Anti-DPPX encephalitis

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.

Anti-DPPX encephalitis is an autoimmune encephalitis with multisystemic involvement.

It can present with psychiatric features such as anxiety, agitation, confusion, behavioural change, mood symptoms, sleep disturbance, hallucinations, and psychosis, particularly in the context of encephalopathy.

Other characteristic features include cognitive impairment, central nervous system hyperexcitability with myoclonus, tremor, startle responses, seizures, and hyperekplexia (pathological exaggerated startle responses to unexpected tactile or acoustic stimuli). A distinctive feature is the combination of neurological symptoms with prominent gastrointestinal symptoms, particularly chronic diarrhoea and weight loss.

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

  • Gastrointestinal: chronic diarrhoea, gastrointestinal dysmotility, and weight loss are characteristic features and may precede neurological symptoms.

  • Renal/electrolytes: dehydration and electrolyte disturbances may occur secondary to chronic diarrhoea and gastrointestinal fluid losses.

  • Hematologic: association with underlying hematologic malignancy (e.g., B-cell lymphoma or chronic lymphocytic leukemia) has been reported in a subset of patients.

Early diagnosis is important to enable prompt immunotherapy, address nutritional and metabolic consequences of gastrointestinal involvement, reduce the risk of persistent neurological symptoms and functional decline, and improve prognosis and quality of life. Evaluation for an underlying hematologic malignancy may be considered given the reported association.

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.