Alcoholism and traumatic subarachnoid hemorrhage: an experimental study on vascular morphology and biomechanics

Altered Mental Status: Current Evidence-based Recommendations for Prehospital Care

Introduction

In the United States emergency medical services (EMS) protocols vary widely across jurisdictions. We sought to develop evidence-based recommendations for the prehospital evaluation and treatment of a patient with an acute change in mental status and to compare these recommendations against the current protocols used by the 33 EMS agencies in the State of California.

Methods

We performed a literature review of the current evidence in the prehospital treatment of a patient with altered mental status (AMS) and augmented this review with guidelines from various national and international societies to create our evidence-based recommendations. We then compared the AMS protocols of each of the 33 EMS agencies for consistency with these recommendations. The specific protocol components that we analyzed were patient assessment, point-of-care tests, supplemental oxygen, use of standardized scoring, evaluating for causes of AMS, blood glucose evaluation, toxicological treatment, and pediatric evaluation and management.

Results

Protocols across 33 EMS agencies in California varied widely. All protocols call for a blood glucose check, 21 (64%) suggest treating adults at <60mg/dL, and half allow for the use of dextrose 10%. All the protocols recommend naloxone for signs of opioid overdose, but only 13 (39%) give specific parameters. Half the agencies (52%) recommend considering other toxicological causes of AMS, often by using the mnemonic AEIOU TIPS. Eight (24%) recommend a 12-lead electrocardiogram; others simply suggest cardiac monitoring. Fourteen (42%) advise supplemental oxygen as needed; only seven (21%) give specific parameters. In terms of considering various etiologies of AMS, 25 (76%) give instructions to consider trauma, 20 (61%) to consider stroke, and 18 (55%) to consider seizure. Twenty-three (70%) of the agencies have separate pediatric AMS protocols; others include pediatric considerations within the adult protocol.

Conclusion

Protocols for patients with AMS vary widely across the State of California. The evidence-based recommendations that we present for the prehospital diagnosis and treatment of this condition may be useful for EMS medical directors tasked with creating and revising these protocols.

Severe diffuse axon injury in chronic alcoholic rat medulla oblongata following a concussion blow

AIMS

We investigated the axonal morphological changes and expression of both tau protein and β-APP following concussion to the medulla oblongata, in a rat model of chronic alcoholism.

METHODS

Fifty-nine male Sprague-Dawley rats were randomly divided into EtOH, EtOH-TBI and control groups (water group, water-TBI group). To establish chronic alcoholic rats, rats were intragastrically given edible spirituous liquor twice daily. Rats also received a blow on the occipital tuberosity with an iron pendulum. Morphological changes and expression of tau and β-APP proteins in the medulla oblongata were examined.

RESULTS

(a) Nerve fibre thickening and twisting were observed in alcoholic rats, with nerve fibre changes becoming more significant following a concussion blow, which leads to some nerve fibres fracturing. (b) Transmission electron microscopy revealed that the nerve fibre myelin became loosened and displayed lamellar separation, which became more significant following concussion. (c) The integral optical density (IOD) sum value of β-APP of the EtOH-TBI group was lower than that in the EtOH group (P < 0.05); the Tau IOD sum value of the EtOH-TBI group was higher than that in the EtOH group (P < 0.05).

CONCLUSION

(a) Chronic alcoholism caused nerve fibre and neuronal morphology damage in the rat medulla oblongata, with structural damage becoming more significant following concussion. (b) Concussion changed the expression of β-APP and tau protein in chronic alcoholic rat medulla oblongata, suggesting that chronic alcoholism can lead to severe axonal injury following a concussion blow. (c) The effect of chronic alcoholism may be synergistic the concussion blow to promote animal injury and death.

Comprehensive assessment of isolated traumatic subarachnoid hemorrhage

Recent studies have shown that isolated traumatic subarachnoid hemorrhage (tSAH) in the setting of a high Glasgow Coma Scale (GCS) score (13-15) is a relatively less severe finding not likely to require operative neurosurgical intervention. This study sought to provide a more comprehensive assessment of isolated tSAH among patients with any GCS score, and to expand the analysis to examine the potential need for aggressive medical, endovascular, or open surgical interventions in these patients. By undertaking a retrospective review of all patients admitted to our trauma center from 2003-2012, we identified 661 patients with isolated tSAH. Only four patients (0.61%) underwent any sort of aggressive neurosurgical, medical, or endovascular intervention, regardless of GCS score. Most tSAH patients without additional systemic injury were discharged home (68%), including 53% of patients with a GCS score of 3-8. However, older patients were more likely to be discharged to a rehabilitation facility (p<0.01). There were six (1.7%) in-hospital deaths, and five patients of these patients were older than 80 years old. We conclude that isolated tSAH, regardless of admission GCS score, is a less severe intracranial injury that is highly unlikely to require aggressive operative, medical, or endovascular intervention, and is unlikely to be associated with major neurologic morbidity or mortality, except perhaps in elderly patients. Based upon our findings, we argue that impaired consciousness in the setting of isolated tSAH should strongly compel a consideration of non-traumatic factors in the etiology of the altered neurological status.

