2026 American Academy of Neurology Autoimmune Abstract Website

Objective:

To identify and classify neurological disorders associated with elevated cerebrospinal fluid (CSF) angiotensin-converting enzyme (ACE).

Background:

CSF ACE is most associated with neurosarcoidosis. However, diagnostic utility is debatable as literature has shown varying specificity and sensitivity. We aimed to investigate what diagnoses are associated with elevated CSF ACE.

Design/Methods:

Single-center retrospective electronic medical record (EMR) review of adult patients who underwent CSF ACE testing from 1/1/12 to 12/31/25. Patients identified using IRB-approved institutional analytic tools. EMRs of identified patients were manually reviewed to ensure exclusion/inclusion criteria were met. Demographical data were recorded. Patients with elevated CSF ACE (>2.5 U/L) underwent additional analysis, and relevant diagnoses categorized.

Results:

1186 patients underwent CSF ACE testing; elevated in 66 (median level: 4.4 U/L, range 2.6-40.0 U/L). Mean age 55.7 ±14.2, 40 females, 26 males. Diagnoses included: meningitis (n=13; 6 aseptic, 2 bacterial, 3 fungal, 1 viral, 1 parasitic), miscellaneous neurologic presentations (n=10; 3 headache, 3 encephalopathy, 2 seizure, 1 spinocerebellar ataxia, 1 acute stroke), neurosarcoidosis (n=9; 8 probable, 1 possible), CNS malignancy (n=10; 5 primary, 5 secondary), structural (n=7; 3 CSF leak, 2 hydrocephalus, 2 compressive myelopathy), autoimmune/inflammatory (n=7; 5 CNS demyelination, 2 Guillain Barre Syndrome), unclassified (n=7; 5 incomplete workup, 2 lost to follow-up), neuromuscular (n=5; 4 peripheral neuropathy, 1 myopathy), idiopathic meningeal enhancement (n=4). Neuroleptic use found in 2 secondary CNS malignancy, 2 encephalopathy, 1 aseptic meningitis, 1 headache (n=6). 24/66 (36.4%) demonstrated meningeal enhancement on MRI (10 leptomeningeal, 10 pachymeningeal, 4 both).

Conclusions:

Elevated CSF ACE was seen in association with a variety of neurologic diagnoses demonstrating elevated CSF ACE is not specific for sarcoidosis and actually may be more associated with meningitis (19.7%) than sarcoidosis (13.6%). Across diagnoses, meningeal enhancement was a relatively common finding, 36.4% of cases, indicating CSF ACE may be a more common marker of meningeal pathology than of sarcoidosis.