Small Intestine Flashcards
Describe the management of enterocutaneous fistulae
S- Sepsis
S- Skin
N- Nutrition (and electrolytes!)
A- Anatomy of the fistula
P- Planning of corrective surgery
Features of Crohns
Macroscopic
Endoscopic
Microscopic
Macroscopic
- Skip lesions/Discontinuous
- Distribution anywhere in the GI tract
- Transmural- fat wrapping occurs
Endoscopic
- Linear ulcers- progress to additional transverse sinuses and subsequent cobblestone appearance
- Skip lesions
Microscopic
- Transmural lymphoid infiltrates
- Sarcoid-like non caseating granulomas
- 50%
- Paneth cell hyperplasia is also common
Crohns distribution
55% SB and colon
30% SB only
15% Colon only
Classification of EC fistulae
Category
Low<200mL
Intermediate 200-500mL
High>500mL
Anatomy
site of defect in viscus e.g Jejunal, gastric etc
Etiology
IBD
Radiation
Iatrogenic
Foreign body
Spontaneous EC Fistula resolution timing
90% that close will do by 1 month
10% in months 1-3
None over 3 months
What is blind loop syndrome
Rare disorder secondary to bacterial overgrowth in areas of SB stasis
diarrhoea
steatorrhoea
Megaloblastic anaemia
Abdominal pain
Fat soluble vitamin deficiencies
B12 supplementation and Abx can resolve this temporarily
Surgical correction needed long term
Complications of jejunal diverticulosis
Bleeding
Enterolith formation
Perforation
Blind loop syndrome/malabsorption
Chronic pain
Malignancies with a preponderence for small bowel mets
Intraabdominal/transcoelomic/Local invasion (most common cause of SB malignancy)
Ovarian
Gastric
Cervical
Renal
Pancreas
Colon
Extraabdominal (rare)
Melanoma (most common)
Breast
Lung
SB GIST
- Origin
- Cellular markers
- Mutation
- Growth and Metastasis
- Adjuvant treatment
Origin
- Mesenchymal
- interstitial cells of Cajal
Cellular markers
- CD117 (molecular component of c-kit)
- ~85%
- DOG1 (Discovered on GIST-1)
- ~100%
- PKC-theta (Protein Kinase C- theta)
- ~100%
Mutation
- c-kit (of which the CD117 molecule is a component) present in most (~85%)
- position of c-kit mutation is important
- exon 11, codon 557/558 due to high recurrence risk
- Of those tumours without c-kt mutation many will have a PDGFRA mutation
- position of c-kit mutation is important
- 10-15% wild type
- NF-1
- Carney complex and Carney-Stratakis syndrome
- Succinate dehydrogenase
Growth and metastasis
- Invade locally, spread haematogenous- liver, lung, bone
Adjuvant (or neoadjuvant) treatment
- c-kit is a receptor tyrosine kinase
- Tyrosine kinase inhibitors are the agent of choice
- 3 years of adjuvant Imatanib is standard of care for intermediate to high risk disease
- induces cellular quiescence rather than demise
- TKI’s also have demonstrable antitumour activity in most tumours with PDGFRA mutations
How are GISTs risk stratified
What is the risk of progressive disease
Crohns perianal manifestations
Fissures
Fistulas
Abscesses
Cholecystokinin
Secreted by I cells in the duo and jej
- Response to lipid, protein and carb in duo
Actions
- Pancreatic enzyme release
- Relaxation of SOD
- GB contraction
Secretin
Secreted by S cells in Duo
- Response to low pH
Actions
- Secretion of Bicarb and water from pancreas
GIP
Gastric inhibitory polypeptide
Secreted by K cells in duo and jej
Acts to
- reduce gastric acid production
- Increase insulin release
Intestinal Malrotation
Normal rotation is counter clockwie (as the surgeon looks down on the abdomen
- 270 degrees
Non rotation is more common but not usually symptomatic
Ix-
- UGI series- bird beak at D3 with displaced ligament of Trietz
- USS- Alteration of usual SMA/SMV relationship
Management:
- Ladds procedure
How are GI neuroendocrine neoplasms subclassed
What genetic markers is each associated with
NENs are subdivided into:
- neuroendocrine tumours (NET)
- referring to well differentiated tumours
- MEN1, DAXX, ATRX
- grade low, int, high subtypes
- referring to well differentiated tumours
- neuroendocrine carcinoma (NEC)
- referring to poorly differentiated tumours
- TP53, RB1
- Small cell, large cell subtypes
- referring to poorly differentiated tumours
- mixed adenoneuroendocrine carcinoma (MANEC)
- Features of neuroendocrine and epithelial derived malignancy
Carcinoid syndrome
Carcinoid syndrome is classically characterised by:
- flushing (70%)
- diarrhoea (50%)
- intermittent abdominal pain (40%)
Due to the secretion of bioactive amines, most commonly serotonin, directly into the systemic circulation from either metastatic neuroendocrine tumour to liver or less commonly retroperitoneum.
