According to Blumenthal-Hippius the condition of the urine is said to be diagnostically important even in the catarrhal stage. It is of a pale yellow color, strongly acid, of a high specific gravity (1.022 to 1.032) precipitating a large number of crystals of free uric acid. The daily quantity of uric acid secreted exceeds the normal by two or three fold. Co-existing febrile complications very much lessen the value of urinary findings as specific symptoms.
Glycosuria in whooping-cough has been frequently reported, but the excretion of sugar is far from being constant.
With regard to the condition of the blood in whooping-cough it may be said, according to recent examinations (F. Cima), that in simple pertussis leucocytosis occurs at the very inception, three times as many white blood corpuscles as in the normal condition being usually found. The intensity of leucocytosis runs parallel to the intensity of the dis ease. The increase in the number of leucocytes is greater in smaller children and during complications. With regard to the increase of the several forms of leucocytes in the sense that the increase of the lympho cytes precedes that of the polymorphonuclear leucocytes, or that the number of the former decreases in proportion as the latter increase, no definite law has been observed. Consequently, nothing positive can be enunciated concerning the pathogenetic mechanism of the leucocytosis. In doubtful eases the blood findings may be of diagnos tic value.
Examinations of the blood (by Crisafi) in whooping-cough are said to give positive iodine reaction in SO per cent. of the cases. The iodo phile granules are present in variable numbers, especially in the polynu clear leucocytes, less frequently in the eosinophiles and rarely in the lymphocytes.
Under certain circumstances we meet with variations from the usual course of pertussis. Here belongs the frequently shortened and scarcely characterized catarrhal stage in young infants. In such cases the spasmodic paroxysms set in rapidly, often in the first days of the illness. In children of the first year of life the characteristic stridulous inspiration following the succession of staccato-like coughing efforts is lacking, and the rarity or total absence of deep inspiration easily leads to apnoea and to syncopal accidents.
At the beginning of the convulsive stage, rarely during its whole course, the paroxysms at times set in with spasmodic sneezing, which presently passes into a convulsive cough, or, seldom, by itself constitutes the whole paroxysm, and terminates with choking and vomiting. Such
a vicarious sneezing may persist during the whole of the whooping cough.
A dyspeptic form, too, in which gastric and intestinal disturbances, along with spasmodic cough, arc the salient features, has been observed by several (Jacobson), but such forms are dubious.
Sometimes the course of pertussis is characterized by such mild symptoms that only the existence of an epidemic and the history of ex posure to the infection enable us to form a diagnosis. The paroxysms are but slightly marked, the cough resembles the vigorous and repeated expiratory efforts met with in bronchitis with scant secretion, and the whooping inspiration is lacking. In adults such forms (coqueluchette, forme fruste) are more frequent than in children. A correct recognition of such a case is not merely diagnostically important, but also for the reason that it might easily become the starting-point of a house epidemic and a further spreading of the disease.
In its symptoms pertussis at times becomes indefinite, when accom panied by febrile complications together with great prostration or considerable respiratory disturbances, and above all by broncho pneumonic infiltrations. In such conditions the coughing spells lose their characteristic peculiarities, and assume the form of short, dyspnceic coughing efforts. Now and then the underlying affection betrays itself by severe cyanosis and jerky respiratory efforts ending in syncopal attacks.
The average duration of whooping-cough in light uncomplicated cases, varies between eight and twelve weeks. Still the majority of cases exceed this duration considerably. Exacerbations and various factors prolong each of the several stages. The season of the year at which the illness sets in, constitution, etc., may cause the whooping cough to persist for months. Generally, during the warm, dry months conditions are more favorable. The observation has been made time and again, that weeks and months after the complete disappearance of the characteristic cough, a slight cold or a light bronchitis may revive in the child the typical cough of pertussis. This, justly as it seems, was explained by the assumption of a certain preparation of the nerve paths involved in the cough reflex. The superior laryngeal nerve is regarded as one side of the reflex arc. An abortive, greatly shortened course of pertussis is said to occur at times, but it is very rare.