GI Flashcards
Define intestinal obstruction
Blockage of the lumen of the gut
Arrest of onward propulsion of intestinal contents
Name 3 broad types of causes of intestinal obstruction
- Intraluminal obstruction = something in the bowel
- Intramural obstruction = something in the wall of the bowel
- Extraluminal obstruction = something outside of the bowel
Give 3 causes of intraluminal obstruction of the intestine
- Tumour - carcinoma, lymphoma
- Diaphragm disease
- Meconium ileus
- Gallstone ileus
What is diaphragm disease?
Mucosa/submucosa fold due to fibroid diaphragm leaving a pinhole lumen
What is thought to cause diaphragm disease?
NSAIDs
Give 3 causes of intramural obstruction of the intestine
- Inflammatory disease = Chron’s, Diverticulitis
- Tumours
- Neural = Hirschsprung’s disease
Describe how Crohn’s disease can cause intestinal obstruction
Crohn’s disease –> fibrosis –> contraction –> obstruction
Describe how diverticular disease can cause intestinal obstruction
Out pouching of mucosa –> faeces trapped –> inflammation in bowel wall –> contraction –> obstruction
What is Hirschsprung’s disease?
A congenital condition where there is a lack of nerves in the bowel –> no ganglion cells –> no contraction –> distal obstruction and gross dilation of the bowel
Give 3 causes of extraluminal obstruction of the intestine
- Adhesions
- Volvulus
- Peritoneal tumour
What are adhesions?
Fibrous bands stick 2 bits of bowel together so bowel is pulled and distorted
What causes adhesions?
Often formed after abdominal surgery (pelvic, gynaecologist, colorectal)
What is volvulus?
Bowel twisting around each other cuts off blood supply/ lumen
Risk of ischaemia, necrosis and perforation
Which areas of the bowel are most likely to be affected by volvulus?
Occurs in areas of bowel that have mesentery
Often in the sigmoid colon
Give 4 common causes of small bowel obstruction in adults
- Adhesions
- Hernias
- Crohn’s disease
- Malignancy
Give 3 common causes of small bowel obstruction in children
- Appendicitis
- Volvulus
- Intussusception
What is intussusception?
One part of the intestine telescopes into another section of the intestine
Caused by force in-balances
Give 5 symptoms of small bowel obstruction
- vomiting more common
- periumbilical
- cramping and intermittent pain
- lasts for a few minutes at a time
- Nausea and anorexia
- Early feculent vomit
- Diffuse colicky pain
- Late constipation
- Distention
- Tenderness
- bowel sounds
Does abdominal distension occur more distal or proximal to an intestinal obstruction?
More distal = greater distension
What investigations might you do in someone who you suspect to have a small bowel obstruction?
- FBC
- abdominal x-ray - shows central gas shadow that completely cross the lumen, distended loops of bowel proximal to obstruction, fluid levels seen
- CT - gold standard to localise lesion accurately
What is the management/treatment for small bowel obstruction?
- Fluid resuscitation
- Bowel decompression
- Analgesia and antiemetics
- Antibiotics
- Surgery - laparotomy, bypass segment, resection
Which is more common, small or large bowel obstruction?
Small bowel obstruction = 60-75% of intestinal obstruction
What can untreated intestinal obstruction lead to?
- Ishcaemia
- Necrosis
- Perforation
Give 2 common causes of large bowel obstruction
- Colorectal malignancy - most common in UK
2. Volvulus - more common in Africa
Where is the usual site of perforation in large bowel obstruction if the ileocaecal valve is competent?
Caecum
How long does acute presentation of large bowel obstruction last?
Average of 5 day of symptoms = abdominal pain and constipation
Give 5 symptoms of large bowel obstruction
- lower abdominal pain
- less frequent pain
- episodes last longer
- Bloating/fullness/nausea
- Late vomiting (more faecal like) - may be absent
- Colicky pain - more constant than SBO
- Distension
- Blood in stool
- constipation
- palpable mass
- bowel sounds normal then increase then quiet later
What investigations might you do in someone who you suspect to have a large bowel obstruction?
- Digital rectal examination - empty rectum, hard stools, blood
- abdominal X ray - peripheral gas shadows proximal to blockage, caecum and ascending colon distended
- CT scan
- FBC - low Hb
Describe the management for a large bowel obstruction
- IV fluid replacement
- Bowel decompression
- Surgery - laparotomy
- analgesia and antiemetic
- antibiotics
Define hernia
Abnormal protrusion of an organ into a body cavity it doesn’t normally belong
What are the risks of hernia’s if left untreated?
