Tuesday, October 25, 2011

1621-1675:Willis narrows asthma definition

In the 19th century Dr. Samuel Gee (1839-1911) made a gallant effort to update the definition of asthma for physicians during his era.  He wrote fondly of Dr. Thomas Willis (1671-1675), giving him credit as "innovator of the doctrines of the ancients." (1)

Gee described, in 1899, that prior to the 17th century asthma was considered "any kind of panting, gasping, pursy breathing such as follows on running on exertion." (1)

Back then asthma was considered to be a disease caused by the spirits. Yet in 1678 Thomas described asthma as o"obstruction of bronchi by thick humors, swelling of their walls and obstruction from without." (2)
By these words Dr. Gee gave credit to Dr. Willis for the evolution of asthma as more than simply a disease of dyspnea and wheezing.  Other doctors may have helped to advance the definition (such as Dr. van Helmont), yet it was Dr. Willis who made asthma a unique illness in and of its own, such as Tuberculosis and Epilepsy are unique illnesses treated with unique remedies.

"Hence," Gee wrote, "Asthma and dyspnea were synonyms for most of the older physicians.  A few, such as Celsus (25 B.C.-50 A.D.), signified by asthma the highest degree of dyspnea, but this was all; asthma was never regarded as a special sort of dyspnea." (1)

For Gee, ancient definitions of asthma from Hippocrates to Galen to van Helmont were inaccurate until we get to Thomas Willis of the 17th century.  In Willis's book  "Rational Pharmaceutic," which was published the same year as his death in 1675,  Willis explained that all ancient and modern physicians up to his time acknowledged only one kind of asthma, and this was pneumatic asthma.

Gee explained that pneumatic asthma was described by Willis as when the lungs are "obstructed or not open enough."  Gee wrote that the ancients regarded all asthma as "pneumatic and dependent on bronchial obstruction." (1)

He said the ancient definition of asthma is of little value in modern times (for Gee modern times would be 1899).  Yet, "It is interesting to note that those most conservative of people, the illiterate, continue to use the word in the sense of Hippocrates and Galen." (1)

However, we must note that it was illegal for the Ancient Greeks and Romans to dissect human bodies, and even in the 17th century it was very risky to publish ideas that opposed the beliefs of the church or ruling parties (hence the publishing of Willis's works posthumously).  Plus societies tend to be stubborn to new ideas change.

We see this often as we follow the history of science, medicine, and asthma.  It's perhaps this stubborness of mankind that we can give credit for the slowness to which the term asthma was defined, and why it took until 1901 for good asthma medicine to be discovered.

Orville Harry Brown, in his 1917 book, explained that Willis attributed to the cause of asthma "as some humor in the blood. (5, page 27).

Ernst Shmiegelow, in his 1890 book, said Willis may have been one of the first to explore the idea of the diaphragm as being the cause of asthma, and therefore may also be the creator of the diaphragmatic theory of asthma.  (6, page 4)

Gee said Willis described three forms of asthma: (1, page 817)
  1. Pneumatic Asthma:  Dyspnea is a result of air passages in the lungs being obstructed or not open enough
  2. Convulsive Asthma:  The primary fault of dyspnea comes from the lungs themselves, "in the moving fibres or muscular coats of the air vessels or in the diaphragm and muscles of the chest or in the nerves of the lungs and chest or of the origin of those nerves in the brain."
  3. Mixed Asthma:  Both pneumatic and convulsive.
Gee said that in defining convulsive asthma, Willis pondered all the theories before his time and incorporated them into his newly defined convulsive asthma, which "was soon laid hold of.  The term 'asthma' came to be reserved for the exclusive denomination of that form of the disease which was believed to be spasmotic; and this is the sense in which the word is still used by most parsons even in our own day."  (1)

I must continue to remind my readers that nervous asthma was generally thought to be synonymous with spasmotic or convulsive asthma.  By this the medical community believed the the fit of asthma was caused by nervous pathways from the brain as a result of something exciting these nervous pathways.

