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Pulmonary abscess, bronchiectasis and pulmonary tuberculosis are very often wrongly diagnosed. Unless one has had considerable opportunity to examine patients suffering from each of these diseases, he is liable to experience considerable difficulty in differentiating them. If, however, a careful study of the disease and the manner in which it affects the patients is made the differentiation will not be so difficult. Both pulmonary abscess and bronchiectasis are often diagnosed as tuberculosis on the basis of cough and expectoration. The fact that bacilli are not found is no longer sufficient to prove the non-tuberculous nature of a pulmonary process; consequently, this fact confuses more than it helps. In my own work I have had opportunity to study numbers of patients who were expectorating large quantities of sputum. Some of these have been of a tuberculous nature, yet bacilli have been found only at rare intervals. In other patients who had had a definite tuberculous process which had been accompanied by cavity formation and sputum containing bacilli the general process healed, leaving a secreting cavity, with a considerable amount of expectoration in which tubercle bacilli were not found, even after repeated examination. So while the presence of tubercle bacilli shows the definite tubercular nature of sputum, their absence does not prove the process to be non-tuberculous.
Pulmonary abscess usually follows acute infection of the lung, in which such organisms as streptococci, staphylococci or the pneumococci are the etiological factors, such as have been common during the epidemics in both army and civil life during the past two years. It also follows operations on the teeth, tonsils and nasal cavities now and then, the infectious material being aspirated into the lungs, where it becomes implanted, and is followed, from a few days to a week or two later, by an acute abscess. I am led to believe that abscesses having this etiology are more common after tonsil operation than is generally believed. I have seen more than twenty during the past year and a half, and other observers, as Manges1 and Richardson,2 report cases which have come under their observation. These abscesses always furnish a history of acute onset; expectoration, sometimes foul smelling, usually profuse at first, varying in quantity later; quite often periodical rises of temperature; and sometimes bloody expectoration. Clubbing of the fingers usually comes on quickly. I have seen it very pronounced in abscess following tonsillectomy in less than three months after the abscess formation, and have noted it as early as six weeks.
The most common form of pulmonary abscess that clinicians deal with today is that which followed the recent influenza epidemic. The abscess is usually found in the lower half of the lung and is often situated in fibrous tissue which has resulted from the infection. Not uncommonly a complicating pleurisy was present which has resulted in pleural adhesions and thickening. Prior to the recent epidemic the type of abscess which was most common in my practice was the one following operations on the upper respiratory tract. It was only occasionally that I saw one following an acute respiratory infection.
Bronchiectasis, as I have observed it, usually follows a pneumonia in childhood, although I have seen it follow the same in a few instances in adolescence and early adult life. It sometimes seems to begin with a bronchitis and persists as a chronic form of this affection. I have rarely seen it begin in those past middle life unless it was of a tuberculous nature. The patient usually gives a history of cough which continued after a pneumonia or after a bronchitis as before mentioned. Oftentimes cough, with expectoration, has persisted since the pneumonia; at other times it has appeared only when the patient had, what was termed a “cold.” If the process follows chronic bronchitis it also shows periods of exacerbation. Temperature may be present occasionally and the sputum is at times bloody. The cough in most of my cases has been loose, indicating that the sputum is in the larger tubes, where it is easily moved. The loose nature of this cough itself has proved of diagnostic worth. A history of cough with expectoration, following and persisting after a pneumonia in childhood, is of itself nearly sufficient for the diagnosis of the postpneumonic type. The fingers are often clubbed, but in my experience this sign is not as important as in pulmonary abscess. It is neither as constant nor does it appear as quickly.
Pulmonary tuberculosis with cavity gives a very different history. As a rule, the patient forms an abscess cavity of a tuberculous nature only after the disease has existed as a clinical entity for some time, although now and then we see a sudden onset with cavity following in a short time. Occasionally a mistaken diagnosis is made and the acute signs in the lung at the time of the formation of the cavity are taken for pneumonia. A careful study of the clinical history will often aid in differentiating these processes. Cavity formation in tuberculosis is more liable to be preceded by repeated attacks of toxemia sometimes months apart, while pulmonary abscess usually comes on promptly following an acute infection in a patient who was previously in good health. I have seen a few cases of tuberculous abscess form in which the patient had complained of acute illness for only a short time. The patient with tuberculosis as compared with the one suffering from pulmonary abscess or bronchiectasis is more liable to suffer from nerve irritability, and, as a rule, shows a greater degree of nutritional disturbance when the acute process comes on. Repeated attacks of bronchitis are common in bronchiectasis and in tuberculosis, but not in pulmonary abscess.
Nature Of Processes
Pulmonary abscess is a disease caused by microorganisms which produce acute infections. These organisms are often found in the air passages, as is the case during epidemics of acute respiratory disease. When the abscess follows operation on the upper respiratory tract the bacteria are probably dislodged in large numbers and aspirated directly into the trachea and bronchi. They are capable of ready implantation and rapid multiplication. They follow the direction of the strongest air currents with greatest ease and usually produce their infection in the lower lobes.
