Lower GI Flashcards
(218 cards)
1
Q
What is a Meckel’s diverticulum?
A
Ileal remnant of the vitellointestinal duct which joins the yoke sac to the midgut lumen
2
Q
What are the features of Meckel’s diverticulum (2’s)?
A
- True diverticulum
- 2 inches long
- 2ft from the ileocaecal valve on the antimesenteric border
- 2% of the population
- 2% symptomatic
- Contain ectopic gastric or pancreatic tissue
3
Q
How does symptomatic Meckel’s present?
A
- Rectal bleeding: from gastric mucosa
- Diverticulitis mimicking appendicitis
- Intussusception
- Volvulus
- Malignant change: adenocarcinoma
- Raspberry tumour: mucosa protruding at umbilicus (vitello-intestinal fistula)
- Littre’s hernia: herniation of Meckel’s
4
Q
How is meckel’s diagnosed?
A
Tc pertechnecate scan - detects gastric mucosa and is positive in 70%
5
Q
How is meckel’s managed?
A
Surgical resection
6
Q
What is intussusception?
A
Where a portion of intestine (the intussusception) is invaginated into its own lumen (the intussuscipiens)
7
Q
What are the causes of intussusception?
A
- Hypertrophied Peyer’s patch (post viral)
- Meckel’s
- HSP
- Peutz-Jeghers
- Lymphoma
- Leukaemia
- Duplication cysts
- Haemangioma of bowel
- Inspissated meconium in CF
- Intestinal luminal polyp
- Nephrotic syndrome
8
Q
How does intussusception present?
A
- 6-12 months
- Colicky abdominal pain:
- Episodic inconsolable crying, drawing up legs
- ± bilious vomiting
- Redcurrant jelly stools
- Sausage-shaped abdominal mass
9
Q
How is intussusception managed?
A
- Resuscitate, cross match, NGT
- US and reduction by air enema
- Surgery if not reducible by enema
10
Q
Does intussusception happen in adults?
A
Rarely - if it does think of neoplasm as a lead point
11
Q
What is mesenteric adenitis and what are the differentiating features for it?
A
- Viral infection/URTI leads to enlargement of mesenteric lymph nodes -> pain, tenderness and fever
- Differentiating features:
- Post URTI
- Headache and photophobia
- Higher temperature
- Tenderness is more generalised
- Lymphocytosis
12
Q
What kinds of neoplasms occur in the small bowel?
A
- All quite rare
- Benign: 35%
- Lipoma
- Leiomyoma
- Neurofibroma
- Haemangioma
- Adenomatous polyps (FAP, Peutz-Jeghers)
- Malignant: 65% (only 2% of GI malignancies)
- Adenocarcinoma (40% of malignant tumours)
- Carcinoid (40% of malignant tumours)
- Lymphoma (especially coeliac disease: EATL)
- GIST
13
Q
How do small bowel neoplasms present?
A
- Often non specific symptoms, so late
- Nausea and vomiting, obstruction
- Weight loss and abdominal pain
- Bleeding
- Jaundice from biliary obstruction or liver mets
14
Q
What investigations should you do in a suspected small bowel cancer?
A
- Imaging:
- AXR (SBO)
- Barium follow through
- CT
- Endoscopy
- Push enteroscopy
- Capsule endoscopy
15
Q
What is Gardner’s syndrome?
A
- Small bowel adenomas and carcinomas
- Associated with skeletal abnormalities and desmoid tumours
16
Q
Which cancers can cause secondary tumours in the small bowel?
A
Rarely - lung, breast, malignant melanoma
17
Q
What are carcinoid tumours?
A
Diverse group of neuroendocrine tumours of enterochromaffin cell origin capable of producing 5HT.
18
Q
Where might carcinoid tumours be derived from?
A
- Foregut: respiratory tract
- Midgut: stomach, ileum, appendix
- Hindgut: colorectum
19
Q
Which hormones can carcinoid tumours secrete?
A
- 5-HT
- Hindgut tumours rarely secrete 5HT
- VIP
- Gastrin
- Glucagon
- Insulin
- ACTH
20
Q
What does carcinoid syndrome suggest?
A
Bypass of firstpass metabolism - strongly associated with metastatic disease
21
Q
Which MEN are carcinoid tumours associated with and how commonly?
A
10% part of MEN1
22
Q
Where are carcinoid tumours found?
A
- Appendix: 45%
- Ileum: 30%
- Colorectum: 20%
- Stomach: 10%
- Elsewhere in GIT
- Bronchus: 10%
23
Q
How do carcinoid tumours present?
A
- Appendicitis
- Intussusception or obstruction
- Abdominal pain
- Carcinoid syndrome
24
Q
What are the features of carcinoid syndrome?
A
- FIVE HT
- Flushing: paroxysmal, upper body ± wheals
- Intestinal: diarrhoea
- Valve fibrosis: tricuspid regurg and pulmonary stenosis
- Wheeze: bronchoconstriction
- Hepatic involvement: bypassed first pass metabolism
- Tryptophan deficiency: pellagra (3Ds)
25
What are the key investigations in a suspected carcinoid tumour?
* Raised urine 5-hydroxyindoleacetic acid
* Raised plasma chromogranin A
* CT/MRI to find the primary
26
How do you treat carcinoid tumours?
* Symptoms: octreotide or loperamide
* Curative:
* Resection: tumours are very yellow
* Also give octreotide to avoid carcinoid crisis
27
What is a carcinoid crisis and how do you treat it?
* Tumour outgrows blood supply or is handled too much and there is a massive mediator release
* Features: vasodilatation, hypotension, bronchoconstriction, hyperglycaemia
* Treat with high dose octreotide
28
What is the prognosis in carcinoid tumours?
Median survival is 5-8 years (~3 years if mets present)
29
What is the definition of acute appendicitis?
