What does topic marked as adult mean

Functional bowel problems in adults

Background: Chronic abdominal pain, flatulence, constipation, diarrhea and stool irregularities are common symptoms in general medical and gastroenterological practice. In around 50% of those affected, no findings can be found in routine diagnostics that adequately explain the symptoms (so-called functional intestinal complaints). There is uncertainty among doctors about the extent of the necessary exclusion diagnostics.

Methodology: Selective literature research taking into account German and international guidelines.

Results: The diagnosis of functional intestinal complaints is made through the history of a typical symptom pattern (positive criteria) and the exclusion of other pathological findings that adequately explain the complaints (exclusion criteria). In addition to basic diagnostics (physical examination, basic laboratory, ultrasound examination of the abdomen, gynecological examination in women), further exclusion diagnostics are based on the main symptoms. A colonoscopy is required for final confirmation of the diagnosis. Communicating a diagnosis of irritable bowel syndrome takes the patient's complaints and worries seriously. Information about the benign course as well as the motivation for a healthy lifestyle are the basis of the therapy of functional intestinal complaints. Further therapy options are dietary measures, a time-limited symptom-related drug therapy and psychotherapeutic methods.

Conclusions: The diagnosis of functional intestinal complaints is based on a detailed anamnesis and a streamlined diagnosis of exclusion. Diagnosis and therapy should be based on guidelines.

Abdominal discomfort (pain, gas, stool irregularities, diarrhea, constipation) are common symptoms in the population. In a survey of a sample of the German population, 13% of 2,050 people reported flatulence and 11% reported abdominal pain in the last 7 days (1). 30–50% of people with persistent abdominal discomfort see a doctor (2). The symptoms can be a symptom of a somatic illness (for example Crohn's disease), a mental disorder (for example panic disorder) and / or a functional disorder. About 50% of patients who present to a general practitioner or gastroenterologist with persistent abdominal discomfort (> 3 months) have a functional gastrointestinal disorder (2, 3). The diagnosis and treatment of functional intestinal disorders is experienced by many affected persons and practitioners as difficult or frustrating (4). Fears of the doctor and the patient of overlooking a serious somatic disease often require extensive and repeated exclusion diagnoses. Instead of diagnosing a functional bowel disorder, embarrassment diagnoses (e.g. colon elongatum) or misdiagnoses (e.g. candida hypersensitivity syndrome) are made. This often results in medical treatments that are not indicated, for example administration of antimycotics if Candida albicans is found in the stool.

Many doctors consider functional bowel symptoms to be a diagnosis of exclusion. This assumption leads to a more extensive diagnosis by general practitioners than by specialists in functional bowel problems (5).

Even if functional intestinal disorders are often considered harmless from a medical point of view (normal life expectancy), they can be associated with impaired everyday functions of varying degrees (e.g. sick leave, giving up social activities such as going to restaurants or vacations). Non-indicated diagnostics and therapies as well as sick leave contribute to considerable medical costs (6).

The frequency and socio-medical relevance of the complex of complaints, the level of suffering and limitations in the quality of life of many affected persons as well as the uncertainty and frustration of those affected and the doctors with regard to diagnosis and therapy make guideline-oriented diagnostics and therapy useful.

This article is limited to the diagnosis and treatment of functional bowel problems in adults. These are a major form of functional abdominal discomfort. Functional gastroduodenal disorders (7), functional biliary disorders (8), functional anorectal complaints (9) and functional abdominal complaints in children (10) are not shown.

learning goals

The learning objectives for the reader of this article are:

  • get to know appropriate medical step-by-step diagnostics to exclude somatic disease factors
  • To be able to diagnose a functional bowel disorder based on positive anamnestic criteria
  • to be able to adequately convey the diagnosis of a functional bowel disorder to the patient
  • internalize the dietary, medicinal and psychotherapeutic therapy options.

The authors refer to the Rome III expert consensus on functional bowel-related complaints (11), the German (12), British (13) and US (14) guidelines on irritable bowel syndrome (IBS) and the German S3 guideline on functional Body ailments (15).

The authors also carried out a selective literature search in the Pubmed database.

Definition and classification of functional bowel disorders

Different criteria are used to define functional bowel disorders.

