ITP – Immune Thrombocytopenia Purpura
We’ve discussed how rashes often present to the ED… and often I don’t know what they are do to; however, we are trained to look for characteristics that may indicate a concerning etiology and warrant additional work-up (ex. Petechiae, purpura, vesicles, bullae, target lesions, desquamation). ITP is one of those entities that we often consider when we are evaluating a rash.
ITP guidelines have recently been updated:
- ITP is an autoimmune disorder that leads to the destruction of normal platelets
- ITP is an acquired disorder characterized by:
- Thrombocytopenia = platelet < 100 x109/L
- It used to be <150 x109, but only ~7% of pts with plts between 100 x109 – 150 x109 will progress to ITP over the next 10 yrs
- Petechiae and/or purpura
- Normal Hgb and WBC with normal differential.
- The absence of signs of other identifiable causes of thrombocytopenia.
- 75-80% enter remission within 6 months (parents want to know this)
- Only 5-10% will progress to Chronic ITP (>1 year duration)
- H+P, CBC, and peripheral smear are the key components to make the diagnosis!
Historic points favoring another diagnosis:
- Bone/Joint Pain
- Family Hx of easy bruising or low platelets
Exam findings concerning for another diagnosis:
- Soft tissue or skeletal morphologic abnormalities
- Nonpetechial rash
Laboratory findings concerning for another diagnosis:
- Abnormal hemoglobin level
- High or Low WBC count
- Abnormal WBC morphology (hence the peripheral smear)
- The previous recommendation for obtaining a Bone Marrow Biopsy to rule-out acute leukemia or bone marrow aplasia is not advocated for in this current update.
- That being said… make sure you are doing a thorough H+P and getting the peripheral smear!
Therapeutic Goal = “achieve a platelet count that is associated with adequate hemostasis,” rather than a normal platelet count.
- Children with no bleeding or mild bleeding (skin manifestations only, such as bruising and petechiae without mucosal involvement) can be managed with observation alone regardless of platelet count. Certainly this requires long conversation with family and the Hematologist on call.
- If follow-up is not “assured,” there are other social concerns (no transportation, etc), or the activity level of the patient may increase risk of bleeds (toddler who likes to tip-over more than waddle), then treatment may be more appropriate. Certainly, if the child has mucosal involvement or frank bleeding (example – epistaxis), then treatment is preferred.
Therapeutic options include Steroids, IVIG, and Anti-Rh(d)
- Short course of corticosteroids or IVIG are the first line therapies
- No one regimen advocated over others.
- One noted was: 2mg/kg/Day x 2 weeks, then tapered over 21 days.
- Can be used if a more rapid increase in platelet count is needed.
- Certainly IVIG is trickier to give and has more potential side-effects (that is just coming from me… not the recommendations)
- Recommended only in Rh-postive patients who have a negative direct antiglobulin test (DAT) and who have their spleens.
- Anti-D consists of antibiodies to Rh factor. These antibodies will coat the RBC’s and then keep the spleen busy removing the coated RBC’s, thus allowing the platelets to pass on through untouched. So platelet counts will increase… BUT Hemoglobin counts will decrease.
- Not recommended in patients with decreased hemoglobin levels from bleeding.
Without question, even though these patients will generally do well and have low risk for complications, do not treat them cavalierly. Be thorough and consider leukemia or other marrow suppressive conditions. Perform a thorough exam – check all lymph-node areas, look at mucosal surfaces for petechiae! CONSULT the Hematologist and, most importantly, explain your thought process to the family.
PS – this update (link below) has good information about adult patients with ITP as well… for those of us who like adults also.
Neunert C, et al. The American Society of Hematology 2011 evidence-based practice guideline for immune thrombocytopenia. BLOOD 2011; 117 (16): 4190-4207.
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