Inflammation of the vermiform appendix ranging from oedema to ischaemic necrosis and perforation
30
What is the epidemiology of appendicitis?
* 6% lifetime incidence
* Commonest surgical emergency
* Rare \<2 years
* Maximal peak during childhood
31
What is the pathogenesis of acute appendicitis?
* Obstruction of the appendix
* Faeolith most commonly
* Lymphoid hyperplasia post infection
* Tumour e.g. caecal cancer, carcinoid
* Worms e.g. Ascaris lumbicoides, schisto
* Gut organisms -\> infection behind obstruction
* Leads to oedema, ischaemia, necrosis, perforation
* Peritonitis
* Abscess
* Appendix mass
32
What is the pattern of abdominal pain in appendicitis and why?
* Early inflammation -\> appendiceal irritation
* Visceral pain is not well localised compared to somatic pain
* Nociceptive information travels in the sympathetic afferent fibres that supply the viscus
* Pain referred to the dermatome corresponding to the spinal cord entry level of these sympathetic fibres
* Appendix = midgut = lesser splanchnic T10/11 = umbilicus
* Late inflammation -\> parietal peritoneum irritation
* Pain localised in RIF
33
What are the symptoms of appendicitis?
* Colicky abdominal pain
* Central then localised in RIF
* Worse with movement
* Anorexia (variable)
* Nausea (vomiting rarely prominent but moeso if appendix is retroileal)
* Constipation/diarrhoea ± mucus
* Variable urinary symptoms (frequency/dysuria) if appendix is near ureter/bladder
34
What are the signs of appendicitis?
* Low-grade pyrexia: 37.5-38.5
* Raised HR, shallow breathing
* Foetor oris + coated tongue
* Guarding and tenderness at McBurney's point
* Positive cough/percussino tenderness
* McBurney's point = junction of the middle and outer thirds of a line joining the umbilicus to R ASIS
* Appendix mass may be palpable in RIF
* Pain PR suggests pelvic appendix
35
What are the eponymous signs of appendicitis?
* Rovsing's sign
* Pressure in LIF -\> more pain in RIF
* Psoas sign
* Pain on extending the hip: retrocaecal appendix
* Cope sign
* Flexion and internal rotation of the R hip causes pain
* Appendix lying close to obturator internus
36
What are the differentials for acute appendicitis?
* Surgical
* Cholecystitis
* Diverticulitis
* Meckel's diverticulitis
* Gynae
* Cyst accident: torsion, rupture, haemorrhage
* Salpingitis/PID
* Ruptured ectopic
* Medical
* Mesenteric adenitis
* UTI
* Crohn's
37
What are the key investigations in acute appendix?
* Principally clinical
* Bloods: FBC, CRP, amylase, G+S, clotting
* Urine
* Sterile pyuria: may indicate bladder irritation
* Ketones: anorexia
* Exclude UTI
* Beta HCG
* Imaging
* Ultrasound: exclude gynae pathology, visualise inflamed appendix
* CT can be used
* Diagnostic lap
38
How is acute appendicits managed?
* Fluids
* Antibiotics: cef 1.5g and met 500g IV TDS
* Analgesia: paracetamol, NSAIDs, codeine phosphate
* Certain diagnosis -\> appendicectomy (open or lap)
* Uncertain diagnosis -\> active observation
39
What are the 3 most important complications of appendicitis?
* Appendix mass
* Appendix abscess
* Perforation
40
What is an appendix mass and how is it managed?
* Inflamed appendix with adherent covering of omentum and small bowel
* Diagnose with US or CT
* Initially antibiotics and NBM
* Resolution of mass -\> interval appendicectomy
* Exclude a colonic tumour with colonoscopy
41
What causes an appendix abscess and how is it managed?
* Results if appendix mass doesn't resolve
* Mass enlarges and patient deteriorates
* Antibiotics and nil by mouth
* CT guided percutaneous drainage
* If no resolution surgery may involve right hemicolectomy
42
In which patients is a perforation a more common complication of appendicitis?
* If a faecolith is present
* Young children (as diagnosis often delayed)
43
What is the prevalence of UC and Crohn's?
UC: 100-200/100,000
Crohn's: 50-100/100,000
44
What is the peak age for UC and Crohn's?
UC: 30's
Crohn's: 20's
45
Are men or women more affected by IBD?
Women (just) for UC and Crohn's
46
What is the concordance for UC and Crohn's?
UC: 10%
Crohn's: 70%
47
How does smoking affect UC and Crohn's risk?
Current smoking is protective for UC. Smoking increases the risk of Crohn's.
48
Which TH mediates Crohn's and UC?
UC: TH2
Crohn's: TH1/TH17
49
What locations are involved in UC and Crohn's?
UC: Rectum + colon + backwash ileitis
Crohn's: mouth to anus especially terminal ileum
50
What is the distribution of Crohn's and UC?
UC: contiguous
Crohn's: skip lesions
51
Do people get strictures in Crohn's and UC?
UC: No
Crohn's: Yes
52
What are the microscopic pathological features in Crohn's and UC?
UC: mucosal inflammation, shallow, broad ulceration, marked pseudopolyps
Crohn's: transmural inflammatino, cobblestone mucosa (deep, thin, serpiginous), marked fibrosis, granulomas, minimal pseudopolyps, fistulae
53
What are the systemic features in Crohn's and UC?
Fever, malaise, anorexia, weight loss in active disease
54
What are the abdominal features in Crohn's and UC?
* UC: diarrhoea, blood ± mucus PR, abdominal discomfort, tenesmus, faecal urgency
* Crohn's: diarrhoea (not usually bloody), abdo pain, weight loss
55
What are the signs of UC and Crohn's?
