Constipation And Diarrhea Lecture Notes PDF

Constipation And Diarrhea  Constipation: a change from the normal body habits, where normal body habits va from one individual to another, ranging from several stools a day to the passage of one stool eve 2–3 days. Diarrhoea: an increased frequency of bowel movements and the productio...

Constipation And Diarrhea  Constipation: a change from the normal body habits, where normal body habits va from one individual to another, ranging from several stools a day to the passage of one stool eve 2–3 days. Diarrhoea: an increased frequency of bowel movements and the production of soft or wate stools resulting in uid and electrolyte loss.  Constipation Incidence of constipation About 10–20% of individuals believe that they suf fe r from constipation because their normal bowel habits are not occurring on a daily basis. Patient groups at risk of constipation include: – elderly patients: due to sedentar ylifestyle and poor mobility which diminishes colonic activity, due to multiple disease states and polypharmacy, and due to decreased food and uid intake pregna n t wo men : due t o f et a l pres s ure a n d increased progesterone levels, which cause a decrease in peristaltic movements – bed-ridden patients: due to decreased mobility. Aetiology of constipation Inadequate intake of dieta bre Dehydration Lack of exercise and poor mobility Medical causes Drugs Drugs causing constipation Antacids Antidiarrhoeal agents Anticholinergic drugs Antihistamines Anti-parkinsonian drugs Tricyclic antidepressants Diuretics Iron. Symptoms of constipation: Inability to pass stools at regular inte als Production of abnormally hard stools Straining at stool, abdominal pain and discomfo Sensation of incomplete evacuation Mild abdominal distension, headache, slight anorexia. Investigation required Investigation is required if: there is recent onset of symptoms change in bowel habits is detected. Treatment: general measures High- bre diet High uid intake Regular exercise.  Laxatives: ese may cause retention of uid in colonic contents. ey act directly or indirectly on the colonic mucosa to decrease net absorption of water and electrolytes or increase intestinal motility, causing less absorption of salts and water due to reduced transit time. ere are four main types: bulk-forming laxatives: e.g. ispaghula husk (powder) osmotic laxatives: e.g. lactulose (liquid) stimulant laxatives: e.g. senna (tablets), bisacodyl (tablets, suppositories), sodium picosulphate (liquid), glycerol (suppositories) saline laxatives: e.g. magnesium salts (powder).  Bulk-forming laxatives T he se are polysaccharide and cellulose derivatives that are not digested. ey exe an e ect within 12–72 hours of administration and are useful in hard stools. Example: ispaghula husk Action: – bind water and ions in the colonic lumen – suppor tgrowth of colonic bacteria thereby increasing bulk, f ibre digested by bacteria to metabolites which have a laxative e ect Side-e ects: atulence and borbo gmi Counse lling: to take an ade quate supply of f lu id otherwise they may fu her precipitate constipation Contraindications: inte stinal obstru ction, f ae cal impaction, colonic atony, di culty in swallowing.  Stimulant laxatives : T he se stimulate intestinal motility, probably through an e ect on the myenteric ne e plexus, decrease absorption of electrolytes and water, and increase synthesis of prostaglandins which reduce transit time. T hey have a rapid onset of action which makes them suitable for the management of a chronic attack. An ef fect is expected within 6–12 hours after oral administration and within 15–30 minutes when administered rectally  Examples: – senna: which may cause discoloration of the urine, dose: adults: 15–30 mg, 2–4 tablets at night – bisacodyl: diphenylmethane derivative available as enteric-coated tablets which should be swallowed whole not crushed, to reduce occurrence of abdominal cramps, or as suppositories. e oral formulation should not be taken within 1 hour of ingesting antacids or milk. Dose: adults: 5–10 mg at night Side-e ects: may colour urine, dehydration, gastric irritation Counselling: not for chronic use since prolonged use may cause diarrhoea and catha ic colon Contraindication: intestinal obstruction  Glycerol suppositories and enemas Glycerol (glycerin) is a rectal stimulant that is e ective where intestinal obstruction or impaction is suspected. It is safe to use in pediatrics Suppositories: child 1.5 g, adult 3 g Enemas: child 2–5 mL, adult 5–15 mL. Osmotic laxatives Example: lactulose Poorly absorbed, acts in the distal ileum and colon where it is metabolised by the bacteria to fructose and galactose which increase osmotic strength  Increases amount of water in the intestines by osmosis: is increased volume results in distension of the lumen which promotes peristalsis Reduces proliferation of ammonia- producing organisms and for this reason it is useful in hepatic encephalopathy Takes 48 hours to act Side-e ects: atulence, cramps, abdominal discomfo , loss of uid, hypernatraemia Contraindications: galactosaemia, intestinal obstruction Dose: adult 15 mL twice daily orally Saline laxatives Examples: magnesium hydroxide, magnesium sulphate, Epsom salts Increase amount of water in the intestine Cause a ve rapid action, used where complete evacuation is required (e.g. prior to diagnostic or surgical procedure) May lead to electrolyte imbalance, Note: use of enemas, bowel cleansing solutions, before inte entions that require bowel cleansing (e.g. endoscopy). Contraindications: gastrointestinal obstruction, acute gastrointestinal conditions, pe orated bowel, congestive hea failure Side-e ects: systemic absorption, signi cant dehydration.  Diarrhoea Diarrhoea: may be acute or chronic. ere are three main types: Osmotic diarrhoea: non-absorbable solute retains water in the intestine lumen. Examples include osmotic substances such as sorbitol (found in sugar-free sweets) and drugs such as magnesium containing antacids. Secreto diarrhoea: damage to intestinal wall leading to increased secretion in contrast to absorption of electrolytes (e.g. infectious diarrhoea). Motility diarrhoea: decreased contact time of faeces in intestine resulting in uidy faeces (e.g. in ammato gastrointestinal disease, drugs). Common causes of diarrhoea: Gastroenteritis Irritable bowel syndrome Crohn’s disease Ulcerative colitis Neoplasms Metabolic disorders (e.g. hype hyroidism, diabetes) Symptoms of diarrhea Sudden onset Mild abdominal cramping pain Flatulence General weakness Nausea and vomiting may also be present Lifestyle measures To use oral rehydration salts to rehydrate and replace lost electrolytes  Oral rehydration salts Oral rehydration salts (ORSs) : provide f luid and electrolyte replacement. T h ey are presented in the form of powder for reconstitution, consisting of sodium, potassium and glucose. T he intestinal absorption of sodium and water is enhanced by glucose. Patients should be advised to reconstitute ORSs with potable water and any unused reconstituted solution should be discarded within 1 hour after preparation unless stored in a refrigerator where it can be kept for up to 24 hours. Factors that a ect patient acceptance are palatability and avouring. Rehydration, orally or intravenously, is extremely impor ta nt to prevent circulator ycollapse in severe diarrhoea. Antimotility drugs: ese relieve symptoms by reducing peristalsis through stimulation of the mu opioid receptors on the intestinal wall. ey are not recommended for use in children. Examples: codeine, loperamide Side-e ects: abdominal cramps, constipation Chronic use may cause paralytic ileus and toxic megacolon Dose for loperamide: adults 4 mg followed by 2 mg after each unformed stool. Questions?