Lower GI Surgery Flashcards
Small Bowel Neoplasms
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 (esp. c¯ Coeliac disease: EATL)
GIST
Small Bowel Neoplasms Presentation
Often non-specific symptoms so present late
N/V, obstruction
Wt. loss and abdominal pain
Bleeding
Jaundice from biliary obstruction or liver mets.
Meckel’s Diverticulum
Ileal remnant of vitellointestinal duct
Joins yoke sac to midgut lumen
Features
A true diverticulum
2 inches long
2 ft from ileocaecal valve on antimesenteric border
2% of population
2% symptomatic
Contain ectopic gastric or pancreatic tissue
Presentation of Symptomatic Meckel’s Rectal bleeding: from gastric mucosa Diverticulitis mimicking appendicitis Intussusception Volvulus Malignant change: adenocarcinoma Raspberry tumour: mucosa protruding at umbilicus A vitello-intestinal fistula Littre’s Hernia: herniation of Meckel’s
Dx
Tc pertechnecate scan +ve in 70% (detects gastric
mucosa)
Rx
Surgical resection
Intussusception
Portion of intestine (the intussusception) is invaginated into its own lumen (the intussuscipiens)
Cause Hypertrophied Peyer’s patch Meckel’s HSP Peutz-Jeghers Lymphoma
Presentation 6-12mo Colicky abdo pain: Episodic inconsolable crying, drawing up legs ± bilious vomiting Redcurrent jelly stools Sausage-shaped abdominal mass
Mx
Resuscitate, x-match, NGT
US + reduction by air enema
Surgery if not reducible by enema
NB. Intussusception rarely occurs in an adult
If it does, consider neoplasm as lead-point
Mesenteric Adenitis
Viral infection / URTI → enlargement of mesenteric LNs
→ pain, tenderness and fever
Differentiating features Post URTI Headache + photophobia Higher temperature Tenderness is more generalised Lymphocytosis
Acute Appendicitis
Inflammation of the vermiform appendix ranging from oedema to ischaemic necrosis and perforation.
Commonest surgical emergency
Maximal peak in childhood, rare <2y
Acute Appendicitis Pathogenesis
Obstruction of the appendix Faecolith most commonly Lymphoid hyperplasia post-infection Tumour (e.g. caecal Ca, carcinoid) Worms (e.g. Ascaris lumbicoides, Schisto)
Gut organisms → infection behind obstruction
→ oedema → ischaemia → necrosis → perforation
Peritonitis
Abscess
Appendix mass
Acute Appendicitis Pattern of Abdo Pain
Early inflammation > appendiceal irritation
- visceral pain not well localised cf somatic pain
- Nociceptive info > sympathetic afferent fibres that supply viscus
- pain referred to dermatome corresponding to spinal cord entry level of sympathetic fibres
- append - midgut - lesser splanch (T10/11) - umb
Late inflammation
- pain localised in RIF
Acute Appendicitis Sx and Signs
Sx Colicky abdo pain Central → localised in RIF Worse c¯ movement Anorexia Nausea (vomiting is rarely prominent) Constipation / diarrhoea
Signs Low-grade pyrexia: 37.5 – 38.5 ↑HR, shallow breathing Foetor oris - unpleasant smell Guarding and tenderness: @ McBurney’s point +ve cough / percussion tenderness Appendix mass may be palpable in RIF Pain PR suggests pelvic appendix.
Acute Appendicitis Special Signs
Rovgins’s Sign - Pressure in LIF > RIF pain
Psoas sign - pain on extending the hip - retrocaecal appendix
Cope sign - flexion + internal rotation of the hip
Acute Appendicitis Ix
Dx is principally clinical
Bloods: FBC, CRP, amylase, G+S, clotting
Urine Sterile pyuria: may indicate bladder irritation Ketones: anorexia Exclude UTI β-HCG
Imaging
US: exclude gynae path, visualise inflamed
appendix
CT: can be used
Diagnostic lap
Acute Appendicitis Mx
Fluids
Abx: cef 1.5g + met 500g IV TDS
Analgesia: paracetamol, NSAIDs, codeine phosphate
Certain Dx → appendicectomy (open or lap)
Uncertain Dx → active observation
Acute Appendicitis Complications
Appendix Mass - Inflamed appendix c¯ adherent covering of omentum and small bowel - Dx: US or CT - Mx Initially: Abx + NBM Resolution of mass → interval appendicectomy Exclude a colonic tumour: colonoscopy
Appendix Abscess - Results if appendix mass doesn’t resolve - Mass enlarges, pt. deteriorates - Mx Abx + NBM CT-guided percutaneous drainage If no resolution, surgery may involve right hemicolectomy
Perforation
Commoner if faecolith present and in young children (as
Dx is often delayed)
Deteriorating pt. c¯ peritonitis.
