Diverticular Disease

DEFINITION
Common outpouchings of the inner lining of the colon, associated with several possible complications notably bleeding, infection, perforation, stricture and fistula.

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EPIDEMIOLOGY

50% by 50
80% by 80
diet related

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AETIOLOGY

Herniation of mucosa through wall
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BIOLOGICAL BEHAVIOUR

Pathophysiology

Hypertrophied sigmoid SM is probably the primary pathology.
- to rectosigmoid jx but not past.
High sigmoid pressure results
--> herniation of mucosa where blood vessels pass.
Fat creeps up the bowel wall, becomes inflamed, forms a phlegmon or abscess, and heals with fibrosis.
--> often diverticulitis is more a 'sigmoiditis', with inflammation in and around the bowel wall and adjacent mesenteric fat.
May perforate, with or without fecolith impaction of a diverticulum
--> often walled off by omentum / mesentery.
--> may secondarily perf, causing pus contamination in abdomen.

Complications
Bleeding
Diverticulitis / abscess / perforation
Stricture
Fistulation
- unclear why, commonly thought to be a sequelae of an abscess but that is not often found in association.

R-sided Tics
Tend to be Asians, younger mimics appendicitis.
Conservative Rx with Abs.

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MANIFESTATIONS

Classify.
1. Uncomplicated phlegmonous diverticulitis
2. Pericolic abscess
3. Free perf with purulant peritonitis
4. Free perf with fecal peritonitis.

Phlegmonous diverticulitis
LIF pain, peritonism and sepsis
Systemic inflammation with fever.

Hinchey
I abscess
II distant or pelvic abscess
III generalized purulent peritonitis
IV feculant peritonitis; communicates with bowel

Fistulae
Pneumaturia, fecaluria, utis / vaginal infxs, vaginal fecal or flatus discharge
- need endoscopic evaluation to rule out tumours

Haemorrhage
Risk factors:
- hypertension, atherosclerosis
- NSAIDs
80-90% bleeds self-limiting and stop with bowel rest.
Bleeding point can be identified with colonoscopy in ~75%

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INVESTIGATIONS

Imaging
note CT can be negative in mild diverticulitis.

Colonoscopy
Must be done to confirm the diagnosis

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MANAGEMENT

Phlegmonous Uncomplicated Divertic
Traditionally: NBM, IVF, ABs.
- but the colon contains feces anyway so it is irrational.
Feed them if no ileus. Or at least give fluids.
Oral agents are probably fine.
Mild acute diverticulitis can be managed with oral antibiotics on an outpatient basis.
The necessity of antibiotics is questionable and has not been validated by RCTs, which show no benefit.
- this needs to be confirmed by further RCTs before it can be advised.
But patients who come to hospital are probably at the more severe end of the scale

Complicated
Not settling after a couple of days --> time for a CT.

Peritonitis and Sick
Easy decision: operate
Hinchey III,IV = Hartmann's
Laparoscopic washout and conservative Rx for Hinchey III is controversial; good in initial trials, not currently sufficiently established to be routine or generally advisable.
- if can get away with it, probably needn't have operated.

Severe Attack and Stable & Abscesses
Continued conservative Rx under close observation.
Even free air, leak of contrast or abscess: not in themselves indications for surgery if pt clinically stable.
Hinchey I & II:
Abscesses <5cm will usually settle conservatively.
Abscesses >5cm usually need drainage.
- Some surgeons then offer elective resection but controversial; non-op therapy associated with low complication rates.
- Probably higher recurrence in Hinchey II
Contraindications to perc drainage:
- poor access route
- Hinchey III,IV

Operative
Sigmoidectomy
Low midline.
Note sigmoid may be stuck, densely adherent and difficult to work with.
- to help differentiate from cancer: inflammation always at summit of sigmoid loop; rectum and jx anterior to promontory are unaffected.
Finger dissection with pinching of inflamed fat.
Remove sigmoid -- not oncological resection
Resection is from prox colon (where tineae coalesce)
- if sigmoid left behind, recurrence up to 20%; else <10%.
Stay near the bowel wall, away from ureter, gonadals
Linear stapler to bowel at both ends
- distal transection is at rectosigmoid jx.
Deal to sigmoid mesentery.
- prudent to suture-ligate inflamed vessels
Some say remove inflamed mesentery of the sigmoid as well.

What if colon grossly distended with faeces?
Could do wash-out.
But slow and messy and bowel end discrepancy makes anastomosis difficult.
This all counts against anastomosis.
Prefer stoma.

Mobilise Flexure?
Not needed if tension ok and good flow in marginal artery.
But mesocolon often shortened

Found incidental diverticulitis?
If uncomplicated, close and treat as usual.

Anastomose onto descending colon with tics?
Yes, that is ok.

Massive complicated fistulating diverticular mass?
Consider proximal diversion and drainage. Exclude cancer and come back for definitive resection when inflammation settled.

Laparoscopy and peritoneal lavage?
New treatment principle based on observation that disease often resolves with washout and no resection.
Peritoneal lavage with 4L saline, including when free gas, fluid (but not feculant; ie Hinchy III not IV).
- 100 pts, prospective multicentre study; only 2 got further episode of diverticulities in 3yr f/up
Wash out, laparoscopically suture colon hole (often none evident), leave drains.
However local experience probably not as good as published data.
Probably not appropriate for patients with sepsis (remove the source) or multiple comorbidities.
Probably is appropriate for a selective well patient group without comorbidities, but that is not typically the case...
...Probably most of these patients could have been managed conservatively anyway.

Controversies:

1. Colostomy or not in complicated diverticulosis?
- free peritonitis: Hartmann's (Hinchey III and IV) = safe exam answer
- anything less: can anastomose.

2. Need for surgery in uncomplicated, and in complicated disease w abscess?
- used to do it after 2nd attack, now not.
- decision analysis shows colectomy after 4th+ (vs 2nd) attack --> reduced death, hospitalizations, and stomas.
- recurrent attacks tend to be more benign.
- individualize management is key.  few are in need of resection for persisting symptoms, fibrotic stenosis or complicating fistula, depending on QOL.

Fistula
Pinch off, resect disease, suture bladder
Place catheter for 10d (or 5d) with cystogram prior to removal.

Divertic Bleed
Large bleed?:
- Resusc, 2xcannulae, etc
- rapid CT / angiography; must be 1 mL/min
--> 80% can be coiled successfully
- rate of colonic ischaemia <10% ("highly selective coiling") and rebleeding <25%.
- alternatively red blood cell scall; must be 0.1 mL/min
Surgical therapy for massive lower GI is now rare
- unstable pts, those receiving >6u in 24h
- exploratory laparotomy +/- on-table enteroscopy
- if no source and appears colonic, then total colectomy with primary anastomosis.

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REFERENCES
Cameron 10th