Become strangulated
Give 2 symptoms of hernias
- Pain
2. Palpable lump
Describe the progression from normal epithelium to colorectal cancer
Normal epithelia –> adenoma –> colorectal adenocarcinoma –> metastatic colorectal adenocarcinoma
Define adenocarcinoma
A malignant tumour of glandular epithelium
What is familial adenomatous polyposis?
Autosomal dominant condition
- arise from mutation in APC gene- where you develop thousands of polyps in the duodenum and colorectal in teens
What are precursors to colorectal cancer?
Polyploid adenomas
Describe the epidemiology of colorectal cancer
Normally adenocarcinoma - majority in distal colon Incidence peaks around 60-65 years Males > females 2nd most common cause of cancer death in UK
Give 5 risk factors for colorectal cancer
- Increasing age
- Family history
- Western diet - saturated animal fat, red meat consumption, low fibre, high sugar
- Alcohol
- Smoking
Give 3 reasons why bowel cancer survival has increased over recent years
- Introduction of the bowel cancer screening programme
- Colonoscopic techniques
- Improvements in treatment options
What can affect the clinical presentation of a colorectal cancer?
How close the cancer is to the rectum
Give 2 signs of a left sided/sigmoid colorectal cancer
- Altered bowel habit
- diarrhoea
- blood in stool
- alternating diarrhoea and constipation
Give 3 signs of a right sided colorectal cancer
- assymptomatic until presenting with Iron deficiency anaemia
- Right iliac fossa mass
- Weight loss
- low Hb
- abdominal pain
Give 4 signs of rectal carcinoma
- rectal bleeding and mucus
- when cancer grows there will be thinner stools and tenesmus (cramping rectal pain)
- Abdominal mass
- Perforation
- Haemorrhage
- Fistulae
What investigations might you do in someone who you suspect might have colorectal cancer?
- Faecal occult blood test
>50 + bowel habit change / iron deficient anaemia
>60 + anaemia - Colonoscopy + biopsy
- Flexible sigmoidoscopy / barium enema / CT colonoscopy
How can adenoma formation be prevented?
NSAIDs
What screening programme is used to identify bowel cancer?
Faecal occult blood (FOB) screening
For over 65s+ve result = biopsy
What is the management for colorectal adenocarcinoma?
- Surgical resection
- endoscopic stenting for palliative care
- radiation
- chemotherapy - if duke’s stage C
What is the treatment for metastatic colorectal adenocarcinoma?
Chemotherapy and palliative
Explain Dukes staging and prognosis
A = limited to muscularis mucosae = 95% 5-year survival B = extension through muscularis mucosae (not lymph) = 75% 5-year survival C = involvement of regional lymph nodes = 35% 5-year survival D = distant metastases = 25% 5-year survival
What does T refer to in the staging of cancer?
T = refers to primary tumour and suffixed by number that denotes tumour size
What does N refer to in the staging of cancer?
N = refers to lymph node status and is suffixed by numbers that denotes number of lymph nodes or group of lymph nodes containing metastases
What does M refer to in the staging of cancer?
M = refers to anatomical extent of distant metastases
What does the T mean for colorectal cancer staging?
T1 = invades submucosa T2 = Muscularis propria T3 = Bowel wall T4 = Peritoneum
What does the N mean for colorectal cancer staging?
N1 = spread to lymph nodes N2 = spread to lymph nodes above the diaphragm
What does the M mean for colorectal cancer staging?
M1 = surrounding structure involvement (liver)
Name 5 things that can break down the mucin layer in the stomach and cause gastritis
- Mucosal ischameia
- H. pylori
- Aspirin, NSAIDs - most common
- Increased acid (stress)
- Bile reflux
- Alcohol
Give 3 symptoms of gastritis
- Epigastric pain
- Nausea and vomiting (recurrent upset stomach)
- Indigestion
- Haematemesis
- dyspepsia
What investigations are done with someone you suspect has gastritis?
- Endoscopy (erythema)
- Biopsy (histology change)
- Blood tests (inflammation)
- H.pylori testing - urea breath test, stool antigen test
Describe the treatment for gastritis
- Decrease alcohol and smoking
- Antacid (magnesium carbonate)
- PPI (omeprazole)
- H2 receptor antagonist (ranitidine)
- Enteric coated aspirin
- decrease stress
How do you treat H. pylori?
