Lance-Adams Syndrome
Introduction[edit | edit source]
James W Lance and Raymond D Adams described this as a syndrome characterized by intentional myoclonus as a sequel to hypoxic encephalopathy. Hypoxic encephalopathy can occur due to a cardiopulmonary arrest. Despite advanced practices in cardiopulmonary resuscitations, the outcomes after cardiopulmonary arrest seem to be poor and People after successful cardiopulmonary resuscitation often remain with some neurological deficits. LAS is commonly confused with myoclonic status epilepticus (MSE) even though examination, imaging, level of disability and time of onset are very different [1]
The acute post-hypoxic myoclonus (PHM) presents within 24 hours of the event is often called myoclonic status epilepticus (MSE), which is one of the predictors for poor prognosis according to the American Academy of Neurology[2]Acute PHM is considered to be a clinical sign of irreparable brain damage with very less chance of functional recovery in most cases, and when it is accompanied by an absent brainstem reflex and unreactive EEG it becomes a reliable predictor for poor prognosis[3]
The chronic PHM which starts after a few days or weeks in patients who regained consciousness is often stated as LAS, where intentional myoclonus is accompanied when attempting voluntary movements or during a voluntary movement. . Dysmetria, dysarthria and ataxia with preserved cognition is also seen in most cases. There have been very few cases reported with acute onset LAS and people diagnosed with LAS has better outcome compared to MSE. The myoclonus in LAS usually subsides with rest or with relaxation. The severity of the myoclonus is very much related to the precision of the movement[2] and it gets exaggerated with startle or emotional stress.[4]
Clinical Features[edit | edit source]
- Generalized, multifocal or focal myoclonus
- Intentional myoclonus sometimes presents with spontaneous myoclonus
- Limb involvement depends on the area of insult whether Cortical or subcortical
- Coma in the acute phase (can also be due to sedation), otherwise awake, alert and cognition relatively preserved
- Dysmetria, dysarthria and ataxia
Neurophysiological Findings[edit | edit source]
EEG Findings[5]
- One of the three case of LAS presents with epileptiform activity
- Spike or poly spike-wave discharges maximally or primarily at the vertex
- EEG was found to be normal in between the myoclonic jerks in some cases
SSEPs[5]
- Giant and normal-sized somatosensory evoked potentials (Freund et al., 2016)
EEG-EMG Polygraphy[5]
- Demonstrated Jerk-locking noted in 60% of the cases (Freund et al., 2016)
Medical Management[edit | edit source]
It is very essential to distinguish LAS from MSE so that the right prognosis can be provided, and early management benefits the patient
Physiotherapy Management[edit | edit source]
References[edit | edit source]
- ↑ Wijdicks EFM, Hijdra A, Young GB, Bassetti CL, Wiebe S, Quality Standards Subcommittee of the American Academy of Neurology. Practice parameter: prediction of outcome in comatose survivors after cardiopulmonary resuscitation (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 2006 Jul 25;67(2):203–10 https://pubmed.ncbi.nlm.nih.gov/16864809/
- ↑ 2.0 2.1 Yadavmali T, Lane A. The Lance-Adams Syndrome: Helpful or Just Hopeful, after Cardiopulmonary Arrest. J Intensive Care Soc. 2011 Oct 1;12:324–8 https://www.researchgate.net/publication/285909789_The_Lance-Adams_Syndrome_Helpful_or_Just_Hopeful_after_Cardiopulmonary_Arrest
- ↑ Stevens RD, Sutter R. Prognosis in severe brain injury. Crit Care Med. 2013 Apr;41(4):1104–23 https://pubmed.ncbi.nlm.nih.gov/23528755/
- ↑ The syndrome of intention or action myoclonus as a sequel to hypoxic encephalopathy - PubMed [Internet]. [cited 2023 Jun 4]. Available from: https://pubmed.ncbi.nlm.nih.gov/13928398/
- ↑ 5.0 5.1 5.2 Freund B, Kaplan PW. Post-hypoxic myoclonus: Differentiating benign and malignant etiologies in diagnosis and prognosis. Clin Neurophysiol Pract. 2017 Jan 1;2:98–102.https://www.sciencedirect.com/science/article/pii/S2467981X17300100#b0055
