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Open Access Research

Effect of stroke location on the laryngeal cough reflex and pneumonia risk

W Robert Addington1*, Robert E Stephens2, John G Widdicombe3 and Kamel Rekab4

Author Affiliations

1 Brevard Rehabilitation Medicine, 200 Ocean Avenue, Suite 201; Melbourne Beach, Florida, 32951, USA

2 Chair, Department of Anatomy, Kansas City University of Medicine and Biosciences, 1750 Independence Avenue, Kansas City, Missouri, 64106, USA

3 Emeritus Professor, University of London, 116 Pepys Road, London SW20 8NY, UK

4 Chair, Department of Mathematics and Statistics, University of Missouri–Kansas City; Kansas City, Missouri, USA

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Cough 2005, 1:4  doi:10.1186/1745-9974-1-4

Published: 4 August 2005

Abstract

Background

The purpose of this study was to evaluate the risk of developing pneumonia in acute stroke patients comparing the early anatomical stroke location and laryngeal cough reflex (LCR) testing.

Methods

A prospective study of 818 consecutive acute stroke patients utilizing a reflex cough test (RCT), which assesses the neurological status of the LCR compared to magnetic resonance imaging or computerized tomography for stroke location and subsequent pneumonia outcome. Stroke diagnosis and stroke location were made by a neurologist and clinical radiologist, respectively; both were blinded to the RCT results.

Results

Brainstem (p-value < .007) and cerebral strokes (p-value < .005) correlated with the RCT results and pneumonia outcome. Of the 818 patients, 35 (4.3%) developed pneumonia. Of the 736 (90%) patients who had a normal RCT, 26 (3.5%) developed pneumonia, and of the 82 (10%) patients with an abnormal RCT, 9 (11%) developed pneumonia despite preventive interventions (p-value < .005). The RCT had no serious adverse events.

Conclusion

The RCT acted as a reflex hammer or percussor of the LCR and neurological airway protection and indicated pneumonia risk. Despite stroke location, patients may exhibit "brainstem shock," a global neurological condition involving a transient or permanent impairment of respiratory drive, reticular activating system or LCR. Recovery of these functions may indicate emergence from brainstem shock, and help predict morbidity and mortality outcome.

Keywords:
cough; reflex; laryngeal; stroke; pneumonia; brainstem shock