Gastrointestinal Flashcards
Coeliac disease
Inflammation of the mucosa of the upper small bowel in response to GLUTEN
AUTOIMMUNE (T cell mediated)
Intolerance to PROLAMIN (in wheat, barley, rye, oats) which is a component of gluten protein
Causes VILLOUS ATROPHY
Leads to MALABSORPTION
Coeliac disease epidemiology
1% of population in the UK
Peaks in infancy + 40-60 years
Familial link and risk in coeliac disease
10% risk in 1st degree relatives
HLA associated: HLA DQ2 (90%)
Coeliac disease risk factors
Other autoimmune diseases: T1DM, autoimmune thyroid, Addisons
Test all new cases of T1DM for coeliac
Pathophysiology coeliac disease
SMALL BOWEL (particularly the jejunum)
Gliadin = breakdown product of gluten
Tissue transglutaminase (tTG) Ab
Ab-gliadin complex is presented to a transferrin receptor
Endocytosed accross the gastric mucosa into lamina propria
Deamidation
Deamidated gliadin phagocytosed by HALDQ8 cells
Macrophages signal an immune response (pro-inflammatory cytokines > cascade)
Results in:
VILLOUS ATROPHY > malabsorption
CRYPT HYPERPLASIA
Raised intraepithelial lymphocytes
Clinical presentation of coeliac disease
Often asymptomatic Failure to thrive in young children Malabsorption (due to villous atrophy) - STEAORRHOEA (can’t absorb fat) - ANAEMIA (can’t absorb B12, folate, iron) - Osteomalacia (can’t absorb vitamin D) UNINTENTIONAL WEIGHT LOSS Fatigue DIARRHOEA Aphthous ulcers Angular stomatitis Dermatitis herpetiformis
Complications of untreated coeliac disease
Vitamin deficiency
Anaemia
Osteoporosis
Increased risk of malignancy:
Enteropathy-associated T-cell lymphoma
Investigations for coeliac disease
1st line: raised anti-tTG antibodies
- very high sensitivity and specificity
- false negatives may occur in people with IgA deficiency as anti-tTG is IgA
Gold standard: endoscopy + duodenal biopsy
- villous atrophy
- crypt hypertrophy
- raised intracellular WBCs
Can also test for IgA endomysial antibody (anti-EMA) but less sensitive
Treatment of coeliac
Lifelong gluten-free diet
Inflammatory Bowel Disease (IBD)
Chronic
Autoimmune
Umbrella term for two main diseases that cause inflammation of the GI tract:
Crohn’s disease
Ulcerative colitis
Relapsing & remitting
Key features of Crohns: NESTS
Not usually blood or mucus (but can occur)
Entire GI tract (mouth to anus)
Skip lesions on endoscopy (non-continuous inflammation)
Terminal ileum and Transmural
Smoking is a risk factor
Cobblestone appearance (ulcers and fissures in mucosa) Non-caseating granuloma inflammatory lesions
Key features of Ulcerative colitis: UC CLOSE UP
Continuous and circumferential inflammation; crypt abscesses Limited to colon and rectum ONLY superficial mucosa affected Smoking is protective Excrete blood and mucus
Use aminosalicylates and Uveitis
Primary sclerosis cholangitis and pseudo-polyps
DEPLETED goblet cells (mucosal barrier destruction)
Risk factors for ulcerative colitis
Family history
NSAIDs (can trigger onset and flares) Chronic stress (can trigger flares)
Ulcerative colitis epidemiology
Presentation at 20-40 years old
Higher incidence than Crohns
Incidence is 3x higher in non-smokers
Symptoms of UC
Diarrhoea
Abdominal pain
Passing blood and mucus
Weight loss
Signs of UC
Acute: fever, tachycardia, tender abdomen
Extraintestinal: clubbing, nutritional deficits
Complications of UC
Colon:
- Blood loss
- Colorectal cancer
Skin:
- Erythema nodosum
- Pyoderma gangrenosum
Joints:
- Ankylosing spondylitis
- Arthritis
Eyes:
- Uveitis
Liver:
- sclerosing cholangitis
Investigations of UC
Blood tests:
- raised CRP & ESR in active inflammation
- raised WCC
- raised platelets
- anaemia (normocytic of chronic disease)
- pANCA may be +ve (-ve in Crohn’s)
Gold standard:
- DIAGNOSIS: sigmoidoscopy + biopsy
- further: full colonoscopy + biopsy
Further testing:
Abdominal X-Ray
Ultrasound, CT and MRI
Treatment of UC
MILD TO MODERATE DISEASE 1st line: aminosalicylate - 5-aminosalicyclic acid (5-ASA) - sulfasALAZINE, mesALAZINE, olsALAZINE - oral or rectal route 2nd line: oral corticosteroids e.g. prednisolone
SEVERE DISEASE
1st line: IV corticosteroids e.g. hydrocortisone
2nd line: IV ciclosporin
SEVERE W/ NO RESPONSE: colectomy
- surgery is possible as it only affects the colon and rectum
MAINTAINING REMISSION: Aminosalicylate, AZATHIOPRINE
Crohn’s disease risk factors
Stronger genetic association than UC Family history Smoking NSAIDs (exacerbate) Chronic stress (trigger flares)
