Gastrointestinal Medicine - 1 Flashcards
What medications are used for upper GI diseases and what do they do?
Antacids
- elimate acid via neutralising by forming a salt
H2 receptor blocks
- block histamine
PPI (proton pump inhibitors)
- reduce PP acid release
How do H2 receptor antagonists work and why are they limited in benefit?
what are examples?
- Reduce acid production by preventing histamine activation of acid production
- Limited benefit as alternative pathways still operative through Acetylcholine, Gastrin
- Ranitidine
- Cimetidine (many drug interactions)
What are the 3 triggers for parietal cells to secrete acid?
how can stimulation be stopped
ACh (vagus nerve via surgery)
Gastrin
Histamine (H2 blockers)
What are examples of PPI?
omeprazole
lansoprazole
pantoprazole
any prazole ending
Why are oral diseases not part of the GI tract?
they are embryologically not part of the GI tract
oral tissues develop from invaginations of the ectoderm as the head grew to accommodate the brain
What are the types of endoscopy?
esophagogastroduodenoscopy
- flexible scope with light and small forceps for biopsy passed through the GI
capsule endoscopy
- takes photos of the GI as it passes through when swallowing
What can cause dysphagia?
external compression
dysmotility disorder - fibrosis
neruromuscular dysfunction
What can cause compression and what structures can be compressed?
tumours/aneurysm
lung/aorta/trachea/cervical spine
What are examples of fibrosis and what do they cause?
scleroderma (elastic tissue is replaced by fibrous tissue)
acid related fibrosis (GORD) causing chronic inflammation
they cause loss of specalised tissue that aids in swallowing
What are examples of neuromusular dysfunction?
parkinsons disease
diabetes mellitus
achalasia (nerve does not form properly)
Why is the dysphagia localised well by the patient?
the oesophagus is highly innervated
What are the 3 main causes of GORD?
- defective lower oesophageal sphincter
- impaired lower clearing
- impaired gastric emptying
What are the effects of GORD?
- ulceration, inflammation, metaplasia (Gastric)
- Barrett’s Oesphagitis
What is the metaplasia that GORD can cause?
from simple squamous epithlium to gastric (simple columnar)
What are GORD signs and symptoms?
- Heartburn
- Acid reflux
- Chest pain
- Dysphagia
- GI bleeding
How cause GI bleeding diagnosed?
fecal occult blood tests
What is a hiatus hernia?
part of stomach is in thorax
similar symptoms to GORD
How can GORD be managed via lifestyle?
- Stop smoking and excess caffeine - improves sphincter
- Lose weight & avoid triggering activity - fat can cause pressure onto stomach forcing acid up, bending can also force acid up
What medications can manage GORD?
- antacids
- H2 blockers & PPI’s
- ranitidine & omeprazole
What are the causes of PUD (peptic ulcer disease)?
in duodenum and stomach
- High acid secretion - duodenal
- Normal acid secretion - stomach (NSAIDS, steroids, H-pylori)
What major issues can peptic ulcers cause?
ulcer can erode into artery causing bleeding or perforate the peritoneum causing peritonitis
What can be causing excessive acid production?
Gastrinomas are neuroendocrine tumors characterized by the secretion of gastrin with resultant excessive gastric acid production
What is the bacterium that causes PUD?
H. pylori
infects the lower part of the stomach antrum
What does H.pylori cause?
gastric ulcers through loss of mucus barrier which allows acid in stomach to get to gastric wall
chronic inflammation of the gastric mucosa
lymphoma
How is H.pylori eliminated?
TRIPLE THERAPY
* 2 antibiotics
* 1 proton pump inhibitor
What are PUD signs and symptoms?
- Burning stomach pain
- Indigestion
- Acid reflux
- Blood in vomit or stool (serious - means perforation)
How can PUD be investigated?
- Endoscopy
- Radiology - barium meal
- F.B.C (anemia) and faecal occult blood test (FOB’s) (GI bleeding)
- H. pylori - breath, antibodies, mucosa
What are the complications of PUD?
- perforation
- haemorrhage (coffee grounds)
- stricture
- malignancy
- anaemia
What is treatment of PUD?
- Antibiotics (to kill H. pylori)
- Medications to reduce stomach acid (PPIs or H2 blockers)
- Lifestyle changes (quit smoking, limit alcohol)
How can the mucosal barrier be improved?
- Eliminate Helicobacter
- Reduce NSAID (irritant)
- Reduce steroid use (weaken barrier)
What is triple therapy?
For elimination of Helicobacter pylori
Two week course of:
Two antibiotics
Amoxycillin, Metronidazole
Proton Pump Inhibitor
Omeprazole
What are the three surgeries available for PUD?
Bilroth 1 - top half of stomach is reconnected to duodeum, removes part of stomach and sphincter
Bilroth 2 - top half of stomach reconnected to jejunum bypassing duodeum
Highly selective vagotomy
What are the diseases found in small bowel?
- Coeliac Disease
- Pernicious Anaemia
- Crohn’s Disease
- Infections
- Tumours
Why is the duodeum most affected by PUD?
due to gastric emptying and bile/pancreatic secretions
What is the cause of coeliac disease?
Sensitivity to α-gliaden component of Gluten - causing a reactive change in the small bowel
What is the aetiology of coelic disease?
- Genetic susecptibility
- Environmental trigger
What happens in coeliac disease at the enterocytes?
gluten consumed
alpha -gliaden passes through enterocytes and causes an immune reaction
t-cells damage mucosal tissue causing villous atrophy
What is loss of projections called and what does it lead to?
Subtotal villous atrophy of the jejunum > decreased surface area > decreased absorption
What are classic symptoms of coeliac disease?
- Weight loss
- Weakness
- Abdominal pain/swelling
- Diarrhoea
- Canker sore
- Tongue papillary loss
- Steatorrhoea
- Dysphagia - plummer vinson syndrome caused by loss of iron
How can coeliac disease be investigated?
- Autoantibody Test - TTG, anti-gliadin antibodies
- Jejunal Biopsy
- Faecal Fat – increased if malabsorbtion
- Haematinics – B12, Folate, Ferritin
Why is a serum TTG not very accurate?
delivers many false positives
What is the outcome of a gluten free diet for coeliacs?
- Reversal of jejunal atrophy
- Improved well-being
- Reduced risk of lymphoma
What skin disease is associated with coeliac disease?
what does it do
Dermatitis Herpetiformis
skin/oral conditon (granular IgA deposits) that causes itching, blistering and ulcers
What is pernicious anaemia?
failure of body to absorb vit B12
Why is vit b12 complex during absorption?
- Needs intrinsic factor from Gastric parietal cells and R protein in saliva
- Needs functioning of a discrete area of the Terminal Ilium – this is the ONLY vit B12 absorption site in the bowel
What are the possible tests for pernicious anaemia?
serology
blood tests
What causes pernicious anaemia?
- Lack of Vitamin B12 in the diet
- Disease of Gastric parietal cells (autoimmune found in diabetes)
- IBD at terminal end
- Bowel cancer
What can vit B12 deficiency lead to?
permanent neurological damage
bone marrow production damage
