SB Dysmotility
DEFINITION
Notes on a collection of various dysmotility issues.
In general, surgery should only be considered for patients with
extreme symptoms when reasonable efforts at medical management have
failed
D E A B M I M
EPIDEMIOLOGY
As per individual conditions
D E A B M I M
AETIOLOGY
See below
D E A B M I M
BIOLOGICAL BEHAVIOUR
Roux Stasis Syndrome
Encountered after Roux-en-Y gastrojejunostomy.
- Roux-stasis, delayed gastric emptying, or both
- but pure Roux limb dysfunction is generally a late complication,
onset over months to years.
--> difficult to investigate / work out what is the exact
causative segment, could try scintigraphy or manometry
--> can assess vagal function via the pancreatic polypeptide
response to insulin-induced hypoglycaemia test (PP test)
Encompasses symptoms of nausea, vomiting, early satiety, and
abdominal pain; like gastroparesis
- seen in ~25-30% of patients
Risk factors:
- women
- Roux length >40cm
Post-Vagotomy Diarrhoea
Diarrhoea in 20% after truncal vagotomy, severe in 2-4%
- doesn't really occur with selective vagotomy; only truncal
May have up to 20 loose BMs per day.
May get malnutrition, weight loss, orthostatic hypovolaemia.
Unclear why it occurs. Theories:
- impaired gastric relaxation
- bile acid malabsorption
- i.e. alters gastric tone, motility and also facilitates bacterial
overgrowth.
- also hepatic and celiac denervation impairs contractility of
gallbladder, fills up and then dumps out of sync, causing a large
enteral load that overwhelms the enterohepatic circulation
--> direct action of bile salts in colon causes secretary and
osmotic diarrhoea.
More likely in patients with past cholectystectomy, further
implicating role of gallbladder and bile salts
Diagnosis
Difficult as features are non-specific
- Consider bacterial overgrowth, malabsorption, infection (c. diff),
obstruction, IBD,
- Medications may cause diarrhoea (alter intestinal transit time,
luminal osmolarity, ion transport, intestinal flora etc)
Post-Vagotomy Dumping
Up to 25-50% of pts with gastrectomy, gastroenterostomy, vagotomy or
roux-en-Y bypass experience some form of dumping
- less than 5% of these have severe disabling symptoms that actually
require management
Causes:
- loss of reservoir function
- loss of pyloric sphincter tone
- stomach cannot relax and accommodate; elevated intragastric
pressure and common-cavity pressure gradient to duodenum
--> forces contents through more rapidly than should
- also after gastrojejunostomy, normal duodenal feedback on gastric
emptying is lost
Rapid gastric emptying is accompanied by gut hormone release, e.g.
glucagon-like-peptide 1 (GLP-1), eliciting sympathetic activation
Enteroglucagon = inhibits absorption of sodium and water -->
diarrhoea
Severity is proportional to rapidity of gastric emptying
Early dumping
(classified this way, but quite difficult to distinguish the two in
practice).
- most pts suffer early dumping or a combination
Early = within 60min of eating
- GI and vasomotor complaints
- Hyperosmolar food bolus causes osmotic fluid shifts into gut,
distention, increases amplitude and frequency of bowel contraction
- variety of vasoactive transmitters are released
--> splanchnic and systemic vasodilation
--> relative hypovolaemia,
--> symptom complex = pain, bloating, vomiting, diarrhoea,
palpitations, weakness, sweating, fainting, flushing
Late dumping
Late = 1-3h after meal
- Secondary to reactive hypoglycaemia
- Dump of carbs into gut causes GLP-1 release, and exaggerated
insulin response.
- Pts become hypoglycaemic, surge of catecholamines
--> symptoms of lightheadedness, palpitations, diaphoresis,
tremors and confusion.
Rapid weight loss and malnutrition may ensue from fear of eating
from these problems.
Consider other causes, like insulinoma, noninsulinoma
pancreatogenous hypoglycaemic syndrome.
Ileus
See ileus notes
D E A B M I M
MANIFESTATIONS
See above
D E A B M I M
INVESTIGATIONS
Included below
D E A B M I M
MANAGEMENT
Surgery in Gastroparesis
Gastrectomy, pyloroplasty, and surgical drainage
procedures may be offered as a last resort, though data
demonstrating efficacy are limited.
Conversion from a Billroth I to a Billroth II, although tempting, is
rarely an effective intervention.
