GI Flashcards
what is gord?
gastro oesophageal reflux disease
usually caused by weakening/ relaxation in lower oesophageal sphincter
acid from stomach leaks up into esophagus, causing symptoms (heartburn, acid reflux, bad breath…)
what are the risk factors of gord?
- Smoking
- Alcohol
- Coffee
- Chocolate
- Fatty Foods
- Being Overweight
- Stress
- Medicines (calcium channel blockers, nitrates, NSAIDs etc)
- Tight clothing
- Pregnancy
GORD lifestyle advice?
- Lose weight if overweight
- Eating small, frequent meals rather than large meals
- Eat several hours before bedtime
- Cut down on tea/coffee/cola/alcohol
- Avoid triggers, e.g. rich/spicy/fatty foods
- If symptoms worse when lying down, raise head of bed (do not prop up
head with pillows) - Avoid tight waistbands and belts, or tight clothing
- Stop smoking
GORD OTC management
Antacid: Pepto-Bismol®, Rennie®
* Alignate: Gaviscon Advance®
* Dual Product: Gaviscon Dual Action®, Peptac®
PPI or H2 receptor antagonists
GORD red flags needing referal
- Patients over 55 years with new onset symptoms
- Patients over 55 years with unexplained dyspepsia that hasn’t responded to
2 weeks of treatment - Patients who have continuously taken remedies for 4 weeks (risk of
rebound indigestion) - Pregnant or breastfeeding
- Not responded to OTC treatment
- Red flag symptoms:
- Unintentional weight loss
- Epigastric mass
- Stomach pain, pain/difficulty when swallowing
- Persistent vomiting
- Jaundice
- Signs suggestive of GI bleed
GORD POM management
- Once confident patient has GORD and no other sinister condition, can offer
full dose PPI for 4-8 weeks
what are peptic ulcers?
sores that develop in lining of stomach and intestines
gastric ulcer= in stomach
duodenal ulcer= in duodenum
signs of peptoc ulcers
- Burning or gnawing pain in centre of abdomen
- Indigestion
- Heartburn
- Nausea and vomiting
- Pain can last minutes to hours, and can come and go for several days, weeks or
months
peptic ulcers are usually a result of ?
helicobacter pylori infection
taking non-steroidal inflammatories (nsaids)
complications of peptic ulcers
bleeding at site of ulcer
stomach perforation
gastric obstruction
diagnosis of peptic ulcers
- Take a full history
- Especially to identify NSAID use
- Signs and symptoms
- Physical abdo exam
- Feel for mass, listen for bowel sounds, tap abdomen to check for tenderness or pain
- Urea breath test
- To identify H. pylori infection
peptic ulcer POM management
due to NSAIDs= stop NSAIDs, use PPI or H2RA therapy for 8 weeks
due to H.pylori= offer H.pylori eradication course
due to NSAIDs and H.pylori= full dose PPI or H2RA therapy for 8 weeks to help ulcer heal first then eradication course
if not due to nsaids or h.pylori= full dose ppi or H2RA for 4-8 weeks
what is H.pylori?
Helicobacter pylori is a Gram negative bacteria found in the stomach
H pylori risk factors
- Transmission is through direct contact with saliva, vomit or stool of infected
person, or via contaminated food or water - Living in crowded conditions
- Living without a reliable source of clean water
- Living with someone who has H. pylori infection
common in developing countries
complications of h.pylori infection
peptic ulcers
gastricitis
stomach cancer
H.pylori diagnosis
Carbon-13 urea breath test
* Drink liquid containing urea
* If H. pylori present, will break down urea into carbon dioxide
* Patient breathes into bag, which is sent to lab for testing
* If breath sample has higher than normal levels of CO2 , test is positive for H. pylori
infection
* False negatives may occur if test is within 2 weeks of PPI use or 4 weeks of antibiotic
use
management of h.pylori infection
(no pen all)amoxicillin–> clarithromycin –> any PPI–> PPI+ bismuth subsalicylate+ any 2 abx
(pen all) clarythromycin–> metronidazole–> PPI –> PPI+ bismuth subsalicylate+ rifabutin
what are the 2 was of administering tablets
pop bottle method
lean forward method
what do tablets allow for?
