GI Flashcards
Define Chron’s disease
Inflammation and tissue destruction anywhere along the GI tract
Which pathogens can trigger Chron’s disease?
Mycobacterium paratuberculosis
Pseudomonas
Listeria
How can genetics increase the risk of Chron’s disease?
Gene mutations in NOD2 gene cause a dysfunctional step causing unregulated inflammation
In Chron’s disease, IFN-gamma and TNF-alpha stimulate macrophages to produce what 3 things?
Free radicals
Proteases
Platelet-activating factor
How would you describe which parts of the GI tract Chron’s disease affects?
Whole GI tract
Patchy inflammation
Transmural
What is most commonly affected in Chron’s?
Ileum and colon
Give 3 symptoms of Chron’s
R lower quadrant pain
Diarrhoea and blood in stool
Malabsorption
How would you treat Chron’s?
Anti-inflammatories
Abx
Immunosuppressants
What is the most common type of IBD?
Ulcerative colitis
Define ulcerative colitis
Inflammatory disease forming ulcers along the lumen of the colon and rectum
Which layers of the intestinal wall are affected with ulcerative colitis?
Mucosa and submucosa only
Give the two main causes of UC
Autoimmune
Stress/ diet
Name the antibody responsible for attacking the body’s neutrophils in UC
P-ANCA
Perinuclear antineutrophil cytoplasmic antibody
Which groups have a genetic predisposition to UC?
People with a family history
Young women
Caucasians
Eastern european jews
Describe the pattern of inflammation in UC
Circumferential and continuous
Give 2 main symptoms of UC
Pain in lower L quadrant
Sever and frequent diarrhoea (with blood)
How might you treat UC?
Anti-inflammatory drugs- sulfasalazine, mesalamine
Immunosuppressant drugs- corticosteroids, azathioprine, cyclosporine
Colectomy
(Increasingly severe)
Describe IBS
Recurrent abdominal pain and abnormal bowel motility
What is visceral hypersensitivity in the context of IBS?
Sensory nerve endings have an abnormally strong response to stimuli (stretching)
Which short chain-carbohydrates can trigger IBS symptoms and why?
Lactose and fructose as they are metabolised by GI flora, producing gas, causing pain/ cramps
Give 2 key risk factors of IBS
Gastroenteritis- Norovirus/ Rotavirus
Stress
How would you treat IBS?
Diet modification- Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols (FODMAP diet)
For constipation- stool softeners, soluble finer, osmotic laxatives
For spasms/ pain- anti-diarrhoeals, anti-muscarinic
Manage stress, anxiety, depression
Which component of gluten binds to secretory IgA in coeliac disease?
Gliadin
How is gliadin transcytosed across the cell, into the lamina propria?
By binding to transferrin receptor
Which amide is used in the conversion of gliadin to deamidated gliadin?
Tissue transglutaminase
How is deamidated gliadin presented to T-helper CD4+ cells?
Engulfed by macrophage and presented by MHC II
How do T helper CD4+ cells respond to the presentation of deamidated gliadin?
Release inflammatory cytokines: IF-gamma and TNF
B cells produce: Anti-gliadin, anti-tTG and anti-endomysial
Recruitment of killer CD8+ T cells
What damage occurs in the duodenum with coeliac disease?
Flattened villi- villus atrophy
Crypt hyperplasia
Lymphocyte infiltration
Give 3 symptoms of coeliac disease in children
Abdominal distension
Failure to thrive
Diarrhoea
Give 3 symptoms of coeliac disease in adults
Chronic diarrhoea
Bloating
Symptoms vary
How can dermatitis herpetiformis occur as a result of coeliac disease?
Circulating IgA bind to transglutaminase in the dermal papillae
Neutrophils start an inflammatory reaction causing a rash
What are the increased risks of refractory disease in coeliac disease?
