Complications.—The complications of simple catarrhal pneumonia are not numerous. The illness sometimes begins with stridulous laryngitis, and in the rare cases where the spasmodic disease ends fatally death is usually due to the presence of the pulmonary inflammation. Gastric and intestinal catarrh have already been mentioned as frequent complications of the pneumonia. In the child a catarrh is seldom simple ; often several tracts of mucous membrane share in the derangement.
Catarrhal pneumonia is itself also a common complication of other forms of illness. Measles, whooping-cough, and rickets have already been referred to. General tuberculosis in many, perhaps in most, instances becomes complicated with this form of pulmonary inflammation ; and in the case of fibroid induration of the lung the danger of the disease consists in a great measure in the repeated attacks of catarrhal pneu monia to which children with this form of lung affection are peculiarly prone.
Diagnosis.—At the beginning of the illness we have to found our diag nosis upon the general symptoms alone, for there is at first no sign of consolidation, and physical examination of the chest only reveals the pres ence of severe bronchitis. Mere elevation of temperature is no proof that the inflammation has spread to the alveoli, for in many children—especi ally those with scrofulous tendencies—a pulmonary catarrh is accompanied by moderate pyrexia. If, however, the temperature reach 104° or 105,° and at the same time the cough get suddenly short, hacking, and painful, while the breathing becomes disproportionately quickened so as to cause notable perversion of the pulse-respiration ratio, this combination of symptoms is very suggestive of catarrhal pneumonia. A perverted pulse respiration ratio alone is not characteristic, for this may occur in cases of collapse of the lung. Still, if with great hurry of breathing we find the respiratory movements laborious, and notice that the soft parts of the chest recede deeply at each breath, the sign is in favour of pneumonia ; for in pulmonary collapse the breathing, although excessively hurried, is shallow, and unless the ribs are much softened from rickets the recession at the base of the chest is slight.
Quite at the beginning of the illness it may be difficult to distinguish the disease from the croupous form of pneumonia where the signs of consolida tion are delayed. At this time the age of the child, the history of the attack, and the character of the breathing are important points of distinction. In an infant the inflammation is probably catarrhal, and if the child is frail or badly nourished, is almost certainly so. The history of previous cough points strongly to the lobular form ; and laborious breathing, great reces sion of the chest-walls in inspiration and a very evident feeling of dyspncea are distinctive of catarrhal rather than of croupous pneumonia. The latter disease rarely attacks a feeble, ill-nourished ir!fant ; it comes on suddenly without previous catarrh ; the breathing, although hurried, is not labo rious ; and there is no true clyspncea, the child not being distressed by the recumbent posture.
When extensive areas of lung have become consolidated, the catarrhal origin of the lesion is distinguished by attention to the crepitation. This rile in croupous pneumonia ceases to be heard over the solidified area and can only be detected at its confines. In catarrhal pneumonia the crepitat ing rhonchus becomes finer and crisper towards the centre of the consoli dation, and is heard with the most typical bronchial or blowing breathing, being sometimes, indeed, so copious as almost or entirely to cover the breath-sound. Moreover, moist and dry bronchitis riles are heard over the lungs generally. In croupous pneumonia this is not often the case, for al though some sonoro-sibilant rhonchus is occasionally present, this is trifling in amount, and, as a rule, is not accompanied by moist sounds.
One of the chief difficulties in the case of catarrhal pneumonia is to ex clude tuberculosis. That we should be able to do so is of the greatest im portance with regard to prognosis ; for while, if the inflammation be uncom plicated, recovery may take place, if the child is tubercular death is certain. The subacute form of the disease occurring in a weakly child and accompa nied by diarrhoea and rapid wasting, presents symptoms which are identical with those resulting from acute tuberculosis with secondary lung complica tion. The physical signs are also the same, for no additional feature is fur nished by the presence of the gray granulation in the lungs. Family history is here of importance. If we can discover that other children of the same parents have died with symptoms of tubercular meningitis, the history is suggestive of tubercle. If, again, we can learn that before the onset of the disease the child was losing strength and growing pale and thin without evident cause, the fact is also in favour of tuberculosis. Again, the age of the patient must be considered. Over the age of six years catarrhal is less common than croupous pneumonia. Therefore, if the catarrhal inflamma tion occurs in a child more than six years old, who has been previously wasting without apparent reason, and has not lately suffered from measles or. whooping-cough, we have here strong evidence in favour of tubercle. Of the actual symptoms the only one which in any way points to a constitu tional cause for the illness is the presence of mdema without albuminuria ; but this phenomenon, although it may add weight to other evidence, is in itself of little value in a weakly child. If, however, any serious symptoms arise pointing to the brain, and convulsions occur, followed by squint, unequal pupils, ptosis, or rigidity of joints, we can have no hesitation in concluding the case to be one of acute tuberculosis. It must be remem bered that terminal convulsions are common in catarrhal pneumonia from asphyxia, and are quickly followed by death. But convulsions occurring in the course of the illness and not evidently the consequence of impurity of blood, are very suspicious of tuberculosis, even although no other sign of nerve-lesion be immediately manifested.