IliemorrhaOc encephalitis and acute poliomyelitis have been ob served after influenza and severe degenerative changes as in sclerosis have been described.
Psychoses of a more or less severe grade are occasionally seen during convalescence. These are manifested by hallucinations, cataleptic stupor, etc. The mind generally returns to its normal condition after strength has been restored. The disease may be ushered in by mental confusion, as in Ewald's case of a seven-year-old boy who at the outset of the disease went to the railroad station and boarded a train instead of going to school, without any recollection of what he was doing. Many children at the beginning of the disease fall almost in a condition of lethargy for which there is no satisfactory explanation. lleubner also found it during convalescence. Acute dizziness and delirium when present are a result of the high toxic fever.
In most cases of influenza there are no changes in the skin. How ever, it is not at all uncommon to find an exanthem in the course of this disease upon which too little emphasis has been placed. Generally this is a small, punctate, confluent erythema with itching which is found on the chest, abdomen and sides of the extremities. The exanthem in the majority of cases is very similar to that of scarlet fever and this may render the diagnosis under certain conditions exceedingly difficult..
Other eruptions may appear after a few days or in the second week. Filatow and others have described an eruption similar to measles and cases resembling urticaria, roseola, and purpura have been described.
It is doubtful if these rashes are a result of a mixed infection with influenza. In a large number of exanthemic infectious diseases the in fluenza bacillus has been found in the blood and different organs. A mixed infection with diphtheria has been reported and Jochmann found the influenza bacillus in a case of pertussis. Many authors have found the influenza bacillus to be the cause of a pneumonia occurring in the course of other diseases.
The lymphatic system plays a small part in influenza.
An uncomplicated case of influenza is generally only of a. few clays duration but it may be prolonged several weeks. The various complica
tions make the course of the disease very uncertain. This is especially true when the lungs are involved and a chronic congestion results which is very slow in disappearing. Filatow and others have described a pro tracted form of influenza which may persist for months without any special catarrhal manifestations, but showing a mild degree of fever, headache and weakness. The possibility of tuberculosis must not be overlooked.
The prognosis of uncomplicated influenza in children is favorable even when the lungs are involved but it should be guarded when the heart is affected. In general the prognosis depends upon the sympto niatology of the individual case. An influenza grafted on an existing tuberculosis is very unfavorable.
The diagnosis of influenza in children is not always simple when there is no epidemic, but when whole districts are affected it is a very easy matter. At such times the possibility of other diseases with symp toms similar to influenza should be borne in mind. After the exclusion of other diseases, the symptom-complex on the part of the various organs, the height of the fever and extreme weakness, the typical appearance of the mouth and throat all tend to establish the diagnosis.
Unfortunately the bacteriological diagnosis is seldom available for practical purposes. It is difficult to make the diagnosis when the symptoms described as meningismus are present. Have we to deal with a beginning influenza, or some form of true meningitis? In influ enza we may find some retraction of the head with tenderness on motion and irregular pulse and respiration. Rapidity and arrhythmia of the pulse are characteristic of influenza when it is present. Lumbar punc ture in these cases is of the greatest diagnostic importance.
In the differential diagnosis several possibilities must. be borne in mind. with sore throat and a. scarlatiform rash may simulate scarlet fever but the course of the fever and rapid disappearance of the rash will suffice in most cases to clear the diagnosis. Desquamation and infection of the lymphatic nodes never occur in influenza.