Small bowel cancer
T-cell lymphoma
Due to chronic inflammation and immune activation
Describe GORD
Transient lower oesophageal sphincter relaxations
Give 5 risk factors of GORD
Weight gain Fatty foods Caffeine Alcohol/ smoking Medications
Give 4 symptoms of GORD
Heartburn Cough Hoarseness Dysphagia Odynophagia
How may you diagnose GORD?
Often clinical based
Endoscopy
pH testing
Give a key complication of GORD
Barrett’s oesophagus which is a metaplasia of squamous to columnar epithelium
This can progress to cancer
Give 3 lifestyle modifications in the treatment of GORD
Elevated head of the bed
Diet modification
No coffee, alcohol, fats, smoking
Give 2 types of medications used to treat GORD
PPI
H2 blockers
What is the most common type of colorectal polyp?
Adenomatous polyps
From with a mutation in the APC gene
How may an adenomatous polyp become malignant?
If there is a mutation in another tumour suppressor gene e.g. K-ras and p53
What is familial adenomatous polyposis syndrome and what precaution may be taken?
Mutation in APC gene: many polyps
Often colon is removed to prevent malignancy
What type of adenomatous polyps most often progress to malignancy?
Sessile, villous polyps
Give 3 types of colonic polyps
Adenomatous
Serrated polyps
Inflammatory polyps
How do serrated polyps form?
DNA repair genes are silenced
Errors during DNA transcription do not get fixed, causing more mutations
Why do inflammatory polyps form?
Following bouts of IBD
Give 3 risk factors for developing colonic polyps
More cell divisions
Genetic conditions
Injury to the bowel wall- cigarette smoke, IBD, old age
What symptoms can occur as a result of polyps?
If they ulcerate and bleed: anaemia
If large: can cause abdominal pain/ constipation
How would you diagnose colonic polyps?
Biopsy, may do a loop cauterisation
Which section of the oesophagus would you see an increased incidence of cancer?
Lower 1/3 and gastro-oesophageal junction
Give 4 causes of oesophageal cancer
Barret’s oesophagus
Smoking
GO reflux
Drinking alcohol
Which investigations would you carry out for suspected oesophageal cancer?
Endoscopy
CT
PET scan
Endoscopic US
How would you treat oesophageal cancer?
2/3 cycles of chemotherapy
Surgery
Give 5 risk factors of gastric cancer
H. Pylori infection Male High salt and processed food diet Smoking FHx
Which investigation would you carry out for suspected gastric cancer?
Loproscopy
Why is the prognosis for gastric cancer often poor?
Often a late diagnosis
Few curative resections
How would you treat a tumour of the distal stomach?
Remove if stenosis/ bleeding
How would you treat a tumour of the proximal stomach?
Remove entire stomach- need vitamin B12 injections
Why can atelectasis occur in gastric cancer?
Alveoli collapses as the patient doesn’t breathe using the diaphragm because it causes pain
What are the most common sites of colorectal cancer?
Rectum, sigmoid and ascending colon
Give 3 risk factors of colorectal cancer
Diet high in red meat and fibre
Alcohol
Smoking
Give 4 conditions which predispose you to colorectal cancer
Neoplastic polyps
UC
Chron’s
Hereditary nonpolyposis colorectal cancer
How might L-sided bowel and sigmoid cancer present?
Change in bowel habit: diarrhoea/ constipation, thin stool, blood in stool
How might rectal cancer present?
PR bleeding, mucus, tenesmus (continuous inclination to empty the bowels), mass in PR
How might right sided bowel cancer present?
Weight loss
Anaemia
Mass
Which imaging investigations might you carry out in suspected colorectal cancer?
Liver US
CT/MRI
Barium enema- XR colon
Sigmoidoscopy/ colonoscopy
Which non-imaging investigations might you carry out in suspected colorectal cancer?