Carcinoid crisis
Characterised by:
- profound flushing
- bronchospasm
- tachycardia
- labile blood pressure
Caused by:
- release of high levels of serotonin or other bioactive amines, such as histamine.
Can be precipitated by:
- induction of anaesthesia
- intraoperative tumour handling
- invasive techniques such as tumour ablation.
- histamine releasing drugs (e.g morphine)
- sympthomimetic drugs (e.g adrenaline)
It is critical that patients with known carcinoid syndrome or at those at risk of carcinoid crisis are managed appropriately in the perioperative period.
- octreotide and its analogues
Carcinoid heart disease
Seen in 20% of patients with carcinoid syndrome
Fibrosis of the right-side heart valves caused by many years of high serotonin levels
Perioperative octreotide in GI NETs
Grading of GI NETs
Describe the surgical management of intestinal malrotation
Ladds procedure has 5 steps
- Counter clockwise detorsion
- Division of Ladds bands
- Elongation of the mesentary
- Appendicectomy
- Placement of bowel to right and colon to left
What are the tumour markers for NETs
Why are they elevated in NET
What factors might falsely elevate each
Chromogranin A
- granins are proteins involved in exocytosis of secretory vesicles
- found in both functional and non functional NETs
- higher with higher secretion (volume or function)
- also elevated by:
- PPI use
- CHF
- CRF
5-HIAA (5-hydroxyindoleacetic acid)
- degradation product of serotonin
- Direct assay of serotonin is difficult
- Serotonin produced by >70% of NETS
- also elevated by
- chocolate, caffeine, nuts, nicotine, banana
Diagnostic imaging for GI NETs
Imaging for GI NETs may be either radiological or endoscopic
- Radiology
- CT is the most useful modality
- Mesenteric disease is a common feature
- spiculated/stellate mesenteric mass
- Primary tumour
- Mucocoele of appendix
- Mesenteric disease is a common feature
- PET
- Gallium Dotatate (GaTate)
- Gallium 68 labelled rapidly cleared novel somatostatin analogue
- The most sensitive investigation for metastatic disease
- Gallium Dotatate (GaTate)
- Somatostatin receptor scintigraphy
- Previously used
- Long imaging protocol (2 days)
- Accuracy improved by SPECT but now superceeded by GaTate PET
- MRE
- More accurate than WCE for identifying (and localising) small intestinal primaries
- CT is the most useful modality
- Endoscopy
- Allows direct visualisation
- Limited by access to OGD and colonoscopy distributions
- WCE is part of the diagnostic work up of the SB
- cannot identify exact site
- May cause luminal obstruction
- Allows direct visualisation
What staging systems are used for GI neurgoendocrine neoplasms (NENs)
How do they differ
ENETS
- European Neuroendocrine Tumour Society
- Covers all NENs
- NETs
- NECs
- Covers all NENs
AJCC/UICC
- American Joint Cancer Committee/ Union for International Cancer Control
- Covers only NETs
There are some also specific differences in T staging of appendix and stomach NETs
Small bowel NETs
epidemiology
NETs are the most common SB primary tumour
The majority have lymph node metastasis at the time of initial diagnosis
- Interestingly there does not appear to be a relationship between size and grade and the risk of nodal spread as is seen in appendiceal NETs
Primaries are often small at diagnosis
- 30% have multifocal small bowel primary
What genes are associated with Crohns disease
what is the mechanism of action
NOD2
- decreased paneth cell antimicrobial action
CARD15
- impaired NF-kB
Many others
- HLA, MHC
What grading system can be used to classify the phenotype of crohns
The Vienna classification was modified to the montreal system to include under 16 as an additional age group
Age at diagnosis
- A1: <16 (Vienna<40)
- A2: 16-40 (Vienna >40)
- A3 >40 (No corresponding Vienna group)
Location
- L1: TI
- L2: colon
- L3: ileocolonic
- L4: upper GI tract (L4 can also be used when occuring concurrent with another distribution)
Behaviour
- B1: non stricturing
- B2: stricturing
- B3: penetrating
- the suffix modifier “p” is used where concurrent perianal disease exists
ECCO surgery in UC guidelines.
admission of patients with acute severe UC
ECCO surgery in UC guidelines.