Rome III and DGVS criteria

The classification criteria for functional gastrointestinal disorders are drawn up in the context of consensus meetings. The third version of the classification criteria, the so-called Rome III criteria, is currently available. Functional bowel disorders are defined as follows:

  • symptoms related to the middle and lower gastrointestinal tract (abdominal pain, flatulence, irregular stool, diarrhea, constipation)
  • First onset at least six months ago, with complaints on at least three days per month for the past three months.

Passive mood disorders are delimited by a defined period of time (11). The Rome I and Rome II criteria listed the exclusion of a biochemical or structural disorder as a definition criterion. The Rome III criteria state that future research will demonstrate biochemical or structural disorders in functional bowel disorders (11).

In some of the patients with functional intestinal complaints, special methods that are not part of routine medical diagnostics can be used to detect molecular and cellular abnormalities (e.g. increased local proinflammatory cytokines), the specificity of which has not yet been clarified. A biomarker for functional intestinal complaints is not available. The German guideline therefore cites as a further definition criterion for IBS that there are no changes characteristic of other clinical pictures that are probably responsible for these symptoms (12).

The Rome III expert group differentiates between the following functional bowel disorders:

  • Irritable bowel syndrome
  • functional flatulence
  • functional constipation
  • functional diarrhea
  • unspecified functional bowel disorder.

The most common disorder is irritable bowel syndrome. The Rome III Expert Group defines irritable bowel syndrome as follows:

  • Abdominal pain or discomfort for at least three days per month for the previous three months
  • Started at least six months ago with at least two of the following characters:

- Improvement through defecation

- Start with changing stool frequency

- Start with changing stool consistency
and appearance.

For research purposes, a distinction is made between a constipation-dominant type, a diarrhea-dominant type, and a mixed type (11).

The German guideline on irritable bowel syndrome points out that the "classic" symptom cluster "abdominal pain and changes in bowel movements" is only found in subgroups of irritable bowel syndrome patients. For this reason, the German guideline recommends avoiding an obligatory combination of symptoms when defining IBS.

IBS is present when all three of the following points are met:

  • There are chronic complaints, i.e. symptoms lasting longer than three months (for example abdominal pain, flatulence), which the patient and doctor relate to the intestine and which are usually associated with changes in bowel movements.
  • The complaints justify that the patient is looking for help and / or worried and that the quality of life is impaired.
  • There are no changes characteristic of other clinical pictures that are probably responsible for these symptoms (12, e1).

However, the exclusion of structural diseases that explain the symptoms does not mean that functional intestinal problems have no biological basis. Advances in basic research are increasingly challenging the dichotomy between organic diseases and mental disorders (16).

Classification criteria of psychosocial medicine

The complex of functional intestinal complaints is classified in psychosocial medicine as a somatoform autonomic disorder of the lower gastrointestinal tract (F 45.32) or as a somatization disorder (F 45.0). This classification takes into account that many patients report further non-gastrointestinal complaints, general complaints such as tiredness and sleep disorders, further pain such as headache and backache and other organ-related complaints (urogenital, cardiovascular). It often overlaps with other functional disorders such as fibromyalgia syndrome (e3). However, only some of the patients with functional disorders meet the overarching criteria for somatoform disorders (somatic fixation) (15).

The diagnosis of irritable bowel syndrome is always preferable if the patient's current symptoms are limited to this organ system. If there are several relevant extraintestinal complaints and / or if the patient's behavior is conspicuous in terms of high health anxiety, intense preoccupation with the complaints or persistent conviction that a serious somatic disease is present, the diagnosis of a somatoform disorder should be made. 15 to 48% of patients with irritable bowel syndrome meet the criteria for a somatoform disorder (12). Depressive disorders can be detected in 20 to 70% and anxiety disorders in 20 to 50% of patients with irritable bowel syndrome (12).

Progressive forms of functional intestinal complaints

People with functional intestinal complaints differ considerably in the extent of gastrointestinal and other physical and emotional complaints, in their subjective experience of impairment, subjective assumptions about the causes and course of the disease, and the use of medical services (Table 1).

Clinical characteristics of milder and more severe forms of functional bowel complaints (smooth transitions, no mandatory criteria)

The following classification is useful for assessing the need for treatment (15, e2):

  • “Non-patients”: people with functional intestinal complaints without feeling sick
  • "Non-Consulter": People with functional intestinal complaints who feel sick and do not make use of medical services (possibly self-medication or paramedical treatment)
  • Patients with mild forms
  • Patients with severe forms.

