The lower GI tract Flashcards
Malabsorption
- failure of normal absorption of nutrients by the GIT
- prolonged malabsorption can result in malnutrition and vitamin deficiencies
- caused by deficient digestion or deficient absorption
there are two types of malabsorption :
- specific
- general
Specific malabsorption
failure to absorb one class of nutrient.
frequently genetic origin
general malabsorption
affects several classes of nutrients
there are four main causes of general malabsorption :
- pancreatic enzyme deficiency
- bile salt deficiency
- reduction of absorptive mucosa
- increased rate of intestinal transit
RFEER TO LOWE GI TRACT PPT
Functional GI disorders
Definition - symptoms in the absence of mucosal, structural or biochemical disease
IBS
- assumed to be a colon motility disorder
- altered CNS processing of visceral pain
- syndrome of recurrent abdominal pain and altered bowel habit
Diagnosis of IBS tests :
- full blood count
- erythrocyte sedimentation rate
- c reactive protein
- tissue transglutaminase
- faecal calprotectin
presence of :
- abdominal pain or discomfort
- bloating
- change in bowel habit
Treatment of IBS
- lifestyle changes
- dietary advice
for pain/bloating :
- analgesia
- antidepressants
- antispasmodic / anticholinergic
for altered bowel habit ( constipation :
- laxatives
- linaclotide
- prucalopride
Antispasmodics
Act to reduce intestinal motility and so relieve the pain associated with abdominal cramps.
REFER TO LOWER GIT PPT
Antidepressants
Used to treat abdominal pain / discomfort
Mechanism of action unclear, they could reduce visceral hypersensitivity or act centrally
Constipation
- Consequence of increased water reabsorption
- main symptom of impaired colon function
Therapy
- lifestyle modifications
- Laxatives ( osmotic, bulk forming, faecal softeners and stimulant laxatives )
- prucalopride
- linaclotide
- lubiprostone
How the different types of laxatives work
Osmotic Laxatives
- poorly absorbed solutes lead to osmotic retention of fluid in bowel lumen
- increased the rate of transfer of contents through the small intestine
- increased volume enters colon, faeces softens or become liquid
REFER TO LOWER GI TRACT PPT
Diarrhoea
Causes :
- chronic disease
- infective agents
- diet - drugs
Definition - decreased consistency of faeces and increased liquidity
Treatment of diarrhoea :
- maintain fluid and electrolyte balance = oral rehydration therapy
- use of infective agents depending on the cause
- reduce symptoms
Anti motility agents
Opioids reduce ACH release resulting in :
- decreases stomach emptying
- increases sphincter tone
- inhibits peristalsis
- increases rhythmic contractions
- reduces intestinal secretions
Overall : increased net fluid and electrolyte absorption. Eg. morphine, codeine, loperamide.
Morphine and codeine - specificity for gut is low. crosses the blood brain barrier (BBB) and is unsuitable for prolonged use
Loperamide - not readily absorbed from GI tract and does not readily cross BBB . Low incidence of side effects
LOPERAMIDE IS THE OPIOID OF CHOICE FOR TREATENT OF DIARRHOEA
Summary of treatments choices for Diarrhoea
- oral rehydration therapy
- adults wanting to curtail diarrhoea quickly = loperamide
- adults suffering from ibs ( WITH PAIN ) =
- loperamide for diarrhoea
- mebeverine or peppermint oil for spasm pain
