Colorectal Surgery Flashcards
Pathophysiology of Acute Apendicitis?
Luminal Obstruction (due to lymphoid hyperplasia or fecolith, more rarely stricture, tumor or parasite)
=> INC Luminal pressure and Reduced lymphatic/venous drainage
=> Necrosis of appendix w/ venous congestion
=> Bacterial proliferation due to stasis/ischemia
=> invasion to the submucosa and muscularis propria, causing acute appendicitis
=> Further ischemia can lead to a gangrenous appendix and bacterial spread to the serosa, and in cases of perforation spread to the peritoneal cavity=> peri-appendiceal abscess
Presentation of Acute Apendicitis
- Classical history is Colicky Periumbilical Pain (‘midgut’) which migrates to and becomes localized in the RIF (worsened by coughing/movement)
- Nausea and anorexia are common
- low grade fever (usually 37.5-38) and slight tachycardia. High temperatures are more typical of perforated appendicitis
- Urinary symptoms sometimes if appendix is sitting on the bladder (Urinealysis will show leucocytes but NO NITRATES in keeping with ‘steile pyruria’)
Risk Factors for Acute appendicitis?
Clinical Signs of Acute Appendicitis
- What is the point of maximum tenderness/Where is it Located?
- Other Signs and how they’re Illicited?
- On palpation of the abdomen, McBurney’s point is classically the point of maximal tenderness, with associated guarding and rebound tenderness (1/3 along a line drawn from the Anterior Superior Iliac Spine (ASIS) to the umbilicus)
- A retrocaecal appendix may have relatively few abdominal signs
Scoring System for Acute Pancreatitis?
Alvarado Score for Acute Appendicitis (MANTRELS)
- Migratory abdominal pain (1)
- Anorexia (1)
- Nausea (1)
- Tender right lower quadrant (2)
- Rebound pain (1)
- Elevated temperature (1)
- Leucocytosis (2)
- Shift in WCC to the left (1)
Differential Diagnoses for Acute Apendacitis?
Complications of Acute Appendicitis?
- Perforation w/ local peritonitis
- Perforation w/ diffuse peritonitis
- Septic Shock
- Appendiceal Mass
- Appendiceal Abscess
Investigations for Acute Appendicitis?
- Bloods
- Radiology (Demographics?)
Indications for conservative management of acute appendicitis?
Peri-apendiceal or phlemonous mass
- non-operative management w/ aim of cooling inflammation is first step as surgery carries an increased risk at this time
- Younger patients (<40 years) with an appendiceal mass, an observation period of 6 months should be undertaken. If the patient has recurrent symptoms in this time, an interval appendicectomy should be offered.
- Patients over 40 years with a conservatively managed appendiceal mass have a higher likelihood of underlying malignant pathology and a much lower threshold for offering interval appendicectomy should be utilized. Shoul receive a colonoscopy 6 weeks following event to ruleout malignancy
Uncomplicated appendicitis
- Confirmed by CT
- Comparable alternative, though high rate of recurrence
30% of patients treated conservatively for acute uncomplicated appendicitis will require an appendicectomy for recurrence within the first year
Surgical management of acute appendicitis?
Consenting laparoscopic appendicectomy
- General Risks
- Specific Risks
- post-operative care/follow-up
General
- bleeding
- surgical site infection
- post-operative pain
- venous thromboembolism
- respiratory infection
- anaesthetic risks
Specific
- conversion to an open procedure
- pelvic/intraabdominal abscess (up to 10%)
- damage to surrounding structures
- leak from appendiceal stump
- stump appendicitis
- possibility of the need for more extensive resection
- possibility of a normal appendix o histology
Most common sites for Diverticular disease/Diverticulosis?
Pathogenesis?
The insertion points of the vessels supplying the colon, vasa recta, are common sites for diverticula.
Diverticula most commonly occur in the sigmoid colon. The increased pressure theory is that because of a low fibre diet there is increased intraluminal pressure over time and this leads to building of mucosa and submucosa the site of weaknesses in the wall of the colon between the taenia coli where the vasa recta penetrate.
True vs. False Diverticula?
True diverticula involve all layers of the muscle wall e.g. Meckel’s Diverticulum.