FBC: anaemia
Faecal occult blood test: blood in stool
Describe Dukes staging for colorectal cancer
A= confined to bowel wall B= Extended through bowel wall C= Involvement of regional lymph nodes D= Metastases
What pre-operative treatment would you give for colorectal cancer?
Abx prophylaxis
DVT/ PE prophylaxis- LMW heparin
What post-operative treatment would you give for Dukes C colorectal cancer?
Adjuvant chemotherapy
Name and describe the function of the first 3 layers of the stomach
Epithelial layer- absorbs and secretes mucus and digestive enzymes
Lamina propria- contains blood and lymph vessels
Muscularis mucosa- smooth muscle contracts and breaks down food
What are the main cells found in the cardia of the stomach?
Foveolar cells secreting mucus (water and glycoproteins)
What are the main cells found in the fundus and body of the stomach?
Parietal cells: secrete HCl
Chief cells: secrete pepsinogen
What are the main cells found in the antrum of the stomach?
G cells: secrete gastrin in response to food entering the stomach
What is the purpose of gastrin secretion?
Stimulates parietal cells to secrete HCl
This stimulates growth of glands in the epithelial layer
What is the function of Brunner glands and where are they found?
Secrete mucous rich in bicarbonate ions into the lumen of the duodenum
Stomach and duodenal mucosa would get digested if not for mucous and bicarbonate ions which neutralise acid
How do prostagladins protect the stomach and duodenal mucosa?
Stimulate mucous and bicarbonate
Vasodilate nearby blood vessels so there is more blood flowing to the stomach bringing in more bicarbonate
Describe and explain 3 causes of peptic ulcers
H.pylori bacteria: Gram -ve, colonise in gastric mucosa, proteases damage mucosal cells
NSAIDs: Inhibit cyclooxygenase (COX) which is an enzyme important in the synthesis of inflammatory prostagladins, leaves the mucosa susceptible to damage
Zollinger-Ellison syndrome: Gastrinoma- secretes abnormal amounts of gastrin, parietal cels release excess HCl
Where is the most common site for the formation of a gastric ulcer?
Lessure curvature of the antrum
Where is the most common site for the formation of a duodenal ulcer?
Right after the pyloric sphincter
Why might you see Brunner gland hypertrophy in peptic ulcer disease?
Duodenal ulcer, so glands hypertrophy to produce more mucous and protect the damaged area
What is the major complication with a deep peptic ulcer?
Haemorrhage into the GI tract leading to rapid blood loss and shock
Which two arteries are at highest risk of haemorrhaging and bleeding into the GI tract as a result of a peptic ulcer?
L gastric artery
Gastroduodenal artery
Describe and explain the consequences of peptic ulcer perforation
Gastrointestinal contents can enter the peritoneal space which is usually sterile
Air can collect under the diaphragm, irritating the phrenic nerve and causing referred pain to the shoulder
Give a key complication of long-standing duodenal ulcers near the pyloric sphincter
So much oedema and scarring that the passage of gastric contents into the intestine is obstructed, this causes nausea and vomiting
Give 4 symptoms of a peptic ulcer
Epigastric pain: aching/ burning
Bloating
Belching
Vomiting
How might you differentiate between a gastric and duodenal ulcer?
Gastric ulcer pain increases while eating
Duodenal ulcer pain lessens while eating
How would you diagnose a peptic ulcer?
Upper endoscopy into stomach and proximal duodenum
Biopsy is done to look for malignant cells or sign of a H.pylori infection
How would you treat peptic ulcer disease?
If H.pylori: combination of Abx and acid lowering medications (PPIs)
Stop using NSAIDs, alcohol, tobacco and caffeine
Give the most common cause of appendicitis
Obstruction:
Fecalith
Undigested seeds
Lymphoid hyperplasia
How does the obstruction of the appendix lead to abdominal pain?
Despite the obstruction the appendix continues to secrete mucous which builds up and increases the pressure
This acts on abdominal nerve fibres causing abdominal pain
What are the consequences of the trapping of gut flora and bacteria in the appendix?
