Platelets, Who?
CASE:
A 12-year-old female with no significant past medical history presents with a non-painful, non-pruritic rash. The rash started 3 days ago diffusely, but primarily on her legs. It began to spread to her neck today. She has also noted new bruising on her elbow, forearm, and legs without preceding injury to these areas. Her mom notes that she had a nose bleed yesterday, and this is now resolved. She has otherwise been in her usual state of health with the exception of cold and cough symptoms about 2 weeks ago. She denies any fevers, night sweats, weight changes, changes in mental status, hemoptysis, blood in her bowels or urine, recent travel, new lotions/soaps/detergents or undercooked foods. Her family is Dominican, and there is no family history of blood or autoimmune disorders. She has not seen any doctors since her PCP retired last year.
On evaluation, she is afebrile, normotensive with a normal heart rate, and saturating well on room air. Examination reveals a well-appearing child with bruising, as above, as well as a petechial rash along her neck, chest, trunk, and bilateral lower extremities. She has no neurological deficits or signs of bleeding in her nose or mouth. Her only complaint is the appearance of the rash.
Laboratory studies are pursued given the concern for an oncologic process, and a complete blood count reveals a platelet count of <2,000 platelets per microliter of blood. All other cell lines are normal.
DIAGNOSIS:
This patient has idiopathic thrombocytopenic purpura (ITP).
DISCUSSION:
ITP is associated with autoimmune destruction of platelets, resulting in an isolated thrombocytopenia. It can be either a primary or acquired disorder, though the majority of cases are acquired from an inciting event, such as a viral infection. Mechanistically, inciting events cause a cascade of autoimmune reactions, specifically against the GPIIb/IIIa glycoproteins present on platelet cells (depicted below, from Neunert, C (2013)).
Children will often present within several days or weeks of a viral infection. Patients may report episodes of mucosal bleeding as well as easy bruising, but large volume blood loss is typically rare. On physical examination, patients may have petechiae or ecchymosis, and an otherwise normal physical examination. It is important to check mucosal surfaces as well as genitalia for a thorough physical examination. Work-up should include a CBC and a peripheral blood smear. Imaging is not usually necessary in otherwise stable patients.
Differential diagnosis includes other causes of thrombocytopenia, such as immunodeficiency, congenital thrombocytopenia, liver dysfunction, medication effects, zoonotic illness like malaria, bone marrow abnormalities like aplastic anemia, and of course, malignancy. Furthermore, ITP should be distinguished from thrombotic thrombocytopenic purpura (TTP). Patients with TTP will present with additional signs, such as schistocytes on peripheral blood smear (depicted below from Tefferi & Elliott, 2004), and will appear much sicker. TTP is also less common in children. In cases of ITP, contrastingly, laboratory work-up will reveal an isolated thrombocytopenia, with otherwise normal cell lines. If there are associated changes in other cell lines, additional diagnoses should be considered.
Management of ITP in children differs greatly from that of adults. In adults, treatment upon initial presentation is usually indicated. On the other hand, children can be observed for spontaneous resolution of ITP. One study reported that manifestations of ITP usually resolve spontaneously in 6 months. Primary care physicians or hematologists may draw serial CBCs outpatient until platelets have rebounded to safe levels, or monitor patients for symptoms of fatigue or health-related quality-of-life (HRQOL) measures. In the meantime, patients should be counseled on risk avoidance and to refrain from contact sports or high-intensity sports or unhelmeted bike riding.
First-line treatments, such as corticosteroids, IVIG, and anti-D Rh immune globulin, can be considered in patients with evidence of mucosal involvement or severe bleeding. Second-line options, such as rituximab, are usually employed only in cases of severe, refractory, or chronic ITP. Definitive treatment is considered splenectomy, though this is less successful in patients with ITP that is associated with antiphospholipid antibody syndrome (APLS) or Evans Syndrome.
CASE RESOLUTION:
This patient was discharged from the ED following hematology consultation. Hematology recommended close-follow-up in their office for a repeat CBC. Her repeat blood work re-demonstrated an isolated thrombocytopenia, though mildly improved from initial presentation, so she was started on a short steroid taper through shared-decision making with her family. Her platelet count slowly increased over two months. She continues to follow with hematology outpatient.
TAKE-AWAYS:
Treatment for ITP in children is not necessary, and children will experience spontaneous resolution of symptoms without intervention if there are no signs of life-threatening bleeding on initial presentation.
Author: Ambuj Suri, MD is a PGY-2 resident at Brown University/Rhode Island Hospital.
Faculty Reviewer: Meghan R. Beucher, MD
REFERENCES:
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