Constipation-predominant IBS (IBS-C) or BSFS type 1/2)
Diarrhoea predominant IBS (IBS-D) or BSFS type 6/7
Mixed subtype IBS (IBS-M) (M/C)
Postinfectious IBS (IBS-PI): Characterized by persistent abdominal pain and diarrhoea, typically following an episode of infectious gastroenteritis.
Postinfectious IBS (IBS-PI):
Serotonin (5-HT) may contribute to the postprandial symptoms of these patients and provide a rationale for the use of serotonin antagonist in the treatment of this disorder.
Cortical structures associated with IBS:
Mid cingulate cortex
Increased end-organ sensitivity with recruitment of “silent” nociceptors
Spinal hyperexcitability with activation of nitric oxide and possibly other neurotransmitters
Endogenous (cortical and brainstem) modulation of caudal nociceptive transmission
Development of neuroplasticity
High-amplitude propagating contractions (HAPCs)
Rapid colonic transit and accompanied by abdominal pain
Defining features of IBS are the presence of recurrent abdominal pain in association with altered bowel habits (diarrhoea, constipation or both). The spectrum, duration and severity of symptoms can range from inconvenient to incapacitating and can prevent individuals from participating in everyday activities.
Abdominal pain or discomfort which improves with defecation
Association of symptoms with stress or emotional upset
Absence of fever and weight loss
Small volume stools
No evidence of blood in stools
First time in old age
Persistent diarrhoea after a 48 hour fast
Presence of nocturnal diarrhoea
Rome IV diagnostic criteria:
Recurrent abdominal pain, on average, at least 1 day/week in the last 3 months associated with ≥ 2 of the following for the last 3 months with symptom onset at least 6 months before diagnosis.
Related to defecation
Associated with a change in the stool frequency
Associated with a change in the stool form (appearance)
Low FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diet: Ingestion of FODMAPs such as lactose, fructose, or sorbitol, alone or in combination, produce gut symptoms such as gas and diarrhoea.
Alosetron | S/E: Ischaemic colitis
Tegaserod | S/E: Cardiac toxicity.
Lubiprostone| S/E: Nausea, headache, diarrhea, allergic reactions, and dyspnea.