E.coli and bacteroides fragillis are free to multiply and so immune cells are recruited and pus accumulates, therefore there is an increase in WBC serum count
Give 4 symptoms of appendicitis
Nausea
Vomiting
Fever
Pain at McBurney’s point (R lower quadrant)
How might appendicitis cause a ruptured appendix and what are the complications of this?
Increased pressure causes blood vessels to become compressed causing ischaemia
Cells producing mucous are dead and growing bacteria can invade the wall of the appendix which becomes weaker
If the appendix ruptures this may cause:
Peritonitis: pain with rebound tenderness and abdominal guarding
Periappendiceal abscess: pus and fluid forming an abscess around the appendix
How would you treat appendicitis?
Abscess drainage
Appendectomy
Describe a volvulus
An obstruction caused by a loop in the intestines that twists around itself and surrounding mesentery
What is the most common type of volvulus
Sigmoid volvulus
How might a sigmoid volvulus occur?
During pregnancy- foetus can cause displacement and twisting of the colon
In middle aged/ elderly- chronic constipation as colon can twist around large load of stool
Abdominal adhesions- physical attachment between two parts of the abdomen serves as the pivot point
Why can a cecal volvulus occur in young adults?
If there is abnormal development of the abdominal mesentery, the colon can flop around freely
Which age group are most prone to midgut volvulus and why?
Babies/ small children
As a result of abnormal intestinal development in foetuses: If there is malrotation at 12 weeks and the cecum and appendix stay on the upper R side
This often causes later twisting of the small intestine
What are the risks if the mesentery is tightly twisted in a volvulus?
Infarction leading to bloating, constipation, severe pain and bloody stool
The intestinal wall can break down, releasing bacteria and causing sepsis and cardiovascular collapse
How would you diagnose a volvulus?
Abdominal XR: looks like a coffee bean
Barium enema: shows bird’s beak shape (enlarged at one end, tapered at the other)
How would you treat a volvulus?
Sigmoidoscopy: if looks normal and pink, untwist tubes and decompress colon to relieve pressure
When would you require immediate surgery on a volvulus and what would this involve?
If bowel is severely twisted
If blood supply is cut off
Involves the untwisting of bowel and attaching it to the abdominal wall
What is a bowel intussusception?
Where the intestine folds in on itself, usually when the ileum folds into the cecum
Give 2 common causes of intussusception in adults
Polyps
Tumour
(Contracting intestines can grab the leading edge and pull it ahead)
What is the main cause of intussusception in babies?
Leading edge is often lymphoid hyperplasia
Payers patches: many tiny lymph nodes common in the ileum which enlarge to fight off infection- form a lead point
What is Meckel’s diverticulum and how can it cause intussusception?
Out-pouching of GI tissue
Usually sticks out into the peritoneal cavity
Occasionally can invert and stick back into the intestine, drawing the ileum into the cecum
Give 3 risk factors for intussusception
Having previously had an intussusception
Having a sibling with an intussusception
Intestinal malrotation
Describe the nature of the pain with intussusception
Intermittent abdominal pain
Worse with peristalsis
May cause child to guard abdomen
May draw knees to chest
Give 3 signs/ symptoms of intussusception
Abdominal pain
Vomiting
Hard, sausage-lek mass in abdomen
Explain the complications as a result of the pressure exerted on the walls of the trapped bowel due to intussusception?
Squeezes blood vessels shut causing ischaemia/ infarction
Intestinal mucosa, blood and mucus enters the gut
If there is intestinal tearing, there is release of bacteria causing sepsis/ fever
How can an intussusception cause a volvulus?
It can prevent food/ fluid passing, this large mass acts as a pivot point causing the intestine to twist
How would you diagnose an intussusception?
In children: may be felt during a DRE
Definite diagnosis requires imaging:
US, X-ray, CT
‘Bulls-eye’ telescoped inside
How would you treat an intussusception?
