Editing Lower GI bleeding

Bleeding originating distal to the ligament of Treitz

* Often colloquially used to     mean colonic bleeding

== '''Aetiology''' (40% have two potential lesions) ==

=== '''Colonic     (95%)''' ===

** '''Anatomic      (painless, large-volume)'''
*** '''Diverticulosis       (30-40%)'''
**** As the dome of the        diverticulum forms, the vessel entering at that point becomes stretched        and can rupture
**** Bleeding usually occurs in        the absence of diverticulitis
**** Right colon is the source        of bleeding in >50% of patients (usual demographics)
**** Resolves spontaneously in        80% overall and 98.5% of those receiving <4 units pRBC per day. 10%        will rebleed within a year and nearly 50% within 10 years.
**** Intervention generally        considered necessary if >6U pRBC per day
***** IR - 85% success rate,         low rate of re-bleeding
***** Colonoscopy
****** Treat          if there are stigmata of recent haemorrhage - visualised bleeding,          exposed blood vessel, adherent clots
****** Dual          modality: can use adrenaline, coagulation, APC, and fibrin glue
****** Clipping          safer than bipolar (risk of perf), and also marks area
****** Tattoo          area?
***** OT (last resort)
**** Up to a third recur within        a year
*** '''Aorto-enteric       fistula'''
**** Suspect if previous aortic        surgery
** '''Vascular      (painless, large-volume)'''
*** '''Angiodysplasia       aka AVM/angiectasias/vascular ectasia (3%)'''
**** Acquired degenerative        lesions secondary to progressive dilatation of normal submucosal blood        vessels due to venous obstruction - distinct from true congenital AVMs
**** Can occur anywhere in the        GIT, but most commonly caecum
**** Painless/mild cramping.        Episodic venous bleeding. Increased prevalence in elderly. Often right        colonic/caecal.
**** 90% resolve spontaneously        - but can recur
**** Associated with aortic        stenosis, CCF, end-stage CKD, von Willebrand's disease, left        ventricular assist devices
**** Colonoscopy
***** APC is best, but can also         be treated with bipolar electrocoagulation or heater probe
***** Incidentally-discovered         lesions do not require any further treatment
**** IR 50% success rate
**** Thalidomide and octreotide        have demonstrated efficacy in treating chronic angiodysplastic bleeding
** '''Colitis/proctitis''' - most often associated      with pain and diarrhoea
*** '''IBD (3-4%)'''
**** Mostly UC
**** Bleeding almost always        from diffuse colitis with no discrete lesions amenable to treatment
**** Exclude infection as cause        of bleeding
**** Crohn disease can        sometimes produce discrete ulcers that have eroded into a vessel,        giving a good target for embolization
**** Very rare for major        bleeding to be the initial presentation of either Crohns or UC.
**** Schein recommends total        colectomy for major bleeding, as it signifies a failure of medical        management.
*** '''Infectious       (3-8%)''' -       separate topic
**** Especially CMV and C. diff
*** '''Radiation-induced       (1-3%)''' -       separate topic
*** '''Ischaemia       (5-10%)''' -       separate topic
** '''Neoplastic      (5-10%)'''
*** Responsible for 10% of       lower GI bleeding in pts >50
*** Bleeding tends to be minor       and sporadic
*** Iron deficiency anaemia
*** GISTs in particular can       erode into blood vessels
*** Resect colonic cancers if       causing massive bleeding
*** Rectal cancers: attempt to       avoid acute resection, which would be difficult and also spoil       neoadjuvant therapy. Reasonable to attempt endoscopic first. Then pack       the rectum with adrenaline-soaked gauze, which often works. Can then try       a few other things in OT via a trans-anal approach if possible. If all       else fails, have to resect and accept compromised oncologic outcomes.       Chronic bleeding can sometimes be treated with RTx.
** '''Miscellaneous      anorectal disorders (5-15%)'''
*** '''Haemorrhoids''' - most common cause in       young patients
**** External - painful,        sporadic, low-volume bleeds with red blood coating stool
**** Internal - painless        sporadic, low-volume bleeds with red blood coating stool
*** '''Anal       fissure'''
**** Tearing pain and bleeding        with defaecation
*** Temporise with a big Foley       catheter inflated in the rectal vault then tractioned against the anus
*** If operating, prone       jack-knife may be better - blood falls away and is easier to suction       clear
** '''Iatrogenic'''
*** '''Post-polypectomy       (3-7%)'''
**** Can usually be treated        endoscopically
*** '''Anastomotic'''
** '''Other/unknown      (11-30%)'''

=== '''Small bowel     (5%)''' ===

** '''Angiodysplasias'''
** '''Erosions or      ulcers'''
** '''Crohn      disease'''
** '''Radiation -'''      see separate      topic
** '''Meckel      diverticulum''' -      separate topic
** '''Neoplasia'''
** '''Aortoenteric      fistula'''