False diverticula do not involve all layers (submucosa and mucosa only) e.g. colonic diverticula
Uncomplicated vs. Complicated Diverticulitis?
Uncomplicated: Simple inflammation of the diverticular segment.
Complicated: Associated abscess, perforation, peritonitis, stricturing, fistulae or haemorrhage.
Complications of Diverticulosis?
- Diverticulitis
- Diverticular bleeding
- Diverticular fistula (most commonly a colovesical or colovaginal fistula)
- Faecal peritonitis
- Diverticular abscess
- Diverticular stricture (causing large bowel obstruction)
Classification of Diverticulitis?
Hinchey 1a: Paracolonic inflammation, no abscess
Hinchey 1b: Paracolonic abscess <4cm
Hinchey 2: Pelvic abscess, interloop abscess, para-colonic abscess >4cm
Hinchey 3: Purulent peritonitis (four-quadrant pus)
Hinchey 4: Faeculent peritonitis (four quadrant feces)
Epidemiological/Genetic Factors contributing to Diverticulosis
The majority of diverticulosis is left-sided involving the sigmoid colon in the Western World, whereas right-sided diverticulosis is more common in Asian populations suggesting some genetic component.
Connective tissue disease (Marfan’s syndrome, Ehler-Danlos syndrome) also increases the risk.
10% of patients aged>40 years and over 50% of people >80 will have colonic diverticula, but a much smaller proportion (2-25%)will develop symptoms
Diverticulitis History/Exam
Diverticular Abscess History/Exam
Diverticular Stricture History/Exam
Diverticular Bleed History/Exam
Diverticular Fistula History/Exam
Investigations for Diverticulitis?
Management of Acute uncomplicated diverticulitis?
Management of Diverticular Abscess
Management of Diverticular Stricture
Management of Diverticular Bleed?
Management of Diverticular Fistula
Management of Diverticular Perforation?
Hartmann’s procedure: Emergency resection of the sigmoid colon with formation of an end colostomy and leaving the stapled off rectal stump in the abdominal cavity
Risk Factors for Colorectal Cancer
- Age >50
- Family History
- Genetic Condition (FAP, HNPCC)
- Adenomatous Polyps
- Inflammatory Bowel Disease
- Previous Colorectal Cancer
- Obsesity
- Diet high in fat/red meat
Bowel Cancer Screening Guidelines
Clinical Features of Colorectal Cancer
- Presentation
- Examination
Investigations for Colorectal Cancer?
Alternatives to Colonoscopy?
Staging Investigations for Colorectal Cancer?
Standard staging for distant metastases in colon and rectal cancer is a CT TAP
In rectal cancer, an MRI of the rectum is needed for local staging
If CT Abnormallities=> MRI of the liver or a PET scan to further evaluate for metastatic disease
Colorectal Cancer Staging System and Survival Rates
Management of Colon Cancer?
- Surgical
- Adjuvant Chemo Options?
Management of Rectal Cancer?
Rectal cancer management depends on how close the tumour is to the resection margin(CRM)
Rectal cancer surgery involves a total mesorectal excision, taking the entire envelope the rectum is enclosed in, as this results in an oncological lymph node excision.
T1/T2: Upfront surgery w/o neoadjuvant chemoradiotherapy
T3 w/ threated CRM + T4 are offered neoadjuvant (prior to survey) chemoradiotherapy
Management of Emergency Obstructing Colonic Tumor?
