Definition:—An inflammation of the serous envelope of the heart—the pericardium—exhibiting under different circumstances the essential phenomena of an acute fibrinous or plastic, serofibrinous or sub-acute inflammation. Other phenomena which are, however, only forms or stages of development of the above named varieties, have been classed as purulent, adhesive or hemorrhagic. The disease seldom occurs as a primary or idiopathic disorder. It is usually secondary to some other inflammation.

Etiology:—No specific micro-organism has yet been shown to be the cause of the disease. Its immediate development may be due to an injury to the chest walls, to exposure to extreme cold or to severe physical effort, but it is more apt to occur as the sequel of other acute inflammations, as rheumatism, measles, scarlet fever, smallpox, erysipelas or typhoid fever, and it is not infrequently associated with kidney disease and other severe local and constitutional disorders. An extension of the inflammatory action from pleuritis, or pneumonitis, or even from bronchopneumonia, is not uncommon. The disorder is of common occurrence as the result of severe acute rheumatism in boys and young men, observed more frequently in males than in females.

Symptomatology:—The disease usually develops insidiously, during the progress of some other inflammation, and no plainly marked symptoms are apparent until it has passed through the preliminary stages to complete development. Among the first symptoms of its secondary development are pain in the left side of the chest and in the left shoulder and arm. The fever is not high, the temperature rising to about 102.5° F. As effusion develops, there is oppression in the chest, some difficulty in breathing and some palpitation. The pulse is not at first irregular, but is rapid, full and quite strong. Tenderness over the region of the heart, with some cough, develops in the later stages of the disease, and if the inflammation assumes a purulent form, there is septic infection, with hectic fever and chilliness. If the disease occurs as a primary acute inflammation, idiopathically, there may be a sharp initial chill, quite high fever, with nausea, vomiting and pain in the praecordium, with marked constitutional impairment.

In cases where effusion occurs from the disease the evidences may be very conspicuous. The fever continues and may be increased. There is usually considerable embarrassment of the heart's action, with restriction and oppression of the respiration to a marked difficulty of breathing, with cyanosis, first apparent by blueness of the lips, and subsequently accompanied by an anxious countenance. The voice changes and becomes feeble or distant and husky, the pulse and the respiration quicker, and there may be some delirium, or even mild coma. These symptoms vary with the quantity of the effusion, being very severe indeed when the effusion is present in an extreme quantity. As the disease abates the fever declines, the respiration is relieved and the anxious countenance disappears. But unless quickly influenced by the treatment the fever increases to hyperpyrexia; there is great restlessness, with active delirium; the pain may be excruciating and the dyspnoea and cyanosis will be extreme, with a very rapid and feeble pulse and great prostration. In an occasional case death will occur very suddenly, sometimes in a most violent manner.

Physical Examination:—Percussion and inspection in the first stages will be negative, except perhaps an increase in the sharpness of the apex beat of the heart may be observed. When effusion occurs there is some bulging and an increased dulness, with diminished respiratory murmur over the praecordium. There is a distinct friction, or nibbing sound, which is quite characteristic at the base of the heart as the disease progresses. This may be heard in the third and also in the fourth and fifth interspaces. This is increased on pressure and decreases on deep inspiration and upon change in the position of the patient.

Where adhesion takes place it will be seen that the area of impulse is enlarged, and that upon systole there is a retraction at the point of the apex beat. Freidreich says: Collapse of the jugular vein is apparent on diastole.

Diagnosis:—The disease may be distinguished from acute endocarditis by the fact that the latter disease has no friction sound, but has a widely diffused blowing murmur and a more rapid and feeble pulse beat. In cardiac enlargement there is an enlarged area of dulness, which, however, does not extend beyond the apex. There are no friction sounds and the apex beat is distinct. In acute pleurisy the sounds are synchronous with the respiratory movements, and there is acute pain on inspiration or on movement.

Prognosis:—The disease in its acute form will usually run its full course within a few days, but it is so apt to be overlooked until it has fully developed, or until effusion has taken place, that it may become sub-acute, or chronic, and may last for weeks and terminate in permanent hypertrophy and dilatation. When it is caused by a metastasis of a rheumatic inflammation it is amenable to treatment and may terminate within a few days, with but little effusion, which usually is quickly absorbed.

The disease may be complicated with pleuritis, myocarditis or endocarditis, in which case recovery depends somewhat upon the character and progress of the complications. The disease terminates fatally in only a few of the complicated cases, but it often becomes chronic and important and intractable changes, as dilatation and adhesion result, as stated.

