Etiology is the study of the causes of diseases. By extension, this word can also designate all the factors and mechanisms that lead to a given pathology.

Originally, etiology was a philosophical school which, during Antiquity, was interested in the causes of things. The term was then taken up in theology, then in all the sciences seeking to understand phenomena: biology, physics, geology, geography, sociology, etc.

In medicine, etiology refers to the study of the causes of disease. Thus, the etiology of a neurosis or cancer corresponds to the search for conditions which allow, promote or determine the appearance of this pathology in a patient: 

• age ;
• genetic or familial predispositions;
• lifestyle ;
• exposure to an infectious agent or a toxic product;
• immune system dysfunction, etc. 

By extension, the word etiology is also used to refer to all the causes of a disease.

All physicians use knowledge of etiology as part of their diagnostic process. The general practitioner, in particular, is frequently confronted with patients presenting not very specific symptoms: 

• fever;
• cough;
• abdominal or muscle pain.

These clinical signs can be the manifestation of many different pathologies, ranging from the mildest (a cold, gastroenteritis, etc.) to the most severe (cancer, vascular disease, etc.). Without a technical platform, the general practitioner has limited diagnostic resources but also a very short consultation time (18 minutes on average) to decide on the disease which could explain these symptoms. At the end of the meeting, he is therefore sometimes unable to be 100% sure of its conclusion.

Faced with the vesicles of a chickenpox, he can make his diagnosis with certainty. Likewise, there is little risk of making a mistake in the event of diarrhea and vomiting associated with fever in the midst of an epidemic of gastroenteritis. On the other hand, he will have more difficulty in front of a not very specific symptom, such as myalgia or a headache. In these cases, he will stop at the consultation result which seems to him the most plausible in view of the clinical examination, the information given by the patient, his medical history (age, associated pathologies, antecedents, behavior to risk, etc.), its socio-cultural determinants (income level, type of job, etc.), its family situation, etc. But he will also keep in mind the possibility, often weak but not zero, of other aetiologies. The probability being low, he will not embark on an anxiety-inducing investigation for the patient, but will suggest that he return if his symptoms persist or worsen. He will then prescribe additional examinations to explore the other diseases possibly involved.

Etiology is also very present in medical research. Many laboratories continue to explore the causes of certain diseases. There are still many of which we do not know the etiology (we say that they are idiopathic), which makes them difficult to treat definitively. Research focuses on genetics, biochemical mechanisms and epidemiological studies. The latter, by studying populations more likely than others to develop a pathology, help identify risk factors (age, sex, place of life, profession, exposure to certain types of pollution, etc.), and therefore the means of prevention this illness.

A specialist in internal medicine, this doctor is interested in all the internal organs of the body (digestive, respiratory, urinary system, etc.). Like Dr. House in the series of the same name, he is the specialist in complex cases. It supports patients with a pathology affecting the whole body (autoimmune diseases, diabetes, pathologies linked to the environment, immunodeficiencies, etc.) or having several pathologies simultaneously affecting several organs, in order to offer them treatment. full adequate. This is why it is often found in the intensive care units of hospitals.

General practitioners also refer their patients to the internist doctor when they cannot find the etiology of their symptoms. His broad-spectrum knowledge, in several medical specialties, allows him to diagnose a combination of pathologies or risk factors that may explain a patient’s condition, but also rare diseases or diseases which had disappeared in France but which operate. today a return (syphilis, scurvy, scabies, etc.).

Like general practitioners, internists are not physicians without specialties. They are specialists as such, who, like all the others, have had to pass a Specialized Studies Diploma (DES), after at least 9 to 12 years of study and internship.

Apart from the results of examinations that have already been carried out (medical imaging, analyzes, etc.), there is generally nothing to bring to the consultation. On the other hand, the doctor may have to ask very personal questions, about the patient’s and his family’s history, his lifestyle, his risky behaviors, etc. If it has something to do with the subject, you shouldn’t be uncomfortable answering it, especially since doctors are subject to medical confidentiality.

When the patient suspects a product or food to be at the origin of his symptoms, of an allergy for example, he should not hesitate either to bring it to the appointment, so that the doctor can refute his hypothesis or consider it. He will then need to consult the composition of the product.