Completion gastrectomy with preservation of a small cuff of gastric
tissue may have some long-term benefits
- but up to 25% of patients still require some form of parenteral
support.
Roux Stasis Syndrome
Exclude mechanical obstruction by OGD and small bowel series
Motility agents
Cisapride provides long-lasting symptomatic relief from
pain, fullness, nausea and vomiting
- improves transit in ~40%
Erythromycin improves
gastric emptying
Bethanecol short term
relief to gastric retention
Surgery
Up to 50% of patients may eventually need subtotal or total
gastrectomy to relieve symptoms
Completion gastrectomy works in ~50%, less likely in more severe
cases
Uncut Roux Procedure
Prevents dysfunction in the intestinal limb.
Antrectomy, Bilroth II reconstruction
Then side-side anastomosis between afferent and efferent ~40cm
distal to gastrojejunostomy
Rho-shaped Roux-en-Y, & Noh's operation
No convincing evidence for these
- coils bowel up like spaghetti to "try to control ectopic
pacemaking"; sounds like BS
Post-Vagotomy Diarrhoea
Most cases are self-limiting and resolve with time
1. Modify diet
- small, frequent, low-fat meals
- bulking agents
2. Loperamide (12-24mg) and codeine phosphate (60mg)
- codeine makes some people v. drowsy though
3. Cholestyramine binds diarrhoeal bile salts
- significantly reduces stool volume
- but poorly tolerated and unconfirmed long-term benefit.
Do not use ocreotide; not effective and may make things worse as
messes with pancreatic exocrine fx.
4. Conservative approach should resolve symptoms by 18m after
vagotomy
- if not effective, re-evaluate the entire GI tract and look for
alternate causes again.
... Correcting rapid gastric emptying may help dumping symptoms but
does not help diarrhoea.
5. More successful approach = slow transit through SB
- e.g. 10cm antiperistaltic duodenal segment 70-100cm from ligament
of Treitz
... mixed results, short lived, risk of partial obstrucitons
- passive non-propulsive reversed ileal graft 30cm from ileocaecal
junction.
--> last resorts in patients with disabling symptoms.
Post-Vagotomy Dumping
1. Provocation testing
To confirm diagnosis
Ingest a 50g oral glucose load at 30 min intervals over 3h
Measure plasma glucose for hypoglycaemia, hematocrit (increases
>3%), HR (increases >10 bpm)
And reproduces patients' symptoms
2. Solid meal scintigraphy test
for rapid gastric emptying
- 30% left after just 1 hr = rapid
3. Dietary modification
- Eat small meals
- Avoid fluid intake while eating solids and for 2h post-prandially
to maintain gastric retention
- Minimise ingestion of simple carbohydrates
- Nonabsorbable polysaccharides such as pectin, guar gum, can
alleviate dumping symptoms and reduce symptoms from reactive
hypoglycaemia.
4. If dumping persists,
pharmaceutical intervention
Acarbase = alpha-glucosidase inhibitor
- attenuates post-prandial increase in plasma glucose
- helps, but pay-off is unfermented carbs in system increasing
flatulence and diarrhoea
Ocreotide = somatostatin analog
- use long-acting analog, sandostatin-LR depot injection; better QOL
rating.
- effectively controls symptoms of dumping by slowing gastric
emptying
- inhibits secretion of insulin and enteric peptides
- mitigates postprandial haemodynamic changes, by limiting hormonal
release and splanchnic vasoconstriction.
--> reduces dumping 50% in short term, long term = limited
benefit; also causes steatorrhoea and gallstones
5. Remedial surgery?
Not always very effective.
Reserved for refractory patients as a desperate measure.
Aim is to create a gastric reservoir, prevent uncontrolled delivery
of food into the small intestine.
- anti-peristaltic jejunal interposition loops and conversion
Roux-en-Y gastrojejunostomy are generally thought to provide best
results.
If dumping after pyloroplasty, consider pyloric reconstruction
- convert Bilroth I or II to a Roux-en-Y gastrojejunostomy. Slows
motility by interrupting MMC and creates retrograde jejunal
contractions.
- could convert II to I but ineffective in 25%.
Jejunal interposition can be a meter or a reservoir;
- 10cm can serve as a 'valve' to delay transit
- 10-20cm will dilate over time and serve as a reservoir.
- can interpose the reversed segment into an efferent Billroth II
limb.
Ileus
See ileus notes
D E A B M I M
REFERENCES
Cameron 10th