UC: fever, tender, distended abdo
Crohn's: aphthous ulcers, glossitis, abdo tenderness, RIF mass, perianal abscesses, fistulae, tags, anal/rectal strictures
56
What are the extra abdominal features of UC and Crohn's?
* Skin: clubbing, erythema nodosum, pyoderma gangrenosum (esp UC)
* Eyes: iritis, conjunctivitis, episcleritis, scleritis
* Joints: arthritis (non deforming, asymmetrical), sacroiliitis, ank spond
* HPB: PSC + cholangiocarcinoma (esp UC), gallstones (esp Crohn's), fatty liver
* Other: amyloidosis, oxalate renal stones (esp Crohn's)
57
What are the complications of UC?
* Toxic megacolon
* \>6cm, risk of perf
* Bleeding
* Malignancy
* CRC in 15% with pancolitis for 20 years
* Cholangiocarcinoma
* Strictures causing obstruction
* Venous thrombosis
58
What are the complications of Crohn's?
* Fistulae
* Entero-enteric/colonic -\> diarrhoea
* Enterovesical -\> frequency, UTI
* Enterovaginal
* Perianal -\> "pepperpot" anus
* Strictures -\> obstruction
* Abscesses
* Abdominal
* Anorectal
* Malabsorption
* Fat -\> steatorrhoea, gallstones
* B12 -\> megaloblastic anaemia
* Vit D -\> osteomalacia
* Protein -\> oedema
* Toxic megacolon and cancer can happen, but less than in UC
59
What are the complications of toxic megacolon?
* Toxaemia
* Anaemia from bleeding
* Acute loss of water and electrolyte issues
* Progressive abdominal distension
60
What investigations should you do in UC?
* Bloods:
* FBC (low Hb raised WCC)
* LFT: low albumin
* Raised CRP/ESR
* Stool:
* MCS: explude Campylobacter, Shigella, Salmonella
* CDT: C diff can complicate or mimic
* Imaging:
* AXR: megacolon (\>6cm), wall thickening
* CXR: perforation
* CT
* Barium/gastrograffin enema
* Lead pipe: no haustra
* Thumbprinting: mucosal thickening
* Pseudopolyps: regenerating mucosal island
* Ileocolonoscopy + regional biopsy: Baron score
61
What are the Truelove and Witts Criteria?
* Mild:
* \<4 motions, small PR bleed, apyrexic, HR\<70, Hb\>11, ESR\<30
* Moderate:
* 4-6 motions, moderate PR bleed, T 37.1-37.8, HR 70-90, Hb 10.5-11
* Severe:
* \>6 motions, large PR bleed, T\>37.8, HR\>90, Hb\<10.5, ESR\>30
62
What is the management for acute severe UC?
* Resus: admit, IV hydration, NBM
* Hydrocortisone: IV 100mg QDS + PR
* Transfuse if needed
* Thromboprophylaxis: LMWH
* Monitoring:
* Bloods: FBC, ESR, CRP, U+E
* Vitals and stool chart
* Twice daily examination
* ± AXR
* RCTs don't show a benefit from Abx so only considered if megacolon, perf, uncertain Dx
63
What are the acute complications of severe UC?
* Perforation
* Bleeding
* Toxic megacolon
* VTE
64
What is the continuing therapy for acute severe UC?
* If improving: switch to oral pred and 5-ASA, taper pred after a full remission
* If no improvement, rescue therapy:
* On day 3 a stool frequency of \>8 or a CRP\>45 predicts an 85% chance of needing a colectomy during the admission
* Medical management: ciclosporin, infliximab or visilizumab (anti T cell)
* Or surgery
65
How do you induce remission in mild/mod UC?
* Oral therapy:
* 1st line: 5-ASAs
* 2nd line: pred
* Topical therapy (mainly L sided disease)
* Proctitis: suppositories
* More proximal disease: enemas or foams
* 5-ASAs ± steroids (prednisolone or budesonide)
* Additional therapy: steroid sparing
* Azathioprine or mercaptopurine
* Infliximab for steroid dependent patients
66
How do you maintain remission in mild/mod UC?
* 1st line: 5-ASAs PO - sulfasalazine or mesalazine
* Topical therapy can be used in proctitis
* 2nd line: azathioprine or mercaptopurine
* Relapsed on ASA or are steroid dependent
* Give 6-mercaptopurine ir azathioprine intolerant
* 3rd line: infliximab/adalimumab
67
How common is the need for surgery in UC?
* 20% need surgery at some point
* 30% with colitis require surgery within 5 years
68
What are the indications for emergency surgery in UC?
* Toxic megacolon
* Perforation
* Massive haemorrhage
* Failure to respond to medical therapy
69
What procesdures are done in UC as emergency surgery?
* Total/subtotal colectomy with end ileostomy ± mucus fistula
* Followed after about 3 months be either:
* Completion proctectomy and ileal pouch anal anastomosis (IPAA) or end ileostomy ileorectal anastomosis (IRA)
* Panproctocolectomy + permanent end ileostomy
* Acute colitis op mortality is 7% (30% if perforated)
70
What are the indications for elective surgery in UC?
* Chronic symptoms despite medical therapy
* Carcinoma or high grade dysplasia
71
Which procedures are done as elective surgery in UC?
* Panproctocolectomy with end ileostomy or IPAA
* Total colectomy with IRA
72
What are the possible surgical complications from UC operations?
* Abdominal
* SBO
* Anastomotic stricture
* Pelvic abscesses
* Stoma: retraction, stenosis, prolapse, dermatitis
* Pouch
* Pouchitis (50%): metronidazole + cipro
* Reduced female fertility
* Faecal leakage
* Renal calculi
* Electrolyte imbalance
* Psychological/sexual issues
73
What investigations should you do in Crohn's?
