Digestive Flashcards
What are two key histological findings in Crohn disease?
- Transmural inflammation (mucosa to serosa)
- Non-necrotising granuloma
Why might patients with Crohn disease present with anaemia and/or iron and B12 deficiency?
- Anaemia due to bleeding from chronic inflammation
- Iron/B12 deficiency if small intestine is affected, less efficient absorption
Which part of the GI tract is affected by Crohn disease?
Entire tract can be affected, most commonly ileum + colon
What is the most commonly used anti-inflammatory for Crohn disease?
5-ASA
Which investigations are most commonly used for structural conditions of the oesophagus?
Gastroscopy and barium swallow
Which investigations are most commonly used for functional conditions of the oesophagus?
Manometry and pH study
How would a baby with an oesophageal fistula present?
Frequent vomiting following feeding
A patient presents with:
- Heartburn
- Regurgitation
- Bitter taste in the mouth
- Exacerbation when lying down
What GI pathology could this relate to?
GORD
What is Barrett’s Oesophagus?
Transition from stratified squamous to columnar, glandular epithelium in the oesophagus following chronic acid exposure
What are key symptoms of reflux oesophagitis?
- Pain/discomfort in chest
- Bleeding (haematmesis)
- Dysphagia
Chronic GORD can lead to which conditions?
- Reflux oesophagitis
- Peptic stricutration
- Oesophageal cancer (AdenoCa)
Anatomically, where are you most likely to find oesophageal SqCC?
High in the oesophagus
Which form of oesophageal cancer is associated with smoking, alcohol and poor diet?
SqCC
What is Zenker’s diverticulum?
A pouch that develops at the weakest portion of the pharynx due to excessive pressure
What are viral causes of oesophageal ulceration?
Herpes simplex, cytomegalovirus
What are pill induced causes of oesophageal ulceration?
Dioxycycilne and bisphosphonates
What is a characteristic macroscopic feature of eosinophilic oesophagitis?
Rings/circles/fissures in the oesophagus
What is achalasia?
Degeneration of the myenteric plexus and LOS inhibitory nerve
What causes the ‘bird beak’ appearance of an x-ray of a patient with achalasia?
- Loss of peristalsis in distal oesophagus
- Failure of LOS to relax with swallow
How does scleoderma affect the oesophagus?
- Absent peristalsis
- LOS has no tone
- Weak contraction
Why would manometry show high amplitude of contraction for nutracker oesophagus?
Normal peristalsis but amplitude of contraction is too strong
Why is vomiting of patients with congenital hypertrophic pyloric stenosis non-billous?
Stomach contents do not enter the duodenum due to thickening of pyloric wall
Which gastric tumour produces excess gastrin, causing destruction of gastric mucosa?
Gastrinoma
Which cell type is destroyed in pernicious anaemia?
Parietal cells
What are the symptoms of peptic ulcer disease?
- Burning epigastric pain
- Bleeding
- Perforation
- Obstruction
Which antibiotics comprise ‘triple therapy’ for peptic ulcer disease?
- Omeprazole
- Clarithromycin
- Amoxycillin
Which gastric cells secrete HCl?
Parietal cells
Why are cramping and diarrhoea symptoms of rapid gastric emptying?
Due to osmotic effect of large particles and fluid in the small intestine
What is the mechanism of H2 antagonists?
- Bind to H2 receptors on parietal cells for histamine
- Prevents parietal cell stimulation
What is the most commonly used H2 receptor antagonist?
Ranitidine
Why are H2 antagonists not effective for heartburn/oesophagitis?
Don’t allow mucosal healing - acid still secreted
What is the mechanism of action of PPIs?
Irreversibly bind to an activated proton pump
What are consequences of prolonged acid inhibition (e.g. chronic use of PPIs)?
- Bacterial overgrowth
- Lack of sterilisation
- Impaired absorption
- ECL hyperplasia
Increase in unconjugated bilirubin would be indicative of what kind of problem?
Vascular - bilirubin is not able to travel to the liver to become conjugated
What are symptoms of increase in conjugated bilirubin?
- Dark urine
- Obstructive jaundice
What causes steatorrhoea?
Loss of bile -> inability to break down fats
Which type of hepatitis is benign?
Hepatitis A
What is the incubation period of hepatitis A?
2-6 weeks
What are the causes of hepatitis A?
Poor sanitation and hygiene
What is the mechanism of hepatitis B?
Viral antigens expressed on hepatocytes -> immune response -> damage of liver cells
What is the current treatment for hepatitis C?
