TTP is thrombotic thrombocytopenic purpura, characterized by a pentad (FATRN)
- Anemia (microangiopathic hemolytic),
- Renal dysfunction,
- Neurologic dysfunction (that may be transient)
All of these are present only 1/3 of the time.
- TTP occurs usually in adults and rarely in children, while HUS is more common from age 6 mos to 5 years.
- TTP is a hematologic emergency with 100% mortality if untreated, and 10-20% if treated- bad stuff.
- If TTP is suspected, steroids should be started, give FFP, and consult hematology for plasma exchange therapy.
- Why FFP?
As in treatment of hereditary angioedema which lacks C1 esterase, in TTP the protease ADAMTS13 (aka vWF-cleaving protease) is qualitatively or quantitatively absent, but this is found in FFP.
- Avoid platelet transfusion unless there is bleeding that will kill the patient before TTP does, as platelet replacement may exacerbate the thrombus formation.
- All of the pentad are cause by the effects of large, uncleaved vWF monomers clumping with platelets, causing unstable thrombi that transiently cause vessel occlusions, leading to renal and neurologic dysfunction, the shearing of RBCs in the small vessels, and low platelets.
- So what causes TTP anyway?
It is associated with HIV, flu vaccination, acute pancreatitis, and often medication use including Plavix, flouroquinolones, resperdol, valacyclovir, and infliximab, among others.
References: Koyfman A. Thrombotic Thrombocytopenic Purpura.[Review] Pediatric Emergency Care. 27(11):1085-1088, November 2011.; uptodate.com; picture