1873: Berkart says asthma is merely a symptom

Dr. J.B. Berkart was Asistant-Physician to the Victoria Park Hospital for Diseases of the Chest.  So he was well acquainted with asthma.  Unlike his predecessor, Dr. Henry Hyde Salter, Berkart opposed the nervous and spasmotic theories of asthma.

Berkart understood that, as Dr. C.B. Williams proved in 1840, that the muscles surrounding the air passages could contract or spasm.  However, he believed that Paul Bert, who published the results of his own studies on the contractility of the lungs in 1870, proved that the lungs do not contract during an asthma attack.

Of Bert, Berkart wrote:

"In many of his experiments he failed to demonstrate the contractility of the lungs, but at last he succeeded in doing so; and he found, as the reason of his failure, that he "insufflated the lungs too much", which circumstance impedes their contraction.  But if Paul Bert has thus proven the contractility of the bronchial muscles, he has at the same time conclusively shown the impossibility that asthma can be due to a spasmodic stricture of the bronchial tubes in those cases in which it forms an integral part of the disease, namely, in emphysema. For that same cause which hinders the success of the physiological experiments fully exists under those pathological conditions. (1, page 537)

Berkart believed that Henry Hyde's theory that asthma is nervous simply because asthma leaves behind no physical signs was poppycock. (2, page 49-50) Of this, Berkart said:

For the absence of physical signs is no safe indicator of the absence also of pathological conditions, and all the positive evidence derived from experimental physiology only goes to show that the "bronchial muscles may contract"; but as to "how" and as to "when" nothing is known. (1, page 537)

Berkart likewise explained:

I  am prepared to show that, were even the entire nervous system bent upon producing a spasmotic contraction of the bronchial muscles, it would fail in its attempts, because they are in cases of asthma in such a state of nutrition as to be utterly incapable of contracting at all." (1, page 537)

Instead, asthma being the result of a neurosis that causes spasms of the air passages, Berkart postulated that asthma was merely a symptom that accompanies other diseases: (1, page 537)(2, page 110)

1. Emphysema
2. Bronchitis
3. Other pulmonary affections 
4. Cardiac affections (1, page 537)(2, page 110

Furthermore, he said asthma is most often secondary to emphysema and bronchitis, and "the rare cases in which these are supposed to be absent could only constitute an exception to the rule.  The exception, however, does by no means invalidate the rule." (1, page 438)

The proof that the exception "does by no means invalidate the rule," was proved, according to Berkart, by the experiments of Walshe.  Of this, Berkart wrote: 

So well has this fact been recognised by all clinical observers, that they more or less explicitly mention "an acute relaxation" (Walshe*, Diseases of the Lungs, 1871, page 209) of the bronchial walls in cases of acute bronchitis.  Therefore, what holds good in the acute, still more forcibly applies to the chronic affection.  Here indeed, are the bronchial muscles so completely soaked with serum, that, were this the sole change they undergo, it alone would surfice to render contraction of the muscles a matter of impossibility.  But very often the first outbreak  of an asthmatic attack is preceded by pathological changes of greater moment than bronchitis -- namely, by catarrhal pneumonia, the anatomical basis of whooping-cough, measles, etc; and that disease inflicts such injuries upon the bronchial walls, that their contraction is irrevocably lost." (1, page 538)

He therefore argued that there was no point in debating what causes the attack, as such debates were frivolous.  He said:

Gentlemen, we shall never arrive at the true nature of bronchial asthma if we continue to confine our attention to an attack itself, to its immediate causes, and to its peculiar type of respiration. In asthma, as well as in any other disease, the history of the case and its sequele will have to be carefully considered ; and then we shall find that, indeed, asthma is no independent disease, no dynamic affection of a nerve, but that it really forms a link in a chain of diseases, which commence with affections of the bronchi and terminate with emphysema, whilst asthma itself represents the stage intermediate between these two. (1, page 538)

As Salter was ultimately proved correct in his assertion that asthma was indeed a disease of bronchospasm, he was eventually proved wrong that asthma was a neurosis.  To the contrary, Berkart was ultimately proved wrong in his assertion that asthma was not a disease of bronchospasm, and was eventually proved correct that asthma was not a neurosis.

Berkart believed that asthma starts as a chronic catarrh, often in childhood, and over time develops into emphysema.  Since emphysema is rarely found in children, it usually gradually develops unnoticed into adulthood.

