Friday, July 8, 2016

1819: Laennec accurately groups emphysema and bronchitis

Laennec accurately described emphysema (13)
Dr. Rene Laennec was known as the father of chest medicine, and this is mainly due to the fact he was the first to have the tools necessary to compare what he learned upon assessment of the chest during life, with what he saw when inspecting the lungs during autopsy after life.

The tools he had access to were chest percussion and the monaural stethoscope he invented. He used these to perform complete assessments of the chest on any of his patients who complained of asthma or asthma-like symptoms, such as dyspnea, chest tightness, chest pain, increased phlegm, and coughing. By doing this he became the first physician to accurately distinguish asthma from chronic bronchitis and emphysema.

That said, here is how he described bronchitis and emphysema.

Bronchitis:  He defined it as "Chronic Mucous Catarrh."

He said bronchitic airways are sometimes present with a "general or partial dilation of the bronchi.  Pulmonary vessels are often congested, and this can often be diagnosed by sputum that is tinged with blood. In fact, while the amount expectorated varies from day to day, colorful sputum is almost always produced. However, when the person becomes weak, expectoration may become difficult. (2, page 81)

He said bronchitis usually occurs in the aging, and usually after a severe acute attack, and as it worsens often produces dyspnea.  (2, page 83)

He said if it does occur in the young, however, it usually disappears in a year or two.  However, the only time it disappears in the aging is during the summer months, only to return during the winter months. In such cases it usually returns with a fever and copious expectoration.  After a few times of this happening... (2, page 83) terminates in a continual mucous catarrh... the great expectoration of which weakens and emaciates the patient." (2, page 83)
Since he had access to his stethoscope, he would use it to help him diagnose chronic mucous catarrh.  He would generally hear "mucous rhonchus, sometimes indeed pretty loud and abundant, but very rarely continuous, and still rarely general over the chest." (2, page 83-84)

Laennec said emphysema has been described by some previous authors -- Bonetus, Morgagni, and Floyer,  who observed emphysema in a "broken winded mare" --although "none of these various authors appear to have been acquainted with the real character of the affection, viz -- dilation of the bronchial cells." (2, pages 161,165)

So he said it had never been accurately described. There were two exceptions to this, and these include Ruysh and Valsalva. (2, page 165)

Some might say that Dr. Ballie accurately described emphysema, but Laennec disagrees.  He said:
Dr. Baillie, author of the Morbid Anatomy, has correctly observed the three principal circumstances which constitute emphysema of the lungs, namely—the great size of these organs,—the dilatation of the cells,—and the vesicles formed by the extravasation of air under the pleura; but he does not appear to have been acquainted with the mutual dependence of these three states, and describes them as three different affections. (2, page 166)
In fact, he said that even he thought it was a rare disease until he started making use of the stethoscope.  Since then he said he has verified it in the living as well as the dead.  In fact, he became so adept at diagnosing it that he figured that many cases previously defined as asthma were actually emphysema.  (2, page 161, 163, 165)

He defined it simply as...
...dilation of the air cells... the cavity of these dilated cells descends some little way into the substance of the viscus, and there its walls do not collapse... the bronchial tubes, especially those of the small calibre, are sometimes very evidently dilated in those portions of the lung where the emphysema exists. (2, page 161-163)
He observed that while many of the cells were dilated, some were ruptured. Interestingly, Laennec said:
When we blow into an emphysematous lung, the dilated and projecting cells seem to become flatter the more they are distended, and fall down to the general level of the surface. This is owing to the greater relative extensibility and elasticity of the healthy cells, which in the first instance rise to the level of the dilated cells, and then fall below them, to their natural level. The continued projection of the dilated cells may be partly owing, also, to the difficulty with which the air escapes from them, more especially when the exciting cause of the emphysema is the dry catarrh. (2, page 163)
He also said:
On placing an emphysematous lung in a vessel of water, it sinks much less than a healthy lung; sometimes it floats on the surface with scarcely any obvious immersion."  (2, page 164) 
Laennec became the first to describe emphysema due to aging, and he was the first to define emphysema as tissue damage in the peripheral air passages. He further defined emphysema as a breakdown of tissue in the parynchema of the lungs as opposed to air trapped in the alveoli due to an obstruction such as occurs in asthma and bronchitis.

He said the disease could be diagnosed upon autopsy, although he further stated it could be diagnosed in life by using the stethoscope. He said:
The respiratory sound is inaudible over the greater parts of the chest, and is very feeble in the points where it is audible... from time to time, while exploring the respiration or cough, a slight sibilous rhonchus... by the displacement of the pearly sputa. (2, page 172)
He also noted other signs that emphysema should be diagnosed over asthma: (2, page 172)
  • Diminished lung sounds
  • The long continuance of the disorder (chronic)
  • The severity of the habitual (chronic) dyspnea
  • The asthmatic paroxysm occasionally occurring
  • The cylindrical form of the chest (barrel chest)
  • The slight lividity of the skin
  • Occasional dry crepitous rhonchus on inspiration or with cough (inspiratory crackles due to secretions)
  • Occasional crackle where the rhonchus is heard
  • When the complaint is of long standing and the patient far advanced in life, the paroxysms become more frequent and severe
M. Andral suggests that the dry crepitous rhonchus described by Laennec was the first description of crackles "at the moment of rupture of the air cells."  In modern medical language, this would be crackles on inspiration due to the alveolar cells popping open.  This may have been the first description of this commonly heard lungsound. (3, page 173)

Interestingly, Laennec offers the following about the prognosis of this disease.
Pulmonary emphysema.  is not a disease of great severity.  Of all the varieties of asthma it is unquestionably that which affords to the patient the best prospect of long life. The long continuance and slow progress of the disease and the nature of its causes, render it possible to struggle against the organic lesion, and permit the functional disorders resulting from it to be kept within tolerable bounds (3, page 174)
In this way, it was Laennec who became the first to distinguish chronic bronchitis and emphysema as separate entities from asthma.  He was the first to speculate that they ought to be extricated from the umbrella term asthma, to become disease entities of their own with their own treatments.

  1. Petty, Thomas L, "The History of COPD,"Int. J. Chron. Obstruct. Pulmon. Dis., 2006, March; 1(1): 3-14
  2. Laennec, Rene, "Mediate Auscultation," translated by John Forbes, Notes by professor Andral, 4th edition, 1838, New York, Samuel S. and William Wood
  3. Andras, author of the notes in the book, "Mediate Auscultation, by Rene Laennec," ibid
  4. Laennec, Rene, "A Treaties on the Diseases of the Chest and on Mediate Auscultation, " 1834, London (copius notes by John Forbes)
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