* Bloods
* Severity markers: FBC (low Hb, raised WCC), LFT (low albumin), raised CRP/ESR
* Haematinics: Fe, B12, folate
* Blood cultures
* Stool
* MCS: exclude campylobacter, shigella, salmonella
* CDT: C diff may complicate or mimic
* Imaging
* AXR: obstruction, sacrioileitis
* CXR: perforation
* MRI
* Assess pelvic disease and fistula
* Assess disease severity
* Small bowel follow through or enteroclysis
* Skip lesions
* Rosethorn ulcers
* Cobblestoning
* String sign of Kantor: narrow terminal ileum
* Endoscopy
* Ileocolonoscopy + regional biopsy: investigation of choice
* Wireless capsule endoscopy
* Small bowel endoscopy
74
How should you assess a severe attack of Crohn's?
* Raised temp
* Raised HR
* Raised ESR
* Raised CRP
* Raised WCC
* Low albumin
75
How do you manage a severe attack of Crohn's?
* Resus: admit, NBM, IV hydration
* Hydrocortisone: IV + PR if recal disease
* Abx: metronidazole PO or IV
* Thromboprophylaxis: LMWH
* Dietician review: elemental diet (liquid prep of amino acids, glucose and fatty acids), consider parenteral
* Monitoring: vitals + stool chart, daily examination
76
What is the continuing therapy for a severe attack of Crohn's?
* Improvement: switch to oral therapy (40mg/d)
* No improvement - rescue therapy
* Discussion betweeen patient, doctor and surgeon
* Medical: methotrexate ± infliximab
* Surgical
77
How do you induce remission in mild/mod Crohn's?
* Supportive: high fibre diet, vitamin supplements
* Oral therapy:
* 1st line: ileocaecal: budesonide
* Colitis: sulfasalazine
* 2nd line: pred (tapering)
* 3rd line: methotrexate
* 4th line: infliximab or adalimumab
78
How do you manage perianal disease in Crohn's?
* Oral abx: metronidazole
* Immunosuppression ± infliximab
* Local surgery ± seton insertion
79
How do you maintain remission in Crohn's?
* 1st line: azathioprine or mercaptopurine
* 2nd line: methotrexate
* 3rd line: infliximab/adalimumab
80
How commonly do Crohn's patients need surgery?
* 50-80% need ≥1 operation in their life
* Never curative
* Should be as conservative as possible
81
What are the indications for surgery in Crohn's?
* Emergency
* Failure to respond to medical therapy
* Inestinal obstruction or perforation
* Massive haemorrhage
* Elective
* Abscess or fistula
* Perianal disease
* Chronic ill health
* Carcinoma
82
What procedures are done in Crohn's?
* Limited resection e.g. ileocaecal
* Stricturoplasty
* Defunction distal disease with temporary loop ileostomy
83
What complications do you get from Crohn's surgery?
* Stoma complications
* Enterocutaneous fistulae
* Anastomotic leak or stricture
84
What length of bowel causes short bowel syndrome?
\<1-2m small bowel
85
What are the features of short gut syndrome?
* Steatorrhoea
* ADEK and B12 malabsorption
* Bile acid depletion -\> gallstones
* Hyperoxaluria -\> renal stones
86
What is the treatment for short gut syndrome?
* Dietician
* Supplements or TPN
* Loperamide
87
Define "diverticulum"
Outpouching of tubular structure
88
Define "true" and "false" diverticulum
true = composed of complete wall e.g. Meckel's
false = composed of mucosa only (pharyngeal, colonic)
89
What is diverticular disease?
Symptomatic diverticulosis
90
What is diverticulitis?
Inflammation of diverticula
91
Who gets diverticular disease?
30% Westerner's have diverticulosis by 60 years, F\>M
92
What is the pathophysiology of diverticular disease?
* Associated with increased intraluminal pressure (low fibre diet -\> no osmotic effect to keep stool wet)
* Mucosa herniates through muscularis propria at points of weakness where perforating arteries enter
* Most commonly located in sigmoid colon
* Commoner in obese patients
93
What is Saint's triad?
* Hiatus hernia
* Cholelithiasis
* Diverticular disease
94
What are the symptoms of diverticular disease?
* Aleterd bowel habit ± left sided colic, relieved by defecation
* Nausea
* Flatulence
95
What is the treatment for diverticular disease?
* High fibre diet
* Mebeverine may help
* Elective resection for chronic pain
96
What is the pathophysiology of diverticulitis?
Inspissated faeces -\> obstruction of diverticulum
97
How does diverticulitis present?
* Typically an elderly patient with a previous history of constipation
* Abdo pain and tenderness - typically LIF, localised peritonitis
* Pyrexia
98
What investigations should you do in diverticulitis?
* Bloods
* FBC: raised WCC
* Raised CRP/ESR
* Amylase
* G+S/cross match
* Imaging:
* Erect CXR: look for perf
* AXR: fluid level/air in bowel wall
* Contrast CT if complications
* Gastrograffin enema
* Endoscopy
* Flexi sig
* Colonoscopy: not in acute attack
99
What grading system is used in diverticulitis?
1. Small confined percolic abscesses = surgery rarely needed
2. Large abscess extending into pelvis - may resolve without surgery
3. Generalised purulent peritonitis - surgery needed
4. Generalised faecal peritonitis - surgery needed
100
How do you manage mild attacks of diverticulitis?
Can be treated at home with bowel rest (fluids only) and augmentin ± metronidazole
101
When should you admit acute diverticulitis?
* Unwell
* Fluids can't be tolerated
* Pain can't be controlled
102
What is the medical management of acute diverticulitis?
* NBM
* IV fluids
* Analgesia
* Antibiotics: cefuroxime + metronidazole
* Most cases settle
103
What are the indications for surgery in diverticulitis and what procedure do you do?
* Indications:
* Perforation
* Large haemorrhage
* Stricture -\> obstruction
* Procedure is a Hartmann's to resect the diseased bowel
104
What are the complications of diverticular disease?
