Hematology: Primary ITP and TTP Comparison

Flashcards covering the diagnosis, pathophysiology, symptoms, and treatment of Primary Immune Thrombocytopenia (ITP) and Thrombotic Thrombocytopenic Purpura (TTP) based on lecture notes.

What is the definition of primary immune thrombocytopenia (ITP)?

An acquired immune disorder causing isolated thrombocytopenia, most often in young women, which is considered a diagnosis of exclusion.

How does the clinical course of ITP typically differ between children and adults?

In children, it commonly follows an acute viral illness and spontaneously resolves in the majority, while in adults it is usually idiopathic and follows a more chronic course.

What is the typical management for severe symptomatic case of primary ITP?

Management typically involves high-dose steroids and intravenous immunoglobulin (IVIG).

What treatments are reserved for cases of ITP that are steroid-refractory?

Thrombopoietin receptor agonists and other immunosuppressants.

What is the core underlying problem in Thrombotic thrombocytopenic purpura (TTP)?

Thrombotic microangiopathy caused by a severe deficiency of the VWF-cleaving protease ADAMTS13.

What is the pathophysiology behind the formation of microthrombi in TTP?

Severe deficiency of ADAMTS13 leads to ultra-large VWF multimers, causing platelet aggregation in small vessels (brain, kidneys, heart) and mechanical red cell fragmentation (MAHA).

What platelet count is typically observed in patients with TTP?

Markedly low, often below $30 \times 10^9/L$.

What clinical symptoms may indicate multi-organ ischemia in a TTP patient?

Fluctuating neurologic deficits, renal impairment, chest or abdominal pain, fever, and jaundice.

What is the emergent treatment required for TTP, and how soon should it be initiated?

Rapid plasma exchange, ideally initiated within hours when macroangiopathic hemolytic anemia (MAHA) and thrombocytopenia are present.

What are the mortality rates for TTP when left untreated versus when treated with timely plasma exchange?

The mortality rate is $>90\%$ if untreated, which reduces to approximately $10\text{--}20\%$ with timely treatment.

How do blood film findings differ between Primary ITP and TTP regarding red cells?

Primary ITP shows no MAHA and the smear is without schistocytes, whereas TTP shows MAHA with schistocytes and increased hemolysis markers.

In terms of clinical urgency, how are ITP and TTP distinguished?

ITP is often urgent but not typically immediately life-threatening; TTP is a true medical emergency due to its high mortality if untreated.