PERTUSSIS (WHOOPING-COUGH).
Definition.—An acute infectious dis ease manifesting itself, at the onset, by catarrhal symptoms confined chiefly to the upper respiratory passages, larynx, and trachea, and of which the cough toward the end of the second week as sumes a peculiar convulsive character known as the "whoop." Symptoms.—After a variable incuba tion-period of from five to thirteen days, the symptoms of a more or less severe coryza present themselves: a coryza at the onset unable to be distinguished from that due to other diseases. The cough at this period is not characteristic; gradually, however, it assumes a parox ysmal character and is more frequent during the night than is the case with cough due to ordinary causes. At this stage it is seldom that any adventitious sounds are to be heard in the chest.
Toward the end of the second or dur ing the third week the characteristic cough develops. The child recognizes its oncoming and endeavors to suppress it,. or runs to its mother or nurse for sup port; a series of qnickly-repeated short coughs bursts forth and persists until the chest is in a state of extreme expiration; the face becomes congested and cyanotic, and the eyes suffused; then follows the long-drawn inspiration accompanied by the characteristic "whoop." This may be repeated two or three times. The parox ysm generally ends with the expulsion of a large quantity of clear, thick, tenacious mucus from the upper part of the throat. Vomiting, with complete unloading of the stomach, frequently takes place at the same time. In delicate children, and especially in infants, these paroxysms produce great exhaustion, and the little patient falls back with lived face and pulse almost uncountable; the great strain may also induce tenderness of the respiratory muscles.
The frequency with which these parox ysms occur varies much according to the period in the disease and the severity of the attack. In mild cases, eight or ten, in severe cases twenty or thirty, may oc cur during the twenty-four hours. Their severity is also variable. Both the fre quency and severity of the spasms are greatest during the first two weeks of the spasmodic stage, after which they gradu ally lessen. In some undoubted instances
of the disease the characteristic whoop is quite absent. The disease generally runs a longer and more severe course during the late autumn and winter months than during the spring and summer. Impure air, cool draughts of air, and the recum bent posture are apt to increase the fre quency and severity of the spasms. The total duration of the disease varies from two or three weeks to eight or ten. The presence of adenoid vegetations in the naso-pharynx adds to the severity and duration of an attack.
Pertussis does, on rare occasions, at tack persons of adult age; in such the spasms are not so severe, the whoop is seldom characteristic, and complications are infrequent.
Diagnosis.—During the early catarrhal stage it is difficult, except in those cases in which we know there has been a direct exposure, to distinguish between pertus sis and a catarrhal condition arising from other causes. Toward the close of the catarrhal stage, the spasmodic character of the cough, its frequency and severity during the night, the suffusion of the eyes, and puffiness of the lower lids, are all suggestive symptoms, but not abso lutely diagnostic. Slight ulceration of the frcenum linguae due to the violence of the cough frequently occurs in young infants in whom the incisor teeth have been cut.
After the second week the cough gen erally becomes characteristic and is easily recognized by the attendant. A parox ysmal cough closely resembling that of whooping-cough may be induced by en largement of the bronchial glands. In early infancy laryngeal spasm producing stridor closely resembling the whoop of pertussis may be due to a catarrhal laryn gitis.
Blood examined in 55 cases of whoop ing-cough, and constant leucocytosis, sometimes considerable in amount, found. In 32 of the cases the leucocytes num bered more than 20,000 in the cubic millimetre. The number was highest in the third and fourth weeks of the dis ease,. when the fits of coughing were at their worst. This corroborates the view that whooping-cough is a general, and not a local, disease. Frohlich (Jahrbuch f. Kinderh., vol. xliv, No. 1, p. 53, '97).