A classic symptom such as heartburn is easy to notice. But ‘silent’ reflux can progress into chronic cough or asthma and not be properly diagnosed.
http://www.latimes.com/health/la-he-0914-reflux-20130914,0,6608458.story
http://www.latimes.com/health/la-he-0914-reflux-20130914,0,6608458.story