Diverticular Disease
Diverticulum = out-pouching of tubular structure
True = composed of complete wall (e.g. Meckel’s)
False = composed of mucosa only (pharyngeal, colonic)
Diverticular disease: symptomatic diverticulosis
Diverticulitis: inflammation of diverticula
f>m
Diverticular disease pathophysiology
Assoc. c¯ ↑ 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 pts. Uniting factor in Saint’s Triad? Hiatus Hernia Cholelithiasis Diverticular disease
Diverticular Disease Sx + Rx
Altered bowel habit ± left-sided colic
Relieved by defecation
Nausea
Flatulence
Rx
High fibre diet, mebeverine may help
Elective resection for chronic pain
Diverticulitis Presentation
Insipissated faeces > obstruction of diverticulum
Elderly w Hx of constipation
Presents abdo pain + tenderness - typically LIF - localised periotnitis pyrexia
Diverticulitis Ix
Bloods FBC: ↑WCC ↑CRP/ESR Amylase G+S/x-match
Imaging Erect CXR: look for perforation AXR: fluid level / air in bowel wall Contrast CT Gastrograffin enema
Endoscopy
Flexi Sig
Colonoscopy: not in acute attack
Hinchey Grading
Diverticulitis
1 Small confined pericolic abscesses - Surgery rarely
needed
2 Large abscess extending into pelvis - May resolve w/o
surgery
3 Generalised purulent peritonitis - Surgery needed
4 Generalised faecal peritonitis - Surgery needed
Mx of acute Diverticulitis
Mild Attacks - can be Mx at home w bowel rest (fluids only) + augmentin+/-metronidazole
Admit if - unwell, fluids not tolerated, pain uncontrolled
Medical - NBM, IV fluids, analgesia
- abx (cefuroxime + metronidazole)
- most cases settle
Surgical if - perforation - large haemorrhage - Stricture → obstruction Procedure - Hartmann's to resect diseased bowel
Other complications of diverticular disease
Perforation
- sudden onset of pain (w/(o) preceedint diverticulitis)
- generalised peritonitis + shock
- CXR - free air under diaphragm
- Rx haartmann’s
Other complications of diverticular disease
Abscess
Walled-off perforation
Swinging fever
Localising signs: e.g. boggy rectal mass
Leukocytosis
Rx: Abx + CT/US-guided drainage
Other complications of diverticular disease
Fistulae
Enterocolic
Colovaginal
Colovesicular: pneumaturia + intractable UTIs
Rx: resection
Other complications of diverticular disease
Strictures
After diverticulitis, colon may heal c¯ fibrous strictures
Rx
Resection (usually c¯ 1O anastomosis)
Stenting
Bowel Obstruction Classification
Simple
1 obstructing point + no vascular compromise
May be partial or complete
Closed Loop Bowel obstructed @ two points - Left CRC c¯ competent ileocaecal valve - Volvulus Gross distension → perforation
Strangulated
Compromised blood supply
Localised, constant pain + peritonism
Fever + ↑WCC
Commonest Causes of Bowel Obstruction
SBO
Adhesions: 60%
Hernia
LBO
Colorectal Neoplasia: 60%
Diverticular stricture: 20%
Volvulus: 5%
Non-mechanical causes of bowel obstruction
Paralytic ileus (usually small bowel)
Post-op Peritonitis Pancreatitis or any localised inflammation Poisons / Drugs: anti-AChM (e.g. TCAs) Pseudo-obstruction Metabolic: ↓K, ↓Na, ↓Mg, uraemia Mesenteric ischaemia
Mechanical causes of bowel obstruction
Intraluminal
Impacted matter: faeces, worms, bezoars
Intussusception
Gallstones
Mechanical causes of bowel obstruction
Intramural
Benign Stricture IBD Surgery Ischaemic colitis Diverticulitis Radiotherapy
Neoplasia
Congenital atresia
Mechanical causes of bowel obstruction
Extramural
