There is nothing to be gained by treatment.
Rupture of the Pulmonary Artery.
Violent effort and great excitement have been followed by rupture of the trunk or a main branch of the pulmonary artery. In the majority of cases the coats were degenerated, though this was not always the case (Chevers). Death is often instantaneous, but sometimes is delayed some hours. In one case observed by Ollivier the duration was twenty-seven hours.
Thrombosis and Embolism.
The pulmonary artery, from its position, is especially prone to become plugged, either by substances coming from other parts of the body or by coagula originating in the vessel itself. Pieces of disintegrated coagula from the systemic veins, the contents of echinococcus cysts ruptured into the venous current, fragments of new growths, are carried to the heart and pass into the pulmonary artery, or large thrombi may be detached from their position in a vein and lodge in the trunk or main branches of the pulmonary artery.
Primary thrombosis of the pulmonary artery is very uncommon. In certain septic conditions, in parturient women, in typhoid fever, and in extreme anæmia thrombosis of the pulmonary artery may occur. It commences perhaps in the right ventricle or at the pulmonary valves, though it is also seen farther up.
SYMPTOMS.—The severity of the symptoms depends on the completeness of the obstruction. There is dyspnoea, more or less marked according to the size of the thrombus or embolus, pain in the præcordia, great distress, anxiety, faintness, sense of suffocation, tightness in the chest, palpitation, lividity and extreme pallor, cold sweats, an almost imperceptible pulse, great restlessness, and occasionally convulsions. The mind remains clear. The symptoms develop gradually or rapidly—in the former case depending on the slow increase of a small thrombus—and remissions are often seen; in the latter case depending on the sudden lodgment of an embolus of large size. Sometimes the symptoms are extremely marked, and death takes place in a few minutes. The appearances are not those of asphyxia, and death is usually attributed to want of arterial blood-supply to the brain and medulla oblongata, and not to suffocation or paralysis of the heart.
Percussion shows a normally resonant chest. Auscultation gives normal breath sounds with free inspiration and expiration. There is very likely a basic systolic murmur conducted along the course of the pulmonary artery, but this is not constant. The cardiac second sound and impulse are increased. At the post-mortem examination the heart is found in diastole, the left cavities and pulmonary veins empty, the right cavities filled with blood, and the cardiac veins strongly distended.
DIAGNOSIS.—The diagnosis is often uncertain. When not developing with extreme rapidity the symptoms are very similar to those caused by stenosis of the pulmonary artery, and in the suddenly fatal cases they are almost identical with rupture of the heart or rupture of a thoracic aneurism, or even angina pectoris. The history of an antecedent thrombus or of a disease of the heart which is likely to be accompanied by thrombus, together with the absence of physical signs, render a diagnosis many times probable.
PROGNOSIS.—To be regarded as of the gravest character.