Triple therapy:
Normal –> amoxicillin, omeprazole and clarithromycin/metronidazole
Penicillin resistance –> clarithromycin, omeprazole and metronidazole
Give 4 causes of peptic ulcers
- NSAIDs
- Mucosal ischaemia
- Increased acid production (stress)
- Bile reflux
- Alcohol
- H. pylori
How does mucosal ischaemia cause ulcer formation?
Lack of blood flow to cells –> no mucin production = no mucosal protection –> ulcer formation
How does increased acid production (stress) cause ulcer formation?
Mucosa overwhelmed –> corrosion –> ulcer formation
How does NSAIDs cause ulcer formation?
Reduced prostaglandin synthesis due to salicylic acid release –> cell death –> no mucin production = no mucosal protection –> ulcer formation
How does bile reflux cause ulcer formation?
Mucosal cell damages –> no mucin production = no mucosal protection –> ulcer formation
How does H. pylori cause ulcer formation?
- causes decrease in HCO3- which increases acidity
- H.pylori secretes urease
- splits urea into CO2 and ammonia
- ammonia + H+ forms ammonium which is toxic to gastric mucosa
- Acute inflammatory reaction (neutrophils) with less mucosal defence
Give 3 symptoms of peptic ulcers
- recurrent burning epigastric pain
- pain relieved by antacids and is worse when hungry
- pain occurs at night
- nausea
- anorexia and weight loss
What investigations might you do in someone who you suspect to have peptic ulcers?
H. Pylori Test (Urease breath test)
Endoscopy (if Over 55 or Red Flags Present)
How can you treat peptic ulcers?
- lifestyle changes
- reduce stress, avoid irritating food, reduce smoking
- Stop NSAIDs
- H.Pylori eradication (triple therapy):
- PPI - OMEPRAZOLE
- 2 of following:
- AMOXICILLIN
- CLARITHROMYCIN
Name 2 complications of peptic ulcers
- Haemorrhage due to erosion to artery
- Peritonitis due to erosion through wall
Give 5 broad causes of malabsorption
- Defective intraluminal digestion
- Insufficient absorptive area
- Lack of digestive enzymes
- Defective epithelial transport
- Lymphatic obstruction
Malabsorption: what can cause defective intraluminal digestion?
- Pancreatic insufficiency due to pancreatitis/CF - lack of digestive enzymes
- Defective bile secretion due to biliary obstruction or ileal resection
- Bacterial overgrowth
Malabsorption: what can cause insufficient absorptive area?
- Coeliac disease
- Crohn’s disease
- Extensive surface parasitisation
- Small intestinal resection or bypass
Malabsorption: give an example of when there is a lack of digestive enzymes
Lactose intolerance - disaccharide enzyme deficiency
Malabsorption: what can cause lymphatic obstruction?
- Lymphoma
2. TB
Describe the distribution of inflammation seen in Crohn’s disease
Patchy (skip lesions), granulomatous, transmural inflammation
Describe the distribution of inflammation seen in Ulcerative colitis
Continuous inflammation affecting only the mucosa
What part of the bowel is commonly affected by Crohn’s disease?
Can affect anywhere from the mouth to anus
Terminal ileum is most affected
What part of the bowel is commonly affected by Ulcerative colitis?
Spreads proximally from the rectum but only affects the colon
give 3 microscopic features that will be seen in ulcerative colitis
- Crypt abscess
- goblet cell depletion
- mucosal inflammation - does not go deeper
what are the macroscopic features of crohn’s disease?
- Deep ulcers and fissures –> cobblestone look
- skip lesions
- involved bowel often thickened and narrowed
In Crohn’s or UC is smoking a protective factor?
Ulcerative colitis
Name 3 causes of IBD
- Genetic
- Stress/depression
- Inappropriate immune response
Give 4 signs and symptoms of Ulcerative colitis
- Episodic/chronic diarrhoea +/- blood/ mucus
- Abdominal pain - left lower quadrant
- Systemic - fever, malaise, anorexia, weight loss
- Clubbing
- Erythema nodosum
- Amyloidosis
Give 4 signs and symptoms of Crohn’s disease
- Diarrhoea - urgency
- Abdominal pain
- Systemic - weight loss, fatigue, fever, malaise
- Bowel ulceration
- Anal fistulae/stricture
- Clubbing
- Skin/joint/eye problems
What investigations might you do in someone with IBD?
