Ongoing abdominal status myoclonus in postanoxic coma

The Spinal Cord Damage in a Rat Asphyxial Cardiac Arrest/Resuscitation Model

BACKGROUND

After cardiac arrest/resuscitation (CA/R), animals often had massive functional restrictions including spastic paralysis of hind legs, disturbed balance and reflex abnormalities. Patients who have survived CA also develop movement restrictions/disorders. A successful therapy requires detailed knowledge of the intrinsic damage pattern and the respective mechanisms. Beside neurodegenerations in the cerebellum and cortex, neuronal loss in the spinal cord could be a further origin of such movement artifacts.

METHODS

Thus, we aimed to evaluate the CA/R-induced degeneration pattern of the lumbar medulla spinalis by immunocytochemical expression of SMI 311 (marker of neuronal perikarya and dendrites), IBA1 (microglia marker), GFAP (marker of astroglia), calbindin D28k (marker of the cellular neuroprotective calcium-buffering system), MnSOD (neuroprotective antioxidant), the transcription factor PPARγ and the mitochondrial marker protein PDH after survival times of 7 and 21 days. The CA/R specimens were compared with those from sham-operated and completely naïve rats. RESULTS & CONCLUSION: The main ACA/R-mediated results were: (1) degeneration of lumbar spinal cord motor neurons, characterized by neuronal pyknotization and peri-neuronal tissue artifacts; (2) attendant activation of microglia in the short-term group; (3) attendant activation of astroglia in the long-term group; (4) degenerative pattern in the intermediate gray matter; (5) activation of the endogenous anti-oxidative defense systems calbindin D28k and MnSOD; (6) activation of the transcription factor PPARγ, especially in glial cells of the gray matter penumbra; and (7) activation of mitochondria. Moreover, marginal signs of anesthesia-induced cell stress were already evident in sham animals when compared with completely naïve spinal cords. A correlation between the NDS and the motor neuronal loss could not be verified. Thus, the NDS appears to be unsuitable as prognostic tool.

Post-hypoxic Myoclonus: Current Concepts, Neurophysiology, and Treatment

Background

Myoclonus may occur after hypoxia. In 1963, Lance and Adams described persistent myoclonus with other features after hypoxia. However, myoclonus occurring immediately after hypoxia may demonstrate different syndromic features from classic Lance–Adams syndrome (LAS). The aim of this review is to provide up-to-date information about the spectrum of myoclonus occurring after hypoxia with emphasis on neurophysiological features.

Methods

A literature search was performed on PubMed database from 1960 to 2015. The following search terms were used: “myoclonus,” “post anoxic myoclonus,” “post hypoxic myoclonus,” and “Lance Adams syndrome.” The articles describing clinical features, neurophysiology, management, and prognosis of post-hypoxic myoclonus cases were included for review.

Results

Several reports in the literature were separated clinically into “acute post-hypoxic myoclonus,” which occurred within hours of severe hypoxia, and “chronic post-hypoxic myoclonus,” which occurred with some recovery of mental status as the LAS. Acute post-hypoxic myoclonus was generalized in the setting of coma. Chronic post-hypoxic myoclonus presented as multifocal cortical action myoclonus that was significantly disabling. There was overlap of neurophysiological findings for these two syndromes but also different features. Treatment options for these two distinct clinical–neurophysiologic post-hypoxic myoclonus syndromes were approached differently.

Discussion

The review of clinical and neurophysiological findings suggests that myoclonus after hypoxia manifests in one or a combination of distinct syndromes: acute and/or chronic myoclonus. The mechanism of post-hypoxic myoclonus may arise either from cortical and/or subcortical structures. More research is needed to clarify mechanisms and treatment of post-hypoxic myoclonus.

Prognostic value of electrographic postanoxic status epilepticus in comatose cardiac-arrest survivors in the therapeutic hypothermia era

BACKGROUND

The independent prognostic significance of postanoxic status epilepticus (PSE) has not been evaluated prospectively since the introduction of therapeutic hypothermia. We studied 1-year functional outcomes and their determinants in comatose survivors of cardiac arrest (CA), with special attention to PSE.

METHODS

106 comatose CA survivors admitted to the intensive care unit in 2005-2010 were included in a prospective observational study. The main outcome measure was a Cerebral Performance Category scale (CPC) of 1 or 2 (favorable outcome) 1 year after CA.

RESULTS

CA occurred out-of-hospital in 89 (84%) patients and was witnessed from onset in 94 (89%). Median times were 6 min (IQR, 0-11) from CA to first-responder arrival and 23 min (14-40) from collapse to return of spontaneous circulation. PSE was diagnosed in 33 (31%) patients at a median of 39 h (4-49) after CA. PSE was refractory in 24 (22%) cases and malignant in 19 (20%). After 1 year, 31 (29.3%) patients had favorable outcomes including 2 (6.44%) with PSE. Factors independently associated with poor outcome (CPC ≥ 3) were PSE (odds ratio [OR], 14.28; 95% confidence interval [95% CI], 2.77-50.0; P=0.001), time to restoration of spontaneous circulation (OR, 1.04/min; 95% CI, 1-1.07; P=0.035), and LOD score on day 1 (OR, 1.28/point; 95% CI, 1.08-1.54; P=0.003).

CONCLUSION

PSE strongly and independently predicts a poor outcome in comatose CA survivors receiving therapeutic hypothermia, but some patients with PSE survive with good functional outcomes. PSE alone is not sufficient to predict failure to awaken after CA in the era of therapeutic hypothermia.