Thrombotic thrombocytopenic purpura

Page most recently updated 7 September 2026

This page focuses on the reported psychiatric associations, which may be the initial presenting manifestation, and on other clinical features that may assist the psychiatrist or primary care physician in identifying the underlying diagnosis, considered through the lenses of the diagnostic lenses framework.

Thrombotic thrombocytopenic purpura (TTP) is an immune-mediated thrombotic microangiopathy that can cause acute neurological and systemic manifestations due to widespread small-vessel thrombosis.

It can present with psychiatric features such as confusion, agitation, behavioural change, mood disturbance, cognitive impairment, hallucinations, and, less commonly, psychosis, typically in the context of neurological involvement.

Other characteristic features include neurological manifestations such as headache, altered mental status, seizures, focal neurological deficits, transient ischaemic attacks, and stroke-like episodes. Other characteristic features include microangiopathic haemolytic anaemia and thrombocytopenia, with possible fever and fluctuating neurological symptoms due to widespread microvascular platelet thrombi.

From a multisystemic lens perspective, clinical features in other body systems include (but are not limited to):

  • Renal/electrolytes: renal involvement may occur, typically with less severe kidney injury than seen in other thrombotic microangiopathies; acute kidney injury and urinary abnormalities may occur.

  • Hematologic: thrombocytopenia and microangiopathic haemolytic anaemia are defining features, with schistocytes on blood film, elevated LDH, reduced haptoglobin, and increased indirect bilirubin.

  • Dermatologic: purpura and petechiae may occur due to thrombocytopenia.

Early diagnosis is important to enable urgent plasma exchange and immunomodulatory treatment, prevent rapid progression of microvascular organ injury, reduce the risk of irreversible neurological complications and death, and improve prognosis and quality of life.

Selected references and further reading — Multisystemic lens

Cardinal RN, Bullmore ET. The diagnosis of psychosis. Cambridge: Cambridge University Press; 2011.

Sachdev PS, Keshavan MS, editors. Secondary schizophrenia. Cambridge: Cambridge University Press; 2010.

Levenson JL, editor. The American Psychiatric Association Publishing textbook of psychosomatic medicine and consultation-liaison psychiatry. 3rd ed. Washington (DC): American Psychiatric Association Publishing; 2019.

Stern TA, Beach SR, Smith FA, Freudenreich O, Vranceau AM, Fava M, editors. Massachusetts General Hospital handbook of general hospital psychiatry. 8th ed. Philadelphia: Elsevier; 2025.

Arciniegas DB, Yudofsky SC, Hales RE, editors. The American Psychiatric Association Publishing textbook of neuropsychiatry and clinical neurosciences. 6th ed. Washington (DC): American Psychiatric Association Publishing; 2018.

Agrawal N, Faruqui R, Bodani M, editors. Oxford textbook of neuropsychiatry. Oxford: Oxford University Press; 2020.

Boland R, Verduin M, editors. Kaplan and Sadock's comprehensive textbook of psychiatry. 11th ed. Philadelphia: Wolters Kluwer; 2024.

Loscalzo J, Fauci AS, Kasper DL, Hauser SL, Longo DL, Jameson JL, editors. Harrison's principles of internal medicine. 22nd ed. New York: McGraw Hill; 2025.