- Bloods - FBC, ESR, CRP
- Faecal calprotectin - shows inflammation but is not specific for IBD
- Flexible sigmoidoscopy
- Colonoscopy - biopsy to confirm
- examination
What is the treatment for Crohn’s disease?
- Smoking cessation
- 1st line = Corticosteroids - BUDESONIDE (controlled release) or ORAL PREDNISOLONE (for severe attacks)
- Surgical resection - only minimal
What is the treatment for Ulcerative colitis?
- Aminosalicylates
- 5-ASA (SULFASALAZINE)
- PREDNISOLONE
- HYDROCORTISONE
- Surgical resection
Give 5 complications of Ulcerative colitis
- Colon –> blood loss, colorectal cancer, toxic dilatation
- Arthritis
- Iritis, episcleritis
- Fatty liver and primary sclerosing cholangitis
- Erythema nodosum
Give 5 complications of Crohn’s
PERFORATION AND BLEEDING = MAJOR
- Malabsorption
- Obstruction –> toxic dilatation
- Fistula/abscess formation
- Anal skin tag/fissures/fistula
- Neoplasia
- Amyloidosis
Describe the pathophysiology of Coeliac disease
- Gliadin from gluten deaminated by tissue transglutaminase –> increases immunogenicity
- Gliadin recognised by HLA-DQ2 receptor on APC –> inflammatory response
- Plasma cells produce anti-gliadin and tissue transglutaminase –> T cell/cytokine activated
- Villous atrophy and crypt hyperplasia –> malabsorption
When does Coeliac disease usually present?
2 peaks - infancy and 5th decade
Give 5 symptoms of Coeliac disease
- Diarrhoea and steatorrhoea (stinking/fatty)
- Weight loss
- Irritable bowel
- Iron deficiency anaemia
- Osteomalacia
- Fatigue
- abdominal pain
- angular stomatitis
- dermatitis herpetiform
What investigations might you do in someone who you suspect to have coeliac disease?
- anti-tTg antibody test - must keep gluten diet 6 weeks prior
- Endoscopy - duodenal biopsy post 6 weeks gluten diet (gold standard)
What 3 histological features are needed in order to make a diagnosis of coeliac disease?
- Raised intraepithelial lymphocytes
- Crypt hyperplasia
- Villous atrophy
What part of the bowel is mostly affected in coeliac disease?
Proximal small bowel (duodenum)
mean B12, folate and iron cannot be absorbed = anaemia
How do you treat coeliac disease?
- Lifelong gluten free diet
- correction of mineral and vitamin deficiency
- DEXA scan for osteoporosis risk
Give 3 complications of Coeliac disease
- Osteoporosis
- Anaemia
- Increased risk of GI tumours
- secondary lactose intolerance
- T-cell lymphoma
What cells normally line the oesophagus?
Stratified squamous non-keratinising cells
Give 3 causes of squamous cell carcinoma
- Smoking
- Alcohol
- Poor diet/obesity
- coeliac disease
Name 2 types of Oesophageal cancer
- Adenocarcinoma - distal 1/3rd of oesophagus
2. Squamous cell carcinoma - proximal 2/3rds of oesophagus
What can cause oesophageal adenocarcinoma?
Barrett’s oesophagus
Give 5 symptoms of oesophageal carcinoma
- progressive dysphagia
- Weight loss
- Heartburn
- Haematemesis
- Anorexia
- Pain
What investigations might be done on someone you suspect has oesophageal cancer?
upper GI endoscopy and biopsy = 1st line
Barium swallow - to see strictures
CT/MRI for staging
How can you treat oesophageal cancer?
- Surgical resection
- best chance of cure if not infiltrated through oesophageal wall
- Chemotherapy - Palliative care
Give 3 causes of gastric cancer
- Smoked foods
- Pickles
- H. pylori infection
- Pernicious anaemia
- Gastritis
- family history
Describe how gastric cancer can develop from normal gastric mucosa
Smoked/pickled food diet leads to intestinal metaplasia of normal gastric mucosa
Several genetic changes lead to dysplasia and then eventually intra-mucosal and invasive carcinoma
Give 3 symptoms and signs of gastric cancer
- Weight loss
- Anaemia (pernicious)
- nausea and Vomiting
- Dyspepsia and dysphasia
- palpable epigastric mass
- Hepatomegaly, jaundice and ascites
- Enlarged supraclavicular nodes
- epigastric pain