Lower GI Flashcards
Describe the differentials for acute lower abdominal pain
GI:
- Appendicitis
- Intestinal ischaemia
- Diverticulitis
- Bowel obstruction, strangulated hernia
- Mesenteric adenitis (kids)
- Meckel’s diverticulitis
Urological:
- Renal colic
- Pyelonephritis
Gynae:
- PID
- Ectopic pregnancy
- Cyst accident: rupture, torsion
Describe the epidemiology of appendicitis
Very common (12%) Any age
Describe the presentation of appendicitis
- Acute abdo pain: constant, increasing, umbilical->RIF
- N+V, anorexia
- Fever
- Retrocaecal appendix may cause back/flank pain
Describe the signs of appendicitis on examination
-General: tachycardia, fever, sweating
-Abdo: RIF tenderness (McBurney’s sign), Rovsing’s sign (press on LIF), Psoas sign (flexed right hip), Obturator sign
+/- peritonitis if perf, sepsis, mass if abscess
Describe the investigations for acute appendicitis
- History and examination
- Bloods: FBC, CRP, U+Es, amylase/lipase, VBG, culture if indicated
- Usually no need for further Ix. Imaging if unclear/>40: USS, CT/MRI
Describe the management of acute appendicitis
- Make NBM, give analgesia, IV fluids, and IV Abx
- Contact senior + surgeons
- Laparoscopic appendicectomy +/-postop Abx
Describe the complications of appendicitis
- Gangrenous appendix +/- perforation
- Abscess
- Phlegmon
Describe the postop care for appendicectomy
- Admission usually until 1 day postop (longer if complicated), until E+D and infection settled
- Need about 1 week off work/school
- Avoid heavy lifting/manual labour/contact sports 1 month
- No OP followup needed
Describe the risks of appendicectomy
- Removal of normal appendix (1/5 no appendicitis)
- Surgical: pain, bruising, wound infection, damage to other organs, intra-abdominal abscess, DVT
- Anaesthetic: N+V, headache, muscle soreness, allergy/anaphylaxis, cardiac arrest, etc
Describe the types of intestinal ischaemia
1) Acute mesenteric ischaemia: affects SMA branches (SB mostly). Not very common
2) Chronic mesenteric ischaemia (intestinal angina)
3) Ischaemic colitis: most common. Affects IMA branches (LB)
Describe the epidemiology of intestinal ischaemia
- Vasculopaths eg. AF, hypercoagulable state, smoking, HTN, DM
- Older adults
Describe the aetiology of intestinal ischaemia
AMI:
- Arterial compromise: embolism (50%, assoc w AF), thrombosis (20%), vasculitis
- Venous compromise: thrombosis (5%)- hypercoagulable states
- Hypoperfusion (20%): shock, surgery/trauma
CMI: atherosclerosis mostly
Ischaemic colitis: usually hypoperfusion
Describe the blood supply to the GI tract
Foregut: coeliac artery- common hepatic, splenic, left gastric arteries
Midgut: SMA- middle colic, right colic, ileocolic arteries
Hindgut: IMA- left colic, sigmoid, superior rectal arteries
Describe the divisions of the GI tract
Foregut: mouth to the 2nd part of the duodenum
Midgut: 2nd part of the duodenum up to 2/3 of the transverse colon
Hindgut: the distal 1/3 of the transverse colon to the anus
Describe the presentation of intestinal ischaemia
- Ischaemic colitis: mild/mod abdo pain felt laterally, faecal urgency, bloody diarrhoea
- AMI: severe acute abdominal pain, peri-umbilical and worsening. *Out of proportion to examination/obs. N+V, anorexia. +/- bloody diarrhoea
- CMI: insidious onset. 1) episodes of colicky central postprandial abdo pain 2) Weight loss 3) Abdo bruit
What is the classic description of acute mesenteric ischaemia?