* Perforation
* Haemorrhage
* Abscess
* Fistulae
* Strictures
105
How does perforation present and what do you do about it?
* Sudden onset pain (± preceding diverticulitis)
* Generalised peritonitis and shock
* CXR: free air under the diaphragm
* Do a Hartmann's
106
What kind of haemorrhage do you get in diverticulitis and what do you do about it?
* Sudden, painless, bright red PR bleed
* Investigate: mesenteric angiography or colonoscopy
* Treat:
* Usually stops spontaneously
* May need transfusion
* Colonoscopy ± diathermy/adrenaline
* Embolisation
* Resection
107
How does an abscess present in diverticulitis and what do you do about it?
* Walled-off perforation
* Swinging fever
* Localising signs: e.g. boggy rectal mass
* Leukocytosis
* Treat: Abx + CT/US guided drainage
108
What kind of fistulae do you get in diverticular disease?
* Enterocolic
* Colovaginal
* Colovesicular: pneumaturia + intractable UTIs
109
Why do you get strictures in diverticulitis?
Colon can heal with fibrous strictures after the diverticulitis
110
How do you classify bowel obstruction?
* Simple
* 1 obstructing point and no vascular compromise
* May be partial or complete
* Closed loop
* Bowel obstructed at 2 points
* Left CRC with competent ileocaecal valve
* Volvulus
* Gross distension leading to perforation
* Strangulated
* Compromised blood supply
111
What are the features of a strangulated bowel obstruction and what's the risk?
* Localised constant pain and peritonism
* Fever
* Raised WCC
* Dies within 4-6 hours and ruptures
112
What are the commonest causes of bowel obstruction?
* SBO:
* Adhesions: 60%
* Hernia
* LBO:
* Colorectal neoplasia: 60%
* Diverticular stricture: 20%
* Volvulus: 5%
113
What are the non-mechanical causes of bowel obstruction?
* Post op
* Peritonitis
* Pancreatitis or any localised inflammation
* Poisons/drugs: anti-AChM e.g. TCAs
* Pseudo obstruction
* Metabolic: hypokalaemia, hyponatraemia, hypomangnesaemia, uraemia
* Mesenteric ischaemia
114
What are the mechanical causes of bowel obstruction?
* Intraluminal
* Impacted matter: faeces, worms, bezoars
* Intussusception
* Gallstones
* Intramural
* Benign stricture (IBD, surgery, ischaemic colitis, diverticulitis, radiotherapy)
* Neoplasia
* Congenital atresia
* Extramural
* Hernia
* Adhesions
* Volvulus (sigmoid, caecal, gastric)
* Extrinsic compression
* Pseudocyst
* Abscess
* Haematoma
* Tumour e.g. ovarian
* Congenital bands (e.g. Ladd's)
115
How does bowel obstruction present?
* Abdo pain (colicky, central)
* Distension (moreso if lower obstructions)
* Vomiting (early in high, late or absent in low)
* Absolute constipation
116
What examination findings suggest bowel obstruction?
* Tachycardia (hypovolaemia, strangulation)
* Dehydration, hypovolaemia
* Fever (inflammation/strangulation)
* Surgical scars
* Hernias
* Mass (neoplastic/inflammatory)
* Bowel sounds (increased if mechanical, decreased in ileus)
* PR: empty rectum, rectal mass, hard stool, blood from higher pathology)
* Do a vaginal exam too
117
How should you investigate bowel obstruction?
* Bloods:
* FBC (raised WCC)
* U+E (dehydration, electrolyte abnormalities)
* Amylase: increased in strangulation/perforation
* VBG: raised lactate in strangulation
* G+S, clotting
* Imaging
* Erect CXR
* AXR ± erect film for fluid levels
* CT: can show transition point
* Gastrograffin studies
* Loow for mechanical obstruction
* Follow through or enema
* Follow through may relieve mild mechanical obstruction esp adhesional
* Colonoscopy
* Can be used in some cases but there is a risk of perforation
* May be used therapeutically to stent
118
What are the AXR findings in small bowel obstruction?
* ≥3 diameter
* Central location
* Valvulae coniventes - completely across
* Absent LB gas
* Many loops
* Many, short fluid levels
119
What are the AXR findings in large bowel obstruction?
* ≥6cm diameter (caecum ≥9)
* Peripheral
* Haustra - partially across
* LB gas present but not in rectum
* Few loops
* Few, long fluid levels
120
What are the AXR findings in ileus?
Both small and large bowel may be visible but no clear transition point
121
What is the initial therapy for bowel obstruction?
* Resus - drip and suck
* NBM
* IV fluids: aggressive
* NGT: decompress upper GIT, stops vomiting, prevents aspiration
* Catheterise to monitor UO
* Then
* Analgesia (may need strong opioid)
* Antibiotics (cef and met if strangulation/perforation)
* Gastrograffin study (oral or via NGT)
* Consider need for parenteral nutrition
122
How should you monitor a patient with bowel obstruction?
* Regular examination 4-6 hourly to make sure they're not deteriorating
* Distension
* Pain/tenderness
* Raised HR/RR
* Repeat imaging and bloods
123
How many patients with bowel obstruction need surgery?
* Non operative Mx is successful in ~80% patients with SBO without peritonitis
* LBO patients more likely to need surgery
124
What are the indications for non surgical management of bowel obstruction?
* Firm evidence there is no threat to the viability of the bowel
* Incomplete obstruction in the small or large bowel with features suggesting non progression
* Some instances of complete SBO e.g. adhesive obstruction
125
What are the indications for surgical management of bowel obstruction?
* Closed loop obstruction
* Obstructing neoplasm (or other cause needing removal)
* Strangulation/perforation -\> sepsis, peritonitis
* Failure of conservative management (up to 72 hours)
126
What are the principles of surgical management of bowel obstruction?
