Stomal complications

In general:

End ileostomies and end colostomies have the lowest complication rate
Loop ileostomies have the highest complication rate

Very early (days) - often require return to OT

LBO due to twist in bowel

Early (<3 months)

Stomal ischaemia/necrosis

- Incidence 14%
- Preventative factors:
  - Adequate mobilisation of bowel
  - Preservation of blood supply
  - Adequate trephine size
- Risk factors:
  - Emergency surgery
  - Obesity
  - IBD - especially Crohn's
  - Occurs more often in end stomas due to more tenuous blood supply
- Pathophysiology
  - Hypotension or a technical problem
  - Occurs as a result of either venous congestion or arterial insufficiency (tight fascial opening, excessive mesenteric stripping)
  - Mostly limited to mucosa above the fascia
- Assessment
  - If it appears black, then it is black - don't shy from the truth!
  - Usually evident early in the post-op period
  - Extent of necrosis - insert test tube, or alternatively and flexible sigmoidoscope
  - Severity - varies from minor mucosal hypoperfusion to a black, completely necrotic stoma
  - Sabiston - a viable stoma transilluminates bright red, even in the face of venous congestion; failure to transilluminate indicates ischaemia
  - Can also check bleeding
- Management:
  - Necrosis extends to proximal bowel below anterior fascia, immediate revision required
  - Proximal bowel viable and necrosis limited to stoma: observation may be appropriate. This can lead to a stricture in the future, though.
    - If necrosis progresses, revise it.
    - If sloughing occurs, only gentle debridement may be necessary. Can result in stomal retraction and pouching challenges but may not require re-intervention.

Stomal bleeding

- Uncommon - usually indicates either a stomal laceration from a poorly-fitting appliance, or the presence of peristomal varices in the patient with portal HTN.
- Minor bleeding can occur early with overly vigorous stomal cleansing.
- Initial management: direct pressure and local cauterisation (diathermy or silver nitrate) or suturing of the bleeding vessel, if identifiable.
- Peristomal varices are most often seen in patients who underwent a colectomy for UC in the setting of PSC. Can also develop in patients with other causes of portal HTN. Management with direct pressure + injection sclerotherapy or direct suture. Recurrence is frequent, and may even need other interventions e.g. TIPS.

Stomal retraction

- Defined as 0.5cm or more below the skin surface within 6 weeks of construction
- Typically occurs as a result of tension on the stoma.
- Can be intermittent (posture-dependent) or fixed - generally worse lying down
- Leads to leakage and difficulties with pouch adherence, resulting in peristomal skin irritation.
- Risk factors:
  - Obesity
  - Initial stoma height <10mm
- Management:
  - Retracts below fascia: immediate revision to prevent contamination
  - Retracted, but stays above fascia: local wound care, convex pouching system, and the use of a belt or binder. Revise only if improved outcome expected, and not if the root cause hasn't been addressed. Lose weight prior to revision.
  - If non-operative management of a retracted stoma fails, needs revision/re-siting. Re-siting to upper abdominal wall, which is thinner, may be helpful.

Mucocutaneous separation

- Results in leakage and skin irritation
- Incidence 12-24%
- Prevent it with meticulous technique.
- Assess
  - Partial
  - Circumferential - stomal stenosis can occur as the tissue heals by secondary intention
- Manage
  - Usually heals with conservative management
  - Re-suturing is usually not helpful
  - Circumferential - strongly consider revision
  - Partial - fill defect with kaltestat or barrier powder/paste to protect it from effluent and allow healing

Late (>3 months)

Parastomal hernia

- Risk factors
  - Colostomy
  - Obesity
  - Poor abdominal muscle tone
  - Conditions with chronic cough
  - Placement outside rectus muscle
  - Large fascial opening
- See separate topic under 'abdo wall'

Stomal prolapse

- The telescoping of the intestine out from the stoma
- Can lead to intestinal oedema, and even incarceration/strangulation
- Risk factors
  - Loop transverse colostomy and end descending colostomies
  - Large abdominal trephine
  - Increased intra-abdominal pressure
  - Redundant loop of bowel proximal to the stoma
- Management:
  - Uncomplicated: cool compresses and application of an osmotic agent (sugar/honey) to reduce oedema, followed by manual reduction of the prolapse and application of a binder with a prolapse over-belt to keep the bowel in the abdomen, or pouching modifications to accommodate the prolapsed bowel if reduction can't be established or maintained
    - Manual reduction: press gently at the very tip of the prolapse, with gentle slow invagination, allowing the prolapse to intussuscept back into the abdomen.
  - Complicated: full-thickness resection with reconstruction at the original site. Relocation may be necessary.
- Operative for revision:
  - Circumferential dissection down to fascia
  - Divide at new level, appropriate for skin height
  - Refashion stoma

Stomal stenosis

- Narrowing sufficient to interfere with normal function
- Most common with end ileostomy
- Pathophysiology:
  - Secondary to scarring or tightness of the mucocutaneous junction
  - Peristomal sepsis
  - Retraction
  - Ill-fitting pouch
  - Suboptimal surgical technique
  - Crohns
  - Malignancy
- Most likely to develop months later
- Early stenosis - manage conservatively, should improve as the oedema settles - insert a large 36Fr soft-tipped Foley catheter just beyond the fascia, without inflating the balloon
- Later stenosis
  - Mild - dietary modifications - avoid insoluble fibre. Gentle routine dilatation of stoma may help but not evidence-based.
  - Significant - cramping pain followed by explosive output. Usually requires surgical correction. Local revision may be preferred to dilatation. Enlargement of the skin opening may be useful in some situations.

