General - Large Bowel Flashcards
What is the name given to acute pseudo-obstruction?
Oglivie’s syndrome
Define pseudo-obstruction
Dilation of the colon due to an adynamic bowel in the absence of mechanical obstruction
What is thought to cause pseudo obstruction?
Interruption of autonomic nervous supply to the colon resulting in the absence of smooth muscle action in the bowel
What are some of the common causes of pseudo obstruction?
- Electrolyte imbalance
- Endocrine disorders
- Medication eg. opioids, CCBs, antidepressants
- Recent stress to the body
- Recent CVS event
- Parkinsons
- Hirschsprung’s
Describe the typical clinical presentation of pseudo obstruction
- Abdo pain
- Abdo distension
- Constipation
- Vomiting
What is focal tenderness indicative of on an abdo exam?
Ischaemia - key warning sign
Why do you still usually hear bowel sounds in pseudo obstruction?
Colon specific pathology
Give the main DDx for pseudo obstruction
- Mechanical obstruction
- Paralytic ileum
- Toxic megacolon
How is pseudo-obstruction investigated for radiologically? Why?
CT Abdo-Pelvis with IV contrast
- Dilation of colon
- Excludes mechanical obstruction
- Assesses for complications
What is done for cases of pseudo obstruction lasting >24hrs with conservative management?
Endoscopic decompression
What medication can be given in pseudo obstruction?
IV neostigmine (anti cholinesterase)
What is a volvulus?
Twisting of an intestinal loop around its mesenteric attachment causing a closed loop bowel obstruction
Why is the sigmoid colon the most common site of volvulus?
Long mesentery (which increases with age)
What are the risk factors for volvulus development?
- Increasing age
- Neuropsychiatric disorders
- Nursing home resident
- Chronic constipation/laxative use
- Male
- Previous abdo surgery
Describe the classical presentation of a sigmoid volvulus
- Colicky pain
- Abdo distension
- Absolute constipation
- Late vomiting
How may volvulus be differentiated from other obstructional causes in terms of presentation?
Rapid onset of symptoms (over a few hours) and degree of distension
What is the initial investigation for suspected bowel obstruction?
CT Abdo-Pelvis scan with contrast
What is seen on a CT scan of sigmoid volvulus?
Very dilated sigmoid colon with a ‘whirl sign’ (from twisting mesentery at base)
What is the characteristic finding on an AXR for sigmoid volvulus?
Coffee bean sign
What are the indications for surgical management of a sigmoid volvulus?
- Colonic ischaemia
- Perforation
- Repeated failed attempts at decompression
- Necrotic bowel noted at endoscopy
What is the initial management for sigmoid volvulus?
Sigmoidoscope decompression with insertion of a flatus tube
What surgery is definitive for recurrent volvulus?
Elective sigmoidectomy with primary anastomosis
In what age groups does caecal volvulus tend to occur?
Bimodal distribution
- 10-29yrs
- 60-79yrs
What is the management for caecal volvulus?
Laparotomy and ileocaecal resection
What is a diverticulum?
Outpouching of bowel wall composed of mucosa
What are the three manifestations of diverticular disease?
- Diverticulosis = presence of diverticulum
- Divertucular disease = symptomatic diverticulum
- Diverticulitis = diverticular inflammation
Where are diverticulum most commonly found?
Sigmoid colon
Briefly describe the pathophysiology of divertucular disease
- With age there is weakening of the bowel wall
- Movement of stool causes an increase in luminal pressure
- This causes out pouching of the mucosa in weaker areas
What is complicated diverticulitis?
Presence of abscesses, fistulae, strictures, or free perforation
What risk factors are there for formation of diverticulum?
- Low fibre
- Obesity
- Smoking
- FHx
- NSAID use
How is diverticulosis normally diagnosed?
Incidentally on a routine CT or colonoscopy
Describe the classic clinical features of a patient with diverticular disease
- Left lower abdo pain
- Colicky pain relieved by defecation
- Altered bowel habit
- Nausea
- Flatulence
What will diverticulitis typically present with?
- Abdominal pain
- Localised tenderness (Typically LIF)
- Pyrexia
- N +/- V
- PR bleeding (sudden + painless)
- Anorexia
List the main complications of diverticular disease
- Pericolic abscess
- Fistula formation
- Bowel obstruction
What are the main DDx for diverticular disease?
- IBD
- Bowel cancer
What initial investigation is used for diverticular disease?
Flexible sigmoidoscopy
Why should a sigmoidoscopy or colonoscopy never be used for suspected diverticulitis?
Risk of perforation
What investigation is used for suspected diverticulitis?
CT abdo-pelvis scan
What findings are seen on a CT scan in diverticulitis?
- Thickening of colonic wall
- Pericolonic fat stranding
- Abscesses
- Localised air bubbles/free air
What staging system is used for acute diverticulitis?
What is it based on?
Hinchey Classification
Uses CT findings
What conservative management should be given for suspected diverticulitis?
- IV ABx
- IV fluids
- Bowel rest
- Analgesia
How long do symptoms typically take to improve with conservative management of diverticulitis?
2-3 days
When is emergency surgery needed for diverticulitis?
- Perforation with faecal peritonitis
- Overwhelming sepsis
When is urgent surgery indicated in diverticulitis?
Those failing to improve despite medical therapy or percutaneous drainage
What surgical intervention may be indicated for diverticulitis?
Bowel resection - typically Hartmann’s procedure
What is Hartmann’s procedure?
Resection of the sigmoid colon with the formation of an end colostomy and closure of the rectal stump
What is needed following resolution of diverticulitis?
