Primary Immune Thrombocytopenia (ITP) – CPS Podcast From PedsCases

In this post, I link to and excerpt from the PedsCases‘ [Link is to the latestcontent] podcast and show notes, Primary Immune Thrombocytopenia (ITP) – CPS Podcast, by Stephanie Zachary, Oct 26, 2018.

All that follows is from the above resource.

This podcast is an overview of the newly published 2018 Canadian Paediatric Society (CPS) statement on the Diagnosis and Management of typical, newly diagnosed primary immune thrombocytopenia of childhood. It was developed by Stephanie Zachary and Sarah Weicker, fourth year medical students at the University of British Columbia. Dr. Jeremy Friedman, a general and complex care pediatrician at the University of Toronto, and Dr. Carolyn Beck, a general pediatrician at the University of Toronto who are the lead authors of this CPS statement, as well as Dr. Lauren Kitney, a general pediatrician at the University of British Columbia in Victoria, assisted in the development of this podcast.

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All that follows is from PDF show notes.

Today, our learning objectives are to

1. Define Immune thrombocytopenia, which we will abbreviate as ITP
2. Review the diagnostic criteria for typical ITP
3. Discuss red flag features, suggestive of other diagnoses
4. Review the management of ITP
5. Apply the CPS management recommendations to a clinical case

Now, let’s get started with a clinical case. You are working in a community pediatrics office,and your preceptor asks you to see a 5-year-old girl, Victoria, who is accompanied by her
mother. She was referred to your clinic due to a history of bruising and petechiae.

Your differential diagnosis includes but is not limited to isolated thrombocytopenias such as ITP, coagulopathies such as von Willebrands disease, vasculitides such as HSP, trauma including non-accidental injury, malignancies such as leukemia, and infectious causes such as meningococcus.

When you walk into the room, you see a playful, well-appearing child with a diffuse petechial rash on her limbs. Her family doctor has already ordered some bloodwork, whichshows an isolated thrombocytopenia with normal hemoglobin and white cell count. Her peripheral smear is normal. You wonder if Victoria may have ITP. You go to the CPSwebsite and pull up the new 2018 statement on ITP.*

*CPS Position Statement: Diagnosis and Management of typical, newly diagnosed primary immune thrombocytopenia (ITP) of childhood

Let’s take a pause from the case and review the key points from the CPS statement.

Primary immune thrombocytopenia or ITP, is a condition characterized by immune-mediated destruction of platelets. The condition most commonly affects children ages 2 to 5; however, this CPS statement can be applied to children aged 90 days old to 17 years of age. ITP typically presents as mild petechiae and bruising; although, some cases present with more severe bleeding episodes.

Usually, the cause of ITP is not known; however, in some cases, preceding viral illnesses or other immune mediated phenomena are triggers. The incidence of ITP is 5 in 100,000 children per year. ITP is typically a self-limited illness, lasting less than 6 months in 75-80% of cases and approximately 90% of cases resolved by one year.

Stephanie, now that we suspect Victoria may have ITP, how can we diagnose it?

[Stephanie]: Typical ITP can be diagnosed with a thorough history, physical examination and review of laboratory investigations. Clinical features often include a sudden onset
petechial rash, bruising, and/or new onset bleeding in an otherwise well and healthy child. The majority of children present with mild symptoms but up to 3% may have more serious bleeding such as prolonged epistaxis, mucosal bleeding or melena. Intracranial hemorrhage is rare, occurring in less than 1% of cases. The presence of any systemic symptoms point away from a diagnosis of primary ITP. We will discuss these “red flag” features in a later portion of this podcast.

Lab investigations should reveal an isolated thrombocytopenia with a platelet countof below 100 x 109/L, but this is often below 20 x 109/L. There should be no abnormalities of hemoglobin, reticulocyte or WBC count, including differential. Peripheral blood smear should be normal without evidence of hemolysis or blasts. Presence of these should prompt further investigations and an alternative diagnosis.

Bone marrow aspirations are not performed in children with suspected ITP unless clinical and laboratory findings raise suspicion for an alternative diagnosis. Hematology consultation should be considered in the presence of any red flags.

[Sarah]: Ok, so in summary, the key features that suggest a diagnosis of ITP are

1. New onset petechiae, bruising, and/or bleeding in an otherwise healthy child                                                                              2. Isolated thrombocytopenia with an otherwise normal CBC and a normal peripheral smear
3. Absence of systemic symptoms or red flags to raise concerns for other diagnoses

Red flags on history include:
1. Constitutional symptoms, such as fevers, weight loss, and night sweats
2. Bone pain
3. Poor response to treatment
4. Recurrent thrombocytopenia

Red flags on history include:
1. Constitutional symptoms, such as fevers, weight loss, and night sweats
2. Bone pain
3. Poor response to treatment
4. Recurrent thrombocytopenia

Red flags in investigations include:
1. Unexplained abnormalities in hemoglobin, WBC or neutrophil count
2. Abnormalities in the peripheral smear
Presence of any of these red flags should prompt you to consider alternative diagnoses, such as coagulopathies, vasculitides, trauma, malignancies, and infectious causes, and to involve a pediatric hematologist.

You assess Victoria and perform a history and physical exam. The patient’s mother reports that she first noticed a red rash on her daughter’s legs about a week ago. She has experienced several mild nose bleeds since then, lasting only a few minutes each time. There has been no oral mucosal bleeding or GI bleeding. She has not had any headache. Upon further questioning, Victoria is generally healthy and does not take any medications. There is no history of a preceding viral illnesses, weight loss, anorexia, or bony pain.

On exam, Victoria is well-appearing and afebrile with normal vital signs. You find that she has a diffuse non-blanchable, petechial rash on her limbs and torso. There is no palpable lymphadenopathy and abdominal exam is unremarkable with no hepatosplenomegaly. Her neurological exam is normal.

On her laboratory investigations, Victoria has an isolated thrombocytopenia. Her most recent platelet count is 5 x 109/L. The rest of her CBC is unremarkable and she has a normal peripheral smear, with no abnormal cellular morphology.
After reviewing with your preceptor, you make the diagnosis of ITP.

[Sarah]: Now that we’ve made a diagnosis, let’s go back to the CPS statement and explore the management recommendations.
Management options for ITP depend on the severity of bleeding, and include observation with or without pharmacologic therapies – such as corticosteroids and IVIG. ITP
is often a self limiting condition in 75-80% of cases, regardless of treatment. For patients
with mild or no bleeding, treatment does not statistically impact the overall rates of bleeding or developing of chronic ITP. The decision making process should include a family centered approach to discuss what the best management plan is according to each individual patient’s needs. This is known as shared decision making.

Please see p. 4 of the transcript PDF for a full discussion of ITP decision making.

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