Bronchiectasis, being a disease of the bronchi in which dilatation and distortion occur as a result of pathological changes in their walls, often follows fibrosis and contraction of pulmonary tissue. It is commonly found near the hilum, although the affection may involve the bronchi in all parts of the lung.
Pulmonary tuberculosis, being a chronic infection resulting from microorganisms which are not commonly found in the air passages of those who are not suffering from tuberculosis, and which require time for multiplication, is not a disease which results immediately on the bacteria gaining access to the air passages. If the patient has not been previously infected, the bacilli, after entering the tissues pass readily to and settle in the lymphatic glands and are later carried through the blood or lymph stream to be deposited in the capillaries or lymph spaces of the pulmonary tissue. This is the manner in which lung infection most probably takes place. While implantation of the microorganisms which produce the acute infections is favored by the relatively greater motion and greater force of the air currents in the lower lobes of the lung which force the bacteria deeper into the tissues, the relatively lessened motion of the apex favors implantation of the slowly developing blood and lymphborne tubercle bacilli; consequently, active tuberculosis with cavity formation is usually first found near the apices while pulmonary abscess is usually found in the lower lobes, and bronchiectasis may be found in any portion, but often affecting the large bronchi near the hilum.
On careful inspection a diminution of motion will nearly always be noted on the side of the involvement in all of these affections, because all reduce the elasticity of the lung tissue, cause a loss of tissue and produce a reflex diminution of motion through the diaphragm and other muscles of respiration. In pulmonary tuberculosis this may be difficult to ascertain in those instances in which there is a lesion in both lungs. In bronchiectasis the lung involved is practically always contracted and the mediastinum shifted toward that side. In pulmonary abscess, contraction with shifting of the mediastinum may or may not take place, although it usually does if the process is a chronic one. The same is true of tuberculosis.
Reflex Changes In Muscles And Other Soft Tissues Determined Mined By Inspection And Palpation
The reflex spasm in the muscles and degeneration of the soft tissues–skin, subcutaneous tissue and muscles–is, as a rule, not as marked in pulmonary abscess and bronchiectasis as it is in pulmonary tuberculosis. The extent of the degeneration, when the process has become chronic, depends upon the extent and character of the previous inflammatory process. Pulmonary abscess is a focal infection in the lung. It may be single or multiple, but, as a rule, it appears as an acute disease in tissue which has not been, as is the case with tuberculosis, for a long time previously the seat of widespread foci of infection. Those abscesses which have followed our recent epidemics of acute respiratory infections, however, often occur near the base in the midst of areas of widespread fibrosis of pulmonary and pleural tissue. Bronchiectasis is, as a rule, limited in the amount of tissue involved. Like pulmonary abscess and unlike pulmonary tuberculosis it is rarely found in the midst of numerous active foci of infection. Pulmonary tuberculosis, on the other hand, when it becomes an active clinical process with cough, expectoration and cavity formation, is nearly always a chronic disease and the cavity is formed in tissue which, as a rule, is and usually has been, for a long time, the seat of many foci of infection which have been undergoing all degrees of active inflammation. The result is that pulmonary tuberculosis offers the greatest opportunity for reflexes. The muscles of the shoulder girdle and diaphragm are more tense (increased tension in the latter is inferred from the limited motion) during the activity of the tuberculous process than is found in the other diseases. When the disease becomes chronic these muscles and the soft structures (skin and subcutaneous tissue) in the neck and down to the second rib anteriorly and the spine of the scapula posteriorly show far more reflex trophic changes in tuberculosis than in the other two diseases. In fact, chronic tuberculosis of the lung may be suspected whenever the neck muscles and the subcutaneous tissue and skin of the neck and chest above the second rib anteriorly and the spine of the scapula posteriorly are markedly degenerated. Pulmonary abscess and bronchiectasis also cause degeneration in these same tissues, but, as a rule, it is not so extensive, and I have seen instances of these affections which caused practically no reflex trophic changes.
Palpation And Percussion
Percussion may give little or much information in abscess and bronchiectasis, but is of far more importance in pulmonary tuberculosis. Palpation has been of more aid to me than percussion.
On auscultation the signs elicited in pulmonary tuberculosis with expectoration are usually more or less definite. If a cavity is present in active tuberculosis it is found in the midst of actively diseased tissue, which usually gives rise to characteristic respiratory sounds and many rales; if chronic, the tuberculous process outside the cavity may be partly or wholly healed, under which circumstances the signs elicited on auscultation may be similar to those of pulmonary abscess. The signs of pulmonary abscess and bronchiectasis, as determined on auscultation, are usually few and often very indefinite. In fact, the nature of the process may be suspected from this fact: a definite history of cough and expectoration, usually a fairly large quantity, sometimes even several ounces a day, and comparatively few signs of moisture on auscultation.