Effect of alcohol on diffuse axonal injury in rat brainstem: diffusion tensor imaging and aquaporin-4 expression study

The aim of this study is to assess the effects of alcohol on traumatic brain injury by using diffusion tensor imaging (DTI) and evaluate aquaporin-4(AQP4) expression changes in rat brainstems following acute alcohol intoxication with diffuse axonal injury (DAI). We further investigated the correlation between the AQP4 expression and DTI in the brain edema. Eighty-five rats were imaged before and after injury at various stages. DTI was used to measure brainstem apparent diffusion coefficient (ADC) and fractional anisotropy (FA), with immunostaining being used to determine AQP4 expression. After acute alcoholism with DAI, ADC values of the brainstem first decreased within 6 h and then elevated. FA values began to decline by 1 h, reaching a minimum at 24 h after trauma. There was a negative correlation between ADC values and brainstem AQP4 expression at 6 h and positive correlation at 6 h to 24 h. Changes of ADC and FA values in DAI with acute alcoholism indicate the effects of ethanol on brain edema and the severity of axonal injury. The correlations between ADC values and the brainstem AQP4 expression at different time points suggest that AQP4 expression follows an adaptative profile to the severity of brain edema.

Chronic alcoholism-mediated impairment in the medulla oblongata: a mechanism of alcohol-related mortality in traumatic brain injury?

Alcohol-related traumatic brain injury (TBI) is a common condition in medical and forensic practice, and results in high prehospital mortality. We investigated the mechanism of chronic alcoholism-related mortality by examining the effects of alcohol on the synapses of the medulla oblongata in a rat model of TBI. Seventy adult male Sprague-Dawley rats were randomly assigned to either ethanol (EtOH) group, EtOH-TBI group, or control groups (water group, water-TBI group). To establish chronic alcoholism model, rats in the EtOH group were given EtOH twice daily (4 g/kg for 2 weeks and 6 g/kg for another 2 weeks). The rats also received a minor strike on the occipital tuberosity with an iron pendulum. Histopathologic and ultrastructure changes and the numerical density of the synapses in the medulla oblongata were examined. Expression of postsynaptic density-95 (PSD-95) in the medulla oblongata was measured by ELISA. Compared with rats in the control group, rats in the chronic alcoholism group showed: (1) minor axonal degeneration; (2) a significant decrease in the numerical density of synapses (p < 0.01); and (3) compensatory increase in PSD-95 expression (p < 0.01). Rats in the EtOH-TBI group showed: (1) high mortality (50%, p < 0.01); (2) inhibited respiration before death; (3) severe axonal injury; and (4) decrease in PSD-95 expression (p < 0.05). Chronic alcoholism induces significant synapse loss and axonal impairment in the medulla oblongata and renders the brain more susceptible to TBI. The combined effects of chronic alcoholism and TBI induce significant synapse and axon impairment and result in high mortality.

Posterior reversible encephalopathy syndrome in liver transplant patients: clinical presentation, risk factors and initial management

Posterior reversible encephalopathy syndrome (PRES) is an uncommon but well-known complication after transplantation diagnosed by characteristic radiological features. As limited data on this complex syndrome exist we sought to better define the incidence, clinical presentation and risk factors for PRES in liver transplant (LTx) patients. We conducted a retrospective analysis of 1923 adult LTx recipients transplanted between 2000 and 2010. PRES was diagnosed radiologically in 19 patients (1%), with 84% of cases occurring within 3 months post-LTX. We compared this cohort of PRES patients to 316 other LTx recipients also requiring radiographic imaging within 3 months after LTx for neurological symptoms. Seizure was the most common clinical manifestation in the PRES group (88% vs. 16%, p< 0.001) and 31% had an intracranial hemorrhage. Those with hemorrhage on imaging were more likely to be coagulopathic. PRES patients were significantly more likely to have had alcoholic liver disease and infection/sepsis. These factors may be related to a common pathway of vascular dysregulation/damage that appears to characterize this complex syndrome. Intracranial bleeding and seizures may be the end result of these phenomena. The relationship of these associated factors to the hypothesized pathophysiology of PRES is discussed.