* Aim to treat the cause
* Typically involves resection of the obstructing lesion
* Colon hasn't been cleansed so most surgeons use a proximal ostomy post resection
* Patients with a substantial comorbidity or unresectable tumours may be offerd bypass procedures
* Endoscopically placed expanding metal stents offer palliation or a briedge to surgery allowing optimisation
127
What procedures are done to treat bowel obstruction?
* Consent for possible resection ± stoma
* SBO: adhesiolysis
* LBO:
* Hartmann's
* Colectomy + primary anastomosis and on table lavage
* Palliative bypass procedure
* Transverse loop colostomy or loop ileostomy
* Caecostomy
128
What is the most common location for volvulus?
Sigmoid - 80%
129
What is the pathophysiology of sigmoid volvulus?
* Long mesentery with a narrow base so predisposed to torsion
* Usually due to sigmoid elongation secondary to chronic constipation
* Increased risk in neuropsych patients - MS, PD, psychiatric (disease/treatment interferes with intestinal motility)
* Closed loop obstruction
130
How does sigmoid volvulus present?
* Commoner in males
* Often elderly, constipated, co-morbid patients
* Massive distension with tympanic abdomen
131
What is the AXR appearance in sigmoid volvulus?
Coffee bean sign
132
What is the management for sigmoid volvulus?
* Often relieved by sigmoidoscopy and flatus tube insertion
* Monitor for signs of bowel ischaemia following decompression
* Sigmoid colectomy occasionally required
* Failed endoscopic decompression
* Bowel necrosis
* Often recurs so elective sigmoidectomy may be needed
133
What is a caecal volvulus often associated with?
Congenital malformation where the caecum is not fixed in the RIF
134
How is a caecal volvulus managed?
* Only ~10% patients can be detorsed with a colonoscopy
* Typically needs surgery
* Right hemi with primary ielocolic anastomosis
* Caecostomy
135
What is the triad of gastrooesophageal obstruction?
* Vomiting -\> retching with regurgitation of saliva
* Pain
* Failed attempts to pass an NGT
136
What are the risk factors for gastric volvulus?
* Congenital
* Bands
* Rolling/paraoesophageal hernia
* Pyloric stenosis
* Acquired
* Gastric/oesophageal surgery
* adhesions
137
What investigation findings suggest gastric volvulus?
* Gastric dilatation
* Double fluid level on erect films
138
What is the management for a gastric volvulus?
Endoscopic manipulation or emergency laparotomy
139
How does paralytic ileus present?
* Reduced or absent bowel sounds
* Mild abdo pain - not colicky
140
What is paralytic ileus?
Adynamic bowel secondary to the absence of normal peristalsis - usually SBO
141
What are the causes of paralytic ileus?
* Post op
* Peritonitis
* Pancreatitis or any localised inflammation
* Poisons/drugs: anti-AChM (e.g. TCAs)
* Pseudo-obstruction
* Metabolic: hypokalaemia, hyponatraemia, hypomagnesaemia, uraemia
* Mesenteric ischaemia
142
How do you prevent paralytic ileus?
* Minimal bowel handling
* Laparoscopic approach
* Peritoneal lavage after peritonitis
* Unstarched gloves
143
How do you manage paralytic ileus?
* Conservative 'drip and suck' management
* Correct underlying causes (drugs, metabolic abnormalities)
* Consider need for parenteral nutrition
* Exclude mechanical cause if protracted
144
What is Ogilvie's syndrome?
* Acute intestinal pseudo obstruction associated with massive dilatatoin
* Usually of colon but also small intestine
* Mechanical obstruction absent
* Parasympathetic nerve dysfunction
145
How does colonic pseudo obstruction present?
* Clinical signs of mechanical obstruction
* No obstructing lesion found
* Usually distension only with no colic
146
What are the causes of colonic pseudo obstruction?
* Usually no cause found
* But associated with:
* Elderly
* Cardiorespiratory disorders
* Pelvic surgery e.g. hip arthroplasty
* Trauma
147
How should you investigate suspected pseudo obstruction?
Gastrograffin enema to exclude a mechanical cause
148
How do you treat colonic pseudo obstruction?
* Neostigmine: anticholinesterase
* Colonoscopic decompression: 80% successful
149
What is the epidemiology of colorectal ca?
* 3rd commonest cancer
* 2nd commonest cause of cancer deaths
* Peaks in 60s
* Rectal ca commoner in men
* Westerners
150
What are colonic adenomas?
Dysplastic epithelium - benign precursors to CRC
151
How do you classify colonic adenomas?
* Tubular: small, pedunculated, tubular glands
* Villous: large, sessile, covered by villi
* Tubulovillous: mixture
152
How do colonic adenomas present?
* Typically asymptomatic
* LArge polyps can bleed causing IDA
* Villous adenomas can cause hypokalaemia and hypoproteinaemia
153
What factors increase the malignant potential of colonic adenomas?
* Bigger
* More dysplastic
* Greater villous component
154
What is APC and what is its role in CRC?
* Negative regulator of beta catenin (component of WNT pathway)
* APC binds to and promotes degradation of beta catenin
* APC mutations -\> increased beta catenin -\> increased transcription of genes which promote cell proliferation
* Proliferation leads to mutation of other genes which promote growth and prevent apoptosis e.g. KRAS (protooncogene) and p53 (TSG)
155
What are the stages in the adenoma-carcinoma sequence?
1. Mutation of one APC copy
2. Mutation of second APC copy -\> adenoma formation
3. Additional mutations in adenoma -\> malignant transformatone.g. KRAS, p53
156
What are the aetiological factors in CRC?
