Paraneoplastic autoantibody panels: sensitivity and specificity, a retrospective cohort.

BACKGROUND: Experts in the autoimmune paraneoplastic field recommend autoantibody testing as "panels" to improve the poor sensitivity of individual autoantibodies in detecting paraneoplastic neurological syndromes (PNS). The sensitivity of those panels was not reported to date in a fashion devoid of incorporation bias. We aimed to assess the collective sensitivity and specificity of one of the commonly used panels in detecting PNS. METHODS: A single-centered retrospective cohort of all patients tested for paraneoplastic evaluation panel (PAVAL; test ID: 83380) over one year for the suspicion of PNS. Case adjudication was based on newly proposed diagnostic criteria in line with previously published literature, but modified to exclude serological status to avoid incorporation bias. Measures of diagnostic accuracy were subsequently calculated. Cases that failed to show association with malignancy within the follow-up time studied, reflecting a possibly pure autoimmune process was considered paraneoplastic-like syndromes. RESULTS: Out of 321 patients tested, 51 patients tested positive. Thirty-two patients met diagnostic criteria for paraneoplastic/paraneoplastic-like syndromes. The calculated collective sensitivity was 34% (95% CI: 17-53), specificity was 86% (95% CI: 81-90), Youden's index 0.2 and a positive clinical utility index 0.07 suggesting poor utility for case-detection. CONCLUSION: This is the first reported diagnostic accuracy measures of paraneoplastic panels without incorporation bias. Despite recommended panel testing to improve detection of PNS, sensitivity remains low with poor utility for case-detection. The high-calculated specificity suggests a possible role in confirming the condition in difficult cases suspicious for PNS, when enough supportive evidence is lacking on ancillary testing.

Postictal ammonia as a biomarker for electrographic convulsive seizures: A prospective study.

OBJECTIVE: Transient hyperammonemia (THA) was reported to follow generalized convulsions without sufficient evidence to confirm the epileptic nature of those events. We aimed to determine if postictal THA can differentiate between different types of events as confirmed electroencephalographically using video-electroencephalography (vEEG) monitoring. METHODS: In our prospective cohort, we screened all consented adults (>18 years) admitted to the epilepsy monitoring unit. Ammonia was checked at baseline, within 60 min of the event (for all patients) and 24 h after event (whenever possible). Patients were grouped into generalized convulsive seizures (GCS), psychogenic nonepileptic seizures with convulsions (PNES-C), or focal seizures (FS) based on vEEG. Data were analyzed using descriptive statistics and parametric/nonparametric methods. RESULTS: Of 78 patients enrolled, 13 had GCS, 8 had FS, and 9 had PNES-C. The groups were different with regard to gender (p = 0.04) and baseline ammonia (p = 0.02), but not age. The change in ammonia postictally from baseline was significantly different among the three groups (p = 0.004). The area under the receiver operator characteristic (ROC) curve for postictal ammonia to distinguish GCS from other groups was 0.88 (95% confidence interval [CI] 0.69-0.96) suggesting ammonia to be a good test differentiating epileptic GCS from other events. An ammonia level of ≥80 µmol/L correctly classified 80% of our patients (sensitivity 53.9%, specificity 100%). SIGNIFICANCE: Our results provide objective evidence for the association between THA and GCS seizures utilizing vEEG monitoring, and a basis for future studies to determine the role of postictal ammonia as an inexpensive diagnostic test to diagnose GCS.

Unusually Prolonged Presentation of Designer Drug Encephalopathy Responsive to Steroids.

The availability and use of novel psychoactive substances has risen dramatically over the last decade. The unpredictability of their toxicity constitutes a real challenge. We report a case of an adolescent who developed prolonged encephalopathy after ingesting "Hot Molly," which was found to contain the novel psychoactive substance, methylenedioxybenzylpiperazine when analyzed by high resolution mass spectrometry assay. This is the first case of human toxicity from methylenedioxybenzylpiperazine ingestion in the medical literature confirmed by body fluid analysis presenting with significant and prolonged encephalopathy. The prolonged course may be due to CYP2D6 inhibition from a combination of the methylenedioxyphenyl moiety and the patient's ultrarapid metabolizer pharmacokinetics. The response to high dose corticosteroids suggests a possible inflammatory effect that warrants further investigation.