Microscopic polyangiitis

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.

Microscopic polyangiitis is a systemic vasculitis.

It can present with psychiatric features such as depression, anxiety, behavioural change, cognitive dysfunction, mood disturbance, and, less commonly, psychosis.

Other characteristic features include headache, peripheral neuropathy (particularly mononeuritis multiplex), seizures, cerebrovascular events, and, less commonly, encephalopathy. Distinctive features include necrotizing small-vessel vasculitis with a pauci-immune pattern, classically affecting the kidneys and lungs. Myeloperoxidase (MPO)-ANCA positivity is a characteristic serological finding.

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

  • Respiratory: pulmonary capillaritis causing diffuse alveolar haemorrhage, dyspnoea, cough, and haemoptysis may occur.

  • Renal/electrolytes: rapidly progressive glomerulonephritis with haematuria, proteinuria, and declining renal function is common and may be a presenting feature.

  • Cardiovascular: pericarditis, myocarditis, and other cardiovascular complications may occur.

  • Musculoskeletal: arthralgia, myalgia, and inflammatory arthritis may occur.

  • Dermatologic: palpable purpura, skin ulcers, and other cutaneous vasculitic manifestations may occur.

Early diagnosis is important to enable prompt immunosuppressive therapy, prevent irreversible renal failure and life-threatening pulmonary haemorrhage, reduce systemic complications, and improve long-term 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.