* Diet: low fibre and high refined carbohydrate
* IBD: CRC in 15% of those with pancolitis for 20 years
* Familial: FAP, HNPCC, Peutz-Jeghers
* Smoking
* Genetics
* No relative: 1/50 risk
* One 1st degree relative: 1/10 risk
* NSAIDs/aspirin 300g/d protective
157
What kinds of tumour are in the colon?
95% adenocarcinoma
Rest: lymphoma, GIST, carcinoid
158
What location are colorectal tumours usually in?
* Rectum 35%
* Sigmoid 25%
* Caecum and ascending colon 20%
* Transverse 10%
* Descending 5%
159
What kinds of colorectal carcinomas are proximal and distal tumours?
Proximal: sessile or polypoid
Distal: annular stenosing
160
How does colorectal carcinoma spread?
* Local
* Lymphatic
* Blood (liver, lungs)
* Transcoelomic
161
Which presenting features are specific to left sided colorectal cancers?
* Altered bowel habit (because stool is at least semisolid and calibre of bowel is less)
* PR mass (60%)
* Obstruction (25%)
* Bleeding/mucus PR (rare)
* Tenesmus
162
What presenting features are common to both left and right sided colonic tumours?
* Abdominal mass
* Perforation
* Haemorrhage
* Fistula
163
What are the examination findings suggestive of colorectal ca?
* Palpable mass: per abdomen or PR
* Perianal fistulae
* Hepatomegaly
* Anaemia
* Signs of obstruction
164
What investigations should you do in colorectal ca?
* Bloods
* FBC (Hb)
* LFTs - mets
* Tumour marker - CEA which is a useful marker of disease and emergence of recurrence
* Imaging
* CXR: lung mets
* US liver: mets
* CT and MRI (staging - MRI best for rectal ca and liver mets)
* Endoanal US: staging rectal tumours
* Ba/gastrograffin enema: apple core lesion
* Endoscopy and biopsy
* Flexi sig (65% tumours accessible)
* Colonoscopy
165
What is the staging system for colorectal carcinoma?
Dukes:
* A = confined to bowel wall (90% 5 year survival)
* B = through bowel wall but no lymph nodes (60% 5 year survival)
* C = regional LNs (30% 5 year survival)
* D = distant mets (\<10% 5 year survival)
166
What is the TNM staging for colorectal ca?
* Tis: carcinoma in situ
* T1: submucosa
* T2: muscularis propria
* T3: subserosa
* T4: through the serosa to adjacent organs
* N1: 1-3 nodes
* N2: \>4 nodes
167
How do you grade colorectal ca?
* Grading from low to high
* Based on cell morphology
* Dysplasia, mitotic index, hyperchromatism
168
How many CRC patients can have surgery?
60%
169
What are the principals of surgical management of CRC?
* Excision depends on lymphatic drainage which follows arterial supply
* Mobility of bowel and blood supply at cut ends is also important
* Hartmann's often used if obstruction
* Laparoscopic approach is the standard
170
How is rectal cancer managed surgically?
* Neoadjuvant radiotherapy may be used to decrease local recurrence and increase survival
* Anterior resection - tumours 4-5cm from the anal verge
* Defunction with loop ileostomy
* AP resection: \<4cm from the anal verge
* + total mesorectal excision for tumours of the middle and lower third
* Aims to decrease recurrence
* Increased anastomotic leak and faecal incontinence
171
How do you treat colonic cancers surgically depending on their location?
* Sigmoid: high anterior resection or sigmoid colectomy
* Left: left hemicolectomy
* Transverse: extended right hemicolectomy
* Caecal/right: right hemocolectomy
172
What are the treatment options for colorectal cancer other than resections?
* Local excision e.g. transanal endoscopic microsurgery
* Bypass surgery: palliation
* Hepatic resection: if single lobe mets only
* Stenting: palliation or bridge to surgery in obstruction
* Chemo
* Adjuvant 5-FU for Dukes' C decreases mortality by 25%
* High grade tumour
* Palliation of metastatic disease
173
What are the 2 screening programmes for colorectal cancer?
Faecal occult blood testing and flexi sig
174
How does the faecal occult blood screening programme work?
* From 2006
* 60-75 years
* Homr FOB testing every 2 years (1/50 will be positive)
* Colonoscopy if positive (1/10 have cancer)
* Screening has decreased risk of dying from CRC by 25%
175
How does the flexi sig screening programme for CRC work?
* From 2011/12
* 55-60 years
* One only flexi sig
* Decreased incidence by 33% and mortality by 43%
176
What are the 3 main familial CRC syndromes?
* Familial adenomatous polyposis (e.g. Gardener's, Turcot's)
* Hereditary non polyposis colorectal cancer
* Peutz-Jeghers syndrome
177
How is FAP inherited?
Autosomal dominant - APC gene on 5q21
178
How does FAP present?
100s-1000s of adenomas by ~16 years, mainly in the large bowel but also in the stomach and duodenum (near the ampulla)
179
What is the risk with FAP?
100% get CRC often by 40
180
What other congenital problem might FAP be associated with?
Congenital hypertrophy of the retinal pigment epithelium (CHPRE)
181
What are hte features of attenuated FAP?
\<100 adenomas, later CRC (\>50)
182
What are the features of Gardener's syndrome?
* Thyroid tumours
* Osteomas of the mandible, skull and long bones
* Dental abnormalities: supernumerary teeth
* Epidermal cysts
183
What are the features of Turcot's syndrome?
CNS tumours (medullo and glioblastomas), adenomas
184
What is the management plan for FAP?
* Prophylactic colectomy befoer 20
* Total colectomy and IRA
* Requires life long stump surveillance
* PRoctocolectomy and IPAA
* Remain at risk of cancer in stomach and duodenum so they have regular endoscopic screening
185
How is HNPCC inherited?
