What are the Symptoms of Flu?
This is a disease which has ravaged mankind throughout the centuries. One of the most serious outbreaks recorded was that of 1918-1919, when the disease, starting in the East, swept over the greater part of the world, causing an enormous number of deaths. Why this devastating pandemic should have arisen is unknown. But it is noticeable that during epidemics the virulence of the disease increases greatly. It was thought until recently (1933) that influenza was due to a germ -Pfeiffer's bacillus- but it is now established that it is primarily caused by a virus-a germ of minute character which can pass through a porcelain filter impermeable to ordinary germs. Once the virus infection is established, there is a secondary invasion with other well-recognized germs, streptococci, staphylococci and Pfeiffer's bacilli.
The infection proceeds from one person to another probably by means of fine particles from the nose and mouth, and the disease is supposed to be most infectious in its early stages.
Influenza may be divided roughly into three types, the "catarrhal", the "gastro-intestinal," and the "pneumonic," according to the symptoms which specially characterize it, though it must be remembered that symptoms peculiar to each type may be present in the other varieties in greater or lesser degree.
The catarrhal (the commonest) form is usually ushered in by a feeling of lassitude, with headache of the kind that is made worse by movement, pains in the limbs, loss of appetite, and a sore throat. It is not definitely known what length of time elapses between the moment of infection and the development of symptoms, but it is believed to be about forty-eight hours.
Sometimes the first sign is an attack of faintness, sometimes a "rigor," or fit of shivering, but very soon the temperature rises, the general discomfort increases, and for three or four days the sufferer is more or less prostrate. The catarrh in the nose and throat may extend to the larynx, causing hoarseness or even loss of voice, or to the chest, producing tightness, soreness, and a cough. The gastro-intestinal form is not so common, but cases do occur where the fever, catarrh and pains in the limbs are not the most marked feature, but where there is nausea, vomiting, abdominal pain and diarrhea.
The "pneumonic" form was seen in its full virulence in 1918, and has not been of very common occurrence since.
Although called "pneumonic" the condition of the lung which proved fatal in many cases was not true pneumonia, but a filling up of all the air-passages with secretion, with the result that the blood could not receive its due amount of oxygen, and the sufferer showed the dreaded symptom of "cyanosis", or blueness of the face, a symptom which was nearly always an indication of the extreme seriousness of the disease.
In this type of case, the onset of the disease is often accompanied by bleeding from the nose, intense headache, pain and soreness of the chest, and cough. The headache is specially pronounced behind the eyes, partly owing to the general toxic condition produced by the influenza infection, partly to the fact that sometimes the spaces in the bones which make up the face are inflamed, and may even contain pus.
All forms of influenza, whether mild or severe, may be followed by complications which sometimes arise when the course of the disease itself seems to have been arrested.
The heart may be affected, not usually in the form of valvular disease, as in scarlet fever and acute rheumatism, but of inflammation of the membrane surrounding the heart (pericarditis), or of the heart-muscle itself (myocarditis).
Besides these conditions, which give rise to severe symptoms, there may be disturbances of the heart's action (palpitation, pain, a very quick pulse or a very slow one), which are functional in origin, that is to say, they are not caused by any discoverable disease of the heart. Any heart trouble which is already present is, of course, liable to be aggravated by an attack of influenza. The lungs are very commonly involved. Bronchitis and pneumonia are the chief dangers, and occasionally a chronic thickening of the lung remains. Inflammation of the kidneys is not a very common after-effect of influenza, but it does sometimes occur, and may leave permanent damage.
The nervous weakness, prostration and depression which follow influenza are the commonest of all its ill-effects.
Many people, with some justification, date the beginning of a long period of ill health to an attack of influenza. It has been found that very often a condition of low resistance and incapacity is set up by the general poisoning caused by a severe attack.
In rare cases a serious complication is meningitis, or inflammation of the membranes surrounding the brain. Inflammation of the middle ear is a condition which has increased in frequency in recent epidemics. Sometimes, after acute pain in the ear, an abscess is formed, and pus may perforate the drum of the ear and be discharged.
The chief enemy of influenza is fresh air. At any time when it is prevalent, overheated and overcrowded rooms should be avoided. In such an atmosphere the membrane lining the nose and throat becomes swollen and covered with a secretion which stagnates and forms a ready field for the growth of any bacteria inhaled.
The conditions are now such as to prevent a lowered resistance for the virus and other germs such as streptococci and pneumococci which are normally carried in the nose and throat, so that they become capable of producing disease.
For this reason faintly antiseptic gargles and sprays may be useful in preventing infection by stimulating the lining membranes to produce their normal secretion, which washes away the bacteria and tends to prevent their growth. Strong antiseptics constantly used, on the other hand, tend to wash away the protective secretion.
The preventive influence of diet must not be neglected in spite of the statistics which show that influenza took its toll in countries where food was plentiful. A diet which nourishes the tissues must raise their resistance, and a generous allowance of milk, butter, eggs, fruit and wholemeal bread, all containing vitamins and also to prevent stagnation of the contents of the intestine, will help to keep up the defenses against infection.
Special treatment has been instituted of late years in the form of " prophylactic vaccines". These aim at raising the disease-resisting powers of the body by forcing the tissues to produce an antidote against the secondary germ of influenza.
The vaccine given is usually prepared from a mixture of the bacteria (streptococci, pneumococci, bacillus of influenza, etc.), grown from the secretion taken from the nose and throat of persons suffering from influenza, and in many cases they have proved valuable.
Even the mildest cases should go to bed, not only with the object of avoiding complications, but also to avoid infecting others.
The room in which the patient is nursed should, if possible, be light and airy, but he must be kept out of the way of drafts. Fresh air is the best preventive against spreading the infection through the household.
The diet should be light- milk, beaten-up eggs, beef tea, chicken broth, jellies, etc., and a mixture of fruit juices orange, lemon and any stewed fruits will be found both acceptable and beneficial. The bowels should be freely opened at the commencement of the illness, and thereafter regulated by mild aperients.
For the sore throat, barley-water and linseed tea are soothing, and if the voice is very hoarse, inhalations may be given.
To a quart of boiling water in a jug is added a teaspoonful of Friar's balsam, and the patient inhales the steam with his head well covered. When there is tightness of the chest, or soreness of breathing, linseed poultices or applications of antiphlogistine may be used.
There is no specific drug which can be regarded as curative in influenza. In 1945, an influenza vaccine of the antivirus type became available in limited supply. Its preparation is difficult and it is still regarded as in the experimental stage.
The chief danger when broncho-pneumonia sets in is heart failure, and efforts must be made to keep up the patient's strength. Stimulants, drafts for sleeplessness and oxygen must, of course, be administered only under medical supervision. Any immunity from further infection which may be conferred by an attack of influenza has not been found to be lasting.