Oesophagitis
The mucosa lining the oesophagus produces mucous to aid movement of food to the stomach and to provide some protection to the surface layer (epithelium) of the oesophagus. However, acid refluxing can wash away some of the mucosal protection and come into contact with the lining itself. This is highly concentrated hydrochloric acid; strong enough to be able to dissolve metal, if you were to spill some on your hand it was cause significant scarring - which it can also do to the oesophagus.
We may feel the acid burning as heartburn (though 30% with persistent acid reflux report never having felt it).
Inflammation and scarring caused by the acid is called oesophagitis. Sometimes an endoscopist will classify the degree of oesophagitis observed using one of the following scales:
The Savary-Miller grading system is commonly used:
- Grade 1: single or multiple erosions on a single fold. Erosions may ooze fluids or just show redness.
- Grade 2: multiple erosions affecting multiple folds. Erosions may be joined together.
- Grade 3: multiple circumferential erosions.
- Grade 4: ulceration, narrowing or oesophageal shortening.
- Grade 5: Barrett's epithelium. Columnar metaplasia in the form of circular or non-circular (islands or tongues) and extensions.
The more recent and more objective Los Angeles grades A to D classification is also used.
- Grade A: one or more mucosal breaks no longer than 5 mm, none of which extends between the tops of the mucosal folds.
- Grade B: one or more mucosal breaks more than 5 mm long, none of which extends between the tops of two mucosal folds.
- Grade C: mucosal breaks that extend between the tops of two or more mucosal folds, but which involve <75% of the mucosal circumference
- Grade D: mucosal breaks which involve ≥75% of the mucosal circumference