Long-term Glucocorticoid Exposure in Angiostrongylus cantonensis Meningoencephalitis Without Eosinophilic Response—Insights Into Treatment Withdrawal From a Medical- Humanities Perspective: A case report

Abstract Background Angiostrongylus cantonensis is the primary pathogen responsible for human eosinophilic meningitis. Atypical infection presentations lacking peripheral or cerebrospinal fluid (CSF) eosinophilia occasionally occur under immune-modulated conditions. Long-term glucocorticoid use is a plausible contributor to blunted eosinophilic inflammatory responses. This case highlights that chronic steroid-induced immune alteration may lead to diagnostically challenging, eosinophil-negative neuroangiostrongyliasis, requiring heightened clinical vigilance. Case presentation A 48-year-old male with a 30-year history of psoriasis and chronic irregular oral dexamethasone use presented with generalized pain, fever, and altered mental status. Admission laboratory tests revealed neither peripheral nor cerebrospinal fluid eosinophilia. CSF metagenomic next-generation sequencing (mNGS) identified 1853 specific reads of Angiostrongylus cantonensis , confirming the diagnosis of neuroangiostrongyliasis. Given the patient’s critical neurological deterioration and family concerns regarding irreversible severe neurological sequelae, the family declined antiparasitic treatment; the standard albendazole-glucocorticoid regimen was not administered. Conclusions To our knowledge, this is a real-world case of molecularly confirmed A. cantonensis meningoencephalitis characterized by double-negative eosinophil results, strongly associated with decades-long irregular glucocorticoid exposure. Normal eosinophil counts cannot rule out parasitic neuroinfection in patients receiving chronic glucocorticoid therapy. CSF-mNGS successfully resolved this diagnostic deadlock, validating its role as a critical alternative diagnostic tool when conventional testing yields negative results. Family-initiated treatment withdrawal illustrates prevalent real-world challenges in prognostic expectation management, risk communication, and shared decision-making for severe neglected tropical central nervous system infections.