Assoc. Ventsislav Nakov, MD, graduated in 1988 from the Medical University in Sofia. He has two speci alties - internal medicine (1994) and gastroenterology and dietetics (1997). In 1997, he specialized in gastroenterology in the Netherlands. In 2011, he obtained the educational and scientific degree "Doctor", and the topic of his dissertation work was "Fecal calprotectin - a non-invasive marker for the assessment of intestinal inflammation".
From 1996 until now, Associate Professor Nakov has been working at the Gastroenterology Clinic of the University Hospital "Tsaritsa Joanna - ISUL". Deals with diagnosis and treatment of diseases of the small intestine, inflammatory bowel diseases (IBD), etc.; apply coloproctology, small intestinal aspiration biopsy, hydrogen breath test, fecal calprotectin test, polypectomy, etc.
He is a member of the Bulgarian Society of Gastroenterology and the Bulgarian branch of the European Organization for Crohn's Disease and Ulcerative Colitis.
Especially for the readers of "Doctor" Assoc. Nakov explained what irritable bowel syndrome is, how it is diagnosed and treated.
Prof. Nakov, perhaps for 2 - 3 decades people have been talking about irritable bowel syndrome. Is this disease new to medical science?
- Actually, this is not a new disease. By it we mean a condition known to internists for decades, but back then it was called spastic colitis or nervous bowel. Until the 1980s, it was called irritable bowel syndrome, and in the 1990s, the abbreviation IBS appeared, which we translate from English as irritable bowel syndrome.
In recent years, we have paid more attention to this disease due to its high frequency and social importance, as it mainly affects young people who have to be absent from work and take sick leave. Many and various tests are required, some of them expensive, spending money on the He alth Fund. So irritable bowel syndrome is emerging as a serious medico-social problem as its incidence is high.
Has the incidence of this disease increased in recent years?
- Perhaps it has not been given much attention for a long time. But there is probably some increase in frequency as well. Until recently, we had no idea about the real incidence of Irritable Bowel Syndrome in Bulgaria. We knew that worldwide the incidence of the disease in the population was between 5 and 25%. But in 2020, a collective of young doctors led by Dr. Radislav Nakov, who, unfortunately, is no longer with us, conducted a population-based Internet-based survey of almost 2,000 respondents. I was the supervisor of the study. It turned out that the frequency of irritable bowel syndrome in Bulgaria is 20% - among the highest in the world.
What do people with irritable bowel syndrome feel?
- The main symptom is recurrent abdominal pain that has been going on for at least six months, and that pain has occurred at least once a week in the last three months and is associated with a change in defecation, in the frequency of bowel movements or in the type of stool.
The so-called Rome Foundation periodically updates the criteria for irritable bowel syndrome. The most current criteria are called Rome IV and are from 2016. According to them, abdominal pain is leading. The clinical picture is varied. Some patients have abdominal bloating, bowel rumbling, nausea, fatigue, people feel tense and anxious, have sexual disorders.

Assoc. Dr. Ventsislav Nakov
What triggers the disease?
- It is not clear what exactly causes the disease itself. In irritable bowel syndrome, regulation along the brain-intestine axis, that is, the innervation from the brain to the intestine, is disturbed, visceral perception is disturbed (the intestines become more sensitive), there are also disturbances in serotonin signaling, in the motor migrating complex.
Some patients develop the disease after an acute infectious process. There remains chronic low-grade inflammation, which we call post-infectious IBS, but inflammation is not the primary cause of irritable bowel syndrome. The main thing is the disturbed innervation of the intestine.
In the human body, all functions are controlled by the brain, respectively by the sympathetic and parasympathetic nervous systems. The intestines have their own autonomic nervous system, with a complex mechanism of regulation. But it seems that increased visceral perception (sensitivity) is of great importance for the occurrence of the disease. People who have such increased sensitivity feel pain, discomfort, swelling.
Not much is known about this disease yet. It is considered functional. It is not clear if there is any organic cause. The big problem is the high incidence of the disease. In a Bulgaria of 7 million people, 20% of the population having irritable bowel syndrome means that one and a half million suffer from this disease, with two thirds of the patients being women. Usually these are intelligent, working women, of an active age.
We believe that stress, tension, uncertainty, anxiety play a big role in this disease. We did a study in 2021 that found that under covid conditions there is a significant rise in complaints just like irritable bowel syndrome.
How is this disease diagnosed?
- In recent years, so-called positive diagnostics have been used. It is believed that when the patient has no alarming symptoms - weight loss, bleeding with defecation, family history of colorectal cancer, but only recurrent abdominal pain once a week, with change with defecation, then it is 98% certain that it is irritable bowel syndrome gut.
In some cases, however, it is necessary to perform invasive tests such as gastroscopy, colonoscopy, sometimes a scanner and magnetic resonance, which makes the diagnosis much more expensive. To avoid this, in the last twenty years, an inexpensive test of a marker of inflammation - fecal calprotectin (stools are tested).
In case of increased calprotectin, it is clearly a matter of intestinal inflammation. While patients with irritable bowel syndrome have normal calprotectin. Thus, with a high degree of reliability - 98%, we distinguish organic inflammatory diseases from irritable bowel syndrome.
What is the treatment for the syndrome?
- There is no unequivocal and generally applicable treatment. Many things are used, starting with non-pharmacological means. For example, the doctor-patient relationship is extremely important. We owe it to the patients because we are very involved. And in fact, the doctor should spend at least 15-20 minutes to the patient to explain the condition to him, that this disease is not fatal, that it will not shorten his life span, that it may disturb his comfort, but he should calm down, that does not suffer from a serious illness and that he does not need to go from doctor to doctor.
This is the first step to healing. We also recommend patients to have good physical activity and allow themselves more positive emotions. Fermentable carbohydrates should be avoided in foods. Some patients do not tolerate fresh milk, others legumes. Therefore, we recommend that patients limit the foods that cause them complaints. However, we don't want to severely restrict them in their diet, because a serious diet greatly impairs the quality of life, no matter what the disease is. That's why we let the patient find out for himself what he can't tolerate.
We prescribe probiotics that are actually synbiotics – they contain both prebiotics and probiotics. There are hundreds of them on the market. Medical treatment is symptomatic - antidiarrheal agents are prescribed for diarrhea, laxatives for constipation, antispasmodics for pain, etc.