Course and prognosis

Irritable bowel syndrome can regress spontaneously in some of those affected, but it is chronic in most. A follow-up study showed that 55% of IBS patients still met the criteria for IBS after seven years, symptoms were reduced in 21%, and symptoms were free in 13% (e4). IBS is not associated with the development of other organic diseases or increased mortality. However, IBS patients are operated on more frequently (hysterectomy, cholecystectomy) than non-irritable bowel patients (11–14).

Biopsychosocial model of functional intestinal complaints

Functional intestinal complaints can be explained by the interaction of somatic and psychosocial disease factors in terms of predisposition, triggering, and aggravation (16).

Biological factors

Biological factors include a possible genetic predisposition, previous gastrointestinal infections and food intolerance.

Genetics: Twin studies indicate a low genetic and high environmental share in irritable bowel syndrome (13) as well as a common genetic basis for functional disorders (headache, chronic fatigue, chronic pain in several body regions) (17). Around 100 gene variants in almost 60 genes have currently been investigated. Some positive associations have been described, for example with polymorphisms of the serotonin 5 transporter gene (18). The interpretation of genetic studies is made more difficult by covariables such as comorbid mental disorders (13).

Gastrointestinal infections: 7–36% of patients with irritable bowel syndrome develop symptoms after a gastrointestinal infection (e5). A post-infectious irritable bowel syndrome has been described after Salmonella, Shigella, Campylobacter, EHEC, Lamblia and Trichinella infections. The interaction of biological and psychosocial factors can be supported on the basis of post-infectious irritable bowel syndrome: The post-infectious risk of irritable bowel syndrome is predicted by the severity of the initial symptoms, bacterial toxicity and psychological factors (anxiety, depression, psychosocial stressors) (16, e6) ( see eTable 1).

Food intolerances: Food intolerances (NMM) are found in 50–70% of irritable bowel syndrome and in 20–25% of the general population. Immunologically mediated food intolerances (food allergies) are rare, nonimmunological food intolerances predominate in intolerance due to malabsorption of lactose, fructose or sorbitol (19).

Psychological factors

Various psychological factors contribute to the development and course of IBS.

Parental behavior: Model learning from parents with functional intestinal complaints and reinforcement of abdominal illness behavior by caregivers increase the risk of functional abdominal complaints in adulthood (13). In twins, one parent with irritable bowel syndrome is an independent risk factor for functional gastrointestinal disease in the child (e7).

Biographical stress factors: Compared to healthy individuals and patients with somatic gastrointestinal diseases, patients with irritable bowel syndrome report more frequently sexual abuse in childhood (odds ratio 4.1 [95% CI 1.9–8.6]) (e8). The association of biographical stress factors and irritable bowel syndrome is mediated by evidence of further physical symptoms (so-called tendency to somatization) (20).

Stress: Stressful life events and chronic psychosocial stress increase the risk of post-infectious IBS (see eTable 1) and worsen the symptoms of IBS (13, 16).

Personality traits: In a prospective population-based study, pronounced disease behavior (OR 5.2 [95% CI 2.5–11.0]) and increased anxiety (OR 2.0 [95% CI 1.0–4, 1]) Predictors of the development of IBS (21).

Social factors: Doctors can trigger or intensify inappropriate anxiety and behavior in those affected by non-indicated diagnostics and therapies (15).

Pathophysiological Mechanisms

Possible pathomechanisms are shown in Box 1.

Associations with somatic and psychological risk factors have been described for individual pathophysiological mechanisms, for example:
  • gastrointestinal infections with disturbances of the intestinal flora and peripheral sensitization
  • Emotions (for example, fear) with visceral hypersensitivity and dysmotility
  • biographical stress factors with changed central stimulus processing
  • and psychosocial stressors with disorders of the hypothalamic-pituitary-adrenal axis (16, 20).


The diagnosis of IBS is based on a graded somatic and psychological diagnosis.

Basic diagnostics

Simultaneous diagnosis of somatic and psychosocial factors should be carried out (Box 2).

In the initial anamnesis, the patient should be given the opportunity to freely describe his complaints through open questions. Thereafter, alarm symptoms for possible serious (malignant or inflammatory) diseases (“red flags”) as well as indications of functional and / or psychological disorders (“yellow flags”) should be actively explored. “Red flags” have a low sensitivity, but a high specificity for organic diseases (Box 3).

