Tuesday, April 29, 2014

1878: Thorowgood supports Salter's asthma theories x

Dr. John Charles Thorowgood wrote a book called "Notes on Asthma" that went through a variety of editions.  Probably due to a wave of new evidence learned about the disease, the later editions were called "Asthma and Chronic Bronchitis, which sheds light for historians on the evidence clearly separating these two diseases.

Thorowgood's basic description of asthma  in not far removed from the theories postulated by Dr. Henry Hyde Salter, that: (1, page 1-2)(2, page 16)

  1. The main component of an asthma attack is spasms of the unstriped contractible fibres (bronchial muscles) that wrap around the bronchi that results in narrowing of these air passages
  2. That the main cause of such spasming is due to a nervous disorder, as can be confirmed by autopsy when an asthmatic dies: no lung scarring can be found.  This lack of any evidence of disease clearly indicates asthma is nervous in origin.  There are two routes the nerves can cause asthma:
    • Central Nervous System: Some exciting cause, probably emotional, triggers the asthmatic response, and causes narrowed air passages. 
    • Reflex Action: Something stimulates the vagus nerve or pneumogastric nerve, such as overeating, forced expiration (coughing or laughing)
He also agrees with other physicians of his era, Salter included, when he writes the following: (1, page 2)(2, page 16)
During the intervals between his attacks the patient probably enjoys fair health, and, as a rule, lives to a good age; should he, however, be cut off prematurely by death, what do we find as the morbid anatomy to explain the wellmarked symptoms seen during life?
 In other words, he believes that pure asthma is intermittent in nature, allows the patient to live a relatively normal life between attacks, and that asthma rarely causes death.  In the rare cases asthma does cause death, the asthma is not pure: it is associated with some type of morbid condition such as chronic bronchitis or heart failure.

He describes an attack this way: (1, page 2)(2, page 16)
He defines asthma as symptoms "distressing enough to endure or to witness; and yet, when things seem to be at their worse, and the patient well-nigh at his last gasp, a remission comes on, the spasm yields, air enters the lungs, and the attack subsides, coincidentally often with access of cough and mucous expectoration." 
He likewise agrees with Salter that while pure asthma may present with no structural changes, that after years of repeated and violent attacks, "cannot but lead to some alteration of tissue, and the microscope will probably show some granular or fatty degeneration in the air cells of the lungs, though to the naked eye appearances may be normal." (1, page 3)(2, page 17)

So in the rare event someone does die from asthma, it will be due to some form of organic changes that take place after years of asthma attacks.  Either that, or it was some organic change, such as occurs with chronic bronchitis and heart failure, caused the asthma and ultimately lead to that person's death.  (2, page 17-18)

These are things that both Salter and Thorowgood agree upon.

References:
  1. Thorowgood, John C., "Notes on Asthma," 1878, 3rd edition, London, J & A Churchill
  2. Thorowgood, John C., "Asthma and Chronic Bronchitis: A New Edition of Notes on Asthma and Bronchial Asthma," 1894, London, Bailliere, Tyndall, & Cox

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