There are other affections with which pericarditis is likely to be confounded, such as gastric irritation and acute inflammation of the brain. When pericarditis resembles gastric disorder the thoracic symptoms may be latent, but the disease produce the manifestations of extreme gastric irritation or inflammation. There are nausea and vomiting, and tenderness on pressure in the epigastric region, yet no disease of the stomach may be present. An examination of the cardiac region for the physical signs of pericarditis should be made in every case of persistent vomiting or of hiccough.
Where the symptoms are chiefly cerebral, the cardiac disease may be overlooked; indeed, in both endocarditis and pericarditis the insomnia and the active delirium may throw all the other symptoms into the shade. The violent disturbance of the brain may have its origin, in part at least, in the contaminated state of the blood which occurs in the affections, as rheumatism or Bright's disease, with which pericarditis is often associated. But it is possible also that it may be due to a coexisting endocarditis of which the products are washed into the brain. In ulcerative endocarditis cerebral manifestations are especially common, and there may be acute mania of the most violent type, as in the case reported by Sioli.15 Sibson in his exhaustive analysis points out what I have known to happen in more than one instance, that the desponding and taciturn—or, as he calls it, sombre—delirium of pericarditis lasts from two to three weeks to as many months. Indeed, it may terminate in confirmed insanity. Any form of nervous disturbance having its centre of disorder in the cerebro-spinal axis and of any degree of intensity may be seen in cases of pericarditis, whether produced as a consequence of rheumatism, of albuminuria, or by other causes. The cases with marked nervous symptoms are apt to present high temperature, 105° or more.
15 Archiv für Psychiatrie, Bd. x.
The diagnosis of pericarditis from hypertrophy of the heart is made by remembering that in pericarditis we find friction sound, præcordial bulging, peculiar enlargement of percussion area, enfeebled impulse and heart sounds, besides the presence of pain, of fever, of dyspnoea. In hypertrophy the area of percussion dulness is enlarged, but the shape is normal; the impulse and heart sounds are strong; no pain or fever, no friction sounds exist. The chance of mistaking dilatation of the heart for pericarditis is much greater. In the early stage of pericarditis the area of percussion dulness is generally similar in size and shape to the dulness in dilatation. But soon the difference both in size and shape of the cardiac area becomes marked, the shape being pyramidal or pyriform in pericardial effusion, while in dilatation the increase is lateral and does not extend beyond the point of impulse. There is no friction sound in dilatation; and if the first sound be weakened, though it may be also sharp and short, the second sound is everywhere distinct, unlike the muffling of the cardiac sounds, except at the base, in pericardial effusion.
Tumor of the anterior mediastinum, whether solid or fluid, may become a source of perplexity in determining the diagnosis of pericarditis; for by the interposition of the morbid mass between the chest-wall and the heart the cardiac dulness is increased and the heart sounds are lessened in distinctness and perhaps in force; though if the tumor be solid and very dense the sounds may be intensified. Pericarditis may also be associated with a tumor, and a diagnosis under such circumstances is attended with great difficulty. A tumor of the anterior mediastinum is comparatively rare, and seems to be more frequent in females than in males, although the statistics are meagre and not conclusive. There may be displacement of the heart in any direction as the result of pressure from the growth. Should this be equable in front of the heart, the diagnosis becomes one of doubt, for the same alteration of the shape of the chest may be present as in pericarditis with effusion. If the tumor be malignant or scrofulous, tumors of a similar character may be found in the neck, axilla, or elsewhere, and aid us in arriving at a correct conclusion.
