This section is from the book "The Home Hand-Book of Domestic Hygiene and Rational Medicine. Volume 2.", by J. H. Kellogg, M.D.. Also available from Amazon: The Home Hand-Book of Domestic Hygiene and Rational Medicine, Volume 2.
The causes of chronic bronchitis are essentially the same as those of the acute variety. In fact, it is most commonly produced by the frequent occurrence of acute bronchial catarrh. It is always associated with an inactive condition of the liver and with more or less impairment of the digestion. When it continues a long time there is usually more or less debility. In consequence of the obstruction, the small bronchial tubes become greatly dilated. This affection is known as emphysema. When it is present, the patient suffers much from labored breathing, the chest is generally enlarged, and the space between the ribs is abnormally depressed.
Chronic bronchitis is seldom a direct cause of death, but may lead to a fatal result by producing other diseases. It is often mistaken by unskillful persons for consumption, a much more grave disease; but a careful examination will show the absence of the symptoms characteristic of the latter disease.