Thrombotic thrombocytopenic purpura
{not a sub-type of Immune thrombocytopenia purpura}
Summary
Thrombotic thrombocytopenic purpura (TTP), acquired is a blood disorder characterized by low platelets (i.e., thrombocytopenia), small areas of bleeding under the skin (i.e., purpura), low red blood cell count, and hemolytic anemia. TTP causes blood clots (thrombi) to form in small blood vessels throughout the body. These clots can cause medical problems if they block vessels and decrease or stop blood flow to organs such as the brain, kidneys, and heart…Acquired TTP usually begins in adulthood, but can affect children. An episode of TTP usually occurs suddenly and lasts for days or weeks, but it may continue for months. Relapses (or flareups) can occur in up to 60 percent of people who have acquired TTP.
From the Genetic and Rare Diseases Information Center.
Thrombotic thrombocytopenic purpura is not a sub-type or synonym of Immune thrombocytopenia purpura, despite the similarity in their names. UpToDate provides a useful chart comparing Immune thrombocytopenia purpura and Thrombotic thrombocytopenic purpura, which outlines differences between the two diagnoses in clinical presentation, lab tests, treatments, and known (TTP) vs. unknown (ITP) causes [1].
Additionally, Miller et. al distinguishes the two:
Immune thrombocytopenia (ITP) and thrombotic thrombocytopenic purpura (TTP) are two separate diseases that are characterized by low platelets.
Immune thrombocytopenia (ITP) is an acquired hematologic disorder caused by immune-mediated destruction of platelets that can be classified as idiopathic or secondary to another disease process. ITP is a clinical diagnosis that rests on the presence of isolated thrombocytopenia while excluding other causes of thrombocytopenia and identifying conditions that may be causing secondary ITP [1].
Thrombotic thrombocytopenic purpura (TTP) is a rare thrombotic microangiopathy caused by an acquired autoantibody that leads to decreased activity of the von Willebrand factor-cleaving protease ADAMTS13 that results in hemolytic anemia and severe thrombocytopenia [2]. While the treatment courses for both ITP and TTP may include corticosteroids and rituximab, a key treatment difference is urgent therapeutic plasma exchange (TPE) for all patients with TTP, whereas TPE is not effective for ITP.
[2]
So far, I have not found convincing evidence that Immune thrombocytopenia purpura has a tendency of developing into Thrombotic thrombocytopenic purpura, despite the lone Miller et. al case study outlining existing Immune thrombocytopenia purpura in a man who was later diagnosed with Thrombotic thrombocytopenic purpura [2].
Symptoms
Complications may include neurological problems (such as personality changes, headaches, confusion, and slurred speech), fever, abnormal kidney function, abdominal pain, and heart problems. Hemolytic anemia can lead to paleness, yellowing of the eyes and skin (jaundice), fatigue, shortness of breath, and a rapid heart rate.
From the Genetic and Rare Diseases Information Center.
Diagnostic Criteria
Under Investigation
Diagnostic Tests
Under Investigation
Human Leukocyte Antigen (HLA) Associations
Under Investigation
Tissue-Type or Cell-Type Attacked
Acquired TTP is caused when a person's body mistakingly makes antibodies that block the activity of the ADAMTS13 enzyme. The ADAMTS13 enzyme normally helps control the activity of certain blood clotting factors.
From the Genetic and Rare Diseases Information Center.
Attacking Immune Cell Type or Process
Under Investigation
Treatment Modality
Therapeutic plasma exchange
Glucocorticoids
Rituximab
Caplacizumab in selected cases
Avoid platelet transfusions unless major bleeding
[1]
Managing Specialist(s)
Under Investigation
Associated Infections
Under Investigation
Associated Toxins
Under Investigation
Research Authors
Under Investigation
Research Institutions
Under Investigation
Average Time from Symptom Onset to Diagnosis
Under Investigation
Last Updated
October 17, 2022
References
Distinguishing features between VITT (vaccine-induced immune thrombotic thrombocytopenia), ITP (immune thrombocytopenia), and TTP (thrombotic thrombocytopenia). UpToDate. (2022). Retrieved October 17, 2022, from https://www.uptodate.com/contents/image?imageKey=HEME%2F131494&topicKey=HEME%2F131333&source=see_link
Miller DD, Krenzer JA, Kenkre VP, Rose WN. Sequential Immune Thrombocytopenia (ITP) and Thrombotic Thrombocytopenic Purpura (TTP) in an Elderly Male Patient with Primary Sjogren's Syndrome: When in Doubt, Use the PLASMIC Score. Case Rep Med. 2021 Nov 30;2021:6869342. doi: 10.1155/2021/6869342. PMID: 34887925; PMCID: PMC8651386.
Thrombotic thrombocytopenic purpura, acquired. Genetic and Rare Diseases Information Center. (2021, November 8). Retrieved October 17, 2022, from https://rarediseases.info.nih.gov/diseases/4607/thrombotic-thrombocytopenic-purpura-acquired