Type of Surgical Resection/Anastamosis for Cancer in the Caecum and Ascending Colon
Right Hemicolectomy
Ileocolic
Type of Surgical Resection/Anastamosis for Cancer in the Transverse Colon
Extended Right Hemicolectomy
Ileocolic
Type of Surgical Resection/Anastamosis for Cancer in the Splenic Flexure
Extended Right Hemicolectomy OR Left Hemicolectomy
Ileocolic OR colo-colon
Type of Surgical Resection/Anastamosis for Cancer in the Descending Colon
Left Hemicolectomy
Colo-colon
Type of Surgical Resection/Anastamosis for Cancer in the Sigmoid Colon
High anterior resection
Colorectal
Type of Surgical Resection/Anastamosis for Cancer in the Upper Rectum
Anterior resection with total mesorectal excision
Colorectal
Type of Surgical Resection/Anastamosis for Cancer in the Lower Rectum
Low anterior resection with total mesorectal excision and defunctioning ileostomy
Colorectal
Type of Surgical Resection/Anastamosis for Cancer involving the Anal Verge
Abdomino-peroneal excision of the rectum +/- colon
Anal canal excised and sewn closed
Follow-up after colorectal cancer
CT thorax/abdomen/pelvis every year for 5 years
Colonoscopy at year 1 and year 4
CEA 6-monthly during the surveillance window
Define Bowel Obstruction
Mechanical/functional obstruction of the GI tract inhibiting normal transit of enteric contents. May be a partial or complete obstruction. Can be acute or subacute
Simple Obstruction: One obstruction point & no vascular compromise.
Define Ileus
Disruption to normal gut motility due to a malfunction of peristalsis in the absence of a mechanical obstruction.
A common post-operative complication
Define a Closed Loop Obstruction
Bowel obstruction at two points, can result in ischaemia, necrosis or bowel perforation. Surgical emergency requiring urgent diagnosis and surgical intervention.
Define a Strangulated Bowel
Signs of it?
Bloods?
Bowel obstruction with compromised blood supply and abdominal tenderness as a common sign
Systemic features of toxicity such as pyrexia
Blood indices including elevated inflammatory markers and lactate.
Causes of Small Bowel Obstruction
The majority are adhesional or secondary to a hernia
Other causes include:
- bowel strictures
- Meckel’s diverticulum
- bowel intussusception
- malignancy
Causes of Large Bowel Obstruction
Colorectal neoplasia is most common.
Other causes include:
- diverticular stricture (narrowing)
- volvulus (twisting)
- hernias
- strictures related to inflammatory bowel disease such as Crohn’s Disease
Non-Mechanical Causes of Bowel Obstruction
- Post-operative
- Peritonitis
- Drugs (opioids/antimuscarinics)
- Hypokalaemia
- Hyponatraemia
- Hypomagnesaemia
Mechanical Causes of Bowel Obstruction
Intraluminal:
- Impacted stool
- foreign body
- gallstones
Mural:
- Benign stricture
- neoplasia
- atresia (passage is closed or absent)
- ileus (lack of movement)
- intussusception.
Extramural:
- Hernia
- adhesions
- volvulus
- extrinsic compression.
Types of Vomit Expected in Bowel Obstruction
o Early in high obstruction
o Bilious contents if high obstruction
o Faeculent in distal obstructions
Signs of Bowel Obstruction
Investigations for Bowel Obstruction
3, 6, 9 Rule of Bowel Obstructions?
Management of Bowel Obstruction
Indications for Surgery?
Paralytic Ileus
- Causes
- Prevention
- Management
Ogilvie’s Syndrome
- Cause
- Investigations
- Management
Definition and Etiology of Hemorrhoids
Above vs. Bellow Dentate Line?
Classification of Hemorrhoids
Causes of Hemorrhoids?
1°: Constipation w/ prolonged straining of hard stool (Poor dietary habits, decreased fiber intake, decreased fluid intake.)
2°: Pregnancy and other causes of raised intraabdominal pressure
Signs/Symptoms of Hemorrhoids?
Management of Hemorrhids?
- Conservative
- Medical
- Proctoscopy
- Surgical (indications)
Classification of Anal Fistula
Anterior vs. Posterior Anal Fistula?
Investigations for Anal Fistula
Surgical Management of Anal FIstula
Anal Fissure
- Pathophysiology
- Etiology
- Symptoms
- Signs
- Investigations
- Management (Conservative/Medical/Surgical)
Risk Factors for Anal Carcinoma
Arterial/Venous/Lymph Drainage of Anal Canal Above/Bellow Dentate Line
Above
- superior rectal artery/veins (→ hepatic portal system).
- lumbar (paraaortic) lymph nodes.
Below
- middle and inferior rectal veins/arteries (→body circulation).
- inguinal lymph nodes.
- pudendal nerve is responsible for the sensory innervation.