Sonography is one of the basic diagnostics for the initial clarification of abdominal complaints. Gynecological causes (endometriosis, adnexitis, ovarian cyst, ovarian carcinoma) should be ruled out by a specialist examination (12).

Missing “red flags”, an inconspicuous physical examination and the presence of “yellow flags” (Table 2) allow the working hypothesis of a functional bowel disorder.

Indications of structural and functional intestinal complaints ("yellow flags") at the first medical history
Screening questions on impairments in everyday life ("How do the complaints affect your everyday life / your performance?) And your current emotional state (" Did you often feel down or listless in the last month? Did you often feel anxious or nervous in the last month? “) Are recommended (13, 15). The indication of further physical and mental complaints as well as relevant impairments in everyday life are indications of a severe form.

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Advanced diagnostics

The extended diagnosis should be discussed with the patient. It is important to convey the low probability of a serious illness to the patient. ("It is very unlikely that we will find a serious illness during the examinations") (Box 4) (15).

Special diagnostics

The specific diagnosis is based on the main symptoms (Box 5) (12).

In many patients with chronic diarrhea, somatic, treatable causes of disease such as microscopic / collagenous colitis, celiac disease, inflammatory bowel disease, giardiasis, lactose or fructose malabsorption or bile acid malabsorption can be detected. An ileocolonoscopy is mandatory.

Diagnostics not recommended

The determination of IgG titers for food allergens and quantitative parameters of the faecal flora (for example “intestinal ecogram”) are not recommended (12).

Dealing with pathological findings

The probability of an abnormal finding increases with the number of examinations carried out. Inappropriate communication of findings can trigger or intensify anxiety about illness and inappropriate illness behavior (e.g. phobic eating behavior). In interpreting the H2Breath tests, for example, it should be taken into account that most people do not consume the test amounts usually used in everyday life: 50 g of lactose are contained in one liter of milk and 50 g of fructose in around 500 g of bananas or cherries (19). These tests are only meaningful if the H2-The increase is accompanied by typical symptoms (12). The possible significance of a pathological and symptomatic H.2Breath tests for the entire complex of complaints should therefore be given to the person concerned in a differentiated manner.

Psychotherapeutic diagnostics

A specialist psychotherapeutic diagnosis is recommended for patients with functional disorders with a severe course (Box 1). This includes a biographical anamnesis and the structured recording of possible psychological comorbidities (15).


When treating IBS, a distinction is made between basic therapy (for all patients) and further therapy (depending on the main symptoms and severity).

Basic therapy

The basic therapy consists of detailed information for the patient. In this conversation, the symptoms should be described positively (positive diagnosis), key words are, for example, "irritable bowel", "sensitive bowel", "functional bowel disorder". Furthermore, the doctor should make it clear to the patient in this conversation that he believes in the authenticity of these complaints. The doctor should convey the following content to his patient in this conversation:

  • Information about normal life expectancy with functional bowel problems
  • Teaching a biopsychosocial model of the complaints, for example stress or vicious circle models
  • Moderate physical activation (endurance sports) (e9) or strengthening of resources (hobbies, social contacts)
  • The following realistic therapy goals should be developed together with the patient, because a cure for functional disorders is rarely possible:

- Relief of complaints (not freedom from complaints)

- Learning techniques that improve self-management and quality of life

- convey the knowledge that no therapy is effective for every patient and for every symptom.

An intensive and empathic doctor-patient relationship is essential for this conversation (22).

Advanced therapies

Further therapies should be discussed in a joint decision-making process for patients who are impaired by the complaints in everyday life. The average effectiveness of drug as well as psychotherapeutic treatments for functional intestinal complaints is low by the standards of evidence-based medicine, but in individual cases it is often impressively high. When selecting therapy options, individual factors such as symptom pattern and severity, personality structure and preferences of the patient, the doctor's expertise and availability (medication, psychotherapy place) must be taken into account.

Dietary measures

If there is anamnestic evidence that the symptoms are dependent on food, it is advisable to keep a nutritional and symptom diary for a limited period of time. Patients with symptoms of irritable bowel syndrome and confirmed carbohydrate malabsorption (for example of lactose, fructose or sorbitol) should eat a low-sugar diet for at least 14 days. All diet suggestions should only be continued in the long term if the symptoms are clearly reduced (level of evidence [EG] B). Elimination diets require follow-up checks to avoid malnutrition (12