Presentation
You are working for a transporting ALS service and receive a call for a sick child. Upon arrival you find a 4-year-old male child with a PAT showing normal appearance, no increased work of breathing and no signs of poor perfusion. You continue your primary assessment which is normal with the exception of a wide spread rash on all extremities, back, chest and abdomen.
You continue your assessment by completing a SAMPLE history.
Signs diffuse rash on all extremities, trunk and back
Allergies NKDA
Medications none
PMH no significant history
Last meal breakfast 1 hour ago
Events leading up, awoke with rash and parents state that they noticed some bleeding while brushing the child’s teeth.
Considering that this is a child, you ask some additional questions such as immunization history. Immunizations are up to date. Parents state they took the child to their primary care provider a month ago for 4 year immunizations. Parents deny any recent fever or any suspected ingestions.
You are getting ready to call in your radio report; how do you describe this rash?
A Closer Look
This rash is classified as a petechial rash. Petechiae are pinpoint areas of hemorrhage (less than 2 mm in size). This is different from purpura which is a reddish to purplish spots on the skin that don’t blanch with pressure. Purpura can be relatively small in size or classified as purpura fulminans which is a fancy word to say the purpura is widespread.
Your assessment doesn’t reveal any life threats so you decide to transport basic to your local critical access hospital.
Evaluation in the ED consisted of obtaining a CBC. The CBC results were as follows:
Normal values for a CBC are center specific but generally,
WBC between 4-10
HGB between 12-16
HCT between 35-45
PLT 150-350
The Diagnosis
Based on the laboratory values, thrombocytopenia (low platelet count) is confirmed. Platelets are integral for blood clotting. When there is damage to a blood vessel, platelets adhere to the site of damage and activate. When platelets activate they change their shape making them extremely sticky and release granules which contain additional clotting factors helping to form a platelet plug to stop bleeding.
A short time later you are called to transfer the patient to a larger pediatric center for a pediatric hematologist-oncologist evaluation. After evaluation, the child was diagnosed with Immune ThrombocytoPenia (ITP). ITP was previously called Idiopathic thrombocytopenic purpura. It is a diagnosis made after exclusion of other causes of thrombocytopenia. It is characterized by a low platelet count, sudden appearance of a petechial rash, bruising and/or bleeding in an otherwise healthy child. ITP is the most common cause of symptomatic thrombocytopenia in children. It occurs slight more often in males than females, typically between 2 and 5 years of age. ITP is presumptively considered if the platelet count is below 100K, in 80% of cases the platelet count is under 20K.
60% of child diagnosed with ITP have a history of preceding illness or vaccination within a month of the diagnosis. Our patient underwent recent vaccination. According to the CDC the suggested vaccinations for children between 4-6 years are Diphtheria, Tetanus and Pertussis (DTaP). Poliovirus, Measles, mumps, rubella (MMR), Varicella. The MMR vaccine has been shown to have a slight risk of ITP, occurring approx. 2.6 times per 100,000 doses.
Typically, patients don’t have any other systemic signs or symptoms such as swollen lymph nodes, fever, headaches, GI symptoms, exposure to medications with side effects of thrombocytopenia. Mild spleen enlargement may be seen.
Differentials
Differential diagnosis that need to be considered before a diagnosis of ITP include:
- Malignancy
- Systemic illness or recurrent infection i.e.
- Lupus
- HIV
- Hepatitis C
- Other immune deficiencies.
- Anemia
- Hemolytic uremic syndrome (ask about a history of recent diarrheal illness)
- Thrombotic thrombocytopenic purpura, associated with hemolysis and thrombocytopenia
- Bone marrow failure syndromes
- Excessive bleeding which requires evaluation by coagulation studies
Treatment is usually supportive and consists of limiting activities to reduce the chance of bleeding from trauma and avoiding medications that inhibit platelet activity such as aspirin and nonsteroidal anti-inflammatory drugs. Anticoagulants are typically avoided as well.
In cases where the patient has more severe signs and symptoms, glucocorticoid steroids, IVIG and platelet transfusions may be required.
Glucocorticoid steroids such as methylprednisolone or prednisone and Intravenous immune globulin (IVIG) are presumed to reduce phagocytosis of platelets but exactly how they work is unclear.
Platelet transfusion can be administered to increase platelet counts, however due to the increased rate of platelet destruction the transfused platelets will probably have a short lifespan.
Most children recover within 3-6 months regardless of the treatment provided although in 10-20% of cases thrombocytopenia can last more than a year.
References
UpToDate, Immune thrombocytopenia (ITP) in children: Initial management. Accessed on 9/12/2020
UpToDate, Immune thrombocytopenia (ITP) in children: clinical features and diagnosis. Accessed on 9/12/2020