ACQUIRED ATELECTASIS Etiology.--Ude from the congenital form, atelectasis develops with relative frequency in young children, since tbe underlying causes are frequently found grouped together, viz., general debility, occlusion of the bronchi, and insufficiency of the respiratory muscular apparatus.
In every case of bronchiolitis and bronchopneumonia, atelectatic spots of varying extent are found beside the inflatned portions. Infants suffering from active rachitis of the thorax are particularly predisposed to atelectasis, becaus.e the primary weakness of the muscular apparatus combined with the flexibility of the ribs favors respiratory insufficiency to a great extent alagenbach). In addition, all debilitating diseases such as typhoid fever, chronic gastro-enteritis, atrophy, etc., bring about a predisposition to this condition.
Pleuritic and pericarditic effusions, ascites, etc., lead to atelectasis by compression. The atelectasis is usually produced in occlusion of the bronchi and insufficient expectoration, by the fact that the air becomes absorbed from the isolated alveoli, causing them to collapse.
The atelectatic portions are naturally found in those situations most frequently predilected by bronchopneumonia; ascending upwards from the lower posterior portions of the lungs, and also in the anterior borders of the lungs. The individual patches vary from the size of a pea to that of a walnut, and by coalescence may even involve an entire lobe. The affected lung tissue is vascular, bluish red (like raw meat), non-crepitant, sharply defined, and depressed below the level of the adjacent portions of the lung.
The symptoms are rarely well marked, and are usually masked by the primary affections, especially bronchiolitis and bronchopneumonia. A clear picture of atelectasis is more readily to be found in severe rachitis and marasmus. The respiration gradually increases in frequency, and becomes superficial. Inspiratory dyspncea and inspiratory recessions appear. The percussion note is tympanitic, and slightly diminished (usually bilateral, behind and below) over the affected portions. The
respiratory murmur is diminished, more rarely bronchial; fine or crepi tant rales are frequently heard in deep respiration. The fremitus may be distinct or diminished (from occlusion of the larger bronchi). In pure atelectasis there is an absence of fever; and the temperature may even be subnormal as a result of insufficient oxidation. Whenever the atelectasis is very extensive, stasis in the puhnonary circulation results, with cyanosis and cedema of the skin. Frequently, however, fever is also present, caused by the existing primary disease. The atelectasis may gradually disappear; or by increase of the respiratory insufficiency and spreading of the bronchitis or bronehopneuinonia may lead to a fatal termination.
The diagnosis is usually difficult, and the etiology must always be considered. A criterion is the gradual development without fever in diseases having a tendency to this condition, in addition to the above mentioned symptoms. A differential diagnosis must be made from croupous and bronchopneumonia, pleurisy, pulmonary tuberculosis, and hypostatic congestion. Pulmonary hypostasis develops under similar circumstances and with similar symptoms in cases of greatly diminished heart action, which leads to a passive congestion of the dependent por tions of the lungs. It is often difficult to distinguish it from broncho pneumonia, especially the afebrile, cachectic form of this disease.
The prognosis depends upon the underlying cause.
The prophylaxis must be directed especially to rachitis. Young infants, particularly those suffering from bronchitis, must be carefully carried about.
The treatment is principally directed the underlying cause. Stag nant expectoration must be actively stimulated, if necessary-, by warm baths and cold douches. The further spread of the atelectasis is to be counteracted by frequent changes of position, and by carrying the patient about.