Toxic levels of ammonia in human brain abscess

Author:

Dahlberg Daniel1,Ivanovic Jugoslav1,Hassel Bjørnar23

Affiliation:

1. Departments of Neurosurgery and

2. Complex Neurology and Neurohabilitation, Oslo University Hospital, Oslo; and

3. Norwegian Defence Research Establishment (FFI), Kjeller, Norway

Abstract

OBJECT Brain abscesses could lead to cerebral symptoms through tissue destruction, edema, changes in brain architecture, and increased intracranial pressure. However, the possibility that the pus itself could contribute to symptoms has received little attention. Brain abscesses are areas of tissue destruction, proteolysis, and formation of free amino acids, which are energy substrates for bacteria and possible sources of ammonia. Ammonia is neurotoxic, may cause brain edema, and could contribute to the symptoms of brain abscesses. METHODS The authors analyzed the extracellular phase of pus from 14 patients with brain abscesses with respect to ammonia and amino acids. For comparison, CSF from 10 patients undergoing external ventricular drainage was included. The ammonia-forming ability of Streptococcus intermedius and Staphylococcus aureus, two common microbial isolates in brain abscesses, was studied in vitro. RESULTS In brain abscesses ammonia was 15.5 mmol/L (median value; range 1.7–69.2 mmol/L). In CSF ammonia was 29 μmol/L (range 17–55 μmol/L; difference from value in pus: p < 0.001). The total concentration of amino acids in brain abscesses was 1.12–16 times higher than the ammonia concentration (p = 0.011). The median glucose value in pus was 0 mmol/L (range 0–2.1 mmol/L), lactate was 21 mmol/L (range 3.3–26.5 mmol/L), and pH was 6.8 (range 6.2–7.3). In vitro, S. intermedius and S. aureus formed ammonia at 6–7 mmol/L in 24 hours when incubated with 20 proteinogenic amino acids plus g-aminobutyric acid (GABA), taurine, and glutathione at 1 mmol/L. CONCLUSIONS Intracerebral abscesses contain toxic levels of ammonia. At the concentrations found in pus, ammonia could contribute to the brain edema and the symptoms of brain abscesses.

Publisher

Journal of Neurosurgery Publishing Group (JNSPG)

Subject

Genetics,Animal Science and Zoology

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3