Autosomal dominant - mutation of mismatch repair enzymes e.g. MSH2 on chromosome 2p
186
What is the commonest cause of hereditary CRC?
HNPCC - 3% of all CRC
187
How does HNPCC present?
* Lynch 1: right sided CRC
* Lynch 2: CRC + gastric, endometrial, prostate, breast
188
How do you diagnose HNPCC?
3-2-1 rule:
≥3 family members over 2 generations with one \<50 years
189
How is Peutz Jeghers inherited and what's the mutation?
Autosomal dominant - STK11 mutation
190
How does Peutz Jeghers present?
* ~10-15 years
* Mucocutaneous hyperpigmentation - macules on palms, buccal mucosa
* Multiple GI hamartomatous polyps - intussusception, haemorrhage
* Increased cancer risk - CRC, pancreas, breast, lung, ovaries, uterus
191
What are the types of GI polyps?
* Inflammatory
* Hyperplastic
* Hamartomatous
* Neoplastic
192
What is the aetiology of inflammatory polyps?
Regenerating islands of mucosa in UC
193
What are the features of hyperplastic polyps?
* Piling up of goblet cells and absorptive cells
* Serrated surface architecture
* No malignant potential
194
What are the features of hamartomatous polyps?
* Tumour like growths composed of tissues present at the site where they develop
* Sporadic or part of familial syndromes
* Juvenile polyp = solitary hamartoma in children (cherry on a stalk)
195
What are the features of neoplastic polyps?
* Tubular or villous adenomas
* Usually asymptomatic
* May have blood/mucus PR, tenesmus
196
What are the faetures of juvenile polyposis?
* Autosomal dominant
* \>10 hamartomatous polyps
* Increased CRC risk: need surveillance and polypectomy
197
What are the features of Cowden syndrome?
* Autosomal dominant
* Macrocephaly and skin stigmata
* Intestinal hamartomas
* Increased risk of extra intestinal Ca
198
What are the causes of acute mesenteric ischaemia?
* Arterial: thrombotic (35%), embolic (35%)
* Non occlusive (20%)
* Splanchnic vasoconstriction e.g. secondary to shock
* Venous thrombosis (5%)
* Other: trauma, vasculitis, strangulation
199
How does acute mesenteric ischaemia present?
* Nearly always small bowel
* Triad:
* Acute severe abdo pain ± PR bleed
* Rapid hypovolaemia -\> shock
* No abdominal signs
* Degree of illness may be greater than clinical signs
* May be in AF
200
How should you investigate suspected acute mesenteric ischaemia?
* Bloods
* High Hb: plasma loss
* Raised WCC
* Raised amyloase
* Persistent metabolic acidosis - raised lactate
* Imaging
* AXR: gasless abdomen
* Arteriography/CT/MRI angio
201
What are the possible complications of mesenteric ischaemia?
Septic peritonitis, SIRS -\> MODS
202
How do you treat acute mesenteric ischaemia?
* Fluids
* Antibiotics: gent and met
* LMWH
* Laparotomy to resect necrotic bowel
203
What is the cause of chronic small bowel ischaemia?
Atheroma + low flow state e.g. LVF
204
How does chronic small bowel ischaemia present?
* Severe, colicky, post prandial abdo pain - 'gut claudication'
* PR bleeding
* Malabsorption
* Weight loss
205
How do you treat chronic small bowel ischaemia?
Angioplasty
206
What is the cause of chronic large bowel ischaemia?
Follows low flow in IMA territory
207
How does chronic large bowel ischaemia present?
* Lower, left sided abdo pain
* Bloody diarrhoea
* Pyrexia
* Tachycardia
208
How should you investigate suspected chronic large bowel ischaemia?
* Raised WCC
* Barium enema: thumb printing
* MR angiography
209
What are the complications of chronic large bowel ischaemia?
* May lead to peritonitis and septic shock
* Strictures in the long term
210
How do you manage chronic large bowel ischaemia?
* Usually conservative: fluids and antibiotics
* Angioplasty and endovascular stenting
211
What are the common causes of lower GI bleeds?
* Rectal: haemorrhoids, fissure
* Diverticulitis
* Neoplasm
212
What are the less common causes of lower GI bleeds?
* Inflammation: IBD
* Infection: shigella, campylobacter, C diff
* Polyps
* Large upper GI bleed (15% of lower GI bleeds)
* Angio: dysplasia, ischaemic colitis, HHT, AV malformation
* Trauma
* Solitary rectal ulcer
* Fistula
* Warts
213
How should you investigate a lower GI bleed?
* Bloods: FBC, U+E, LFT, cross match, clotting, amylase
* Stool: MCS
* Imaging
* AXR, erect CXR
* Angiography necessary if no source on endoscopy
* Red cell scan
* Endoscopy
* 1st: rigid proctoscopy/sigmoidoscopy
* 2nd: OGD
* 3rd: colonoscopy: difficult in major bleeding
214
How do you manage a lower GI bleed?
* Resuscitate
* Urinary catheter
* Antibiotics if evidence of sepsis or perf
* PPI if upper GI bleed possible
* Keep bed bound: if need to pass stool, could be a large bleed leading to collapse
* Stool chart
* Diet: keep on clear fluids to allow colonoscopy
* Surgery if unremitting or massive bleed
215
What is the pathophysiology of angiodysplasia in the bowel?
Submucosal AV malformations - 70-90% are in the right colon and they can affect anywhere in the GIT
216
How does angiodysplasia present?
Elderly, fresh PR bleeding
217
How should you investigate suspected angiodysplasia?
* Exclude other diagnoses: PR exam, barium enema, colonoscopy
* Mesenteric angiography or CT angiography
* Tc-labelled RBC scan: identify active bleeding
218
How do you treat angiodysplasia?
* Embolisation
* Endoscopic laser electrocoagulation
* Resection
