Inflammatory complications sometimes arise in the course of diphthe ria. After the operation of tracheotomy for membranous croup, it is un fortunately far from uncommon to find the temperature rise to 102° or 103', and to discover, on examination of the chest, all the signs of acute consolidation of the lung. Sometimes, however, the pulmonary lesion is an early complication. In any case it greatly lessens the child's chances of recovery.
Inflammation of the pericardium and endocardium are occasional com plications of the illness. Pericarditis occurring alone will probably be overlooked without a careful examination of the precorclial region. Enclo carditis also may give rise to but few symptoms, and is often onlyslis covered on examination of the body after death. We must, however, be on our guard, and avoid attributing to endocarditis the lmmatomatous beading of the mitral valve described by Parrot. (See page 546.) When a thrombus forms in the heart, death may occur either suddenly at the moment of formation of the coagulmn, or gradually after an interval of much anxiety and suffering. Usually the symptoms appear quite sud denly, and at a time when the child seems to be going on favourably to con valescence, or even after recovery is far advanced. If the formation of the clot does not bring the case to a sudden termination, marked clyspnoea is one of the earliest signs of the accident.
Dyspncea arising from want of blood in the pulmonary circulation is shown, as Dr. Richardson has pointed out, by symptoms very different in character from those due to an obstructed larynx. In the first case, al though the breathing is laboured, the lungs are full of air and may even be distended with it sufficiently to produce in the younger subjects a pecu liar prominence in the anterior part of the chest. There are no signs of imperfect aeration of blood, but all the symptoms indicate obstruction to the circulatory current. Thus the lips and cheeks are blue ; the jugular veins distended ; the heart-impulse quick, feeble, and irregular. The body is cold and pale ; it may be marbled, especially at the extremities ; and there is intense anxiety and constant movement. When death occurs, the heart ceases to act before the respiratory movements have come to an end.
On the other hand, when apnea occurs from laryngeal obstruction the symptoms all point to imperfect aeration of blood. The surface of the body is dusky instead of pale ; the heart-sounds are clear ; the cardiac impulse is feeble but rarely tumultuous ; the lungs are congested but not emphyse matous ; there is great recession of the epigastrium and soft parts of the chest at each inspiration ; the muscles are convulsed ; and the breathing stops before the movements of the heart cease.
Sudden death is due in most cases, probably, to the rapid formation of a clot in the right side of the heart. It may be also the consequence of paralysis of the cardiac branches of the par vagum ; but in cases where the sudden end has been attributed to this cause, a granular degeneration of the cardiac muscular fibres with softening of the walls and dilatation of the cavities has been discovered on careful examination. Leyden suggests that the cardiac failure is the result of these changes. According to this observer, dangerous weakness of the heart from this cause is indicated by gallop-rhythm of the heart-sounds with weakness of the impulse and irreg ular tremulous contractions. Vomiting, due to a reflection of the disturb ance to other parts of the pneumogastric nerve, indicates that the danger is pressing. Other observers have noted precordial distress, extreme dysp ncea, smallness and irregularity of the pulse, and attacks of palpitation alternating with slowness of the pulsations. H. Weber has found the pulse fall to twenty-eight or even sixteen beats in the minute.
In a certain proportion of cases of diphtheria convalescence is inter rupted by the appearance of paralytic lesions. The frequency with which this complication is found to occur has been variously estimated. Probably it depends in some measure upon the character of the epidemic. The de gree, too, to which the nervous system is affected is subject to great variety. In some cases the lesion is so trifling as scarcely to attract atten tion. In others it amounts to well-defined and general loss of power. Taking mild and severe forms together, the proportion of patients who suffer from the complication is probably one in every ten or twelve cases.