Treatment:—The medical treatment will be similar to that of an acute inflammation of any serous membrane. Hot applications over the precordium, persisted in, with bryonia and aconite, will meet most of the indications. The bryonia indications are especially conspicuous, but aconite given alternately exercises an especial sedative influence upon the circulation within the structures of the heart, and with the influence of bryonia will prevent effusion and adhesion, or will promote absorption of an effusion before adhesion has taken place.

When the pulse is hard, strong and rapid, the skin moist and cool, the face dull or livid at the onset of the disease, in a distinctly sthenic case, veratrum viride in minim doses of the tincture every hour will tend to abate the disease. It soothes irritation of the nervous system, dilates the capillaries, reduces the intense arterial tension, promotes ready evacuation of the engorged venous capillaries and reduces the pulse and temperature. This remedy must not be given later than two or three days after the onset of the disease, nor where the disease occurs during the progress of some other severe inflammation, from which there is debility or structural change.

Bryonia is so specifically a remedy for inflammation of serous membranes that it is directly called for here. It operates upon the circulation within the diseased membrane and does not affect the action of the heart as do aconite and veratrum. It is doubly indicated in acute rheumatic pericarditis.

When the disease develops idiopathically and in a severe form at the onset most active steps should be taken at once to attract the blood to the extremities. A hot mustard foot bath, or sitz bath, with the hands immersed, will be the first measure. This should be followed with dry cups to the chest and over the spinal ganglia, followed by a mustard poultice to the spine. The patient should be put into bed and kept quiet. He should not be allowed to help himself or exercise in any way, the muscular system should be kept at rest and every possible nervous and mental irritation should be removed. Where there is a serofibrinous exudate, bryonia is of especial service if there are little sharp shooting pains in the heart, or if the patient insists upon lying perfectly quiet for fear that movement will increase the condition of the distress. It should be continued through the period of effusion.

In a plainly congestive type of the disease, with difficult breathing, dull, bloated, purplish countenance, dull eyes, dilated pupils, cool, moist skin, cold extremities and feeble pulse, belladonna will act most satisfactorily. It should be given for twelve or eighteen hours in active doses, alone, unless the temperature is high, in which case small doses of aconite may be given with it. When the above conditions are all changed, aconite alone, or with bryonia, should then be given, and the belladonna may be withdrawn.

Cactus grandiflorus is of much service in pericarditis, where the disease is the result of some other severe acute prostrating disorder. It is a remedy for asthenia. It soothes irritation from weakness, increases the nerve tone of the organ and directly and materially improves the actual nutrition of the organ. This the author has proven beyond all doubt. After the first, the sthenic stage, has passed, it can be given in small quantity, with almost any of the other indicated remedies. If there be a circumscribed area of oppression in the chest, or a sense of constriction, or band-like sensation around the chest, it is directly indicated.

Asclepias tuberosa is an important remedy in the first stage of an acute attack. This is especially true if the skin is dry, the mouth dry and parched, with much thirst, with severe chest pains, especially if from sudden and rapid effusion. It should be given in full doses of the specific medicine, or in infusion drunk freely.

To promote absorption of the effusion in the sub-acute or chronic stages, five grains of sodium salicylate should be given every two or three hours. This may be continued for two or three weeks. It will favorably affect the muscular structure of the heart, except when greatly enfeebled, and will antagonize all rheumatic conditions most directly. It acts in harmony with bryonia. Any deleterious influence upon the stomach should be watched for. The iodids are useful to promote absorption. Sodium iodid in full doses, and phytolacca given in conjunction, are valuable. I am also favorable to the action of the potassium acetate in small doses five times each day, but this is an auxiliary remedy only. The use of stimulants and tonics is imperative in the protracted cases, and where there has been previous severe prostrating disease I have given strychnin in solution, in an elixir of the glycerophosphates, or strychnin and iron with the hypophosphates, in an elixir of hydrastis canadensis. Cactus is here valuable because it not only improves the nutrition of the heart, but of the central nervous system. It will give excellent results if combined with avena sativa. Strophanthus is too irritating to the heart muscle to be given if myocardial inflammation is present, as is more than likely in many cases. The same objection may be applied to digitalis. When cyanosis, with greatly impaired respiration, rapid, feeble and irregular pulse appears, the use of quebracho is important, with oxygen, until cardiocentesis can be performed. A hypodermic needle may be inserted through the fourth or the fifth intercostal space, at the margin of the sternum, determined by the apex beat and fluid withdrawn to assure its presence, and determine its character. If purulent it is safer to open the chest wall by free incision and the sac by resection. If serum is present, aspiration may be performed, but the utmost care must be exercised. The mortality in operative cases is above fifty per cent, but when there is a necessity for operation, recovery without it is hopeless.

The Eclectic Practice of Medicine with especial reference to The Treatment of Disease, 1910, was written by Finley Ellingwood, M.D.