altered GI motility Flashcards
What are the lower GI motility symptoms?
Diarrhoea, constipation
what scoring system is used for describing faeces
bristol stool chart
What is the definition of diarrhoea?
Passage of loose or watery stools, typically at least 3 times a day in a 24hr period.
What are the features of diarrhoea? (2)
- Reduced consistency
- increased frequency
What is dysentery
Diarrhoea with visible blood or mucus - commonly have a fever and abdo pain
What time frame is acute diarrhoea?
<14 days
What time frame
is persistent diarrhoea
14-30 days
what time frame is chronic diarrhoea?
> 30 days
What is acute diarrhoea and what causes it (2)?
Increased water content of the stool - either due to impaired water absorption and/or active water secretion by
bowel
What causes acute diarrhoea? (3)
- INFECTIONS: [viral, bacterial, protozoal]
Rotovirus - kids
Norovirus - adults
Schistosomiasis - tropical infection - DRUGS (SE of many drugs)
- PSYCHOLOGICAL
What are the two types of chronic diarrhoea?
Osmotic and secretory diarrhoea
What is osmotic diarrhoea?
Water is drawn into in the bowel due to the presence of solutes within the lumen (natural osmosis), typically due to:
- Ingestion of a poorly absorbed solute
- Malabsorption
How can you reduce osmotic diarrhoea?
fasting
What are the causes of osmotic diarrhoea?(7)
- Carbohydrate malabsorption (e.g., lactose intolerance)
- Magnesium-induced (e.g., antacids)
- Osmotic laxatives (e.g., lactulose)
- Small intestinal mucosal disease (coeliac dx, severe
Crohn’s, enteritis etc.) - Reduced absorptive area (resection from e.g. Crohn’s)
- Bile acid malabsorption!!
- Pancreatic exocrine insufficiency (CF, pancreatic cancer - if it blocks pancreatic duct in the head of the pancreas,
chronic pancreatitis)
How does coeliac’s cause diarrhoea?
Stops you absorbing osmolytics - viliae atrophy so reduced absorptive area too
What does the pancreas do?
Endocrine and exocrine effects -> to help absorption of food, if it doesn’t work properly, then it will sit in the gut and it will pull water in
Where is bile produced and secreted?
Liver produces and secreted by the bile duct
Where does the secreted bile go?
Into the duodenum where 95% is then absorbed in the terminal ileum and only 5% is excreted
What does the gallbladder do?
Stores bile until fat needs digesting, then the gallbladder is squeezed and bile goes into the duodenum to help the fat be digested
What is bile acid diarrhoea?
Bile isn’t absorbed (e.g. due to resection of the terminal ileum) and so sits in the gut and draws water in to the gut
What is lactulose?
Syrup/sugar drink -> non-absorbable sugar that sits in the gut and drags water in (osmotic laxative)
What is lactose intolerance?
a form of carbohydrate malabsorption - We need lactase in our body to break down milk as babies, and when we get older, the amount of lactase reduces;
More prominent in the East
What is secretory diarrhoea
Actively increased secretion of fluid and electrolytes
What can cause secretory diarrhoea? (6)
- Bacterial endotoxins (E.coli, cholera, c.diff) -> irritates bowel causing secretions
- Stimulant laxatives (senna)
- Hormones (hyperthyroidism)
- Bile acid malabsorption
- Mucosal inflammation (Ulcerative coliits, Crohn’s)
- Rectal villous adenoma (an adenoma with villi-like protrusions that means it is less likely for secretions to be absorbed)