Diagnosis. — When the joint affection is well marked it can scarcely be mistaken. An acute articular inflammation which flies from joint to joint capriciously, is accompanied by redness, swelling, and extreme ten derness, and in a day or a couple of clays has passed completely away from the joint first attacked, to run the same rapid course in another— such a disease can only be rheumatism. Real rheumatic joint affections are very transitory. If redness, pain, and swelling persist in a joint supposed. to be rheumatic, we may suspect strongly that the true cause of the lesion has yet to be discovered. It is often difficult to decide the nature of the obscure pains and stiffnesses from which some children suffer. The so called "growing pains " are often rheumatic in their origin ; and if they occur in children of decided rheumatic family tendency, should be re garded with extreme suspicion. A careful examination of the chest will often clear up obscurity, and it is unfortunately too common to find serious valvular or pericardial mischief associated with a very trifling amount of articular or even muscular pain in young subjects. A to-and-fro friction sound over the priecordial region, if decided, is very suspicious in itself of pericardial inflammation. If the child look ill, and especially if there be also increase of the heart's dulness, the evidence in its favour is complete. A faint double rub at the base of the heart is not in itself sufficient to es tablish this conclusion ; for such a friction may be produced by slight roughness of the pericardial surface, from prominent vessels or other cause, when the membrane is quite free from inflammation.
Dulness of pyramidal shape in the prcordial region, although very suspicious of pericardial effusion, is not conclusive ; such a dulness may be produced by a mass of enlarged glands in the anterior mediastinum. Ex tension of dulness to the left, beyond the point at which the apex beats, is said to be a positive sign of effusion. The increase in the dull area when the patient is placed in the erect position is often absent ; when. present, it is, no doubt, an additional proof of fluid accumulation in the. sac of the heart.
When the fluid becomes purulent, as it may do at an early date, the nature of the contents of the sac may be inferred from the variable temperature, the mercury rising every night to 104° or 105°, and sinking in the morning to the normal level, or even below it ; the early subsidence of the friction, although the amount of the effusion remains unchanged ; the stationary character of the dulness, showing want of absorption of the fluid ; and the appearance, after a time, of more or less general oedema without albuminuria.
On account of the frequency with which pericarditis and pleurisy are combined in young children, we should never neglect to make a careful examination of the heart in every case in which we have ascertained the existence of pleural inflammation. Pericarditis, under these circumstances,
is not easy to detect, as the dulness in the preecordial region is attributed to the effusion in the chest cavity. Unless, however, the pleural effusion be very great, the percussion note in the infra-clavicular region is very different from that obtained in the prwcordia. If, therefore, we find com plete dulness towards the upper part of the sternum, and a fairly resonant or wooden note below the clavicle near the acromial angle, we may strongly suspect accumulation in the pericardial sac. Friction over the heart may then be generally heard on careful auscultation.
A difficulty sometimes arises in these cases from a pleural friction of cardiac rhythm being heard at the limits of the pericardium. This is owing to the action of the heart causing a movement between the adjacent pleural surfaces. In these cases if the child be old enough, or sufficiently amia ble, to follow directions, we should listen at the seat of friction while the breath is held after forced expiration, and if the rub cease or be heard only at this spot, it is probably due to the cause referred to. It is not always possible, however, positively to exclude pericarditis.
If we hear a blowing murmur at the apex of the heart, the question of valvular competence has to be considered. All blowing murmurs at the apex must not be taken to indicate regurgitation, nor, indeed, are they a positive sign that the endocardium is inflamed at all. The murmur may be the consequence of regurgitation, of roughness of the valve or cardiac lining, of anminic dilatation of the ventricle, or of mere abnormal tension of a healthy valve, and there is nothing in the quality of the sound to show to which of these causes it may be properly assigned. If, however, the second sound is evidently intensified over the pulmonary artery ; if the murmur is heard at the angle of the scapula ; and if, with a full contrac tion of the left ventricle, the pulse is feeble, small, and irregular, we may confidently pronounce the mitral valve to be insufficient. Still, regurgi tation may take place without giving rise to these signs. Therefore, in most cases we must reserve a positive opinion, and wait until sufficient time has elapsed to allow of nutritive changes taking place in the wall of the heart. If there be no displacement of the apex-beat at the end of twelve months, we may be satisfied that the cause of the murmur is not regurgitation.
A recent murmur is very soft in quality and of low pitch. After being in existence for some months it becomes harsher and its pitch rises. If in a case of acute rheumatism we hear a harsh and loud endocardial murmur at the apex, we may be sure, whatever its mechanism, that it is not of re cent origin, but is a relic of some former attack.