Case 7 Irritable bowel syndrome
Description of irritable bowel syndrome
Definition
Irritable bowel syndrome (IBS) is a chronic, functional bowel disorder characterised by abnormal defecation, visceral hypersensitivity and altered bowel motility. Depending on the prevailing stool pattern of the condition, IBS may be classified as IBS with constipation (IBS-C), IBS with diarrhoea (IBS-D), mixed IBS (IBS-M) or unclassified IBS (IBS-U).1
Epidemiology
Between four and thirty-five per cent of the world’s population is affected by IBS. Much of this variation can be explained by geographical variability, with higher prevalence rates observed in China and Western countries, and lower rates noted in South Africa and Thailand.1 Onset of IBS typically occurs in the teens or second decade of life; incidence peaks in the third and fourth decades of life and falls in the sixth and seventh decades.1 Race does not appear to be a factor in the incidence of IBS, though the condition does more commonly affect women than men, at a ratio of 3:1.2
Aetiology and pathophysiology
IBS appears to be a disease of multifactorial aetiology. While the primary cause is still not known, a number of factors have been shown to precipitate or aggravate the condition. These triggers include psychosocial stress (e.g. parental rejection, history of abuse, increased life stressors), anxiety, infectious gastroenteritis, diet (e.g. food intolerance), medication (e.g. antibiotics, hormone replacement therapy) and the act of eating.1–3
Even though the cause of IBS is not yet known, many theories have attempted to explain the pathophysiological basis of the disease. It is postulated that exposure to the triggers mentioned above, together with genetic predisposition, contributes to the development of chronic enteric inflammation and/or small intestinal bacterial overgrowth. These pathological changes may be responsible for local neuronal degeneration and immune dysfunction, and the subsequent development of visceral hypersensitivity (which may cause abdominal and/or rectal discomfort) and altered bowel motility (a possible cause of constipation, diarrhoea and nausea).1,3
Clinical manifestations
People with IBS often present with an array of gastrointestinal, psychological and/or systemic symptoms of varying intensity and frequency. Non-specific symptoms such as fatigue, chronic headache and sleep disturbances may be accompanied by psychological manifestations that include poor concentration, anxiety and depression. An individual may also complain of dyspepsia, flatulence, mucorrhoea, rectal sensitivity, nausea, abdominal bloating, left lower quadrant tenderness and periodic constipation and/or diarrhoea.2 According to the Rome III criteria for the diagnosis of IBS, the defining feature is the presence of colicky pain or continuous dull ache to the lower abdomen or left lower abdominal quadrant for at least 3 days a month in the past 3 months (with the onset of symptoms occurring at least 6 months prior), which is associated with at least two of the following: a change in stool consistency, a change in the frequency of defecation and/or improvement post defecation.1
Clinical case
32-year-old woman with irritable bowel syndrome
Rapport
Adopt the practitioner strategies and behaviours highlighted in Table 2.1 (chapter 2) to improve client trust, communication and rapport, as well as the accuracy and comprehensiveness of the clinical assessment.
Medical history
Family history
Mother has asthma and generalised anxiety disorder, father has hypertension.
Lifestyle history
Illicit drug use
| Diet and fluid intake | |
| Breakfast | Coffee, wheat biscuits (breakfast cereal) with full-cream milk. |
| Morning tea | Coffee, 2–3 sweet biscuits, muesli bar. |
| Lunch | Vegetarian pasty, white bread roll with lettuce, tomato and cheese, sandwich with white bread, ham, cheese and tomato, cola. |
| Afternoon tea | Coffee. |
| Dinner | White pasta with Neapolitan or carbonara sauce, chicken Kiev or cordon bleu with cauliflower, broccoli and green beans, omelette with ham and cheese. |
| Fluid intake | 3–4 cups of instant coffee a day, 2–3 cups of water a day, 375 mL cola 1–2 days a week. |
| Food frequency | |
| Fruit | 0–1 serve daily |
| Vegetables | 2–3 serves daily |
| Dairy | 2–3 serves daily |
| Cereals | 5–6 serves daily |
| Red meat | 3–4 serves a week |
| Chicken | 2 serves a week |
| Fish | 0–1 serve a week |
| Takeaway/fast food | once a week |
Physical examination
Olfaction
There is no evidence of halitosis or other abnormal body odours. According to the client, flatus can be foul-smelling, whereas stools generally are not.
Diagnostics
Pathology tests
Carbohydrate breath test
This test examines carbohydrate malabsorption (specifically, lactose and/or fructose malabsorption), orocecal transit time and small intestinal bacterial overgrowth.4 This test may be indicated if carbohydrate malabsorption is a suspected cause of IBS symptoms.
Faecal analysis
This test assesses a number of stool characteristics, including appearance, colour, occult blood, epithelial cells, leucocytes, carbohydrates, fat, meat fibres and trypsin.5 It may also help to exclude colorectal carcinoma, malabsorption, inflammatory bowel disease or intestinal infection as potential causes of IBS symptoms.
Functional tests
A comprehensive digestive stool analysis (CDSA) obtains data on enzymatic digestion, fatty acid absorption, microbiological balance and metabolic markers of disease. This test may be warranted if intestinal dysbiosis, intestinal candidiasis, malabsorption and/or indigestion cannot be excluded as potential causes of IBS symptoms.6
Invasive tests
Invasive tests are not usually required for a diagnosis of IBS. When serious underlying pathology is a suspected cause of the IBS symptoms, certain tests may be indicated, for example, small bowel biopsies can be performed to rule out coeliac disease and a colonoscopy and/or sigmoidoscopy may be indicated if colorectal carcinoma, inflammatory bowel disease or diverticulosis are suspected.
