Diarrhoea Flashcards
describe diarrhoea
refers to the abnormal passing of loose or liquid stools.
In diarrhoea, there is increased frequency, volume or both. And it normally lasts less than 14 days
causes of diarrhoea
Infection(viral or bacterial)
Inflammatory bowel disease
Irritable bowel syndrome
stress/diet/post-infectious
Malignancy
Malabsorption
Malignancy is a medical term that describes the presence of cancerous cells that can spread and invade nearby tissues
what do we do if diarrhoea has lasted less that 4 weeks and what is suspected
what do we do when it has lasted more that 4 weeks and what is suspected
it is suspected to be infectious and a microbiological test of the stool is carried out
a non-infectious cause is suspected and tailored treatment is offered(i guess)
the types of diarrhoea and their descriptions
osmotic: Poorly absorbed solutes within the gut lumen lead to
retention of water into gut (can also be drawn into the
gut). Improves with starvation
secretory : Increased secretion or reduced reabsorption of salt
and water. Due to infection, laxative use, or
inflammatory mediators. Does not improve with
starvation
motility : Decreased transit time (i.e. moves quicker) through
GI tract. Water and electrolyte load from S.I. is too
great for the absorptive capacity of the colon.
inflammatory or exudative: Inflammatory insult to the mucosa eg ulcerative colitis,
or due to an infecting micro-organism causes loss of
integrity of the mucosa. Usually associated with
passage of blood, mucous and WBC’s
name some treatments of diarrhoea
Maintainance of fluid and electrolyte balance
▪ first priority – by means of oral rehydration
▪ can use oral rehydration powders
Use of anti-infective agents
Use of spasmolytic(anti-spasmodics) or other agents to act on the gut
what do you know about antimicrobials in the treatment of diarrhoea
not commonly used to treat diarrhoea
recommended in cases where there is;
* bloody diarrhoea and a high fever,
▪ severe diarrhoea following travelling,
▪ certain infections such as cholera and severe dysentery
▪ people who have specific bacteria or parasites in their
stool
what do you know about the mechanism of opiod related drugs in the treatment of diarrhoea
mechanism:
they increase the tone and rhythmic contractions of the intestine
Decrease propulsive activity ie peristalsis in the intestines.
Pyloric, ileocolic and anal sphincters are contracted
Tone of large intestine is markedly increased
Overall effect is constipating
note that opiods may enhance the the depressant effects of barbiturates, alcohol,
narcotics, tranquilizers, and sedatives
Opioids bind to mu-opioid receptors (MORs) in the gastrointestinal tract, particularly in the myenteric and submucosal plexuses.
opiods increase rhythmic contractions of the intestines but that does not increase propulsion because Opioids increase segmental contractions, which are non-propulsive because they churn contents in place rather than moving them forward.
loperamide readily penetrates the blood brain barrier, true or false
false
name some opiods used in diarrhoea treatment
loperamide(imodium)
codeine
diphenoxylate (Lomotil)
name the contents in the formula for the ORS recommended by WHO and UNICEF
sodium chloride
Anhydrous Glucose
Potassium Chloride
Trisodium citrate/dihydrate
how does loperamide work
it is an antimotility drug, so it slows down the passage of food through the gut(intestines), so more water is absorbed from the content of the gut, making it more solid and less loose.
Loperamide effects on myenteric plexus
and submucosal plexus?
plexus a branching network of vessels or nerves.
Loperamide acts as a mu-opioid receptor agonist, which stimulates the secretion of inhibitory neurotransmitters in the myenteric plexus. This increases non-propulsive contractions in the intestine, which decreases peristalsis and allows more time for absorption.
describe the mechanism of action of loperamide in the myentric plexus and submucosal plexus, in terms in neurotransmitter release
Loperamide binds to mu-opioid receptors in the myenteric plexus. This inhibits the release of excitatory neurotransmitters such as acetylcholine and substance P, which are essential for stimulating muscle contractions and motility.
cAMP and PKA levels decreased, which therefore decreases calcium influx through voltage-gated calcium channels.
Lower intracellular calcium impairs neurotransmitter release, further reducing motility and promoting intestinal constipation.
The inhibition of calcium influx reduces the activation of ATP-sensitive potassium (K_ATP) channels, which are influenced by intracellular calcium levels. This contributes to the overall reduction in motility and muscle contraction. Additionally, loperamide’s effects on calcium and potassium channels reduce excitability and motor activity in the gut.
note the effect is similar in both plexuses.
important thing to note about the submucosal plexus is that fluid secretion is inhibited
loperamide effects on enterocytes
enterocytes are cells in the small intestines
affects enterocytes by reducing the release of acetylcholine and prostaglandins, which inhibits peristaltic movement
myentric and submucosal plexus functions
myentric plexus controls the movement of the gastrointestinal tract by regulating the contraction and relaxation of the gut’s smooth muscles
submucosal plexus innervates the muscularis mucosae, which regulates peristaltic activity
they both have similar function, which is regulating peristalsis
