25 Bristow, St. Thomas's Hosp. Rep., vol. lxxi.: "Influence of Pressure on Trachea without Implication of the Recurrent Laryngeal Nerves."
The symptom of pain is usually far less than in cases of aneurism, since it is only in rare instances that the chest-walls become eroded by the outward pressure of the tumor, as so frequently occurs in aneurism. Moreover, the growth more readily adapts itself to the contour of the chest, and tends to envelop rather than compress organs or nerves. From the time that pressure commences, either on the trachea, bronchi, or intra-thoracic nerves, cough is more or less constant. It may, however, be due to pulmonary changes occasioned by the pressure or actual involvement of the lung by the growth. Cough is an earlier symptom when the growth is situated in the posterior mediastinum than when it is located anteriorly. It is usually laryngeal and ringing in timbre, and may occur paroxysmally, as in pertussis. It is ineffectual, dry, or attended with only scanty mucous or frothy expectoration. The sputa may be tinged with blood, or profuse hæmoptysis is a possible symptom. A microscopic examination of the sputa in a case of intra-thoracic tumor is always important, because portions of the morbid growth may be found, or by perforation of the trachea or oesophagus the pus from a mediastinal abscess may be mixed with the sputa. Mediastinal tumors are not, as a rule, characterized by febrile symptoms. Inflammatory complications of the lungs or pleura may account for the exceptional thermometric variations. Cases have been reported by Bennett and Church in which there was persistent elevation of temperature, with daily fluctuations and rapidity of pulse and respiration. In one instance of lympho-sarcoma the paroxysms of fever corresponded with the periods of growth in the enlarged glands, but in this case the lymphatics of the general system were also implicated. From the fact that the growths are strictly mesial, dysphagia is a far more common and persistent symptom than in aneurism, especially in growths of the posterior mediastinum. When the growth is situated in the anterior mediastinum the dysphagia is less frequent; but it must be borne in mind that prolongations of the tumor may occasion lateral oesophageal pressure, or narrowing of the lumen of the oesophagus can occur from pressure upon the trachea by the growth. Exceptionally, dysphagia may be due to implication of the oesophagus in the new growth. (See [Cancer of the Lung].) Neural influences may increase the dysphagia, in which case it is doubtless a reflex phenomenon and is associated with hiccough or vomiting. The passage of a bougie can be readily effected in such cases.
In reference to the foregoing pressure symptoms one fact deserves recognition—viz. that in aneurismal tumors the pressure symptoms are subject to variations in intensity due to changes in the intra-aneurismal tension, while in morbid growths in the mediastinum the pressure symptoms exhibit a progressive tendency, advance upon the same lines, and are more constant than in aneurism. With this principle in mind, the additional pressure symptoms in doubtful cases of mediastinal growth must all be considered; for instance, in some histories recorded by Rossbach the pupils could be dilated by firm pressure on the tumor above the clavicle. The pulses in the brachials or radials may be unequal, and variations of rhythm, volume, and rate may be noted as evidences of pressure, which may occasion thrombosis by retarding the circulation in the innominate, subclavian, or azygos vein. The blood may reach the heart by the collateral circulation elsewhere described or by the dilated mammary superior and inferior epigastrics and the inferior vena cava. Pressure may therefore give rise to cyanosis, oedema of the upper or lower portions of the body, with enlargement of the superficial veins, or dropsy may be traceable to hydræmia.
PHYSICAL SIGNS.—When mediastinal tumors are of small size, physical signs may afford no help in making a diagnosis, and they will always vary according to the location of the growth.
Inspection may reveal venous repletion of the veins of the face and neck, with distension of the superficial veins of the chest; the latter symptom is more frequently obvious than in aneurism. In the case of sarcoma represented by Fig. 53 the foreign growth was so limited to the mesial line as not to involve the vessels or create pressure symptoms upon them. If the anterior mediastinum is implicated, there may be circumscribed alterations in the contour of the chest. Prominence of the upper piece of the sternum and of the sternal attachment of one or more ribs may be recognized. The sternum itself may appear thickened upon palpation of the notch. One side of the chest may be larger than the other above the nipple-line; the affected side, however, may be smaller, since vicarious respiratory function may create distension. The usual changes in the contour of the chest-walls will indicate pleural effusions. (See [Cancer of the Lungs].) Since tumors of the anterior mediastinum overlie the aorta, transmitted pulsation may be detected in rare instances; this pulsation can be differentiated from aneurismal vibrations by the absence of the sense of expansile pulsation characteristic of dilated aorta or aneurism, but it sometimes closely resembles that yielded by an aneurismal sac thickly lined by coagulum.
