Gastrointestinal Flashcards
What do the following cells of the stomach secrete, and where in the stomach are they located?
- Mucous neck cells
- Parietal Cells
- Chief Cells
- mucous; widespread distribution
- intrinsic factor and HCl; fundus
- digestive enzymes; fundus
Name 3 chemical mediators which regulate gastric acid secretion, and how they do so
- HISTAMINE - released in response to alkaline pH; acts on H2 receptors which increases expression of H+/K+ pump
- AcH - raises intracellular Ca which acts to increase expression of H+/K+ pump
- PROSTAGLANDINS - act to reduce the expression of the H+/K+ pump
How does H. pylori result in the formation of peptic ulcers?
- bacteria secretes urase, which leads to gastritis
- inflammation disrupts the gastric mucosa - stomach acid can infiltrate thus leading to ulceration
How does NSAID use lead to the development of peptic ulcers?
prevents the formation of prostaglandins, which reduce acid secretion and increase mucous and bicarbonate secretion
- What drug classes are used in H. pylori eradication therapy?
- How long is the course of treatment?
- As well as drugs, what additional advice is given?
- antibiotics (2 to reduce resistance) and PPI (reduce stomach acidity to aid healing)
- 7 days
- avoid NSAIDs; avoid alcohol (interraction with metronidazole)
As part of H. pylori eradication therapy, which antibiotics are used first line in:
- patients without penicillin allergy
- patients with penicillin allergy
- amoxicillin and clarythromycin/metronidazole
2. clarythromycin and metronidazole
- Name 2 adverse effects of PPIs
- Name 2 warnings associated with the use of PPIs
- Which drug interracts with PPIs?
- headache; GI disturbance
- increased fracture risk
can mask symptoms of gastro-oesophageal cancer - reduce effect of clopidogrel
- What is the MOA of ranitidine?
2. name 2 warnings associated with the use of ranitidine
- histamine antagonist
- excreted kidneys - requires dose reduction in those with renal impairment
can disguise symptoms of gastro-oesophageal cancer
- What is the MOA of antacids?
- What is the MOA of alginates?
- Name 2 adverse effects of alginates and antacids
- Name 6 interractions with antacids and alginates
- buffers stomach acid
- increases viscosity of stomach contents, forming a floating raft which prevents reflux
- diarrhoea (Mg salts)
constipation (Al salts) - ACEi
cephalospotins, ciprofloxacin, tetracyclines
bisphosphonates
digoxin
levothyroxine
PPIs
*should be separated by 2 hours between administering these drugs
- What is the MOA of bulk forming laxatives?
2. Name an example of bulk forming laxatives
- increases the bulk of stools which aids peristalsis by stimulating stretch receptors
- iphalghula husk
- What is the MOA of osmotic laxatives?
- Name 2 examples of osmotic laxatives?
- Which osmotic laxative is useful at treating constipation associated with hepatic encephalopathy
- Name adverse effects of osmotic laxatives
- hold water in the gut lumen thus maintains stool volume and aids peristalsis
- lactulose; macrogol
- lactulose
- flatulance, abdo cramps and nausea; diarrhoea; electrolyte disturbance
- What is the MOA of irritant and stimulant laxatives?
- Name 2 examples
- name side effects of irritant/stimulant laxatives
- increase water and electrolyte secretion from the colonic mucosa
- senna; bisacodyl
- abdominal cramps and pain, diarrhoea
- What is the MOA of faecal softeners?
2. Name 2 examples of faecal softeners
- act by decreasing surface tension and increasing penetration of intestinal fluid into the faecal mass
- co-danthrusate
decussate sodium
- Name 3 opioids used in the treatment of diarrhoea
- how do opioids treat diarrhoea?
- Name 3 side effects associated with the use of opioids in the management of diarrhoea
- name 4 warnings against the use of opiates for diarrhoea
- codeine phosphate; loperamide; dipenoxylate
- increases non-propulsive contractions of the gut to increase water absorption but reduces peristalstic contractions
- constipation
abdominal cramps
flatulance - acute UC
acute bloody diarrhoea
C diff infection
Which 4 drugs are used in the management of an acute UC flare?
- mesalazine suppositories/enemas
- increased oral mesalazine dose
- oral prednisolone
- IV hydrocortisone
- What is the MOA of aminosalycyclates?
- Name 2 examples of aminosalycyclates
- Name 4 adverse effects of Aminosalycylates
- release 5-ASA which has anti-inflammatory and immunsuppressive effects, whilst acting topically on the gut
- mesalazine, sulfasalazine
- GI upset
headache
thrombocytopenia
renal impairment
What is the indication of corticosteroids for IBD?
indice remission
- Which immunosuppressant is indicated for management of IBD?
