving off of the couch” but nothing like what you see in the ED.
You send off a CBC and note that the white blood cell count is 10.2, the hemoglobin/hematocrit 12.7/38.1 and the platelets 27
Based on the lab results and his reassuring appearance you make the diagnosis of ITP. Idiopathic thrombocytopenic purpura (ITP) is an IgG-mediated antibody reaction versus platelets leading to their premature destruction. The peak age is 2 to 10 years, with most cases seen in those under 5 years. In more than half of all cases the child has had a recent infection (think cold or sore throat). It generally occurs in children between the ages of 2 and 10 years, with the majority of cases occurring in children under 5 years. In more than half of ITP cases there is a history of a recent infection. Lest you jump to conclusions note that infections don’t cause ITP – nor have they been definitively linked to causing the antibody-mediated reaction.
The presentation is relatively characteristic, beginning with sudden bruises, petechiae or bleeding in an otherwise well appearing child. 9/10 will have mucosal bleeding – often minor and more often in the nasal passages. Other mucosal sites include oral cavity, genitourinary tract and gastrointestinal tract in order of decreasing severity.
Intracranial and pulmonary bleeding are very, very rare, even when platelets are under 10,000/microliter. Most patients do not have Hepatomegaly, splenomegaly or lymph node enlargement. If they do, alternative diagnoses should be considered. These include
- Viral infections (EBV, acute HIV and hepatitis with thrombocytopenia)
- Drug-induced thrombocytopenia
- Aplastic anemia
- Inherited disorders associated with thrombocytopenia
Though children are well appearing the initial workup should include a complete blood count with differential and a peripheral smear along with a blood type. Coagulation studies may be helpful, especially if you are concerned about a family history of bleeding disorders. In febrile/ill appearing children obtain a blood culture. You’ll likely want to start antibiotics as well. because, let’s face it – ill appearing + petechiae = sepsis until proven otherwise. In any case, if you think it’s ITP, and the child looks well you’re probably right – and thus you should call a Pediatric Hematologist. If the diagnosis of ITP is suspected, consult with a hematologist to determine appropriate therapy. Therapy is directed towards the immune response and includes intravenous immune globulin (IVIG), systemic corticosteroids, and/or Anti-Rho(D) immune globulin. Despite treatment 1/5 children will have a chronic course (>6 months). Interestingly, there also appears to be a slight increase in the month and a half following MMR vaccination.