He said that even as the lungs become increasingly diseased, breathing is generally easy. "But when an obstacle arises," he said, "which for its removal requires a greater force than that of ordinary respiration, then the inability to effect the removal shows the deficient nutrition of the organ. It is this stage of developing emphysema-this stage of deficient elasticity of the lungs-which constitutes the anatomical basis of bronchial asthma." (1, page 538)

He thus explains asthma this way:

In typical bronchial asthma, the lungs are greatly distended, the thorax is in a position of extreme inspiration, and all the respiratory muscles are firmly contracted. Inspiration is short and abrupt, and the effort of the respiratory muscles, although prolonged and greatly increased, remains ineffectual. If an obstacle arise to the entrance and exit of air from the lungs, say the impaction of a tough pellet of mucus in a bronchus, a supplementary force is necessary in order to displace the obstacle and to effectually carry on the respiratory function. Such additional aid to expiration is obtained by deep inspiration; and this is easily effected, because it proceeds from the action of the inspiratory muscles, to which the lungs deficient in elasticity cannot offer any great resistance. Hence the easy and rapid overdistension of the lungs. (1, page 538)

As far as what triggers an asthma attack, Berkart noted both internal and extarnal "exciting causes," all of which "produce an obstacle to the interchange of gases, against which the deficient expiratory forces will for a long time labour in vain." (1, page 538-539)

These exciting causes were: (1, page 538-539)

1. Tough and fibrinous sputa: The thicker it is, the harder the lungs have to work to expectorate it
2. Inhalation of foreign bodies: Epecacuanha, pollen, etc. 
3. Heat from ambient air:  It causes sputum to become crusty, forcing lungs to work extra hard
4. Excitement, laughter: Sputum is displaced from one part of lung into another, diminishing the surface of respiration
5. Edema (fluid) in lungs:  Occurs when kidney's become diseased
6. Thrombosis and embolism (blood clot): Causes asthma symptoms (1, page 538-539)

In conclusion, Berkart wrote:

I may, therefore, in conclusion, state that asthma is a symptom which accompanies diseases of the lungs in which deficient elasticity is the prominent feature, and in consequences in which the existing expiratory forces are only able to overcome an obstacle to respiration after prolonged and increased efforts." (1, page 539)

Berkart, therefore, believed that asthma was not a disease entity of it's own, but rather was a symptom of, in most cases, bronchitis and emphysema. Therefore, despite physicians not being able to find physical signs that asthma exists, these signs do exist.  Berkart said:

A patient may daily expectorate several spittoonfuls of mucus, and yet the most practised and most careful observer may fail to detect, by means of percussion and auscultation, the least trace of disease. The reason is that the mucus forms and stagnates in a bronchus or bronchi, situated at some distance from the surface of the chest, in which position the adventitious sounds are, as the bronchial respiration is normally, obscured by the intervening healthy tissue of the lungs  (2, page 51-52)

Salter originally published his ideas in various articles throughout the 1950s, and later in the 1969 book: "On Asthma: It's Pathology and Treatment."  Berkart also published his ideas in various articles, and in 1978 published the book: "On Asthma: Its Pathology and Treatment."  While both authors used the same title for their respective books, the theories postulated were opposites.

Both Salter and Berkart are important to our asthma history in that they were both responsible for garnishing attention to our disease.  However, while their opinions were well established regarding the cause of asthma, the debate was ongoing.

*Walter Hayle Walshe (1812-1892)

References:

1. Berkart, J.B., "On the Nature of the so-called bronchial asthma," British Medical Journal, November 8, 1873, 2 (671), pages 537-539
2. Berkart, J.B., "On Asthma: It's pathology and treatment," 1878, London

RT Cave Facebook Page

RT Cave on Twitter

1873: Lebert creates new asthma theory

Herman Lebert (1813-1878)

In 1873, Herman Lebert came up with an interesting theory about asthma that lasted for several decades, and into the 19th century.  

Lebert was born in Germany, and later became professor of pathology in Paris and Zurich.  As a pathologist he spent hours in a lab investigating tissues under the microscope.  

Steven I. Hajdu, in a 2004 article in Annals of Clinical Laboratory Science, said Lebert was one of the first clinical pathologists who often goes unrecognized by pathologists, when he should be a household name to them.  (1)

Hajdu said he sliced"fresh tissues with a razor-like knife and prepared cell samples (smears) by scraping, washing, or by squeezing the tissue slices. Samples from fluids were placed on glass slides without preservatives. Most microscopic preparations were unstained, but occasionally a drop of iodine was applied as a stain." (1)

It was by this approach that he learned about cancerous tumors.  Hajdu said:

In his text on cancer (1851), Lebert gave concise summaries and organ specific descriptions of all forms of tumors. The book consists of 885 pages and discusses the dietary, surgical, and medical treatment of cancer. In 1857, Lebert published a comprehensive pathology text in two volumes that covered everything that was known at that time about anatomic pathology, as well as discussions on clinical pathology. (1)

Hajdu said it was Lebert's work, along with fellow pathologist Julius Vogel (1814-1880) who developed the "concepts of cellular pathology.  Vogel and Lebert established the solid basis on which Rudolph Virchow, in the 1860s, built his general theory about cells."  (1)

Despite his accomplishments, Hajdu said, Lebert (and Vogel too) does not get the credit he deserves, at least as far as pathologists are concerned.  This is yet another example of how history is not always written fairly.