Barry Brenner, in 1999, said Willis also made an "association between food, emotion, heredity, and asthma."    In fact, it was in 1672 that Willis described emotion as bringing about an asthma attack.  (3)

Way back in the 12th century Maimonides described asthma as a nocturnal disease when studying the disease in Saladin's son.   In the 17th century there were many references to asthma as a nocturnal disease, and this was once again mentioned by Willis who, according to T.J.H. Clark, "in his 1987 book Diurnal Rhythm of Asthma," "blamed the heat of the bed as the cause of nocturnal asthma and he advised leaving the bed and sleeping in a chair.  By contrast, Maimonides recommended celibacy." (4)

Even though he wasn't the first to write about asthma as being caused by the mind, Willis is given credit, perhaps due to his vast writings on the subject.  And while the nervous theory of asthma grew in popularity among the medial community during the 18th century, and grew roots in the 19th century, not all physicians supported it.

Perhaps one of his first opponents was Giovanni Batttista Morgagni (1682-1771). He disagreed with Willis that asthma was a nervous disorder, instead he believed that asthma was caused by "concretions (masses) in the bronchial tubes." He believed this because he found "extravasated serum in the vessicles of the lungs in most cases."  (5, page 27)

Albrecht von Haller (1708-1777) believed that "the normal act of expiration hindered the flow of blood through the lungs," and "demonstrated that the lungs contracted when concentrated acid was applied to it."  (5, page 27)

William Herberden (1710-1801) defined "convulsive asthma" the way angina pectoris was later defined: as chest pain or discomfort due to activity or stress. (5, page 27)

Varnier (name and lifespan unknown to me) believed "irritating fluids or fumes forced into the lungs cause contraction therof."  (5, page 27)

Varnier, however, was also among the first physicians to prove by his experiments that muscles that wrap around the bronchial tubes contract, and this is the cause for the symptoms of asthma.

So at the time Willis's theory was just one of many theories regarding the cause of asthma.  Still, it was his nervous theory of asthma that was grabbed by the medical community and grew roots in the minds of physicians.  These roots would grow so deep that even after his theory was disproved in the mid-20th century, it still held sway.

While many before him described asthma as nervous, Willis is often given credit for bringing the idea to the attention of the medical community.  He is given credit for the nervous theory of asthma.

Further reading:
  1. The evolution of the nervous theory of asthma (not yet written)
Click here for more asthma history.

References:
  1. Gee, Samuel, "Bronchitis, Pulmonary Emphysema, and Asthma,", Lancet, March 25, 1899, page 817
  2. Salvi, Sundeep S., "Is Asthma Really Due to a Polarized T Cell Response Toward a helper T-Cell Type 2 Phenotype," American Journal of Respiratory and Critical Care Medicine, Oct. 15, 2001, vol. 164, no. 8, pages 1343-6
  3. Brenner, Barry, "Emergency Medicine," 1999, New York, page 6 (Brenner wrote 
  4. Clark, T.J.H., "Diurnal Rhythm of Asthma," (American College of Chest Physicians), 1987,  page 1375
  5. Brown, Orville Harry, "Asthma, presenting an exposition of nonpassive expiration theory," 1917, St. Louis, C.V. Mosby Company
  6. Shmiegelow, Ernst, "Asthma, considered specially in relation to nasal disease," 1890, London, H.K. Lewis
  7. Garrison, Fielding Hudson, "An introduction to the history of medicine," 1921, 3rd edition, Philadelphia and London, W.B Saunders Company
  8. Ramadge, Francis Hopkins, "Asthma, its species and complications, or researches into pathology or disordered respiration; with remarks on the remedial treatment applicable to each variety; being a practical and theoretical review of this malady, considered in its simple form, and in connection with disease of the heart, catarrh, indigestion, etc." 1835, London,  Longman, Rees, Orme, Brown, Green, and Longman; Ramadge discusses Thomas Willis's views on asthma on pages 93-94.  He also mentions him various other times in his book. 

No comments:

Post a Comment