Friday, February 03, 2012

1800-1900: Spasmotic and nervous theories win the day

Jean Antoine Villemin became famous as the person to prove that tuberculosis was contagious after rabbits he injected with tuberculosis from humans contracted the disease.

In 1860 Jean Antoine Villemin tried to disprove the nervous theory with his own scientific experiments, yet once again the nervous theories were so popular Villemin's common sense approach was ignored.

Villemin actually came up with a theory in a circuitous way describing what we now call air trapping.

Deprived of "nutrition," Berkman wrote in describing Villemin's theory, "the air vesicles (alveoli) became impaired, they were unable to efficiently perform expiration.  At the same time respiratory surface was reduced, and the blood accumulated in the bronchi (inflammation) to such an extent as to convert their mucous membrane into a kind of erectile tissue.

"This condition gave rise to no symptoms," Berkart continued, "either subjective or objective."  The only time symptoms occurred

Villeman's theory here might be a little off, yet our time traveler would benefit history if he could somehow convince Villemin not to give up trying to convince other experts that they were wrong and he was sort of on the right track.  Your time traveler's attempts might prevent the 130 year delay.

So this is how it went throughout most of the 19th century.  Is asthma caused by the vagus?  Is it spasmotic?  Is it a result of spasms of the diaphragm?  Is it a result of paralysis of the air passages?  Is asthma both spasmotic and emphysema?

The debate was pretty much ended when Henry Hyde Salter entered the picture.  Salter would become the pre-eminent asthma expert of the second half of the 19th century.  In fact, he was so famous he was even consulted to be the asthma doctor for a boy who would one day become President of the United States (I'll write about that in the coming weeks).

Salter published the original version of "On Asthma:  It's Pathology and Treatment," in 1864 (Salter's book was published prior to Berkarts).  Based on his own experience with asthma, and observations of his own patients, he accurately described the asthma patient during an asthma attack.

He wrote that he saw enough evidence to believe in the spasmotic theory of asthma, yet he also believed that bronchospasms were caused by nervous stimulation.  He also believed asthma was an inflammatory disease and wrote about asthma as a hereditary disorder.

Salter believed some exciting factor (like dust or sterss) was recognized by the abdulla oblongotta, and a signal was sent via the pneumogastric nerve to the bronchiole fibres that wrap around the lungs signalling them to constrict.  In this way asthma was a nervous condition.

Salter offered the following examples as proof asthma was started in the brain:
  • Many patients feel fine as soon as they enter the doctor's office
  • Mental emotion can bring on a paroxysm of asthma
  • Mental emotion can resolve a paroxysm of asthma
  • Remedies that relax the nervous system resolve asthma, such as tobacco, antispasmodics, and sedatives, nervous depressants. Examples include tobacco, alcohol, morphine, and especially chloroform.
Berkart noted that in 1843 George Hirsh said he (Hirsh) didn't understand how asthma could affect so many boys if it were a nervous disorder. Salter better described this in his book, stating that asthma is a disease that causes the boy to yearn for his mother. It's this yearning that results in an asthma attack.

Thus, it's for this reason Salter justifies using remedies to calm the mind such as smoking cigarettes, alcoholic drinks, formaldehyde, and sedatives. (to see more Salter remedies click here).  Salter didn't deny the convulsive theory of asthma, yet his main focus was on the nervous theory because he believed the mind caused the convulsions or spasms in the lungs.

Pepper and Star explained that by the time the third edition of their book "A System of Practical Medicine" was published in 1885, Williams and Longet's bronchospasm theory of asthma was readily accepted. They wrote that "most modern pathologists have arrived at the conclusion that bronchial asthma is a spasmotic contraction of the middle and finer bronchi dependent on some derangement in the function of the pneumogastric nerve."

Likewise, Whitaker added that "whatever doubt still hung about the contraction of the bronchial tubes themselves would seem to have finally been dissipated by Lazarus (1891), who devised an ingenious apparatus wherewith he could, with the aid of curare and tracheotomy, experiment on animals in life, and whereby he produced the characteristic dyspnea of the disease by irritation of the vagus nerve."

Brenner (page 9) noted that sometime around 1900 Willem Einthoven (the inventor of the EKG) evaluated the bronchospasm theory of asthma and spasming diaphragm theory of asthma and proved the bronchospasm theory.

So based on experiments and personal observation, and with the appraisal of highly rated doctor's like Henry Hyde Salter, the bronchospasm and nervous theory of asthma won the day.  The nervous theory remained popular until it was disproved in the 1950s.  However, it really wasn't until the 1980s that the theory was laid to rest.

The bronchospasm theory of asthma lives on.

Click here for more asthma history.

References:
  1. Pepper, William,  Louis Star, "A System of Practical Medicine," Volume 3, page 184
  2. Berkart, J.B., "On Asthma: It's pathology and treatment," 1878, London,  Chapter II, "History of Asthma," page 12
  3. Bree, Robert, "A Practical Inquiry into Disordered Respiration, distinguishing the Species of Convulsive Asthma, their Causes, and Indications of Cure, London, 1810.  I could not find the 1790 edition online, yet this one serves our purpose.
  4. Schmiegelow, Ernest, "Asthma, considered specially in relation to nasal disease," 1890, London, page 4 
  5. Jackson, Mark, "Asthma: The biography," 2009, London, pages 86-88 (If you're interested in a good asthma history book, this is it.)
  6.  Bryan, Jenny, "Asthma," 2008, page 8
  7. Floyer, John, ed., "The Cyclopaedia of practical medicine," 1833, volume 1, page 186
  8. Whitaker, James Thomas, "The theory and practice of medicine," 1893
  9. Brenner, Barry E, ed, "Emergency Asthma" 1998, page 7 (chapter one is a history of asthma written by Brenner)
  10. Berkart, J.B.,"On Asthma:  It's Pathology and Treatment, 18xx, volume I, page 23 (Berkart started his book with a good history of asthma up to his time.  I base much of this post on his thorough asthma history.)
  11. Pepper, op cit, page 194
  12. Berkart, op cit, page 27
  13. Daintith, John, "Biographical encyclopedia of scientists."
Other readings:

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