Barium/ air enema can unfold an intussusception Surgery may be necessary: Telescoped intestine is freed Obstruction is cleared Dead tissue is removed
Give the 4 layers of the bowel wall
Serosa
Muscle
Submucosa
Mucosa
Describe the difference between a true and false diverticula
True: involves all layers
False(pseudo): only mucosa and submucosa poke through muscle layer (muscle layer is not included)
Where do most diverticula form and why?
Most form in the sigmoid colon as it has the smallest lumen diameter and therefore highest pressure
Also at weak spots where a blood vessel traverses the muscle layer, vessel is more likely to rupture causing rectal bleeding
Give 3 risk factors for diverticula formation
Low fibre- constipation
Fatty foods and red meat
Marfan syndrome and Ehlers-Danlos
How can diverticulitis occur?
Lodged faecalith
Erosion from high pressure
Where would pain be felt with diverticulitis?
L lower quadrant
Why is diverticulitis not associated with bleeding?
Blood vessels are scarred from inflammation
What is the key complication if diverticula rupture?
Fistula formation e.g. a colovesicular fistula (colon to bladder) causing air/ stool in the urine
How would you treat diverticulitis?
Abx- to limit bacterial growth
High fibre diet
Surgical removal
Give 5 examples of true bowel obstructions
Volvulus Adhesion Tumour Intussusception Hernia
Give 3 examples of bowel pseudo-obstructions
Myopathy- no peristaltic contractions occur
Neuropathy- no innervation of the bowel smooth muscle
Hirschsprung’s disease
Describe Hirschsprung’s disease
Rare congenital condition where nerves are missing at the distal end of the colon
Therefore the bowel cannot relax to pass stool, this is corrected by surgery
How would you differentiate between large and small bowel obstruction?
Vomiting: Early= small, late= large
Constipation: Early= large, late= small
More distal the obstruction, more distension
Which investigations would you carry out for suspected bowel obstruction?
Inflammatory markers, lactate: ischaemia
CT scan: give oral and IV contrast
When would you not give contrast to a patient with suspected bowel obstruction and why?
If the patient had a perforation as the contrast could enter the peritoneum
Give 4 symptoms of gastritis
Indigestion
Gnawing/ burning stomach pain
Nausea and vomiting
Feeling full after eating
Give 3 signs/ symptoms of erosive gastritis
Stomach is exposed to acid:
Pain
Bleeding
Stomach ulcer
How would you diagnose gastritis?
Stool test
Breath test for H. pylori infection
Endoscopy
Barium swallow
Give 5 possible causes of gastritis
H. pylori Excessive cocaine/ alcohol use NSAIDs Stressful event Autoimmune reaction
How would you treat gastritis?
Antacids
Histamine 2 blockers (H2 blockers): Ranitidine
PPI: Omeprazole
If H. pylori : Abx
Give the components of the submucosa and muscular propria of the small bowel wall
Submucosa: connective tissue with collagen, elastin and glands/ vessels and Meissner plexus
Muscularis propria: two layers of smooth muscle + Myenteric plexus
Describe the process of ischaemic injury and reperfusion injury in small bowel ischaemia
Ischaemic injury: production of ROS, can damage DNA, RNA and proteins
Reperfusion: increase in oxygen and oxidative stress, increases ROS which attracts immune species
Immune cells remove dead/ damaged cells and release cytokines
How can sepsis occur as a result of small bowel ischaemia?
Food lingers in the ileum and doesn’t get pushed along
Break in the epithelial lining allows bacteria into the peritoneal space, lymphatics and blood vessels
Vessels get leaky leading to septic shock
Give 5 examples of occlusive bowel obstruction
Hernia Embolus Tumour Volvulus Intussusception
Give 3 examples of non-occlusive bowel obstruction
Low CO2
Hypovolemia
Mucosal infarcts
Give a symptom of bowel ischaemia and 4 symptoms of infarction
Ischaemia: Severe abdominal pain Infarction: Vomiting Bloody diarrhoea Distended abdomen Loss of bowel sounds
Give 3 symptoms of sepsis
Fever
Decreased BP
Increased HR and RR
How would you diagnose small bowel ischaemia?