Who should care for patients with acute severe UC
ECCO surgery in UC guidelines.
What is the recommended initial management of patients with acute severe UC
ECCO surgery in UC guidelines.
Monitoring and escalation of initial treatment in UC
ECCO surgery in UC guidelines.
When should a second external pathologist be involved
ECCO surgery in UC guidelines.
Managing low grade dysplasia
ECCO surgery in UC guidelines.
Managing high grade dysplasia
ECCO surgery in UC guidelines.
What is the recommended operation in UC with dysplasia (anywhere in the colon)
ECCO surgery in UC guidelines.
Steroids in UC: how long is too long?
In acute UC the response should be assessed on day 3 and care escalated
in chronic UC:
ECCO surgery in UC guidelines.
surgery in anti-TNF therapy
ECCO surgery in UC guidelines.
What should be done with the rectum in panproctocolectomy for acute UC
ECCO surgery in UC guidelines.
laparoscopic vs open surgery for acute severe UC
ECCO surgery in UC guidelines.
choice of pouch construction
ECCO surgery in UC guidelines.
In patients who are not candidates for restorative procedures following proctocolectomy what procedures are recommended
total colectomy, with (preferably intersphincteric) proctectomy, and end ileostomy with or without Kocks pouch
ECCO surgery in UC guidelines.
Is total colectomy and ileorectal anastomosis a reasonable alternative
ECCO surgery in UC guidelines.
Should patients have a diverting loop ileostomy?
yes
ECCO surgery in UC guidelines.
Sexual function in UC surgery
ECCO surgery in UC guidelines.
Oncological surgery in dysplasia
What are the cell types found in the SB intestinal mucosa
Where is the site of cellular proliferation
The site of cellular proliferation is the crypts
Four cell types are found
- Absorptive enterocytes (95%)
- Paneth cells (do not migrate from the crypts)
- Goblet cells
- Enteroendocrine cells
How can the jejunum and ileum be clinically differentiated
Two main differences
- the vasculature of the mesentary
- jejunum has 1-2 arcades with long straight vasarectae
- ileum has 4-5 arcades and short vasa rectae
- the mucosa
- jejunal mucosa is thickened and palpably mobile within the bowel lumen
Where is iron absorbed
duodenum
Where is calcium absorbed
Duodenum and proximal jejunum
Intussusceptum
The part of an intussusception which passes into the intussuscipiens
Intussuscipiens
The part of the intussusception which receives the intussusceptum
Crohns disease severity: clinical assessment
Crohns disease severity index (CDAI)
- score from 0-1100
- stratified into
- mild < 150
- mild to moderate 150-220
- moderate to severe 220-450
- severe > 450
- stratified into
- components
- stool number (and use if loperamide)
- pain
- general wellbeing
- extraintestinal manifestations
- mass on exam
- weight off baseline by percentage
- perianal disease
- fever
- anaemia
crohns severity: endoscopic
Crohns Disease- Simple Endoscopic Score
- components
- ulcer type
- ulcer size
- ulcerated surface %
- affected surface %
- stenoses
- stratified into
- remission
- mild activity
- moderate activity
- severe activity
Crohns disease severity: imaging
MRE based severity scores have high accuracy for assessing extent and severity of disease
there are no validated USS and CT scores
How should the severity of crohns disease be assessed
By a combined assessment of clinical, endoscopic and imaging scores
- Clinical by Crohns Disease Activity Index
- Endoscopic by Simple Endoscopic Score if Crohns Disease
- Imaging graded score by MRE
How should the severity of UC be assessed
By endoscopic and clinical severity
- clinical severity by Truelove and Witt score
- endoscopic by Ulcerative Colitis Endoscopic Index of Severity (UCEIS)
- this score is the only validated score in UC and is more accurate than the Mayo score for predicting need for colectomy
UC endoscopic severity score
Ulcerative Colitis Endoscopic Index of Severity (UCEIS)
- 0-8 points
- vascular pattern (0-2)
- bleeding (0-3)
- erosions (0-3)
- this score is recommended over the Mayo score by ECCO as it is the only validated score of endoscopic severity, it is easy to calculate with low inter-observer variability and predicts colectomy more accurately
What tests should be done in suspected carcinoid syndrome
CT chest, abdomen and pelvis
Serum chromogranin A
Urinary 5HIAA
Echo
Dotatate PET