ease of administration
accurate dosage
chamical and physical stabiloty
low cost of manufacturing, packaging and shipping
different to tamper with
what is comprwssion?
reduction in bulk volume, removal of void and bringing particles closer
what is consolidation?
increased mechanical strength to interparticulate interaction
tablet problem?
capping and laminating
chipping and cracking
sticking and picking
filming and binding
mottling
capping and laminating
the upper segment of the tablet seperates from the main portion of the tablet
the seperation of the tablet into two or more distinct layers
chipping
Breaking of tablet edges as the
tablet leaves the press or during
subsequent handling and coating
operations
cracking
Small, fine cracks observed on the
upper and lower central surface of
tablets, or very rarely on the side
walls
sticking
Improperly dried or lubricated
granulations causing the tablet
surface to stick to the punch faces
picking
Small portions of the
powders/granules stick to the
punch face and grow with each
revolution of the press, picking out
a cavity on the tablet face
filming
Due to excess moisture in the
granulation, high humidity, high
temperature or loss of highly
polished punch faces due to wear
binding
With excessive binding the tablet
sides are cracked and it may
crumble apart
mottling
Unequal distribution of colour with light or dark spots standing out in an otherwise uniform surface
coarse sucrose characterisation
tend to be affected more by gravitational forces
fine sucrose characterisation
greater surface area possessing attractive forces
factors that affect the flowabiloty of the powder
- Particle size and their
distribution - Particle shape
- Particle interaction forces
(including friction and
electrostatic interactions) - Environmental factors such as
humidity and temperature
factors that could affect tablet hardness
formulation variables
tableting process
storage conditions
a weak tablet could be due to
poor tablet design
insufficient binder
over-lubrication
low moisture content
what are the digestive phases?
cephalic phase
gastric phase
intestinal phase
cephalic phase
anticipatory mechanisms
gastric phase
gastric secretions and motility
intestinal phase
intestinal secretions and motility
4 layers of the gi tract
mucosa
submucosa
muscalaris extera
mucosa
epithelial membrane
secretes mucous, digestive enzymes and horomones
absorbs nutrients
protects from disease
epithelial lining
lamina propria
muscalaris mucosae
submucosa
moderately dense CT with blood, autonomic nerves an d sometimes also glands, lymoh vessels and lymph follicles
regultaes gut brain action
muscalaris externa
intrinsic pacemaker cells regulate smooth muscle contractions
responsible for peristalsis and segmentation
circular layer and longitudinal layer
sphincters (sometimes go thicker to act as valves)
serosa (adventicia)
serosa=visceral peritoneum
advenicia= oesophagus has an outer covering of fibrous connective tissues
intrinsic nerve plexus (gut brain)
myenteric nerve plexuses
submucosal nerve plexus
the gut brain axis
bidirectioal commun ication between the central and the enteric nervous system, linking emotional and conitive centres of the brain with the peripheral intestinal functions
peristalsis motility
circular and longitudinal muscles
what do we release from the stomach
hydrochloric acid
cajal cells in the myenteric plexus
generate rhythm
nerve supply of gi tract
external stimuli= central nervous system and extrinsic autonomic nerves
internal stimuli (GI tract)= chemoreceptors, osmoreceptors or mechanoreceptors. local nerve plexus. effectors (smooth muscle or glands)
response= change in contractile or secretery activity
reflex
extrinsuc= long + external
intrinsic= short+ internal/ local
parasympathetic division to control gastric emptying
increase secretion and motility
release ACh= mucous cells –> mucus
chief cells–> pepsinogen
parietal cells –> HCL
G cells –> gastrin (leave stomach)
sympathetic division to control gastric emptying
decrease of secretion and motlity
release adrenaline= mucous cells do not go to mucus
chief cells do not go to pepsinogen
parietel cells do not turn into HCl
G cells do not turn into gastrin
gastrin
stimulates t cells to produce hydrocloric acid
this is inhibited by histamine, somatostatin…
saliva
can be excreted by intrinsic or extrinsic glands
made of = amylase
mucin
water and protective elements (defensin, IgA, lysozyme)
stages of swallowing
buccal phase