== '''Special populations''' ==

* HIV +
** CMV or lymphoma
* Elderly
** Diverticulosis or vascular      lesions
* Young adults
** Haemorrhoids/fissure
** Meckel
* Children
** Fissure or gastroenteritis      or intussusception

== '''Presentation''' ==

* >90% of melaena originates     from proximal to ligament of Treitz, although it can come from small bowel     or even colon
* Tends to be less severe and     intermittent compared to UGIB
* Right colon bleeding - often     dark red, mixed with stool, occasionally melaena
* Left colon - often bright red
* Haematochezia - bright red     blood, clots, or burgundy stools
* Abdominal pain, diarrhoea and     bleeding: colitis
* Minor LGIB:
** Anorectal lesions, IBD,      infectious colitis, AVM, polyps, malignancy
** Can generally be managed as      outpatients
* Major LGIB:
** Haemodynamic instability,      altered mental status, or need for transfusion
* Massive LGIB:
** MTP

== '''Principles of management''' ==

* Resuscitation as per UGIB     topic
** Can continue aspirin if      strong indication, but stop other anticoagulants
* Indications for admission:
** Can use Oakland score      (MDCalc) to predict risk of discharging from ED
* Anatomic localisation to     either likely UGIB or LGIB, as per UGIB topic
* Compile patient-specific     differential list using demographics, history and examination
** Need to rule out anorectal      causes
* Imaging/endoscopy if     indicated
** Admission CT angio if      suspected active haemodynamically significant bleeding. Generally DO have      time to scan them.
** Admission CT PV if suspected      colitis
** Unstable - angioembolization
** Stable but still bleeding -      prep for colonoscopy ('rapid prep' or no prep, but some PEG is better      than nothing if they are stable, and it is safe in bleeding patients)
*** Especially useful with       suspected diverticular, angioectasia and post-polypectomy bleeds
** Stable and not bleeding -      home with outpatient colonoscopy
** Still bleeding and      imaging/scope options exhausted - manage as per obscure bleeding under      UGIB topic


== '''Investigations''' ==

* Note that initial Hb is often     at baseline as patient is losing whole blood - becomes more diluted over     about 24h
* FBE/UEC/LFT/COAG/G+H + other     tests of clotting function depending on anticoagulant
* Check for microcytosis     suggestive of chronic bleed
* Scans
** Nuclear scintigraphy with      technetium-99m-labelled RBCs: 0.04-0.1mL/min, can also detect      intermittent bleeds. However the actual LOCALISATION is sometimes poor,      so it shouldn't be used as a guide for resection target. Only gives      positive result in 39-45% LGIB.
** CT angio: 0.3-0.5mL/min in      reliable sources, although the range is wider than that and probably      depends on the scanner and how well-timed they are with the phases
* Endoscopy - start off with     gas and colon, then consider targeting small bowel
** Likely to be a hard scope -      get the most experienced colonoscopist around, and/or the person that did      the original procedure, if there was one
** Bleeding from anus/lower      rectum will reflux to at least the rectosigmoid junction
** Preferably have all      haemostasis gadgets available including APC
** ScopeGuide might help
** Don't really need to prep -      see above
** Bleeding from a previous      polypectomy site - clips if sessile, EndoLoop if pedunculated
** Anastomotic bleeding - clips      or adrenaline
** Diverticular bleed - attempt      to clip the vessel, if not possible, adrenaline
** Angiodysplasia - APC or      (second preference) adrenaline
** Consider tattooing the bowel      distal to the bleeding point, and clip locally for marking

== '''Angioembolisation''' ==

* Observe for 3 days afterwards
* Success rates
** Diverticular bleed 75-100%
** Angiodysplasia 50% - not as      good
* Complications
** Femoral access site      pseudo-aneurysm
** Colon ischaemia
*** 3% of patients get       ischaemia requiring intervention
*** Mostly mild - treat       conservatively, monitor closely
** AKI

== '''Surgery''' ==

* Indications
** Failure of endoscopic and      radiologic options
** 4-6 units blood within 24      hours, or 10 units in an admission
** Continued bleeding after 72      hours
* Operation
** If not localised, need to do      total colectomy and end ileostomy (20-30% mortality)
*** Ileorectal anastomosis will       leak
** If localised, can do      segmental resection
*** Bad idea to guess the       segment - don't do it
*** Left side from       diverticulosis: resect the bleeding site and then as far as upper       rectum. Choose between Hartmann's and anastomosis.
*** Right side: RHC
*** Transverse: Extended RHC
** Lithotomy, and repeat the      proctoscopy/sigmoidoscopy at the start, just in case. Midline laparotomy.      Evaluate all small and large bowel for external localising features.      Could do an on-table enteroscopy if small bowel seems to have blood.

== '''Prognosis:''' ==

* Bleeding stops spontaneously     in 85% of patients
* Mortality 2% (5% in >85yo)



[[Category:Colorectal]]
[[Category:Intern education]]