Diarrhoea is an extremely common digestive symptom that almost everyone experiences at least once in their lifetime. Although it is usually harmless and clears up on its own within a short time, in certain cases it can be a sign of a more serious illness. It is important to understand which symptoms to look out for, what might be causing the problems, and when it is necessary to see a doctor, for example in the case of Endomedix Gastroenterology Centre consult specialists to ensure an accurate diagnosis and appropriate treatment.
This article will help you understand the key facts about diarrhoea. We provide a detailed overview of the symptoms, possible causes and the diagnostic methods doctors use to identify the root of the problem.
What do we call diarrhoea?
In everyday language, we often refer to any loose stool as diarrhoea, but the medical definition is more precise. We speak of diarrhoea when bowel movements become more frequent than usual (three or more times a day) and the stools become mushy or watery.
During the normal digestive process, the small and large intestines reabsorb fluid from the intestinal contents, thereby forming solid stools. In the case of diarrhoea, this process is disrupted: either the bowel moves too quickly, leaving insufficient time for fluid to be absorbed, or the bowel wall secretes more fluid for some reason.
The following is used to objectively assess the consistency of stools: Bristol Stool Scale, which classifies stools into 7 types. Types 6 (flaky, fragmented, mushy) and 7 (watery, with no solid lumps) indicate diarrhoea.
The most common symptoms of diarrhoea
Diarrhoea is a symptom in its own right, but it is often accompanied by other symptoms which can help to identify the causes.
Common accompanying symptoms:
- Abdominal cramps and pain: It is common, and its intensity can range from mild to very severe.
- Bloating and increased gas production: Due to the fermentation processes taking place in the gut.
- Urgent urge to go to the toilet: Inflammation or irritation of the rectum may cause the patient to experience a sudden urge that is difficult to suppress.
- Nausea and vomiting: This is particularly common in cases of infection or food poisoning.
- Fever: The body’s response to an inflammatory or infectious process.
- Signs of dehydration: Excessive fluid loss can lead to a dry mouth, reduced urine output, dark-coloured urine, weakness and dizziness (particularly when standing up). It is particularly dangerous for children and the elderly.
Warning signs that may indicate a more serious problem:
- Blood in the stools (bloody diarrhoea): It may be bright red or contain clots. It may indicate inflammatory bowel disease, a serious infection or even a tumour.
- Night-time diarrhoea: The urge to defecate that wakes a person in the middle of the night is often a sign of an organic disease, unlike functional disorders (e.g. IBS), which typically do not cause symptoms during sleep.
- Steatorrhoea: Light-coloured, foul-smelling, oily and shiny stools that stick to the toilet bowl, indicating a digestive or malabsorption disorder (e.g. pancreatic insufficiency, coeliac disease).
- Significant, unintentional weight loss: When accompanied by chronic diarrhoea, this may suggest malabsorption, inflammatory bowel disease or cancer.
Types of diarrhoea and possible causes
Diarrhoea can be categorised according to its duration and nature, which helps to narrow down the possible causes.
Acute diarrhoea (lasting less than 4 weeks)
This is the most common form, which is usually caused by infections or food poisoning.
- Viral and bacterial infections: The most common causes. These include rotaviruses, noroviruses and adenoviruses, as well as the bacteria Salmonella, Campylobacter, E. coli and Clostridioides difficile.
- Food poisoning: It is caused by toxins produced by bacteria that multiply in contaminated food.
- Side effects of medicines: Many medicines can cause diarrhoea, most commonly antibiotics (which upset the balance of the gut flora), but also antacids and certain chemotherapy drugs.
- Traveller’s diarrhoea: In exotic countries, these illnesses are caused by local bacteria and viruses to which our bodies have not yet built up resistance.
Chronic diarrhoea (lasting for more than 4 weeks)
Persistent diarrhoea is often caused by more serious conditions that require further investigation.
- Irritable bowel syndrome (IBS): One of the most common causes. In the diarrhoea-predominant type (IBS-D), recurrent diarrhoea occurs alongside abdominal pain and bloating, which may alternate with constipation.
- Inflammatory bowel diseases (IBD): Crohn’s disease and ulcerative colitis are autoimmune diseases that cause chronic inflammation of the intestinal wall. Their typical symptoms include abdominal pain and frequent bloody diarrhoea.
- Microscopic colitis: A condition characterised by chronic, watery, non-bloody diarrhoea, the diagnosis of which requires a histological examination, as the endoscopic appearance of the colon is usually normal.
- Absorption disorders (malabsorption):
- Coeliac disease (celiac disease): An autoimmune reaction triggered by gluten, which leads to damage to the villi of the small intestine.