Outpatient colonoscopy
What causes appendicitis?
Direct luminal obstruction:
- Faecolith
- Lymphoid hyperplasia
- Impacted stool
- Appendiceal or caecal tumour
What age group does appendicitis tend to affect?
20-30yrs
List the main risk factors for appendicitis
- FHx
- Caucasian
- Seasonal presentation in summer
Describe the pain felt in appendicitis
Peri-umbilical dull and poorly localised initially, then migrates to RIF and is well localised and sharp
What are the main symptoms patients experience in appendicitis?
- Abdominal pain (periumbilical then RIF)
- Vomiting (after pain)
- Anorexia
- Nausea
- Diarrhoea
- Constipation
What specific signs are seen on examination of a patient with appendicitis?
- Rebound tenderness
- Percussion pain over McBurney’s point
- Rovsing’s sign
- Psoas sign
- Guarding (perf)
What is Rovsing’s sign?
RIF pain on palpation in LIF
What is Psoas sign?
RIF pain with extension of the right hip
What are the main GI DDx for appendicitis?
- Mesenteric adenitis
- Diverticulitis
- IBD
- Meckel’s diverticulum
What are the main renal DDx for appendicitis?
- Ureteric stones
- UTI
- Pyelonephritis
What are the main GU DDx for appendicitis?
- Ectopic preg
- Ovarian cyst rupture
- Testicular torsion
- Epidiymo-orchitis
- PID
What investigations are required for a patient with appendicitis?
- Urinalysis
- Pregnancy test
- Routine bloods
What imaging techniques can be used for appendicitis?
- Trans abdominal USS
- CT scan
In which patients is an abdo USS used for appendicitis?
Children
Why is a CT scan useful when assessing appendicitis?
Identifies any potential malignancy causing or presenting as appendicitis
What risk stratification scores are there for appendicitis?
- Alvorado score
- Appendicitis Inflammatory Response Score (AIR)
What does an AIR score of 9-12 mean?
High risk patient - surgical exploration recommended
What is the definitive management for appendicitis?
Laparoscopic appendicectomy
List the main complications of appendicitis
- Perforation
- Surgical site infection
- Appendix mass
- Pelvic abscess
What is an appendix mass?
Where the momentum and small bowel adhere to the appendix
What conservative management is there for appendicitis?
Antibiotics (not fully evidence supported yet)
What does a positive psoas sign suggest?
Inflamed appendix abutting the psoas major muscle in the retrocaecal position
What type of cancer does colorectal cancer tend to be?
Adenocarcinoma
What name is given to the process by which colorectal cancer develops? What is this?
Adenoma-carcinoma sequence –> progression of normal mucosa to colonic adenoma to invasive adenocarcinoma
What genetic mutations of note are there for colorectal cancer?
- Adenomatous polyposis coli (APC)
- Hereditary nonpolyposis colorectal cancer (HNPCC)
What does a mutation in the adenomatous polyposis coli gene cause?
APC is a tumour suppressor gene, so inactivation results in growth of adenomatous tissue
+ responsible for familial adenomatous polyposis (FAP)
What is hereditary nonpolyposis colorectal cancer (HNPCC)?
Mutation to DNA mismatch repair gene –> defects in DNA repair
(accounts for familial risk in colorectal cancer)
What risk factors are there for colorectal cancer?
- Age >60yrs
- FHx
- IBD
- Low fibre diet
- High processed meat diet
- Smoking
- High alcohol intake
NB most are sporadic
What are the common clinical features of bowel cancer?
- Change in bowel habit
- Rectal bleeding
- Weight loss
- Abdominal pain
- Iron deficiency anaemia
What symptoms are specifically seen in RIGHT sided colon cancer?
- Abdominal pain
- Occult bleeding
- Mass in RIF
What symptoms are specifically seen in LEFT sided colon cancer?
- Rectal bleeding
- Change in bowel habit or tenesmus
- Mass in LIF/mass on PR
What are the NICE guidelines on urgent referral for suspected colon cancer?
- ≥40yrs with unexplained weight loss + abdominal pain
- ≥50yrs with unexplained rectal bleeding
- ≥60yrs with iron deficiency anaemia/changes to bowel habit
- +ve faecal occult blood test
What are the main DDx to consider for colorectal cancer?
- IBD
- Haemorrhoids
- Diverticulitis
What is the screening programme in the UK for colorectal cancer?
Every 2 years to people 60-75yrs –> FOB home testing (3 samples)
If any +ve then requires colonoscopy
What may be seen on the FBC for colorectal cancer?
Microcytic anaemia (especially right sided)
What is the tumour marker for colorectal cancer? What is it used for?
Carcinoembryonic antigen (CEA) --> Monitor disease progression
What is the gold standard diagnostic investigation for colorectal cancer?
Colonoscopy with biopsy
What investigations are required for staging of colorectal cancer?
- CT chest/abdo/pelvis
- MRI rectum (rectal cancers)
- Endo-anal USS
What staging system was used for colorectal cancer?
Duke’s staging
What is the curative management for colorectal cancer?
Surgery - regional colectomy followed by either primary anastomosis or formation of a stoma
When is radiotherapy used in colorectal cancer? Why not in other cases?
Rectal cancer
Not in colon due to risk of damage to the small bowel
What palliative care can be given to patients with colorectal cancer?
- Endoluminal stenting –> acute large bowel obstruction
- Stoma formation –> acute obstruction
- Resection of secondaries
Briefly outline Duke’s staging criteria
A - Confined beneath muscular propria
B - Extension through the muscular propria
C - Involvement of regional lymph nodes
D - distant metastasis
