Causes and diagnosis

In case of a common infection, the fever should disappear within 4 days. If the fever persists beyond that or even increases, a doctor should be consulted in any case to find out the cause of the fever. The doctor should ask about previous operations, immuno-choking medication, travel abroad, handling of sick animals and contact with patients with infectious diseases.

If the patient answers in the affirmative, appropriate therapy must be initiated immediately. When measuring fever, the generally valid physical examination of the patient must of course be carried out, including listening to the heart and lungs (auscultation) etc. Infection parameters, such as leukocytes and CRP, which are elevated during an infection, should also be examined.

If a leukocyte increase is detected, it is usually a bacterial infection; if a leukocyte decrease is detected, it is usually a viral infection. In case of a more detailed diagnosis of fever, a urinalysis or an examination of the sputum of the sick patient can be performed. A so-called blood culture can also be made, which after a few days can provide information about the corresponding pathogen.

In most cases, however, the pathogen identification with this method turns out negative. However, a blood culture should be performed on 2 consecutive days (at least 2-3 samples per day). The examination of the so-called “thick drop” can rule out malaria.

However, it is important that the patient’s data are compatible with a malaria infection beforehand. Later, an ultrasound can also provide information as to whether organs are involved in the development of fever due to inflammation. Gynecological and urological examinations as well as X-ray examinations would provide the full picture of the diagnostic measures.

For some diseases it may be useful to draw up a fever curve. For this purpose, the fever is measured at different times of the day and the values are entered into a diagram. This results in a fever curve, which is best plotted for several days.Some diseases, such as malaria, show a characteristic fever pattern, so the fever curve can be helpful in finding the cause.

If the elevated temperature persists for a long period of time, the thyroid gland values in the blood should be examined, as hyperthyroidism can lead to an increase in body temperature. Further diagnostic tests should always be performed if the fever occurs in conjunction with cramps and convulsions. The so-called febrile spasm occurs almost exclusively in small children and represents an absolute pediatric emergency that should be examined immediately in hospital. Frequently, even in small children who are just getting their first teeth, a rise in temperature and fever occurs, which need not worry further.