-Irritable bowel syndrome (IBS) is a functional disorder of the gastrointestinal tract characterized by chronic abdominal pain and altered bowel habits.
-The most common diagnosis made by gastroenterologists.
-Affects predominantly women (70% of patients).
-The location and character of the pain can vary widely.
-The severity of the pain may range from mild to severe.
-The pain is frequently related to defecation.
-Symptoms of IBS include diarrhea, constipation, alternating diarrhea and constipation, or normal bowel habits alternating with either diarrhea and/or constipation.
Rome IV criteria for IBS – According to the Rome IV criteria, IBS is defined as recurrent abdominal pain, on average, at least one day per week in the last three months, associated with two or more of the following criteria:Related to defecation, Associated with a change in stool frequency, Associated with a change in stool form (appearance).
IBS subtypes: IBS with predominant constipation, IBS with predominant diarrhea, IBS with mixed bowel habits, IBS unclassified.
The physical examination is usually normal in patients with IBS.
There is no definitive diagnostic laboratory test for IBS. The diagnosis of the disorder is based on clinical presentation. The purpose of laboratory testing is primarily to exclude an alternative diagnosis: CBC, C-reactive protein and/or fecal calprotectin, serologic testing for celiac disease, colonoscopy etc.
Treatment: Reassurance, dietary modification, In patients with constipation, treat with fibers like psyllium/ispaghula, laxatives like polyethylene glycol, Lubiprostone, Guanylate cyclase agonists (Linaclotide, Plecanatide). In patients with diarrhea, use antidiarrheal agents like loperamide, Eluxadoline (mu-opioid receptor agonist), bile acid sequestrants like cholestyramine, colestipol, colesevelam; 5-hydroxytryptamine-3 receptor (5HT-3) antagonists like Alosetron; In patients with abdominal pain, use antispasmodic agents like Dicyclomine, Hyoscyamine.