Direct acting antiviral agents (tablets)
What is the mechanism of alcoholic liver disease?
Repeat exposure to alcohol -> alterations in lipid metabolism -> decreased export of lipoproteins
What is haemochromatosis?
Abnormality in iron absorption -> excessive iron deposits on organs
What is Budd-Chiari syndrome?
Acute thrombosis of hepatic veins -> restriction of blood outflow from liver -> liver damage
A patient presents with:
- Acute, rapidly progressive severe abdominal pain
- Hepatomegaly
- Ascites
- Hepatic encephalopathy
What could be a suspected diagnosis?
Budd-Chiari syndrome
How is Budd-Chiari syndrome treated?
- Portocaval shunting
- Anticoagulants
- Diuretics
Which enzyme is affected by Gilbert syndrome?
UDP glucuronyl transferase
Oesophageal varices, splenomegaly and intestinal congestion are indicative of which kind of portal blood flow restriction?
Prehepatic (impaired inflow)
Which liver enzymes are indicative of liver inflammation?
ALT and AST
Which liver enzymes are indicative of biliary/cholestatic pathology?
ALP and GGT
Which liver enzyme does alcohol induce?
GGT
Which is more liver specific, ALT or AST?
ALT
Where is albumin produced?
The liver
What is the prothrombin ratio?
Reflects the rate of clotting factor synthesis
Liver failure or vitamin K deficiency
How is excessive ammonia causing encephalopathy treated?
Lactulose
How does lactulose treat hepatic encephalopathy?
- Converts ammonia into a non-soluble molecule
- Inhibits ammonia synthesis by bacteria
- Increases bowel transit
What does CEA test for?
A cancer marker
Why might albumin levels be normal in an acute hepatic pathology?
Half life is 3 weeks (not enough time for levels to drop)
What is choledocholithiasis?
Gall stone blockage in the biliary tree
What would be the expected findings of a blood test for a patient with acute cholecystitis?
- Neutrophil leucocytosis
- Raised bilirubin, ALP, GGT
Why might a patient with prolonged biliary obstruction be vitamin K deficient?
Fat soluble vitamin - loss of bile means fat absorption is impaired
What controls enzyme release from the pancreas?
CCK
What are the most common causes of acute pancreatitis?
Alcohol consumption and gall stones
Why would oedema be seen on a CT in an individual with acute pancreatitis?
Accumulation of fluid -> active enzymes cause fat necrosis -> oedema and local inflammation
Which enzymes are expected to be elevated in acute pancreatitis?
Serum amylase and lipase
How do you treat chronic pancreatitis?
Oral administration of pancreatic enzymes
What are the symptoms of pancreatic adenocarcinoma?
- Obstructive jaundice
- Pain
- Weight loss
- Pancreatitis
- Thrombophlebitis
What is thrombophlebitis?
Blood clotting in a vein causing inflammation and pain
Why might IBS occur after an episode of gastroenteritis?
- Disruption of normal gut flora
- Upregulation of nociceptors
A patient presents with
- Swinging bowel habit
- Abdominal pain relieved by defecation
- Feelings of incomplete evacuation
- Abdominal bloating
What could these symptoms be associated with?
Irritable Bowel Syndrome (IBS)
IBS symptoms should have been present for at least ___ months prior to diagnosis
6
What is loperamide?
An anti-motility drug for bowel frequency
What is used for pain management in IBS?
Low dose tricyclics
- Amitriptyline
- Nortriptyline
The genetic mutation in Coeliac disease is HLA ___ and ____
DQ2 and DQ8
In coeliac disease antibodies are created against ____
Gliadin
Which histological changes occur in coeliac disease?
- Villous atrophy
- Hypertrophy of crypts
- Intraepithelial lymphocytes
What is dermatitis herpetiformis?
Skin manifestation of coeliac disease
Why may individuals with coeliac be iron and/or folate deficient?
Due to lack of absorption in the duodenum
What is the recommended antibody test for coeliac disease?
Anti-TTG
Why can small intestinal bacterial overgrowth cause maldigestion?
Bacteria deconjugate bile acids so fats cannot be digested
What distinguishes ulcerative colitis from Crohn disease?
Affects mucosa and submucosa of large intestine only
What pattern of inflammation is followed in ulcerative colitis?
Circumferential and continuous
Ulcerative colitis/Crohn disease shows small ulcers on the gut mucosa (cobblestone appearance)
Crohn disease