Morbid Anatomy.—The pathological characters of peritonitis are the same in the child as in the adult. The vessels are injected, and the normal polish of the serous surfaces is lost, owing to inflammatory exuda tion. There is infiltration and thickening of the sub-serous tissue, with proliferation of cells in the epithelial covering of the membrane. The exudation poured out from the distended capillaries coagulates on the surface and forms a false membrane, which is at first thin and grayish in colour, afterwards thicker and yellow. It causes adhesion between neigh bouring organs, and glues the coils of intestine to one another. There is besides effusion into the abdominal cavity. Its quantity varies. Some times it is copious. The fluid is usually opalescent, from proliferated epithelial cells, or may be distinctly purulent.
The longer the disease continues, the tougher and thicker the exuda tion becomes, so that it may form bands which pass from one organ to another, and in long-standing cases may constrict portions of the bowel and cause serious consequences. If the patient survive, the fluid becomes absorbed, and the exudation gets tougher and forms firm adhesions be tween neighbouring parts, as well as opaque fibrous patches upon the surface of organs, more or less thick and hard. When the peritonitis is at first partial, as may happen when the inflammation is due to perforation of the bowel, the exudations and consequent adhesions may confine the extravasated matters within certain limits, and thus localise the inflamma tion.
Pent-up collections of matter may also arise in the following manner : On account of gravitation the purulent fluid is apt to collect in certain spots, espeCially above and behind the liver. If the child do not die, the fluid, thus accumulated, may become shut off by adhesions so as to pro duce a local abscess. Abscesses arising in this way are usually seated near the diaphragm, often between that muscle and the liver or spleen. Such a collection of matter may eventually open into the chest and set up pneumothorax.
Symptoms.—In the child peritonitis may give rise to violent and acute symptoms, as it does in the adult. As a rule, it is the primary form— essential peritonitis, as it has been called—which is accompanied by these signs of serious disease. Also, when the inflammation follows upon a blow or other external injury in a child previously in good health, the symptoms are usually striking and severe. In the secondary form, when the child is already reduced by illness, the symptoms, although often sufficiently pro nounced, may yet be to a certain extent masked by the state of profound collapse into which the patient is thrown. In other cases the disease may be more or less latent, and indeed is sometimes not discovered until the body is subjected to examination in the dead-house.
In the severe primary form the child complains, often quite suddenly, of pain in some part of his belly—in either flank, above the pubes, or about the navel At first comparatively slight, the pain soon gets more severe and general, and at the same time the belly becomes tender. Vomiting is
almost always an early symptom. The child first ejects partially digested food, and then glairy and bilious matters. If the efforts to vomit are vio lent, they occasion great distress, on account of the pain and tenderness of the belly ; and after each effort the child lies back with haggard, pale face, beads of sweat standing upon his broev. Fever is present from the begin ning, and may be preceded by a sense of chilliness, or even distinct rigors. The degree to which the temperature rises varies, as it does in inflamma tion of the other serous membranes in the child. Sometimes it may reach 104°, or even higher, but at other times it remains little over 100°. The average degree of pyrexia is perhaps between 101° and 102°. At night the -child is restless and sleeps little, often waking up and crying with pain in his belly. Sometimes he is disturbed by delirious fancies and talks wildly.
Almost from the first the child is unwilling to move, and he soon takes to his bed. There he lies upon his back, or inclining to one side, with legs and thighs flexed. His face is pale and distressed, his nose looks sharp, and the nostrils are thin and expanded. The slightest touch upon the belly is painful, and he seems to dread the least movement. If the coat of the bladder is involved, there is retention of urine. If the peritoneal coat of the bowel is inflamed, attacks of the most violent colic may come on at intervals, and throw the child into an agony of pain. On examination of the belly, this is seen to be distended with gas ; it is motionless in res piration ; there is some tension of the parietes, and the tenderness is exces sive. Gentle percussion elicits a tympauitic sound over the anterior re gions ; but in the depending parts, where the fluid collects, the note is dull. Sometimes the fluid is sufficient in quantity, and sufficiently free, to give a distinct sense of fluctuation ; but the absence of free fluctuation is no sign of the absence of fluid. There is often effusion between the coils of intes tine and in the meshes of the exuded lymph ; but this transmits the wave of fluid very one side of the belly to the other. As a general rule, perhaps, fluctuation is imperfect or absent. In these cases Duparcque has suggested that the child should be placed on his side for a few minutes. The whole quantity of fluid will then gravitate to the flank on the depending side. If the child be then quickly turned upon his back, dulness and fluctuation will be found at first at the site of the accumulated fluid, but owing to the second change of position will quickly disappear.