Any disease is a single process that naturally goes through certain stages as it develops. The most common is the division of the course of the disease into four stages: the latent phase, the prodromal period, the height and end of the disease. This approach was formed historically and was based on the study of cyclically occurring infectious diseases. It is difficult to apply such a classification to many groups of diseases.
Where does the disease begin
We can assume that the disease begins from the moment the human body comes in contact with certain pathogenic factors, after which the latent, latent phase of the disease begins. If we are talking about infectious pathology, then this stage is also called incubation. At this time, the pathogen microorganism (bacteria, viruses or fungi) is already circulating in the circulatory system, interacting with the human body, and the symptoms are still absent. It will appear later when the prodromal period begins, and the first signs of the disease will appear.
The duration of the latent period is very variable. It can be both a few seconds (for cyanide poisoning, for example), and several years (AIDS, hepatitis B). For many diseases, the onset and duration of the latent phase cannot be established. During the incubation period , some preventive measures may be taken. For example, if there is a risk of tetanus or rabies infection. In the infectious process, the causative agent of the disease at this time is not released into the environment.
Harbingers of the disease
A person feels that he is ill when he can reveal some disturbances in his health. The prodromal period is the length of time between the moment when the first signs of the disease appear and the full development of the symptoms of the disease. This term comes from the Greek word, translated meaning "running ahead." This is the phase of the disease when it is obvious that the person is unwell, but it is still difficult to determine which disease struck him.
This is especially true for infectious diseases, because the symptoms of the prodromal period are common to most of them. As a rule, the patient complains of malaise, headache, decreased appetite, poor sleep, chills and a slight increase in temperature. This is the body's response to the introduction of the pathogen and its active reproduction, but only by these signs it is impossible to establish a specific disease.
The boundaries and duration of the prodromal phase
In general, the definition of the boundaries of the prodromal stage is often conditional. It is difficult to distinguish the prodromal period of the disease if it is chronic and develops slowly. Between the latent period and the appearance of the first signs of the disease, it is still possible to more or less clearly trace the border. But how to understand where it is, if we are talking about the initial symptoms, on the one hand, and already pronounced on the other? Often this is only possible with an analysis of the disease after the fact, when it has already ended.
The length of the prodromal period is usually several days: from 1-3 to 7-10. But sometimes the precursor stage may be absent, and then immediately after the latent period a turbulent clinical picture of the disease unfolds. As a rule, the absence of a prodromal period indicates a more severe course of the disease. However, for some diseases it is not typical. The prodromal period ends when the general symptoms are replaced by symptoms characteristic of a particular disease. For some infectious diseases, it is the prodromal period that is characterized by maximum infectiousness.
Specific manifestations of the prodromal period
For some diseases, this period has characteristic manifestations that make it possible to correctly diagnose and begin treatment as early as possible, which is important for infectious diseases. So, reliable precursors of measles, even before the appearance of the rash, are characteristic small spots on the mucous membrane of the cheeks, lips and gums.
In the place of the entrance gate of the infection, inflammatory changes can sometimes be observed. Such a focus of inflammation is called primary affect. Sometimes the lymph nodes are involved in the process at the site of infection, and then they talk about the primary complex. This is typical for infections that enter the body through insect bites or by contact.
Prodromal stage in noncommunicable diseases
Although this stage is more pronounced in infectious processes, it can also be observed in diseases of a different nature. There are certain precursors to a heart attack when angina attacks, leukemia, in the initial period of which changes in the cellular composition of the bone marrow, epilepsy, about which disorientation and photosensitivity are already occurring, are becoming more frequent.