Case Report: Neuropsychiatric instability in structurally compromised CNS Erdheim–Chester disease: a diagnostic and management challenge

Background: Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis involving multiple systems, with central nervous system (CNS) involvement present in a significant subset. Neuropsychiatric symptoms such as cognitive decline, mood disturbances, and psychosis have been documented. However, sensitivity to psychotropic medications in CNS-involved ECD remains underreported. This case highlights a multi-mechanistically compromised CNS posing diagnostic and therapeutic challenges by such sensitivity. Case presentation: A 50-year-old woman with biopsy-confirmed ECD and CNS involvement presented with persistent neuropsychiatric symptom confusion, psychosis, cognitive decline, mood lability, and agitation despite radiologic remission following cladribine and radiotherapy. She exhibited marked sensitivity to multiple psychotropics: haloperidol induced QTc prolongation; risperidone and aripiprazole triggered akathisia and insomnia; olanzapine caused hypotension; chlorpromazine and quetiapine led to oversedation; and benzodiazepines paradoxically worsened agitation. Only valproic acid was tolerated. Factors such as previous chemotherapy, brain radiotherapy, hypernatremia, endocrine dysfunction, and a family history of psychiatric illness were suspected to have a role in predisposition. Imaging showed lesions of the hypothalamus, pituitary stalk, and mesial temporal lobes. Persistent symptoms shared features with Lewy Body Dementia and raised the diagnostic ambiguity. Conclusion: To our knowledge, this is one of the first detailed reports to describe heightened neuropsychiatric instability and psychotropic intolerance in a patient with a compromised CNS through several suspected mechanisms. The case underscores the need for multidisciplinary care and cautious psychiatric management in patients with a compromised CNS. Clinicians should suspect psychotropic sensitivity in cases with paradoxical responses and consider systemic causes such as ECD as a possible contributor.