Crohn’s epidemiology
Northern Europe and North America
Females > males
Presentation mostly at 20-40 years
Crohn’s disease symptoms
Small bowel: Abdo pain, weight loss
Colon: Bloody diarrhoea, pain on defecation
Systemic: Fever, fatigue, anorexia
Crohn’s disease signs
Bowel ulceration
Abdo tenderness
Abdo mass
Extraintestinal:
oral aphthous ulcers (more common in Crohn’s than UC)
skin, joint and eye problems
Crohn’s disease complications
Malabsorption Small bowel obstruction Colorectal cancer Anaemia Perianal disease e.g. fissures
Crohn’s disease investigations
Blood tests:
- raised CRP & ESR
- raised WCC
- raised platelets
- anaemia (normocytic of chronic disease)
- pANCA negative
Gold standard: colonoscopy + biopsy
- granulomatous transmural inflammation
Small bowel imaging: to detect proximal disease
Abdominal X-ray
MRI
Ultrasonography
Crohn’s disease treatment
MILD/MODERATE DISEASE
1st line: Oral prednisolone
SEVERE DISEASE
1st line: IV hydrocortisone
If NOT RESPONSIVE to steroids: Anti-TNF antibodies (Infliximab)
MAINTAINING REMISSION: AZATHIOPRINE (Methotrexate if intolerant to Azathioprine)
OTHER
Smoking cessation
Correct iron/B12 deficiencies
Antibiotics for perianal disease
IBD: upper RIGHT quadrant pain
Crohn’s disease
IBD: LEFT quadrant pain
Ulcerative colitis
Screening test for IBD
Faecal calprotectin
- release by the intestines when inflamed
- > 90% specific and sensitive to IBD in adults
- doesn’t differentiate UC and Crohn’s
Surgery in Crohn’s disease
Resection of worst affected areas of bowel
Never fully cures
Indications:
Failure of medical therapy
Obstruction from strictures
Fistulae, abscesses, perianal disease
Irritable bowel syndrome (IBS)
Functional bowel disorder = mixed group of abdominal symptoms with no organic cause
IBS epidemiology
More common in females
1 in 5 in western world
Age of onset = under 40 years
IBS risk factors
GI infections
Anxiety and depression
Eating disorders
Previous severe long term diarrhoea
IBS symptoms
Chronic: 6+ months
Exacerbated by stress, food, menstruation
3 types:
IBS-C: with constipation
IBS-D: with diarrhoea
IBS-M: mixed
Consider IBS if a patient reports ANY:
Abdominal pain
Bloating
Change in bowel habit
Multi-system disorder:
- painful periods
- bladder symptoms e.g. frequency
- joint hyper mobility
- fatigue
NICE diagnostic criteria for IBS
ABDOMINAL PAIN which is either related to
- DEFECATION
and/or
- associated with altered stool FREQUENCY (increased or decreased)
and/or
- associated with altered STOOL FORM or appearance (hard, lumpy, loose, or watery)
And there are at least two of the following:
Alternative conditions with similar symptoms have been excluded
Passage of rectal mucus
Symptoms worsened by eating
Abdominal bloating (more common in women than men), distension, or hardness
Altered stool passage (straining, urgency, or incomplete evacuation)
Differential diagnoses for IBS
IBD
Coeliac
Lactose intolerance
Colorectal cancer
Investigations for IBS
Rule out differentials:
- tTG for coeliac
- faecal calprotectin for IBD
- FBC for anaemia
- colonoscopy for IBD + colorectal cancer
IBS treatment
1st line: General healthy DIET + exercise ADVICE
- small frequent non-processed meals
- IBS-C: soluble fibre
1st line medication:
IBS-D: Loperamide (Imodium)
IBS-C: Laxatives e.g. docusate, linaclotide
Pain/bloating: antispasmodics e.g. buscopan
2nd line medication: Tricyclic antidepressants (amitriptyline)
3rd line medication
SSRI antidepressants
Can be used in conjunction with psychological therapies e.g. cognitive behaviour therapy (CBT)
Acute appendicitis
Sudden inflammation of the appendix
Most commonly caused by an obstruction of the appendix which results in the invasion of gut organisms into the appendix wall leading to INFLAMMATION, necrosis and rupture
Most common surgical emergency
Causes of obstruction to the appendix
Faecoliths (stony mass of compacted faeces)
Bezoars (partially digested material collected in the stomach)
Trauma
Intestinal worms
Lymphoid hyperplasia
Key clinical presentation of appendicitis
ABDOMINAL PAIN
- starts central (umbilicus) and migrates to the right iliac fossa within the first 24 hours
Inflammation irritates overlying peritoneum (peritonitis) causing tenderness at McBurney’s point (1/3 from anterior superior iliac spine to umbilicus)
Other classic features of appendicitis