Hernia Adhesions Volvulus (sigmoid, caecal, gastric) Extrinsic compression Pseudocyst Abscess Haematoma Tumour: e.g. ovarian Congenital bands (e.g. Ladd’s)
Bowel Obstruction Presentation
Abdominal Pain
Colicky
Central but level depends on gut region
Constant / localised pain suggests strangulation
or impending perforation
Distension (lower obstructions)
Vomiting
Early in high obstruction
Late or absent in low obstructions
Absolute Constipation: flatus and faeces
Bowel Obstruction Examination
↑HR: hypovolaemia, strangulation Dehydration, hypovolaemia Fever: suggests inflammatory disease or strangulation Surgical scars Hernias Mass: neoplastic or inflammatory
Bowel sounds
↑: mechanical obstruction
↓: ileus
PR Empty rectum Rectal mass Hard impacted stool Blood from higher pathology
Bowel Obstruction Ix
Bloods
FBC: ↑WCC
U+E: dehydration, electrolyte abnormalities
Amylase: ↑↑ if strangulation/perforation
VBG: ↑ lactate in strangulation
G+S, clotting: may need surgery
Imaging
Erect CXR
AXR: ± erect film for fluid levels
CT: can show transition point
Gastrograffin studies
Look for mechanical obstruction: no free flow
Follow through or enema
Follow through may relieve mild mechanical
obstruction: usually adhesional
Colonoscopy
Can be used in some cases
Risk of perforation
May be used therapeutically to stent
AXR Findings of Small Bowel obstruction
Diameter ≥3
Location Central
Markings Valvulae coniventes
- completely across
LB Gas Absent
No. of loops Many
Fluid levels Many, short
AXR Findings of Large Bowel obstruction
Diameter ≥6cm (caecum ≥9) Location Peripheral Markings Haustra - partially across LB Gas Present - not in rectum No. loops Few Fluid levels Few, long
Bowel Obstruction Medical Mx
Resuscitate: “Drip and Suck”
NBM
IV fluids: aggressive as pt. may be v. dehydrated
NGT: decompress upper GIT, stops vomiting, prevents
aspiration
Catheterise: monitor UO
Therapy Analgesia: may require strong opioid Antibiotics: cef+met if strangulation or perforation Gastrograffin study: oral or via NGT Consider need for parenteral nutrition
Monitor
- distension, pain/tenderness, HR/RR
- Repeat image/bloods
LBO more likely to need surgery
Surgical Mx of Bowel Obstruction
Indications Closed loop obstruction Obstructing neoplasm Strangulation / perforation → sepsis, peritonitis Failure of conservative Mx (up to 72h)
Principals
Aim to treat the cause
Typically resection obstructing lesion
Colon has not been cleansed :. most surgeons
use proximal ostomy post-resection.
substantial comorbidity or unresectable tumours
may offered bypass procedures.
Endoscopically placed expanding metal stents offer
palliation or a bridge to surgery allowing optimisation.
Surgical Mx of Bowel Obstruction
PROCEDURES
SBO - adhesiolysis
LBO
Hartmann’s
Colectomy + 1O anastomosis + on table lavage
Palliative bypass procedure
Transverse loop colostomy or loop ileostomy
Caecostomy
Sigmoid Volvulus
Long mesentery w narrow base > ^p(torsion)
Usually due to sigmoid elongation 2ndary to chronic
constipation
↑ risk in neuropsych pts.: MS, PD, psychiatric
Disease or Rx interferes w intestinal motility
→ closed loop obstruction
Presents
M>F, elderly constipated, comorbid pts
Massive Distension w TYMPANIC ABDOMEN
Sigmoid Volvulus AXR + Mx
AXR - inverted U/coffee bean sign
Mx
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 elective sigmoidectomy may be needed
Caecal Volvulus
Assw congen malformation -
caecum not fixed in RIF.