Severe abdominal pain out of proportion to clinical findings (eg. no tenderness, no systemic changes)
Describe the investigations for intestinal ischaemia
- History and examination
- Urine dip
- Bloods: FBC, CRP, U+Es, VBG, clotting, LFTs
- Urgent contrast CT -> CTA
After Dx:
- ECG (check AF)
- Bloods: lipids, HbA1c (look for modifiable RFs)
Describe the signs of intestinal ischaemia on CT
- Bowel wall thickening
- Luminal dilatation
- Gas in the bowel wall
- Thumbprinting (oedema)
Describe the management of acute mesenteric ischaemia
- Make NBM, analgesia (opioid), IV fluids and IV Abx
- Consider blood transfusion
- Senior + surgeons
- Consider endovascular treatment (stenting, thrombectomy) or surgical Mx (laparotomy + resection of infarcted/necrotic bowel)
Describe the management of chronic mesenteric ischaemia
Conservative:
-Lifestyle modifications: weight loss, diet, smoking, exercise
Medical:
-RF modification eg. HTN, glycaemic control, statin
Surgical/interventional: revascularisation
- Mesenteric bypass
- Angioplasty
Describe the management of ischaemic colitis
Can usually be managed conservatively unless complications/severe ischaemia
Conservative:
-Supportive: analgesia, bowel rest, IV fluids
Medical:
-IV Abx, IV fluids and prophylactic LMWH
Surgical/interventional:
-Resection and stoma formation if complicated
Describe the complications of intestinal ischaemia
Strictures
Fear of food
Surgical complications: short bowel syndrome, high output stoma, etc
Describe the signs of peritonitis
- Generalised abdominal tenderness
- Guarding, rigidity
- Rebound + percussion tenderness
- Absent bowel sounds
What causes peritonitis?
SBP 2˚ causes: -Perforation eg. BO, appendix, ulcer, diverticulum -Peritoneal dialysis -Pancreatitis -Trauma eg. surgical wound -PID
Describe the epidemiology of bowel obstruction
Common cause of emergency surgery
SBO: more common in previous surgeries + Crohn’s
LBO: less common than SBO.
Describe the aetiology of bowel obstruction
Can be: outside bowel wall (adhesions, hernias), within the wall (malignancy), within the lumen
SBO: adhesions (50-80%), strangulated hernia (20%), Crohn’s, malignancy
LBO: malignancy! Diverticular strictures, volvulus
Describe the pathophysiology of bowel obstruction
Mechanical obstruction -> reduced blood flow
->ischaemia -> necrosis -> perforation
+ transudate into luman -> dehydration + electrolyte imbalance
Describe the presentation of bowel obstruction
- Absolute constipation
- Acute abdominal pain: diffuse, colicky, worsening
- *Constant pain may indicate ischaemia
- Vomiting (occurs earlier in SBO, bad sign in LBO)
- Abdominal distension
- *LBO: possible Hx suggestive of malignancy
Describe the investigations for bowel obstruction
- History and examination (including DRE)
- Urine: dip, UPT, MCS
- Blood: FBC, CRP, U+Es, VBG (for acidosis and lactate), culture (if febrile), lipase/amylase, glucose, clotting
- Imaging: urgent CT (best), AXR (not as good)
Describe the initial management of bowel obstruction (acute)
A to E as needed Call senior Make NBM IV access and bloods, fluid resus Analgesia NG tube decompression if SB distension/vomiting Call surgeons
Describe the management of bowel obstruction (eg treatment)
Conservative (simple adhesional SBO):
-Drip and suck for max 72 hours
Surgical (non-adhesional SBO, complicated SBO, any LBO):
-Exploratory laparoscopy w/ resection + stoma formation
What are the differences between ischaemic colitis and acute mesenteric ischaemia?
IC: affects large bowel (IMA), usually more mild/mod pain, bloody diarrhoea
AMI: affects small bowel (SMA), severe pain with no clinical signs initially
Where is the most common site of rupture in LBO?
Caecum
Where is the most common site of volvulus?