Guarding on abdominal palpating Pyrexia Nausea and vomiting Rosvings sign (palpation of LIF causes pain in RIF) Coughing causes pain
Key differential diagnoses of appendicitis
Ectopic pregnancy: serum hCG Meckel’s diverticulum UTI Constipation Food poisoning Crohn’s (acute terminal ileitis)
Investigations acute appendicitis
Diagnosis:
- Clinical presentation
- Blood tests: raised WCC (neutrophils), raised CRP & ESR (inflammation)
GOLD STANDARD: CT scan (highly specific and sensitive)
Ultrasound: inflamed appendix and appendix mass
Pregnancy test: exclude ectopic pregnancy
Urinalysis: exclude UTI
Management of appendicitis
GOLD STANDARD = laparoscopic appendicectomy
IV antibiotics (metronidazole) and IV fluids
Complications of appendicitis
Perforation
Appendix mass: the omentum sticks to the inflamed appendix forming a mass in the RIF
Three types of bowel obstruction
Small bowel obstruction (60-75%)
Large bowel obstruction
Psuedo-obstruction
All can be serious and potentially fatal
Causes of small bowel obstruction
INTRA-ABDOMINAL ADHESIONS (60%) - usually due to previous abdo surgery or infections e.g. peritonitis
Hernias
Malignancy
Crohn’s disease
Pathophysiology of small bowel obstruction
Distension above the blockage > increased pressure pushes blood vessels within bowel wall > compressed vessels results in ischaemia, necrosis, perforation
Clinical presentation of SBO
PAIN: initially COLICKY but then diffuse, higher in the abdomen than LBO, INTERMITTENT
Profuse VOMITING following pain (occurs earlier in SBO than LBO) - think SB IS CLOSER TO MOUTH
Increased bowel sounds (tinkling)
Abdominal distention
Small bowel obstruction Ix
1st line: abdominal X-ray
- distended loops of bowel proximal to obstruction
- no gas distal to obstruction (i.e. large bowel)
GOLD STANDARD: non-contrast CT - localises the obstruction
Causes of large bowel obstruction
MALIGNANCY (90%) - more common in West
Volvulus (twisting of the bowel on its mesenteric axis, sigmoid colon most common place)
Diverticulitis
Crohn’s disease
Clinical presentation of LBO
Abdominal pain
- more CONSTANT & DIFFUSE than SBO
- usually occurs lower in the abdomen (LIF)
Much more ABDOMINAL DISTENTION than SBO
Palpable mass e.g. hernia
Investigations for LBO
Digital rectal exam (DRE)
- empty rectum
- hard compacted stools
1st line: Abdo X-Ray
- peripheral gas shadows proximal to blockage
Gold standard: CT
Management of an obstructed bowel (SBO, LBO)
Aggressive fluid resuscitation
Decompression of the bowel “drip and suck”
- IV fluids to hydrate
- NG tube
Analgesia, anti-emetics
Antibiotics
Surgery to remove obstruction
Pseudo bowel obstructions
Present identically to SBO/LBO but underlying cause should be treated first
Bacterial causes of diarrhoea
Campylobacter jejuni
E. Coli
Salmonella
Shigella
Viral causes of diarrhoea
Majority of diarrhoea cases are VIRAL
Children = rotavirus Adults = norovirus
Management of diarrhoea
Oral rehydration therapy (IV fluids given if very severe)
Treat the underlying causes (bacterial normally treated with metronidazole)
Anti-emetics e.g. metoclopramide
Anti-motility agents e.g. loperamide
Ischaemic bowel diseases
Acute mesenteric ischaemia
Chronic mesenteric ischaemia (intestinal angina)
Ischaemia colitis
Causes of acute mesenteric ischaemia
Superior mesenteric artery (SMA) THROMBOSIS
SMA EMBOLISM (due to AF)
Mesenteric venous thrombosis
Presentation of acute mesenteric ischaemia
Classic triad:
Acute, severe abdo pain (constant and central)
No abdo signs on examination
Rapid hypovolaemia > shock
AF + severe abdo pain = AMI
Acute mesenteric ischaemia investigations
Diagnostic: CT angiography
- visualise blockages (difficult to perform)
Bloods:
- increased Hb concentration due to blood loss
- metabolic acidosis + raised lactate
Management of AMI
Fluid resuscitation
IV heparin
Antibiotics (metronidazole)
Surgery to remove necrotic bowel
Mortality: >50%
Causes of ischaemic colitis
Thrombosis
Emboli
Low flow states (low CO/arrhythmias)
Surgery
Presentation of ischaemic colitis
Sudden onset LIF pain
Passage of bright red blood
Signs of hypovolaemic shock (tachycardia, fatigue)
Ischaemic colitis investigations
1st line: CT to rule out rupture
Gold standard: colonoscopy + biopsy
Mallory Weiss tear
Haematemesis from tear in oesophageal mucosa
Causes and risk factors for Mallory Weiss tear
ALCOHOLISM Hyperemesis gravidarum (severe nausea and vomiting during pregnancy) Gastroenteritis Bulimia Chronic cough