In this condition there is a mild grade of catarrh of the lining mucous membrane of the larynx, accompanied by marked spasm of the laryngeal muscles. This spasm is an outcome of the excessive reflex nervous irritability common to young children and gives rise to the characteristic features of the disease.
Spasmodic croup may occur during the first six months of life, but is most frequent from this age up to the third year, when the tendency gradually diminishes until after the fifth year attacks are unusual. While it occurs in both healthy and delicate subjects, some children possess a peculiar susceptibility, in which heredity seems to play a part. One attack predisposes to others. The exciting causes are exposure to cold, dampness, and high winds, overeating, and indigestion and constipation.
An attack may come on suddenly or be preceded by hoarseness or by the symptoms of nasal catarrh. The precedent symptoms usually appear about midday and gradually increase. As evening approaches an occasional hollow, barking, evidently painful cough is noticed and the voice is very hoarse; toward midnight the cough becomes more brazen and more frequent and the breathing difficult. In very mild cases these disturbances are not severe enough to wake the child, but when the laryngeal spasm is marked, respiration becomes very labored, especially the inspiratory movement, which is attended by a hissing sound and by visible retraction of the soft parts above and below the breast-bone. Terrified by the want of air the child sits up in bed and struggles for breath. The face has an anxious expression; the cheeks are flushed, although the lips may be bluish, and the forehead is covered with drops of perspiration. The breathing is slow and labored and any excitement or effort increases the difficulty. The voice is hoarse but not lost. The cough has a characteristic brazen tone. The pulse is increased in frequency, and while the temperature may remain normal it is usually moderately elevated.
If untreated such an attack slowly disappears, and in the course of three or more hours the child, exhausted, drops to sleep. Next day, with the exception of hoarseness and an occasional barking cough, nothing seems amiss; but in the late afternoon or near midnight the spasm returns and is even more severe than before, and after a second free day is apt to be repeated on the succeeding night, although this third attack is, as a rule, much less severe than the others.
The treatment of an attack of croup must be left to the physician, but a mother can do much in the way of prevention. When the susceptibility exists, the child must be carefully guarded against exposure to cold, high wind and dampness; must be properly fed, never allowed to become constipated, and everything known to induce an attack must be rigidly avoided. Plenty of outdoor life and fresh air, under proper restrictions, are to be recommended. All local excitant conditions - as adenoid growths or hypertrophied tonsils - should receive attention, and if there be general ill health and want of tone, the system should be built up by food and tonics.
Upon the onset of hoarseness and a croupy cough, syrup of ipecacuanha should be given in doses of 3 to 5 drops in a little sweetened water every two hours, and the throat and anterior part of the chest thoroughly rubbed with camphorated oil every four hours.
When an attack occurs - before the arrival of the physician - hot compresses should be applied to the region of the larynx, and sufficient syrup of ipecacuanha administered to secure free emetic action, and in this way relax the laryngeal spasm - 15 to 20 drops every fifteen minutes, for three or four doses, with intermediate draughts of warm water, will usually accomplish the result quickly. At the same time moistening the air of the chamber with vapor from a croup-kettle will add greatly to the comfort of the patient; or better, a canopy or tent may be placed over the bed and the steam introduced beneath this.