Only ~10% of pts. can be detorsed w colonoscopy
typically requires surgery
Right hemi w primary ileocolic anastomosis
Caecostomy
Gastric Volvulus
Triad of gastro-oesophageal obstruction
Vomiting → retching c¯ regurgitation of saliva
Pain
Failed attempts to pass an NGT
Risk Factors Congenital Bands Rolling / Paraoesophageal hernia Pyloric stenosis Acquired Gastric / oesophageal surgery Adhesions
Ix
Gastric dilatation
Double fluid level on erect films
Mx
Endoscopic manipulation
Emergency laparotomy
Paralytic Ileus Presentation + causes
Presentation Adynamic bowel 2ndary to absence of normal peristalsis Usually SBO Reduced or absent bowel sounds Mild abdominal pain: not colicky
Cause Post-op Peritonitis Pancreatitis or any localised inflammation Poisons / Drugs: anti-AChM (e.g. TCAs) Pseudo-obstruction Metabolic: ↓K, ↓Na, ↓Mg, uraemia Mesenteric ischaemia
Paralytic Ileus Prevention and M
Prevention ↓ bowel handling Laparoscopic approach Peritoneal lavage after peritonitis Unstarched gloves
Mx Conservative “drip and suck” Mx Correct underlying causes - Drugs/Metabolic abnormalities Consider need for parenteral nutrition Exclude mechanical cause if protracted
Colonic Pseudo-obstruction
Ogilvie’s Syndrome
Clinical signs of mechanical obstruction but no
obstructing lesion found
Usually distension only: no colic
Cause unknown
- assw elderly, cardioresp disorders, pelvic surgery, trauma
Ix - gastrograffin enema - exclude mechanical cause
Mx - neostigmine (anticholinesterase)
- colonoscopic decompression 80% successful
Colorectal Carcinoma Surgery
Use ERAS pathway (enhanced recovery after surgery)
Pre-operative bowel prep (except R sided lesions)
E.g. Kleen Prep (Macrogol: osmotic laxative) the
day before and phosphate enema in the AM.
Consent: discuss stomas (Stoma nurse consult for siting)
Principles
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 of care
Rectal carcinoma Surgery
Neo-adjuvant radiotherapy may be used to ↓ local
recurrence and ↑5ys
Anterior resection: tumour 4-5cm from anal verge
Defunction c¯ loop ileostomy
AP (abdominopernieal) resection: <4cm from anal verge
+ Total mesorectal excision for tumours of the middle
and lower third.
Aims to ↓ recurrence
↑ anastomotic leak and faecal incontinence
Sigmoid tumour Surgery
high anterior resection or sigmoid colectomy
Left sided bowel tumours Surgery
Transverse bowel tumour surgery
Caecal/right sided bowel tumorus surgery
left hemicolectomy
Extended right hemicolectomy
Right hemicolectomy
Other procedures/treatment for bowel cancer
Local excision: e.g. Transanal Endoscopic Microsurg
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 ↓ mortality by 25% i.e. LN +ve pts. High grade tumour Palliation of metastatic disease
NHS Screening for CRC
Faecal occult blood testing 60-75yrs Home FOB testing every 2yrs: ~1/50 have +ve FOB Colonoscopy if +ve: ~1/10 have Ca - reduces risk of dying from CRC by 25%
Flexi Sig 55-60yrs Once only flexi Sig ↓ CRC incidence by 33% ↓ CRC mortality by 43%
Familial Adenomatous Polyposis
AD APC geng 5q21
100-1000s of adenomas by ~16yrs
Mainly in large bowel
Also stomach and duodenum (near ampulla)
100% develop CRC, often by ~40yrs
May be assw congen hypertrophy of the retinal
pigment epithelium (CHPRE)
FAP Variants
Attenuated FAP: <100 adenomas, later CRC (>50yrs)
Gardener’s (TODE)
Thyroid tumours
Osteomas of the mandible, skull and long bones
Dental abnormalities: supernumerary teeth
Epidermal cysts
Turcot’s: CNS tumours: medullo- and glio-blastomas