- What is it used to do?
- Name 2 adverse effects of this drug
- azathioprine
- maintain remission
- bone marrow suppression
hepatotoxicity
Name 2 TNF-alpha antagonists indicated for the management of IBD
- adalibumab
2. infliximab
- Name 3 antimuscarinics used to manage symptoms of IBS
- How do they do this?
- Name 4 side effects
- Name 2 contraindications of these drugs
- dicycloverine
hycosine butylbromide
propatheline - reduce smooth muscle tone and peristaltic contraction
- tachycardia
dry mouth
constipation
urinary retention - closed-angle glaucoma
arrythmia
Name risk factors which lead to the recommendation of empiric antibiotic therapy for GI infections
- fever, >6 stools/day, volume depletion warranting hospitalisation
- features suggestive of invasive bacterial infection (bloody/mucoid stools)
- host factors which increase the risk for complications - >70; comorbidities (cardiac disease, immunocompromised)
- Name 3 drugs used in multimodal analgesia?
2. What is the indication of multimodal analgesia?
- IV paracetamol
bupivacaine (local anaesthetic) epidural infusion
hydromorphone (opioid) epidural infusion - control pain preoperatively
- What is breakthrough pain?
- Which drug is useful to control breakthrough pain?
- How is an adequate PRN dose of this drug calculated?
- What should be done if the patient is constantly requiring their rescue dose?
- sudden increase in pain in patients who have chronic pain
- oromorph
- divide the total daily dose (regular dose + number of rescue doses) by 6
- increase regular dose
- How do antihistamines function as antiemetics?
- name 2 antihistamines used as antiemetics
- name 3 warnings when using these antihistamines
- inhibit histamine receptors found within the vomiting centre, which are involved in vestibular inputs
- cyclizine; promethazine
- hepatic enceophalopathy
prostatic enlargement
- How do dopamine antagonists function as antiemetics?
- Name 2 examples
- name 3 side effects
- name 5 warnings/cautions for their use
- name 3 interractions
- inhibits D2 receptors in the chemoreceptor trigger zone; promotes relaxation of the stomach and lower oesophageal sphincter
- doperidone; metoclopramide
- diarrhoea
extrapyramidal side effects
QT elongation and arrythmia
4. <18 years cardiac conduction abnormalities hepatic impairment intestinal obstruction and perforation parkinson's disease
- antipsychotics
dopaminergic agents for PD
drugs that prolong the QT interval
- How do serotonin antagonists act as antiemetics?
- Name an example?
- Name a warning
- serotonin is released by the gut in response to emetogenic stimuli; acts on serotonin receptors in the CTZ
- odansetron
- QT elongation (and thus interracts with other QT prolonging drugs)
What are the indications for IV fluids?
prescribed for patients whose fluid needs can’t be met by oral or enteral routes
- nil by mouth
- vomiting/severe diarrhoea
- patient is hypovolaemic as a result of blood loss
- What are crystalloids?
- What are colloids?
- Which type of fluid is used less often and why?
- solutions of small molecules in water
- solutions of larger organic molecules
- colloids, ad they carry a risk of anaphylaxis
- Name 2 crystalloids used for fluid resuscitation and maintenance
- Name 2 crystalloids used for maintenance only
- Normal saline (0.9% NaCl)
Hartmann’s Solution - sodium chloride 0.18%/glucose 4%
5% dextrose
Name considerations for IV fluid therapy in the initial assessment (5)
- has enteral fluid intake been reduced?
- is patient experiencing dizziness/syncope?
- is the patient thirsty?
- is the patient experiencing abnormal fluid loss
- does the patient have co-morbidities affecting their ability to handle fluids? (HF; renal failure)
Name examination findings which indicate the patient is hypovolaemic
- tachypnoea
- decreased sats
- bilateral crackles
- tachycardia
- hypotension
- prolonged cap refil time
- non visible JVP
- decreased GCS
- decreased urine output
What kind of IV fluid therapy is indicated if:
- the patient is hypovolaemic
- the patient is euvolaemic but can’t take oral/enteral fluids
- patient is hypervolaemic
- resuscitation fluids are required
- maintenance fluids are required
- DO NOT ADMINISTER IV FLUIDS
- How are resuscitation fluids administered?
2. What is the maximum amount of resuscitation fluid which can be administered within 24 hours?
- give an initial fluid bolus of 500ml crystaloloid over <15mins
reassess with the patient
give further fluid bolus of 250-500ml crystalloid - 2000ml
What is the function of maintenance fluids?
to maintain daily fluid, electrolyte and glucose requirements in patients who are haemodynamically stable but unable to meet these needs orally/enterally