Peristomal skin complications (any time)

Mechanical trauma
Dermatitis
Parastomal ulceration
Granulomas
Peristomal pyoderma gangrenosum
Parastomal varices
- Usually seen in cirrhotics/portal hypertension
- If bleeding, can under-run the varix with a deep locking Vicryl suture

Ileostomy-specific

Dehydration

High ostomy output

- Background:
  - A fully-adapted end ileostomy has an output of 500mL/24 hours. Initially post-op, it is usually 1000-1800mL/24 hrs, but usually comes down after a few days.
  - High-output stoma defined as >1.5L per day
- Pathophysiology
  - Coupled absorption of sodium and glucose in jejunum via SGLT1 symporter
    - If chyme is hypotonic, reduced ability to absorb glucose given sodium is working against a concentration gradient, so glucose will remain in lumen, leading to osmotic/secretory 'diarrhoea'
    - If chyme is isotonic (>90mmol/L sodium), glucose and sodium can both be absorbed from lumen, and the water will follow, thus reducing ileostomy output
  - Standard sport drinks are not suitable - Gatorade only has 500mg sodium but 60g glucose per litre (23mmol/L sodium) - it may be called 'isotonic', but doesn't work well for optimising intestinal absorption of fluid because it's lower in salt and higher in sugar than St Mark's
  - Tea, coffee, juice all count as free water
  - To improve the taste of St Mark's:
    - Drink chilled
    - Turn into ice cubes
    - Drink through a straw
    - Add a little juice/soda
- Risk factors:
  - Proximal stoma
  - Intra-abdominal sepsis
  - Following resolution of post-op ileus or SBO
- Classification
  - 1-1.5L/24 hours: 'pre-high'
  - 1.5-2L: mild high
  - 2-3L: moderate high
  - >3L: severe high
- Evaluation of suspected developing high stoma output
  - Observe stoma output for 48 hours before intervening
  - Rule out other causes:
    - Intra-abdominal sepsis
    - Intermittent obstruction
    - Infectious diarrhoea
    - Medications (prokinetics, metformin)
  - MDT involvement
    - Stoma nurse
    - Dietician
    - Daily weights
    - Accurate fluid balance
    - Patient education
  - Urinary sodium levels can be used to guide level of hydration - aim for <20mmol/L
- Management: after 48 hours of high output
  - Use a combination of interventions to match the severity of the insult
  - Escalate to next level (add interventions from that stage) if not seeing improvement
  - Always consider early stoma reversal
  - For a new stoma, if unable to get control of outputs with moderate doses of stoppers (~10mg daily loperamide), ensure there are no contributing factors before increasing further - review medications, strongly consider CT to exclude partial obstruction/collections and stool PCR for infection
  - Stage 1: Establish stability
    - Pre-high
      - Stop free water
      - St Mark's solution for total hydration needs
      - Oral electrolyte replacements
      - Low-residue diet, with thickening foods (starchy foods, soluble fibre including Fybogel/psyllium husk/Metamucil; avoid insoluble fibre)
      - Low-dose loperamide - 2mg QID
    - Mild high
      - Oral St Mark's up to maximum of 1L per day. No water.
      - Add IV hydration and IV electrolytes
      - Loperamide 4mg QID (open capsules, have 30 minutes prior to meals)
      - Pantoprazole 40mg BD
    - Moderate high
      - Loperamide 8mg QID
      - Codeine 15mg TDS
    - Severe high
      - Loperamide 12mg QID
      - Codeine 30mg TDS
      - Consider diphenoxylate/atropine (Lomotil) for additional anti-motility
      - Consider TPN if concerns for malnutrition - high stoma output can compromise absorption
      - Consider chyme reinfusion pump
  - Stage 2: stability and transition to discharge
    - Home when:
      - Self-managing
      - Stable output, ideally <1L
      - Nutritionally ok
  - Stage 3: long-term
    - Link in with dietitian
    - Long-term nutritional deficits in B12, zinc, selenium, and vitamins A, D, E, and K can result

Antimotility agents used for high-output fistulas

Drug	Initial dose	Route	Frequency	Titration	Max dose	Cost*	Special considerations
Loperamide	4 mg	PO	Three times daily with meals or every 6 hours with enteral nutrition	By 2 mg	16 mg/day	$	Avoid liquid due to propylene glycol content
Diphenoxylate/atropine (Lomotil)	2.5 mg/0.025 mg (1 tablet)	PO	Three times daily with meals or every 6 hours with enteral nutrition	By 1 tablet	2 tablets four times daily (20 mg diphenoxylate)	$$	Avoid liquid formulation due to sorbitol content
Pantoprazole	40 mg	IV	Twice daily	None	40 mg twice daily	$$$	Discontinue as soon as feasible
Codeine	15 mg	PO	Three times daily with meals, up to four times daily	By 15 mg	45 mg four times daily	$$	Monitor for CNS effects
Octreotide	100 mcg	SC	Three times daily	None	None	$$$	Discontinue if output not decreased after 3 to 5 days
Clonidine	0.3 mg	Transdermal	Every 7 days	None	0.3 mg every 7 days	$$$$	Monitor HR and BP

Food blockage

Drug malabsorption

Colostomy-specific

Colon irrigation