5305589
Description
Flashcards by lpgalbraith, updated more than 1 year ago
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Created by lpgalbraith
over 10 years ago
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| Question | Answer |
| What are the functions of the colon and small intestine? | Water absorption and stool formation |
| What happens to the surface area of the intestine in diarrhoea? | Surface area for the absorption of nutrients and water is reduced via rapid proliferation - reduced surface area may be due to surgery to remove part of the gut or disease e.g. Coeliac |
| What are the causes of diarrhoea? | Infection: bacteria, virus (most common), parasites Medications Chronic bowel disorders |
| Bacteria in infective diarrhoea | E. coli Salmonella enteritidis/thphi Vibrio cholera Campylobacter jejuni C.difficile Shigella |
| Viruses in infective diarrhoea | Norwalk virus Rotavirus Adenovirus |
| Parasites in infective diarrhoea | Crytasporidium parvum Entamoeba histolyticaB |
| Biggest cause of diarrhoea in under 2s? | Rotavirus (22%) |
| Medications causing diarrhoea | Cholinergics - increased ACh Cytotoxic agents - loss of gut epithelia Broad spectrum antibiotics - change in gut flora |
| Consequences of diarrhoea? | Dehydration Metabolic acidosis Potassium depletion Hypovolaemia CV collapse Death |
| Chronic bowel disorders causing diarrhoea | Endocrine disease - diabetes, thyroid disease Inflammatory bowel disease - UC, Crohn's Diverticular disease Laxative abuse Stress Malabsorption syndromes - Coeliac disease Antibiotic associated colitis |
| Symptoms at 95% hydration | Thirst Skin turgor Tachycardia Dry mucous membranes Sunken eyes Lack of tears Sunken anterior fontanelle Oliguria |
| Symptoms at 90% hydration | Anuria Hypotension Feeble and rapid pulse Cool and moist extremities Diminished consciousness Signs of hypovolaemic shock |
| Treatment options for acute diarrhoea | Oral rehydration therapy Antimotility drugs e.g. loperamide Antispasmodics Antibacterials (usually not required) |
| How does oral rehydration therapy work? | Clean water with glucose and sodium - aids reabsorption of water |
| What are some examples of antimotility drugs? | Loperamide, codeine, morphine, cophenotrope |
| How do antimotility drugs work? | Increase muscle tone but diminish propulsive activity Binding of mu receptor in submucosal plexus of GI tract (relatively selective) |
| Side effects of antimotility drugs | Nausea, vomiting, cramps, paralytic ileus |
| Examples of antispasmodic drugs | Muscarinic antagonists - atropine, propanthelone, dicycloverine |
| Mechanism of antispasmotic drugs | Antimuscarinics inhibit parasympathetic stimulation of the intestinal submucosal and myenteric plexus - prevents peristalsis - inhibit gastric emptying |
| Which antibacterial can be used in the prophylaxis of traveller's diarrhoea? | Co-amoxiclav |
| Which antibiotics are used in the treatment of acute diarrhoea? | Ciprofloxacin, norfloxacin |
| Which antibiotic should be used if infective agent is C. difficile? | Metronidazole or vancomycin |
| What treatments can be used in chronic diarrhoea? | Adsorbants Bulk forming agents Anti-motility drugs |
| Example of an adsorbant? | Kaolin (clay) - binds toxins following ileostomy, colostomy or diverticular disease |
| Example of bulk forming agent? | Methylcellulose - used in colostomy, iliostomy and constipation |
| When should anti-motility drugs not be used in the treatment of diarrhoea? | In children, ulcerative colitis or antibiotic associated colitis |
| What is the clinical definition of constipation? | Fewer than 3 bowel movements per week (but a change to the normal routine) |
| What factors increase the risk of constipation? | Female over 65 Before and after pregnancy Following surgery |
| Reasons for constipation? | Disease - stroke, dehydration, ignoring the urge, laxative abuse, travel, pregnancy, IBS, milk, medications |
| Diseases associated with constipation | Neurological: MS, Parkinsons, stroke, spinal cord injury Metabolic/endocrine: diabetes, poor glycaemic control, uraemia, hyperkalaemia, hypothyroidism Systemic disorders: amyloidosis, lupus, scleroderma |
| Agents used to treat constipation | Bulk formers Stimulants Foecal softeners Osmotics |
| Examples of bulk formers? | Unprocessed wheat bran or ispaghula husk, methylcellulose, sterculia polysaccharide polymers |
| How do bulk formers relieve constipation? | Increasing foecal mass: bacterial proliferation and hydrophilic action Stimulates peristalsis |
| When are bulk formers used? | In colostomy, diverticular disease and IBSS |
| Side effects of bulk formers | Bloating |
| Examples of stimulants in constipation? | Bisacodyl, dantron, senna (decreasing order of stimulation) |
| How do stimulants work in the treatment of constipation? | Stimulate myenteric plexus in intestines, stimulate smooth muscle contraction and water and electrolyte transfer |
| Side effects of stimulants? | Cramp, diarrhoea in long term use, tolerance |
| How long do stimulants take to work? | 6-12 hours (15-30 min with rectal administration) |
| How long do bulk formers take to work? | 24 hours |
| Examples of foecal softeners? | Docusate, liquid paraffin, arachis oil |
| Mechanism of foecal softeners? | Increase fat and fluid in stool, lubricate bowels, promote bowel movements |
| Side effects of liquid paraffin? | Anal seepage and anal irritation, granulomatous reaction, lipoid pneuumonia, reduced lipid soluble vitamin uptake |
| Examples of osmotics used in constipation? | Lactulose, macrogols, magnesium salts, hydroxide salts |
| Mechanism of osmotics in constipation? | Withdraw fluid from the bowel or retain the fluid they are administered with |
| Side effects of osmotics? | Magnesium salts can cause central effects in overdose Can cause dehydration |
| When are bowel cleansers used? | Before colonic surgery, colonoscopy, radiology - not treatments for constipation |
| Examples of bowel cleansers? | Sodium acid phosphate, sodium picosulfate |
| Which drugs are used for symptom relief in acute diarrhoea? | Antimotility and antispasmodic drugs |
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