- Lactose intolerance: An inability to digest milk sugar (lactose) due to a lack of the lactase enzyme.
- Small Intestinal Bacterial Overgrowth (SIBO): Bacteria that multiply abnormally in the small intestine cause bloating, diarrhoea and malabsorption.
- Pancreatic insufficiency: The pancreas does not produce enough digestive enzymes, which leads to fat malabsorption and steatorrhoea.
- Endocrine (hormonal) causes: Hyperthyroidism or certain rare hormone-producing tumours (neuroendocrine tumours) can also cause chronic diarrhoea.
Diagnosis of diarrhoea at Endomedix Centres
When diarrhoea becomes persistent or is accompanied by warning signs, a gastroenterological examination is essential. The Endomedix Gastroenterology Centre Its specialists use the full range of modern diagnostic procedures to establish an accurate diagnosis.
1. Medical history and physical examination
The doctor will ask the patient in detail about their symptoms: how long the diarrhoea has lasted, how many times a day it occurs, the consistency and colour of the stools, and whether it is accompanied by pain, bleeding, a fever or weight loss. Eating habits, any medicines being taken and a family history of illness are also important. During the physical examination, the doctor will palpate the abdomen and assess the patient’s general condition, including any signs of dehydration.
2. Laboratory tests
- Blood collection: A complete blood count can reveal anaemia (a sign of blood loss or malabsorption) and inflammatory processes (high white blood cell count, CRP). The blood test can also indicate nutrient and vitamin deficiencies (e.g. iron, vitamin B12, folic acid) and impaired liver or kidney function.
- Stool tests: This is one of the most important studies.
- Faecal calprotectin: This marker is highly sensitive in detecting inflammation in the gut. It helps to distinguish inflammatory bowel disease (IBD) from irritable bowel syndrome (IBS).
- Stool culture: If an infection is suspected, it detects the pathogenic bacteria.
- Detection of Clostridioides difficile toxin: This is particularly important in cases of diarrhoea following a course of antibiotics.
- Test for occult blood in stools: It may indicate bleeding that is not visible to the naked eye.
- Measuring the fat content of stools: Indicated in cases of suspected malabsorption or steatorrhoea.
3. Special examinations
- Exhalation tests: Simple and painless procedures for diagnosing lactose intolerance, fructose malabsorption and small intestinal bacterial overgrowth (SIBO).
- Serological tests: Specific antibodies characteristic of coeliac disease (e.g. antibodies against tissue transglutaminase) can be detected in the blood.
4. Endoscopic examinations
If laboratory results and other tests suggest organ damage, an endoscopic examination is required.
- Colonoscopy (colonoscopy of the colon): This is the most important examination in cases of chronic diarrhoea. During the procedure, a flexible instrument fitted with a camera (an endoscope) is inserted through the rectum to examine the entire large intestine and the final section of the small intestine. The examination enables the identification of inflammation, ulcers, polyps and tumours. During a colonoscopy, a tissue sample (biopsy) is also taken, which is essential, for example, for the diagnosis of microscopic colitis or inflammatory bowel diseases.
- Gastroscopy (gastroscopy of the stomach): It is performed in cases of suspected upper abdominal symptoms or malabsorption (e.g. coeliac disease). During the procedure, the oesophagus, stomach and upper part of the duodenum are examined, and a tissue sample is also taken from these areas.
5. Imaging examinations
- Abdominal ultrasound: A common, non-invasive examination carried out as a first step, which provides an overview of the abdominal organs (liver, gallbladder, pancreas).
- CT and MRI scans: They provide a more detailed picture of the abdominal organs and the condition of the intestinal wall; they are particularly useful where inflammatory bowel disease or tumours are suspected.
When should we see a doctor?
Although mild, acute diarrhoea can usually be treated at home, it is always advisable to consult a healthcare professional in the following cases, such as the Endomedix Gastroenterology Centre to consult their doctors:
- If the diarrhoea lasts for more than 2–3 days and does not improve.
- If accompanied by a high fever (>38.5 °C).
- If there is blood or pus in the stools.
- If you experience severe, persistent abdominal pain.
- If you experience signs of dehydration (severe thirst, dark urine, dizziness).
- If diarrhoea becomes chronic (lasts for more than 4 weeks).
- If the diarrhoea is accompanied by significant weight loss or night-time symptoms.
Persistent or severe diarrhoea is not only unpleasant, but may also be a sign of an underlying condition that requires treatment. Early and accurate diagnosis is essential for starting effective treatment and avoiding more serious complications. Do not hesitate to seek help if your symptoms give cause for concern!