Lympho-sarcoma and cancer are often accompanied by painless, movable glandular enlargements, recognizable by palpation in the supra-clavicular spaces; but the absence of the glandular implication in sarcomata is conspicuous; swelling occasionally manifests itself in the suprasternal notch. Tumors of the posterior mediastinum must attain considerable size before they can be recognizable by the foregoing methods. Growths in the latter space are those especially liable to complication by pleural effusion in one or both sides. Mediastinal growths may occasion collapse of the lung, or cirrhotic processes or pleural adhesions may diminish the circumferential measurements of the chest. The heart may be displaced backward, downward, to the left or to the right side; and since in aneurism, uncombined with valvular disease, little cardiac displacement occurs, this sign is of importance. Rarely, as in Cotton's case in Brompton Hospital, the heart may be fixed in situ by the extension of the growth on both sides of it.
Percussion.—It has been observed that a very small tumor may, from its particular site, at a very early stage give rise to symptoms both of pressure and disordered innervation of great severity, whilst another may attain considerable magnitude before the patient experiences any distress or any decided evidence of pressure is manifested. It is equally true that percussion and auscultation may be most valuable, or, on the other hand, indefinite. The degree of dulness occasioned by a morbid growth in the anterior mediastinum is dependent on its size, large growths yielding flatness; but when the tumors are small the osteal resonance of the sternum is simply hardened. Respiratory percussion is available if the growth lies anteriorly. The full, clear resonance of full-held inspiration contrasts with the increased dulness developed when the lungs are stripped from the mediastinal space by forced expiration. The boundaries of the growth on either side of the sternum may be defined by percussion, and it is possible that the greater part of one side may be occupied by the new formation. The adjacent tissues are involved by direct invasion, or indirectly by extension along the bronchus from behind forward, thus involving the middle tier of the lung. Mediastinal tumors therefore in their mode of growth yield a contrast with pleural effusions, because the latter usually advance steadily from below upward. When the growth is located in the posterior mediastinum, percussion should be practised after the manner recommended by Mussey to facilitate recognition of enlarged bronchial glands. (See [Pulmonary Syphilis].) The apices, humeral, scapular, basic, or marginal regions often yield a tympanitic type of resonance, since they are often in a condition of vesicular emphysema. The pericardial sac may be distended with effusion or implicated in the growth, and an area of pyramidal dulness with the base above may be recognizable.
Auscultation.—In growths situated anteriorly, in the mesial line, one of the most forcible lessons may be impressed by the distance and obscurity of the second sounds of the heart over the aortic and pulmonary artery, cartilages, or the upper piece of the sternum. The cardiac sounds may be transmitted downward, and can be heard distinctly in some abnormal position. Even a murmur can occur due to compression of the aorta, or pericardial friction. The respiratory murmur will probably seem feeble and distant over one or both apices, and whistling near the trachea.
If the posterior mediastinal space be involved, the respiratory murmur may represent some type of bronchial breathing, or if the lumen of the trachea or one of the bronchi be decidedly lessened, the respiratory murmur may be whistling, feeble, or suppressed over the affected side. Over the other bronchus the respiratory murmur may be more high-pitched than in health, and slightly exaggerated. The rhythm is often jerky and paroxysmal; the paroxysms are more or less constant, but are liable at times to increase. Auscultation should be especially practised over the roots of the lungs or in the neighborhood of the second dorsal vertebra. Frequently it can be demonstrated, both by auscultation and percussion, that there is diminished air-supply to one or other of the lungs, while the respiratory murmur is not sufficiently changed for classification. The respiration may acquire a stridulous or sibilant character, most marked on expiration, but less often than in aneurism, because there is a greater tendency to occlusion of the bronchi. It should always be remembered that the lung undergoes very various and opposite changes as the result of pressure on the bronchi, interrupting the entrance and egress of air from the lobules, and the physical signs of emphysema, infarction, congestion, or consolidation may exist in one or the other side. The ordinary methods of physical examination indicate the existence of pleural effusions, but large growths extending from the mediastinum or originating in the lung may so closely simulate such effusions that a positive diagnosis can be arrived at only by paracentesis.
When tumors exist in the form of very small nodules as diffused sarcomata, no changes in the character of the respiration may be noted. Friction râles and pleuro-pericardial frictions may be heard in some cases. Distension of the bronchial tubes from pressure may occasion the dilatation of the distal bronchial passages and pulmonary lobules with retained muco-purulent secretions. The cross-sections of the bronchi have been described as multiple abscesses. Areas of collapse or slow inflammation with softening of the secondary inflammatory product can follow. The bronchial pressure may prevent the sufficient transit of air through the bronchi to create râles, or moist râles indicative of tracheo-bronchitis or oedema may abound.