The differential diagnosis of pericarditis from inflammation of the anterior mediastinum will cause at times no slight difficulty. However, inflammation of the anterior mediastinum is infrequent. It may come on without assignable cause or as the result of injuries. It may be produced by extension of inflammation from adjacent parts, as in pericarditis; it does not appear in association with, or as a consequence of, other diseases, such as rheumatism, renal diseases, scurvy, or the exanthemata, as is so largely the case with pericarditis. The symptoms resemble those of pericarditis, and there is likely to be chill, followed by fever, substernal pain and weight, pain on pressure over the sternum, accelerated action of the heart. Respiration is more or less difficult and painful, on account of the movements of the cartilages and intercostal muscles. The disorder in respiration becomes the more decided when the inflammation has extended to the pleura; there is also pain on pressure in the epigastrium. The physical signs of mediastinitis may be precisely similar to those of pericarditis. The extension of the inflammation to the adjacent parts produces the characteristics of uncomplicated inflammation of these parts, and under such circumstances the distinction is far from being easily made; the pleuritic and pericardial friction sounds which are developed will naturally be ascribed to affections of the pleura and pericardium alone. In accumulation of pus in the mediastinum no little uncertainty will exist in determining the difference between this and pericardial effusion. The percussion dulness may extend beyond the area of the heart, and take the form of the area in effusion into the pericardial sac. It is true, however, that in purulent collections in the mediastinum the shape of the percussion dulness is often more elongated, extending upward to the sterno-clavicular articulation. Should the accumulation be large, we meet with difficulty of respiration and of deglutition from pressure, as in pericarditis with effusion or in hydropericardium; and there may be elevation of the sternum and intercostal bulging. Abscess of the mediastinum tends to point at an intercostal space; it may also do so in the scrobiculus cordis: the impulse of the heart is weakened or entirely lost and the heart sounds are distant and obscured. There is apt to be hectic, with headache, delirium, and syncope. In fact, there is no symptom of pericarditis or of hydropericardium which may not also be found in acute mediastinitis or in the accumulation of pus in the mediastinum. Where the inflammation can be traced to an injury, as a blow upon the sternum, or where there exists caries or necrosis of the sternum, the diagnosis is greatly facilitated. The inflammatory symptoms, while of all grades of intensity, are, as a rule, more intense in the forms of mediastinitis than in any of the acute stages of pericarditis. In cases of fibrinous mediastinitis associated with fibrinous or fibro-purulent pericarditis, Kussmaul has called attention to the diagnostic value of a pulse intermitting at regular intervals simultaneously with inspiration, the pulsus paradoxicus.
PROGNOSIS.—The prognosis of pericarditis is exceedingly variable, depending largely upon the primary cause, the intensity, the stage and duration of the attack, the prior condition of the individual, and his surroundings. The general prognosis is favorable to life: though some of the older writers were disposed to look upon it as a highly dangerous disease, it is clearly one from which recovery is frequent. In many autopsies of individuals who have subsequently died of other disease the evidences of cured pericarditis have been found. By cured it is not wished to convey the idea that the pericardium was restored to the condition it was in prior to the inflammatory attack, but that the inflammation had ceased without injurious consequences. There may be recurrent attacks, and they are frequently of a subacute character; even when fibrinous deposit and attachments continue to exist, it often happens that the movement and functions of the heart are not interfered with. Unless the disease be exceedingly severe in the acute stage, the prognosis is decidedly favorable. When the attack is very severe there are strong reasons for believing that the structure of the heart is also involved, and death ensues chiefly from the latter complication.
Should adhesions take place, the prognosis is unfavorable in proportion to their extent, though to this rule there are decided exceptions. If effusion rapidly develop, the prognosis becomes at once unfavorable, death resulting in a short time from sudden pressure upon the heart and its palsy. If, however, the effusion accumulate slowly, the parts become tolerant, and a large amount of fluid may be thrown out without fatal consequences. Where death occurs it usually comes on slowly, and the immediate cause is from the pressure of the large effusion upon the heart, preventing its free diastole. The lungs become engorged with venous blood, and asphyxia of the heart ensues. There is apt to be general dropsy in such cases, particularly oedema of the lower limbs and accumulation of fluid in the serous cavities, as in the pleuræ, and the patient becomes gradually exhausted. If effusion of serum be accompanied by pus or by blood, or if there be pericarditis with pus or blood alone, the prognosis is unfavorable. Balfour,16 however, states that recovery is not impossible in purulent pericarditis, "for the elements of pus are more or less present in every pericarditis, and pus may be only a transitional stage, and may result in the breaking down of cell-elements, the formation of a pathological cream, and its complete absorption, and the perfect cure of the disease." The caseous formation, or even the pathological cream, is rarely met with, and cannot be detected prior to death. Burrows17 records a case in which there was a layer of concrete pus over a small space in a pericarditis of seven days' duration. Pericarditis with large amount of membrane, whether this be coated with pus or not, and even without liquid effusion into the sac, is always of grave prognosis; so are cases with high temperature, cases complicated with pneumonia, cases in which the dyspnoea is of intensity disproportionate to the local symptoms, and in which the pulse is not in unison with the impulse of the heart.
16 Diseases of the Heart, 1876, p. 299.
17 Disorders of the Cerebral Circulation, London, 1846, p. 187.