Explanation Of Different Auscultatory Findings
If the examiner only can form a true conception of why there are marked changes on auscultation in pulmonary tuberculosis, and why even with larger quantities of sputum, as is often the case, there is such an absence of changes on auscultation, in pulmonary abscess and bronchiectasis, then the differentiation of these affections will be easier. This I shall attempt to show graphically by the accompanying illustrations.
The explanation of this fact is based upon the difference in pathology as mentioned above when considering the reflexes which arise from these processes.
Mucous rales or crepitations may or may not be elicited over cavities, depending on whether or not the mucus which they contain is disturbed by the ingress and egress of air. Ronchi are sometimes heard over them. Conditions which favor the production of the most constant and greatest quantity of pulmonary rales are not found in the cavity itself but in the surrounding tissue as noted in pulmonary tuberculosis.
The relative prominence of rales in these three affections may be illustrated by the accompanying figures:
Fig. 1 illustrates the conditions present in pulmonary tuberculosis. A large cavity A has formed near the apex. It will be noticed that this has taken place in an area which is the seat of a widespread tubercular involvement, as illustrated by the dotted area B, throughout which there are numerous small cavities C. Here we have the ideal conditions for the production of crepitations and mucous rales: inflammation with foci of necrosis involving the walls of air cells and bronchi accompanied by an increased production of mucus which must find its way toward the trachea through bronchi of all sizes. The cavity itself is at times the seat of coarse rales, at other times no rales are elicited over it. Not infrequently I have seen the sudden disappearance of rales take place over an area of tuberculous infiltration as a result of cavity formation.
Fig. 2 illustrates the condition present in pulmonary abscess. An abscess A has formed as a result of acute bacterial infection. As a rule the first pulmonary abscess which forms is an acute process coming on within a few days after the implantation of bacteria has occurred. The surrounding tissues may not be at all infected. This is particularly characteristic of those abscesses which follow operative procedure upon the upper respiratory tract. The abscess often forms in a single focus the same as a boil forms on the surface of the body. When the pressure in the abscess becomes sufficiently great, rupture occurs at the point of least resistance, which is usually into a bronchus.
FIG. 1–Diagrammatic illustration of a cavity due to pulmonary tuberculosis. The cavity, A, is surrounded by tissue which is the seat of tuberculous infiltration, B, and which contains many small cavities, C. These are ideal conditions for the production of rales.
A pus-forming pocket remains which discharges through the bronchus. The conditions in the surrounding tissues which favor the production of crepitations and rales as shown in pulmonary tuberculosis in Fig. 1 are absent and the chief source of whatever rales may be present is the abscess cavity itself and the bronchus or bronchi which drain it. The result is that crepitations and mucous rales are few in abscess produced by acute infections as compared with the abscess cavities which accompany pulmonary tuberculosis, unless the latter have existed for a long time and the tuberculous involvement of the surrounding tissue has healed.
When multiple abscesses form in non-tuberculous lesions, as they sometimes do, particularly in those cases which become chronic, each one repeats the same cycle of events as noted in the acute single abscess. Varying amounts of scar tissue result, but still the widespread inflammatory and destructive processes which characterize tuberculosis and which favor so greatly the production of crepitations or mucous rales is absent. If the infectious process in either pulmonary tuberculosis or pulmonary abscess involves the pleura, then crepitations may be present which may be differentiated from pulmonary rales only with the greatest difficulty and sometimes not at all.
FIG. 2–Diagrammatic illustration of acute pulmonary abscess. The abscess, A, is situated in the midst of and surrounded by healthy pulmonary tissue. The source of rales is the cavity itself and the bronchi leading from it. This condition is not favorable to the production of many rales.
Much the same condition is found in bronchiectasis as far as the production of rales is concerned as has just been described in pulmonary abscess. The bronchi are dilated and their walls thickened, as shown at A in Fig. 3, in such a manner that the dilatations have much the same physical appearance as abscess cavities. The surrounding tissue is thickened, fibrous in nature and offers little opportunity for the production of crepitations and mucous rales. At times there is constriction of the bronchi proximal to the dilatation which may favor accumulation of secretion and cause sounds on auscultation; but there are rarely heard on auscultation, either in abscess or in bronchiectasis, sounds which will afford any idea at all of the extent or seriousness of the pathological process present.
FIG. 3–Diagrammatic illustration of bronchiectasis. The bronchiectatic dilatations A are surrounded by pulmonary tissue which is not the seat of infection, consequently the main source of rales is the mucus which forms in the dilated bronchi. This condition is not favorable to the production of many rales.
A history of persistent expectoration of moderate or large quantities of sputum, with a diminished respiratory excursion on one side of the chest and an absence or paucity of crepitations or mucous rales on auscultation over the side affected, should make one think of pulmonary abscess or bronchiectasis. Ronchi are often present, but they too may be absent.
- Jour. Am. Med. Assn., May 8, 1915, p. 1554.
- “Abscess of the Lung following Operation on the Tonsils and Upper Air Tract,” The Laryngoscope, St. Louis, Mo., July 1916.