The Potential Role of Steroid-Induced Cerebral Vasospasm in the Pathogenesis of Delayed Cerebral Injury in Bacterial Meningitis*:

Rhinorrhea and increased chloride secretion through the CFTR chloride channel-a systematic review

PURPOSE

Allergic and non-allergic rhinorrhea in the forms of acute or chronic rhinosinusitis can mean a watery nasal discharge that is disabling. Primary objective was to review the evidence supporting the hypothesis that rhinorrhea is due to increased chloride secretion through the CFTR chloride channel.

METHODS

The structure of the evidence review followed the EQUATOR Reporting Guidelines. Databases searched from inception to February 2022 included Pubmed, EMBASE and the Cochrane library using keywords "Rhinorrhea", "chloride", "chloride channel", "CFTR" and "randomized controlled trial". Quality assessment was according to the Oxford Centre for Evidence-based Medicine.

RESULTS

49 articles were included. They included randomized controlled trials out of which subsets of data with the outcome of rhinorrhea on 6038 participants were analysed and in vitro and animal studies. The review revealed that drugs, which activate CFTR are associated with rhinorrhea. Viruses, which cause rhinorrhea like rhinovirus were found to activate CFTR. The chloride concentration in nasal fluid showed an increase in patients with viral upper respiratory tract infection. Increased hydrostatic tissue pressure, which is an activator of CFTR was observed in allergic upper airway inflammation. In this condition exhaled breath condensate chlorine concentration was found to be significantly increased. Drugs, which can reduce CFTR function including steroids, anti-histamines, sympathomimetic and anticholinergic drugs reduced rhinorrhea in randomized controlled trials.

CONCLUSIONS

A model of CFTR activation-mediated rhinorrhea explains the effectiveness of anticholinergic, sympathomimetic, anti-histamine and steroid drugs in reducing rhinorrhea and opens up avenues for further improvement of treatment by already known specific CFTR inhibitors.

Delayed cerebral thrombosis complicating bacterial meningitis

BACKGROUND

Delayed cerebral thrombosis has been described as a potential cause of cerebrovascular complications in patients with bacterial meningitis. We report a case of delayed cerebral thrombosis in a 63-year-old woman admitted for pneumococcal meningitis. Initially, there was a good clinical evolution under treatment with steroids and antibiotics. On day 8 after admission, she was found with a decreased level of consciousness. Her neurological condition gradually worsened. Repeated brain imaging showed extensive ischemic lesions. Despite treatment with high-dose corticosteroids, the patient died.

METHODS

A literature search was conducted. Data on patient characteristics, diagnosis, treatment and outcome were collected.

RESULTS

To date, 28 cases with delayed cerebral thrombosis following bacterial meningitis have been reported. Streptococcus pneumoniae was the pathogen in 89% of cases. Clinical deterioration occurred in all patients, with a duration varying from 5 to 40 days between admission and deterioration. Most common symptom was altered consciousness (83%), followed by hemiparesis (52%). Brain imaging typically shows new infarctions (96%). Fifty-six percent of patients were treated with corticosteroids after deterioration. Outcome was poor with mortality rate of 46%.

CONCLUSION

Delayed cerebral thrombosis presents as a clinical deterioration, typically a sudden decline in consciousness, more than 5 days after meningitis onset. Brain imaging shows new widespread ischemic lesions. Diagnosis should be made carefully, based on clinical findings and brain imaging, after excluding endocarditis. The underlying etiology remains unknown. When delayed cerebral thrombosis is suspected, high-dose corticosteroids should be started empirically. The prognosis remains poor with high mortality rates.