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Tuberculosis

Bryan Applications, T

An infectious disease, characterized by the occurrence of minute rounded bodies known as tubercles, to which circumstance it owes its name, tuberculosis is caused by an organism known as the tubercle bacillus (discovered in 1882 by the German bacteriologist, Robert Koch). In human tuberculosis two types of bacillus are found, the human and the bovine, but other types are found in birds, reptiles, and fish. The bovine type is the one found in cattle.

A tubercle consists of a mass of cells of different kinds, and generally bacilli are found in it. The cells accumulate, in fact, around bacilli, and in consequence of the irritation caused by the latter. Tubercles tend to aggregate and form considerable masses which replace the healthy tissues. Soon, however, the cells in tuberculosis tissue begin to degenerate, and it comes to form a yellowish-white cheesy mass. This is described as caseation. Then this caseous matter may soften and give rise to a tuberculosis abscess.

Should, however, the resistance of the body to the disease process be sufficient, the caseous matter may not form, or may disappear, and be replaced by fibrous tissue, or lime salts may be deposited in the mass. This is called calcification. When a tuberculosis abscess bursts or is opened, an ulcerated surface, covered with unhealthy granulations, is left.

The chief sources of tuberculosis infection are the sputum of persons suffering from consumption, and cow’s milk. Infection from sputum may occur through kissing, inhaling the spray ejected by a consumptive when coughing, inhaling the dust formed by dried sputum, or consuming food contaminated by such dust or by tubercle bacilli which have been carried by flies. Much of the cow’s milk that is purveyed to the public contains the bovine type of bacillus, and is a source of a large proportion of the tuberculosis occurring in young children.

Meat may also contain bacilli, but is much less dangerous, as it is cooked before being consumed. Tubercle bacilli that are inhaled may pass directly into the lungs, but usually are absorbed through the lining of die mouth or throat, and especially through the tonsils, or are swallowed and absorbed through the lining of the bowel. The last happens also when infected food is swallowed. The passage of the bacilli causes little or no change in the lining itself, although when a consumptive swallows his sputa the disease may occur in the lining of the bowel and cause ulceration. Occasionally tubercle bacilli are absorbed through the skin, the so-called butcher’s wart being an instance of this.

Bacilli carried by lymphatic glands:

When bacilli are absorbed, they are carried to the nearest lymphatic glands, and if they are in sufficient numbers, they cause inflammation and swelling of the glands. If their entrance is from the mouth, the glands in the neck become enlarged, if through the bowel, the mesenteric glands, and so on. From one set of glands the bacilli proceed to the next in the chain, and so onward to the main lymphatic drainage channels, through which they are poured into the blood stream. By the blood they are carried to various organs, where they may settle and form tubercles. Very frequently this happens to be the lung. In children the peritoneum (the serous sac lining the abdominal cavity and covering its viscera) is frequently affected, but also bones and joints.

Sometimes there are such swarms of bacilli in the blood as to constitute a septicemia, and tubercles are formed all over the body. This is called acute miliary tuberculosis, and it may cause different types of illness according to the organs principally affected. Thus, it may suggest typhoid fever in some instances, in others it may cause acute lung disease, which is sometimes referred to as galloping consumption, while in others it may take the form of meningitis.

When there is a focus of tuberculosis infection anywhere in the body, there is always a risk of a generalized infection taking place or of extension to some other organ, say, from the bones to the lungs. Tubercle bacilli set free a poison which causes local irritation, but more or less of it is carried throughout the body, and produces fever, anemia, loss of flesh, and other symptoms. Should the tubercles be converted into fibrous tissue, the bacilli are wailed off from the general circulation, and their toxin ceases to enter the blood. The disease is then said to be in a quiescent stage.

When a tuberculosis abscess opens onto anybody surface or into the lung, there is a risk of infection with pus forming microbes also, and should this occur, the toxemia is aggravated, as the toxins of such microbes are added to those of the tubercle bacilli, and the local irritation from toxins is similarly increased. The symptoms of tuberculosis infection consist of those due to the toxemia, and of those proceeding from the damage to particular organs, and the latter will vary with the acuteness of the attack and the amount of the damage. Thus, when the lungs are affected, there may be symptoms of acute bronchial catarrh or pneumonia, of acute pleurisy, or of the more chronic changes of consumption.

Age incidence in tuberculosis infection:

Tuberculosis of the lungs most commonly manifests itself first in adolescence or the early years of adult life. Abdominal tuberculosis is most common between the ages of two and three, gradually declining from then onwards, an age incidence which fixes the chief responsibility for causation on infected milk. Meningitis is most common between the ages of two and five, and generally runs its course in from two to six weeks. Disease of bone and joints is commonest between the ages of three and fifteen, and the spine is frequently affected. Some skin diseases, like lupus and scrofuloderma, are caused by the actual invasion of the skin by bacilli, but others, like lichen scrofulosoram, are due simply to the irritation of the toxins.

The problem of the prevention of tuberculosis must be attacked along various lines. Persons suffering from the disease in an infectious stage must dispose of their sputa in such a way as to prevent danger to others. When the accommodation at home is insufficient to permit of precautions being taken against the spread of infection, the patient should be treated in a suitable institution. Attempts must be made to secure a pure milk supply, though any risk from this source can be removed by boiling milk before use. It has been found that tuberculosis is more prevalent in districts with a wet sub soil, and great improvement follows a thorough drainage of such places.

An adequate supply of good food at a price that can be afforded by the humblest is an end which should be strenuously striven for, as this has a lot to do with the matter. Notification, disinfection of premises, meat inspection, the destruction of flies, and other activities also contribute towards the prevention of the disease. In the general treatment of tuberculosis, sunshine, fresh air and feeding are the important elements, but in the acute stage of the disease, wherever it occurs, rest is equally important.

A vaccine prepared from the tubercle bacillus is known as a tuberculin. There is a large number of tuberculins, some of them containing the toxin set free by the germs, that is to say, the exotoxin, others the poison contained in the germs themselves, the endotoxin, while a third class contains both toxins. Sometimes the use of a tuberculin has valuable results, but, if used unskillfiilly, a remedy of this kind is capable of doing very great harm.

Tuberculosis of the glands, bones and joints is sometimes referred to as surgical tuberculosis because surgical treatment was at one time the rule for such, but now the surgeon is more inclined to stay his hand and trust to rest and light, either natural or artificial for a time, contenting himself with aspirating abscesses or other operations which may become necessary, and operating for the removal of glands or other diseased structures only when a sufficient trial of the other methods has proved ineffectual. On the other hand, operative treatment on a tuberculosis lung is now being undertaken in certain circumstances. See: Lupus..

Application and treatment:

See: Infectious disease..