Abdo CT: Bowel dilation and bowel thickening Intestinal pneumatosis CT angiography Lad studies: Raised WBC Metabolic acidosis
How would you treat small bowel ischaemia?
Increase fluid Manage pain Abx Surgery to reestablish blood flow Thrombolytic enzymes Surgical resection
Describe Mallory-Weiss syndrome
Longitudinal tears near the gastro-oesophageal junction
Give 4 associated causes of Mallory-Weiss syndrome
Vomiting
Retching
Coughing
Straining
How would Mallory-Weiss syndrome present?
Haematemesis
Melena
Dizziness
Abdominal pain
How would you diagnose Mallory-Weiss syndrome?
Endoscopy
How would you treat Mallory-Weiss syndrome?
Cauterisation, epinephrine injection, haemoclipping, band ligation
Embolisation
Surgery
Describe haemorrhoids
Swellings containing enlarged blood vessels found in the rectum and anus
Give 2 causes of haemorrhoids
Prolonged constipation
Chronic diarrhoea
Give 6 risk factors for haemorrhoids
Obesity Age Pregnancy FHx Lifting heavy objects Persistent cough/ repeated vomiting
Give 5 symptoms of haemorrhoids
Bleeding after passing a stool Itchy anus Lump outside anus Mucus discharge after passing a stool Soreness, redness and swelling
Give 4 lifestyle changes for a patient with haemorrhoids
Losing weight
Increase amount of fibre in diet
Drink plenty of fluid
Avoid medication causing constipation: painkillers containing codeine
Describe an anal fistula
Chronic, abnormal communication between epithelial surface of the anal canal and the perianal skin
How might an anal fistula form?
If the outlet of the anal glands becomes blocked, an abscess can form which can eventually extend to the skin surface
Give 5 symptoms of an anal fistula
Skin irritation around the anus Constant throbbing pain Smelly discharge proximal to anus Pus/ blood in faeces Swelling/ redness around anus Fever (if abscess) Bowel incontinence
How would you diagnose an anal fistula?
DRE
Protoscopy
US, MRI, CT
Give 4 causes, other than an anal abscess, of an anal fistula
Caron’s
Diverticulitis
TB/ HIV
Complication of surgery
Describe an anal fissure
Tear or ulcer that develops in the lining of the anal canal
Give 2 symptoms of an anal fissure
Sharp pain when you pass stools, often followed by a deep burning pain
Bleeding when passing stools
Give 5 causes of an anal fissure
STI Constipation Persistent diarrhoea IBD Pregnancy/ childbirth
Give 4 lifestyle changes for someone with an anal fissure
High fibre diet
Increase fluids
Not ignoring the urge to pass stools
Exercise regularly
Describe a perianal abscess
Abscess adjacent to the anus, arising from an infection at one of the anal sinuses
Give 3 bacterial causes of a perianal abscess
E. coli
Staph
MRSA
Give 5 symptoms of a perianal abscess
Pain in the perianal area Constipation Drainage from the rectum Fever Chills Palpable mass near anus
Give 3 risk factors for developing a perianal abscess
Chron’s
Diabetes
Chronic corticosteroid treatment
Describe a pilonidal sinus and what can happen if this becomes infected
Small hole or tunnel in the skin at the top of the buttocks, an infection of this sinus will cause pain, swelling and a pus-filled abscess can develop
Give the key cause of a pilonidal sinus developing
A skin problem, pressure/ friction may cause hair between the buttocks to be pushed inwards
How would you treat an infected pilonidal sinus?
Abx
Painkillers
Drainage of the sinus