Hereditary Non-Polyposis Colorectal Cancers
AD mutation of mismatch repair enzymes
Commonest cause of all hereditary CRC
Presentation
Lynch 1: right sided CRC
Lynch 2: CRC + gastric, endometrial, prostate, breast
Dx: “3, 2, 1, rule”
≥3 family members over 2 generations c¯ one <50yrs
Peutz- Jehgers Syndrome
AD STK11 mut
~ 10-15yrs
Mucocutaneous hyperpigmentation
Macules on palms, buccal mucosa
Multiple GI hamartomatous polyps
Intussusception
Haemorrhage
↑ Ca risk
CRC, pancreas, breast, lung, ovaries, uterus
GI polyps
Inflammatory pseudopolyps - regen islands of mucosa in UC
Hyperplastic polyps
- piling up of goblet cells + absorptive cells
- serrated surface architecture
No malignant potential
Harmatomatmous
- tumour-like growths composed of tissues present at site where they develop
- sporadic or part of familial syndromes
- juvenile polyp - solitary harmatoma in children (cherry on stalk)
Neoplastic
- tubular or villous adenomas
- usually ASx
- may have blood/mucus PR, tenesmus
Juvenile Polyposis
Autosomal dominant
>10 hamartomatous polyps
↑ CRC risk: need surveillance and polypectomy
Cowden Syndrome
Auto dominant
Macrocephaly + skin stigmata
Intestinal hamartomas
↑ risk of extra-intestinal Ca
Acute Mesenteric Ischaemia Causes
Arterial: thrombotic (35%), embolic (35%)
Non-occlusive (20%)
Splanchnic vasoconstriction: e.g. 2O to shock
Venous thrombosis (5%)
Other: trauma, vasculitis, strangulation
Acute Mesenteric Ischaemia Presentation
Nearly always small bowel
Triad
Acute severe abdominal pain ± PR bleed
Rapid hypovolaemia → shock
No abdominal signs
Degree of illness»_space; clinical signs
May be in AF
Acute Mesenteric Ischaemia Ix
Bloods ↑Hb: plasma loss ↑WCC ↑ amylase Persistent metabolic acidosis: ↑lactate
Imaging
AXR: gasless abdomen
Arteriography / CT/MRI angio
Acute Mesenteric Ischaemia Complications Mx
Complications
Septic peritonitis
SIRS → MODS
Mx Fluids Abx: gent + met LMWH Laparotomy: resect necrotic bowel
Chronic Small Bowel Ischaemia
Cause - atheroma + low flow state (eg LVF)
Presents
- severe colicky post prandial abdo pain (gut claudication)
- PR Bleeding
- Malabs, wt loss
Mx - angioplasty
Chronic Large Bowel Ischaemia
Cause - follows low flow IMA territory
Presents
- lower LS abdo pain
- Bloody diarrhoea
- Pyrexia Tachycardia
Ix - ↑WCC
Ba enema: thumb-printing
MR angiography
Complications
- may > peritonitis + septic shock
- long term strictures
Mx
Usually conservative: fluids and Abx
Angioplasty and endovascular stenting
Lower GI bleed Causes
Common / Important
Rectal: haemorrhoids, fissure
Diverticulitis
Neoplasm
Other
Inflammation: IBD
Infection: shigella, campylobacter, C. diff
Polyps
Large upper GI bleed (15% of lower GI bleeds)
Angio: dysplasia, ischaemic colitis, HHT
Lower GI bleed Ix
Bloods: FBC, U+E, LFT, x-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
Lower GI bleed Mx
Resuscitate
Urinary catheter
Abx: if evidence of sepsis or perf
PPI: if upper GI bleed possible
Keep bed bound: need to pass stool may be large bleed
→ collapse
Stool chart
Diet: keep on clear fluids (allows colonoscopy)
Surgery: only if unremitting, massive bleed
Angiodysplasia
Submucosal AV malformation (mainly right colon)
Can affect anywhere in GIT
Presents - elderly - fresh PR bleed
Ix Exclude other Dx PR exam Ba enema Colonoscopy Mesenteric angiography or CT angiography Tc-labelled RBC scan: identify active bleeding
Rx
Embolisation
Endoscopic laser electrocoagulation
Resection
