Elsevier

Resuscitation

Volume 115, June 2017, Pages 169-172
Resuscitation

Short paper
Early Lance–Adams syndrome after cardiac arrest: Prevalence, time to return to awareness, and outcome in a large cohort

https://doi.org/10.1016/j.resuscitation.2017.03.020Get rights and content

Abstract

Introduction

Early myoclonus after cardiac arrest (CA) is traditionally viewed as a poor prognostic sign (status myoclonus). However, some patients may present early Lance–Adams syndrome (LAS): under appropriate treatment, they can reach a satisfactory functional outcome. Our aim was to describe their profile, focusing on pharmacologic management in the ICU, time to return of awareness, and long-term prognosis.

Methods

Adults with early LAS (defined as generalized myoclonus within 96 h, with epileptiform EEG within 48 h after CA) were retrospectively identified in our CA registry between 2006 and 2016. Functional outcome was assessed through cerebral performance categories (CPC) at 3 months, CPC 1–2 defined good outcome.

Results

Among 458 consecutive patients, 7 (1.5%) developed early LAS (4 women, median age 59 years). Within 72 h after CA, in normothemia and off sedation, all showed preserved brainstem reflexes and localized pain. All patients were initially treated with valproate, levetiracetam and clonazepam; additional agents, including propofol and midazolam, were prescribed in the majority. First signs of awareness occurred after 3–23 days (median 11.8); 3/7 reached a good outcome at 3 months.

Conclusion

Early after CA, myoclonus together with a reactive, epileptiform EEG, preserved evoked potentials and brainstem reflexes suggests LAS. This condition was managed with a combination of highly dosed, large spectrum antiepileptic agents including propofol and midazolam. Even if awakening was at times delayed, good outcome occurred in a substantial proportion of patients.

Introduction

Nearly one fifth of patients resuscitated from cardiac arrest (CA) may develop myoclonus [1], [2]. However, clinical and electroencephalographic (EEG) differences exist between “status myoclonus”, a condition strongly related to poor prognosis [3], and myoclonus that is amenable to improvement, including awakening with awareness, which may represent early-appearing Lance–Adams syndrome (LAS) [2], [4], [5]. The latter has been defined as generalized action myoclonus appearing within a few days to weeks after CA and coma, mostly (but not exclusively) of hypoxic origin [6]. It is often accompanied by dysmetria, dysarthria and ataxia, with relative preservation of cognition [7]. This syndrome can become chronic, and patients usually need long-term antiepileptic treatment. Specific EEG features in patients with early myoclonus have been recently outlined [4]: suppression-burst background with high-amplitude, diffuse polyspikes correlate with dismal prognosis (“status myoclonus”), whereas continuous background with narrow, midline centered spike-waves correspond to LAS, and a relatively good outcome.

Clinically, it is of paramount importance to recognize early LAS patients in order to offer them a chance of regaining awareness. Our aim was to describe our experience, focusing on pharmacologic management in the ICU, time to awakening, and long-term prognosis.

Section snippets

Patients

From our prospective CA registry including consecutive adults admitted for CA from June 2006 to November 2016, we retrospectively identified subjects with early LAS defined as follows: survivors at discharge, having presented generalized myoclonus within 96 h after CA (considering the masking effect of acute sedation) together with an epileptiform EEG on a continuous background within 48 h [4].

Until July 2014, patients were managed at 33° during the first 24 h, then increasingly at 36 °C.

Patient characteristics

Among the 458 CA patients, seven survivors (1.5%) developed early LAS as previously defined.

Median age was 57 years, most common CA etiology was cardiac, while first cardiac rhythms were evenly distributed. Median time to ROSC was 22 min. Their clinical characteristics are summarized in Table 1.

Neurological and neurophysiological assessments

Within 72 h after CA, in normothermia and off sedation, all seven patients had preserved brainstem reflexes and localized pain; only two showed spontaneous eye opening (without interaction with the

Discussion

This series shows that early LAS, occurring in only 1.5% of our cohort, represents a rare diagnosis in patients after a CA. A combination of high dosed, relatively broad spectrum AED was used promptly, but the first signs of awareness were relatively delayed (up to 3 weeks); almost half of patients had a complete recovery.

In a previous assessment of our group, including 1 patient described here, 24.8% of the cohort developed a postanoxic status epilepticus, 2 of whom had LAS (3.1% of total) [5]

Conflict of interest statement

The authors declare that they have no conflict of interest.

Acknowledgment

The authors thank Christine Stähli, RN, for help in data acquisition.

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