Gut-Mediated Systemic Toxicity of Micro- and Nanoplastics: Nanoscale Biointerface Properties, Microbiota-Metabolite Crosstalk, and Evidence Across Gut-Organ Axes.

A 65-year-old previously healthy, human immunodeficiency virus (HIV)-negative male presented with 3 days of severe holocranial headache unresponsive to analgesics, progressing to agitation and confusion. He received midazolam without improvement, required intubation, and was transferred to our service. On admission, he was hemodynamically stable but deeply comatose (RASS -5), non-responsive, mechanically ventilated, with absent brainstem reflexes, no motor response to pain, and globally depressed reflexes. Initial laboratory work-up showed preserved renal and hepatic function (Cr 0.67 mg/dL, ALT 14 U/L, AST 12 U/L, bilirubin 1.56 mg/dL, INR 1.12), normal electrolytes—including sodium (137 mEq/L)—, normal inflammatory markers (CRP 0.48 mg/L), and a complete blood count without cytopenias (Hb 12 g/dL, leukocytes 13,950/µL, platelets 240,000/µL). There was no history of diabetes mellitus, alcohol use, chronic kidney disease, chronic liver disease, malignancy, autoimmune disease, or prior use of corticosteroids or other immunosuppressive therapies. Serologies for HIV, hepatitis B virus (HBV), and hepatitis C virus (HCV) were repeatedly negative. Head computed tomography (CT) showed two punctate calcifications compatible with inactive neurocysticercosis, without hydrocephalus or mass effect (

). Brain magnetic resonance imaging (MRI) could not be performed due to the need for sedation and limited availability of anesthesiology. On the day after admission, the first lumbar puncture revealed lymphocytic pleocytosis (298 cells/mm

; 91% lymphocytes), mildly elevated protein (53 mg/dL), low glucose (cerebrospinal fluid [CSF]-to-serum ratio 0.34), negative India ink staining, and positive cryptococcal antigen (latex agglutination). Opening pressure was not measured during the initial lumbar puncture, despite being a standard component of CSF evaluation. This omission, along with the lack of fundoscopy, limited early recognition of ICH and may have delayed optimal management.