The tubercle bacilli destroy the lung tissue and change it into pus, which is coughed out. In this way larger and smaller cavities are formed in the lungs; finally the cavities may even take more space than the remaining lung tissue. When cavities have already been formed, coughing comes easy and with abundant expectoration. Toward the end of life the coughing and spitting stops as a result of the extreme feebleness and weakness.
The violence and frequency of the cough depends mainly whether the larger bronchial tubes and the trachea are affected; the more this is the case, the more violent the inclination to cough. Further the strength of the cough depends on the excitability of the patient; the greater this is, the more as a rule will he cough. Sometimes the position of the patient is of influence; if he lies mostly on the diseased side the expectoration becomes more difficult and coughing increases.
Coughing is generally that symptom which soonest attracts the attention of the patient and his surroundings. For that very reason consumption is in its beginning stages easily confounded with such other diseases as are also accompanied by cough.
At the same time we know of exceptional cases where cough was entirely absent in the first stages of the disease, or was at least so slight that it was overlooked, and under such conditions the pale and poor appearance and reduced strength is mistaken for chlorosis or some other anaemic affection, also the existing febrile excitements are wrongly judged, or on account of lack of appetite or light derangements of the stomach a stomachic affection is surmised, until suddenly a hemorrhage of the lungs clearly defines the true nature of the ailment.
On the other hand the cough may become so violent that vomiting is caused at the same time. Nevertheless many consumptives describe their cough as very unimportant on account of their innate sorrowless nature, and they will not even be discouraged by the gravest symptoms. Often however it is fear that induces the patients to make light of their coughing, their spitting blood, their losing flesh and to place but little importance on these circumstances. A hoarse cough is a sure sign of a diseased larynx.
Many consumptives complain of cutting pains between the shoulderblades, under the clavicles or in the side; but these are rarely intense and are often entirely wanting. Unfortunately it is unknown to the average layman that the internal organs may suffer extensive tearing down without an indication of pain.
The Expectoration of consumptives which is thrown out by coughing with great exertion, is but scant in the beginning, as a rule phlegmy, glassy transparent and sticky. It is one of the suspicious symptoms of developing pulmonary consumption if this lasts for any greater length of time. Sometimes sharply defined, yellowish stripes, at times branching, appear in the same. Later on the expectoration becomes more purulent, and of greenish-yellow or greenish-gray color.
Still later the patients throw out rounded lumps of greenish yellow or yellowish green color, which flatten out like a coin in the spittoon. They sink in water which is a sign of forboding evil.
Blood appears in different quantities in the sputum of consumptives. Bloody streaks are of no importance; they may appear with every violent cough. On the other hand the casting out of pure blood is indeed serious.
The quantity of blood thrown out during an attack may be very different, varying from a few drops hardly a teaspoonful, to hundreds of grammes, even more than a liter. It is generally light red, filled with airbubbles, foamy, and is largely coughed out in coagulated lumps. The coughing of blood is sometimes preceded by a feeling of oppression, rushing of blood to the head and palpitation. Some patients experience a sweet taste in the mouth even before the bleeding. In many cases all preceding symptoms are missing and the patient is suddenly attacked by blood coughing during some more vigorous movement, during the exertion of coughing or even without any direct cause.