pharyngo-oesophageal phase
pharyngo-oesophaegeal phase
peristalsis
sphincter opening
types of cells in the stomach
mucus cells
parietal cells
chief cells
enteroendocrine cells
chief cells release
pepsinogen (precursor for pepsin which is used for protein digestion)
enteroendocrine cells release
gastrin (g cells) pyloric atrium, histamine, endorphins, serotonin, cholecystokinin and somatostatin
ECL cells
produce histamine
dyspepsi
a group of symptoms that alert doctors to consider disease of the upper GI tract, and states that dyspepsia itself is not a diagnosis
- upper abdominal pain or discomfort
- heart burn
- gastric reflux
- nausea or vomiting
pharmacological treatments of dyspepsia
antacids
mucosal strengtheners
regulation of acid secretion (ppi)
H pylori eradication regimes
mechanism of action for ppi
bind covalently to cysteine residues via disulphide bridges on the alpha subunit of the H+/ K+ ATPase pump, inhibiting gastric acid secretion for up to 36 hours. this is antisecretory effect is dose-related and leads to the inhibition of both basal and stimulated acid secretion, regardless of the stimulus
PPIs are pro drugs
sulfenamide binds covalently to exposed cysteine residues of the H+/K+ ATpase pump
pKa ranges from 3.8 to 5.0
metabolised by CYP2c19
omeprazole is an inhibitor of CYP2C9
gastroparesis
delayed gastric emptying in the absense of a mechanical obstruction
condition associated=
diabetes mellitus
hypothyrodism
neurological conditions
viral infections
autoimmune attack
iatrogenic causes=
vagal nerve damage during surgery
opioid
alpha 2 adrenic agonists
tricyclic antidepressants
anticholinergics
treatment is for dietary modifictions and avoiding medications that stop gastric emptying
what are promotility agents
prokinetic agents refer to a class of drugs that promote the passage of ingested material in the GI
important considerations are is the simple stimulation of gut motility a valid target
target disorders are poorly defined
non selectove drugs will have side effects
how do promotility agents work
increase wave like contractions in the oesophagus
increase contractions in the stomach
promote emptying of stomach contents
increase wave like contractions in the intestine
stimulating excitatory chemical messengers
suppressing inhibitory meurotransmitters like dopamine and serotonin
there are 4 types of prokinetic drugs
cholinergc agonists
dopamine antagonist
serotonergic agonists
macrolides
dopamine antagonists
block the effect of dopamine in the CNS ans at the chemoreceptor zone
stimulate peristalsis by releasing acetylcholine
MOA= dopamine d2 antagonist
dopaminergic regulation of gastrointestinal motility and sites of action of metoclopramide and domperidone
metocloperamide inhibit 5 ht3 going to the myenteric neuron, stops d2 from releasing ach, actovates ach with 5 HT4. the ach then activates the m3 receptor on muscle cells in order to contract
domperidone inhibits d2 to release ah and stops it from acting on the beta 2 receptor in order to contract (activation causes relaxation of muscle cells)
seretonergic agonists
mild to moderate gastropresis
serious cardiac risk (doubt to prescribe)
reduce oesophageal acid exposure and promote gastric emptying
motilides
(erythromycin)
enhance peristalsis by acting on motolin receptors or by releasing motolin
colon
convert chyme into faeces for excretion
lacks vili and has many crypts of lieberkuhn
crypts consist of simple short glands lined by mucus secreting goblet enzymes
the epithelial cells contain almost no digestive enzymes
high capability of absorption of sodium, cl and water
the outer longitudinal muscle layer is modified to form three longitudinal bands, called tenia coli visible on the outer surface
wall is sacculated and forms haustra
diarrhoea
abnormal passing of loose or liquid stools, with increased frequecy, increased volume or both
acute= under 14 days
red flag symptoms are weight loss, rectal bleeding, persistant diarrhoea, systemic illness antibiotic or recent hospital treatment, foreign travel
diarrhoea treatment
prevention or reversal of fluid and electrolyte depletion and the management of dehydration when it is present
ORT (oral rehydration therapy)
refer if dehydration is severe
antimotility drug loperamide (rapid control)
codeine phosphate
constipation
infrequent stools, difficult stool passage or seemingly incomplete defecation
red flag symptoms are over 50 yo, anaemia, abdominal pain, weight loss, blood in stools