Sigmoid (75%)
Caecum
Describe the signs of bowel obstruction on examination
General: tachypnoea, tachycardia, pyrexia, hypotension
Abdo distension
Diffuse tenderness +/- caecal tenderness (imminent perf)
Hyperactive bowel sounds
-Peritonitis: rigidity and guarding, rebound tenderness, absent bowel sounds
-Hernia
Define volvulus
Twisting of a loop of bowel on its mesentery
Define bowel obstruction
Mechanical blockage of the bowel, preventing flow of contents
Describe the presentation of volvulus on imaging
Classically on AXR:
- Coffee bean sign: sigmoid volvulus
- Embryo sign: caecal volvulus
CT: whirl sign
Describe the pathophysiology of volvulus
Sigmoid:
Chronic constipation -> chronic faecal loading
-> extension of sigmoid colon -> ^ risk of torsion
Torsion -> impaired blood flow -> ischaemic/necrosis
-> bowel obstruction
Describe the management of volvulus
Initial:
-Fluid resus, analgesia, IV Abx and NGT if indicated
Medical:
-Endoscopic decompression, detorsion -> place soft rectal tube -> 72 hours do surgery
Surgical: if perf/ischaemia
- HD unstable: Hartmann’s
- HD stable: sigmoid colectomy + 1˚ anastomosis
Describe the imaging findings of bowel obstruction and how to distinguish SBO and LBO
Dilated bowel loops (3, 6, 9 cm- SB, LBO, caecum)
Rigler’s sign (can see both sides of bowel wall) in pneumoperitoneum, string of pearls sign, air fluid level
SBO: presence of valvulae conniventes (fully cross bowel)
LBO: presence of haustra (not fully cross)
Describe the aetiology of GI perforation
Infection: appendicitis, diverticulitis Obstruction Ischaemia: AMI, ischaemic colitis Ulceration Trauma
Describe the presentation of GI perforation
BG of cause eg. obstruction, appendicitis
- > acutely worsening pain, becomes constant + severe
- > sepsis/HD unstable
Describe management of GI perforation
Initial: A to E Make NBM IV access and bloods, IV fluid resus, IV BS ABx, analgesia Call surgeons
Emergency surgery- laparoscopy/laparotomy
Describe the epidemiology/RF of rectal prolapse
Occurs in children + elderly
Assoc w multiple pregnancies, obesity, chronic straining/cough
Describe the presentation of rectal prolapse
Painless rectal mass
Incontinence or constipation
Tenesmus, pruritus
Describe the signs of rectal prolapse on examination
Bright pink lump at the anus
+/- bleeding
May be reducible
May have concentric rings (full thickness prolapse)
In F: may also have vaginal/uterine prolapse
Describe the management of rectal prolapse
Conservative: if v frail, mild prolapse
-Lifestyle: reduction, weight loss, increase fibre + hydration
Medical:
-Sclerotherapy
Surgical: definitive
- Laparoscopic rectopexy
- Perineal procedures eg. Delorme/Altemeier procedure
Describe the causes of PR bleeding
- Infection/inflammation: acute diverticulitis, IBD, dysentery
- Malignancy: colorectal cancer
- Vascular: intestinal ischaemia, haemorrhoids
- Trauma eg. fissure, foreign body, colonoscopy
Describe the presentation of colorectal cancer
- PR bleeding
- Change in bowel habits
- Tenesmus
- Pain (abdo, on defaecation)
- Systemic symptoms: weight loss, fever, sweats
Describe the assessment of PR bleeding
-History and examination (abdo and PR)
-Bloods: FBC, CRP, U+Es, LFTs, clotting, CEA
-Imaging: flexi sig -> colonoscopy
+ additional if Dx of cancer eg. CT AP, CXR, USS liver
Describe the 2WW referral criteria for suspected colorectal malignancy
Always refer:
>40 : unexplained weight loss + abdo pain
> 50: unexplained rectal bleeding
> 60: unexplained Fe deficiency anaemia OR change in bowels
Anyone with positive FIIT test
-Consider for anyone <50 with rectal bleeding + other factors eg. weight loss, pain, change in bowels, anaemia
Describe the epidemiology and risk factors for colorectal cancer
Epidemiology: Western countries, M > F, very common
RFs:
-Non-modifiable: M, older age, genetics, IBD
-Modifiable: diet, obesity, smoking
Describe the staging of colorectal cancer
Duke’s + TNM
Duke’s: A (confined to wall), B (spread through bowel wall), C (spread to LNs), D (mets)
Describe the management of colorectal cancer
Medical + surgical
Medical: adjuvant/neoadjuvant chemo/radio
Surgical: for all early stage
-Resection. Type depends on lymphatic drainage (follows arterial supply)
Describe the screening for colorectal cancer
Every adult 60-75 in the UK is sent FIT test in the mail every 2 years (also done at 56 years)
+ FIT -> colonoscopy
Increased screening for higher risk groups with colonoscopy, frequency depends on risk group
- Most IBD: after 8-10 from Dx and possibly 3-5 yearly
- UC + PSC: yearly
Describe some familial syndromes associated with colorectal cancer
FAP: APC gene mutation. Many many polyps, will eventually go on to have cancer -> prophylactic colectomy before 20 years
Lynch syndrome/ HNPCC: ^ risk of breast/uterine etc
Peutz-Jegher syndrome: buccal freckles, GI hamartomas
