Statistics do not give pneumonia its proper place among the fatal diseases of old age. My own experience leads me to believe that it is the most fatal of all acute diseases at this period of life, for the large number of autopsies in which it has been found to be the cause of sudden death in individuals of advanced years, and the frequency with which red or gray hepatization is found at the autopsy when pulmonary disease was not suspected during life, must greatly increase the statistical rate of mortality. Many modern authorities, who have had large experience in the hospital practice of the aged, state that nearly nine-tenths of those who die over sixty-five die of pneumonia. Pneumonia is more fatal in females than in males, in the proportion of about 3 to 2.
Statistics vary in regard to the influence of seasons on the prognosis in pneumonia. In some years the proportion of deaths is far greater in summer than in either the spring or winter. And it must be acknowledged that certain as yet unknown atmospheric influences are of the utmost importance in determining the death-rate in different years. Statistics do not show that the mortality-rate is greatest during cold weather.
The prognosis is greatly influenced by the extent of the pneumonia. Double pneumonia is not often recovered from, and pneumonia of an entire lung is more dangerous than when only a single lobe is involved. In pneumonia at the apex in infancy and old age the prognosis is unfavorable. The more feeble the patient at the time of the attack, the less are his chances of recovery. Previous attacks have no influence over the prognosis.
Most authors make mention of certain diseases that complicate pneumonia. Few give condensed statements of their influence on the death-rate. In 255 cases of my own, 87 were fatal and 168 recovered. Of these 255 cases, 124 were complicated and 131 were uncomplicated. Of the complicated cases, 75 died; of the uncomplicated, 12. Of these complications, alcoholism was present in 30 cases, pleurisy in 17, Bright's disease in 13, pericarditis in 9, hypertrophy and dilatation of the heart in 3, peritonitis in 2, fibrinous bronchitis in 1, and rubeola in 1. Lebert in his statistical report on pneumonia states that he lost only 5½ per cent. of his uncomplicated cases and all of his complicated cases. Huss of Stockholm lost 6 per cent. of his uncomplicated and 20 per cent. of his complicated cases. Wilson Fox says that, according to the reports of English physicians, pneumonia complicated by endocarditis is fatal in 75 per cent. of the cases; complicated by pericarditis, in 54 per cent.; by Bright's disease, in 50 per cent.; and by alcoholism, in 25 per cent. Brundes of Copenhagen in 120 uncomplicated cases lost only 62/3 per cent., while of 22 complicated cases he lost all, or 100 per cent. Thus it is evident from my own records, as well as from those of others which I have given, that the rate of mortality in complicated pneumonia is much greater than in uncomplicated.
By a careful study of these complications it is apparent that they all exert a direct influence upon the heart, diminishing its power and crippling its action by obstructing the blood-current from the right ventricle toward the lungs. It is unnecessary to discuss these complications in detail; it is sufficient to state that weakening of the contractile power of the cardiac muscle is an essential feature of endocarditis, pericarditis, Bright's disease, and alcoholismus. In all acute infectious diseases such complications are regarded as dangerous, because they increase the liability of heart-failure when such failure is especially to be feared.
Other complications in addition to those already mentioned which increase the mortality-rate in pneumonia are chlorosis, phthisis, emphysema, laryngitis, oedema glottidis, bronchitis, pleurisy, parotitis, pregnancy, erysipelas, and rheumatism. Bronchitis, pleuritis, and jaundice do not seem to increase the mortality-rate very much, although they certainly influence it; while pregnancy, parotitis, and affections of the joints are very serious complications. Excepting small-pox and cholera, abortion is more apt to occur during the course of pneumonia than in any other acute disease.
A case of pneumonia may be called mild so long as the temperature does not rise above 104° F.; an elevation of temperature above 106° F. for two days renders the prognosis unfavorable. Wunderlich48 says that a gradual rise in temperature after the fourth day is always an unfavorable symptom. A low temperature is dangerous only when the respirations are very much accelerated.
48 In Die Eigenwärme in Krankheiten.
When the pulse is 120 or 130 for two or three days, the prognosis is bad; if the pulse reach 150 per minute, a pneumonia patient rarely recovers. An irregular and intermittent pulse, and one whose tracing exhibits dicrotism, has a most unfavorable prognosis. In children the rapidity of the pulse is not of so much importance, while in old age the pulse is seldom or never a reliable element in prognosis. A feeble, irregular, and intermitted pulse is always an unfavorable symptom.
Prune-juice expectoration is also an unfavorable sign, as it indicates extensive blood-changes or a depraved condition of the patient. If there is an entire absence of expectoration in the second or third stage of a pneumonia, or if it becomes scanty and difficult, the prognosis is unfavorable. Any sudden suppression of the expectoration, with coincident tracheal râles, in any period of the disease, indicates impending death.