Along with his other accomplishments, Lebert also did research on lungs and vessels, and he used this to establish opinions about asthma.

In 1873, he supported both the spasmotic theory of asthma and the diaphragmatic theory of asthma. However, he  believed asthma was caused by dilation of the blood vessels in the lungs. (2, page 45)

In fact, this theory was still believed to be true when epinephrine was later invented in 1900, as the vasoconstricting (vasopressor) component of epinephrine was thought to increase blood flow to the lungs to make breathing easier. (3, page 38)

Lebert also offered an interesting remedy for asthma. Rene Laennec, among other asthma experts of the 19th century, observed asthmatics often developed asthma at night, or in the dark.  Based on this observation, "Lebert advised the use of as many candles as possible in the rooms of asthmatics," said Orville Brown in 1917.(3, page 38)

References: 

1. Hajdu, Steven I, "The first cellular pathologists," Annals of Clinical Laboratory Science, 2004, http://www.annclinlabsci.org/content/34/4/481.full, accessed 3/11/14
2. Berkart, J.B., "On Asthma: It's pathology and treatment," 1878, London, J. & A. Churchill
3. Brown, Orville Harry, "Asthma, presenting an exposition of nonpassive expiration theory," 1917, St. Louis, C.V. Mosby Company

RT Cave Facebook Page
RT Cave on Twitter

1860: Salter disproves ancient asthma theories

Dr. Henry Hyde Salter was among the first physicians to believe that diseases ought to be defined based on personal experiences with the diseases, observing patients, and studying autopsies, as opposed to speculation.  Later physicians said it was this technique that made him the most famous asthma doctor of his era.  

In the opening chapter of his 1960 book "Asthma: Its Pathology and Treatment" he put to rest any theories about asthma that didn't support modern evidence. While he shunned the humoral ideas of ancient writers, he also shunned the bronchitic theories of the famous Dr. Robert Bree  who's believed asthma was caused by some peccant matter entering the lungs

Salter said that Bree was so convincing, and had obtained such a large following, that he had to dedicate almost an entire chapter to disproving his theories.

However, in the end, Dr. Salter said Dr. Bree's theory was disproved simply by the invention of the stethoscope.  He said if Bree had access to a stethoscope he would have easily heard the wheezes caused by narrowed air passages due to neurosis, and would have heard that the wheezes persist even after mucus is expectorated, as opposed to before.

One of the reasons Dr. Bree's ideas were so well accepted was because they were more in line with the Hippocratic doctrine, which was still well accepted by many prominent physicians when Bree first wrote his 1798 book "A Practical Inquiry into Disordered Respiration."

Since Hippocrates, many asthma experts believed asthma was caused by an imbalance of the four humors. Salter doesn't deny...

..."that in some cases the exciting cause of the attack is humoral; but what I would deny is, that the humoral derangement has any higher place than that of an exciting cause; and what I would insist upon is, that the heart and core of the disease is nervous; that the essential peculiarity of the asthmatic is a vice in his nervous system, a peculiar morbid irritability of it, whereby a certain portion of it is thrown into a state of excitement from the application of stimuli which another person would produce no effect at all, or a very different effect." (1, page 25)

Salter disproved the idea that congestion, or phlegm, or mucus, was the cause of asthma, because the attack usually ends with the expectoration of phlegm. He wrote:

"We admit the fact to be true, but doubt very much the correctness of the inference; at least it is certain that, in ordinary bronchitis, enormously greater accumulations of mucus take place with comparatively few signs of general obstruction. We think this position must be admitted by any unbiased observer; and it is, in our opinion, fatal to this theory. (1, page 25)

Given the tools available to Salter, wasn't hard for him to disprove old asthma theories in favor of science. He went on to prove that asthma was nervous and spasmotic, and was so convincing that his ideas were referenced by nearly every author on asthma for the next 50 plus years.

References:

1. Salter, Henry Hyde, "Asthma: It's Pathology and Treatment," 1864, Philadelphia, Blanchard and Lea

RT Cave Facebook Page
RT Cave on Twitter