Gastric outlet obstruction (GOO) is caused by any disease process that mechanically impedes gastric emptying. Common benign causes include peptic ulcer disease and gastric polyps, while pancreatic cancer is the most common malignant cause. GOO presents with non-bilious vomiting, weight loss, and dehydration. Management involves resuscitation with IV fluids and correcting metabolic abnormalities, then treating the underlying cause surgically if medical management fails or for palliation of malignant obstructions. Diagnosis in resource-limited areas relies on clinical exam findings, while challenges include limited imaging and laboratory resources.

1. GASTRIC OUTLET
OBSTRUCTION

2. DEFINITION
 Gastric outlet obstruction (GOO) represents a clinical
and pathophysiological consequence of any disease
process which produces mechanical impediment to
gastric emptying

3. Causes
Two well-defined groups of causes—
Benign & Malignant
 In the past-- peptic ulcer disease more prevalent, benign causes
most common BUT IN RESOURCE CHALLENGED COUNTRIES WHERE IT
MAY STILL BE THE COMMONEST CAUSE
 Now-- only 37% have benign disease and the remaining have
obstruction secondary to malignancy

4. Etiology
Major benign causes of gastric outlet
obstruction (GOO) are---
 PUD
 gastric polyps
 ingestion of caustics
 pyloric stenosis
 congenital duodenal webs
 gallstone obstruction (Bouveret syndrome)
 pancreatic pseudocysts
 and bezoars

5. Etiology(Contd)
 Pancreatic cancer is the most common malignancy causing GOO
 Outlet obstruction may occur in 10-20%
 Ampullary cancer
 Duodenal cancer
 Cholangiocarcinomas
 Gastric cancer
 Metastases to the gastric outlet by other primary tumors

6. Pathogenesis
 Intrinsic or extrinsic obstruction of the pyloric channel
or duodenum
 Depends upon the underlying etiology

7. Obstruction of the stomach
Hypertrophy of the stomach
Dilatation
Gastritis & depressed acid secretion

8. Metabolic effects
 Dehydration and electrolyte abnormalities-- Increase in BUN and
creatinine are late features of dehydration
 Prolonged vomiting causes loss of hydrochloric acid & produces
an increase of bicarbonate in the plasma to compensate for the lost
chloride-------hypokalemic hypochloremic metabolic alkalosis
 Alkalosis shifts the intracellular potassium to the extracellular
compartment, and the serum potassium is increased factitiously
 With continued vomiting, the renal excretion of potassium increases
in order to preserve sodium
 The adrenocortical response to hypovolemia intensifies the
exchange of potassium for sodium at the distal tubule, with
subsequent aggravation of the hypokalemia

9. Paradoxically acidic urine
 Initially, the urine has a low chloride and high
bicarbonate content, reflecting the primary metabolic
abnormality
 This bicarbonate is excreted along with sodium and so,
with time, the patient becomes progressively
hyponatraemic and more profoundly dehydrated.
 Because of the dehydration, a phase of sodium
retention follows and potassium and hydrogen are
excreted in preference.
 This results in the urine becoming paradoxically acidic.
 Alkalosis leads to a lowering of the circulating ionised
calcium, and tetany can occur.

10. Clinical features
 Nausea and vomiting are the cardinal symptoms
 Vomiting -- Nonbilious, and it characteristically contains
undigested food particles
 Early stages --- vomiting intermittent and usually occurs within 1
hour of a meal
 Very often it is possible to recognise foodstuff taken several days
previously
 Pt. loses weight, appears unwell & dehydrated

11. Clinical features(Contd)
GOO from a duodenal ulcer or incomplete obstruction typically present
with symptoms of-----------
 Gastric retention, including early satiety, bloating or epigastric
fullness, indigestion, anorexia, nausea, vomiting, epigastric pain, and
weight loss
 Frequently malnourished and dehydrated and have a metabolic
insufficiency
 Weight loss , most significant with malignant disease
Abdominal pain is not frequent and usually relates to the underlying
cause, eg, PUD, pancreatic cancer

12. Examination
 Chronically ill looking
 Wasted
 Dehydrated
 may be pale due either to a bleeding ulcer, malignancy
 Shock
 Epigastric / Rt hypochondrial tenderness
 Distended abdomen
 Visible gastric peristalsis
 Succussion splash

13. PRINCIPLES OF MANAGEMENT .
Guiding Principles lies in the
recognition of GOO as an
emergency, as such, GOAL of
treatment include:
-1)Resuscitation/stabilization.;
-2)Relieve obstruction;
-3)Patient selection/categorization;
- patient related factors
-4)Offer definitive curative care;
- Lesion related factors
-5)Prevent recurrence/Follow up care.

14. Management
Involves
 Correcting the metabolic abnormality &
 Dealing with the mechanical problem
Rehydrated with i/v isotonic saline with potassium supplementation/
Ringer’s . Replacing the sodium chloride and water allows the kidney
to correct the acid–base abnormality

15. investigations
1) Stabilise patient
 FBC (anaemia)
 SEUCR (hypochloraemia,
hypokalaemia,hyponatraemia,elevated Hco3)
 BLOOD GASES(metabolic alkalosis)
 URINALYSIS (paradoxical aciduria)

16. investigation
2)To confirm diagnosis
 Plain x-ray of abdomen:shows large gastric shadow and a large
amount of gastric fluid.
 Gastric aspiration:a wide bore stomach tube is placed early in the
morning and the stomach is aspirated of resting juice.if >400ml of
juice is obtained a presumptive diagnosis of GOO can be made.

17. investigation
 Esophagogastroduodenoscopy + biopsy(histology and bacterioloical
investigation).
Aim is to visualise the stomach mucosa and any ulcer.
 Barium meal:
-markely dilated stomach with a lot of residue
-presence of an ulcer crater
-trifoil deformity of the duodenal cap.

18. Indications(Surgery)GOO due to benign ulcer disease may be treated medically if results
of imaging studies or endoscopy determine - acute inflammation and
edema are the principle causes (as opposed to scarring and fibrosis,
which may be fixed)
If medical therapy -- fails, then surgical
Typically, if resolution or improvement is not seen within 48-72 hours,
surgical intervention is necessary
The choice of surgical procedure depends upon the patient's particular
circumstances

19.  In cases of malignant obstruction, weigh the extent of surgical
intervention for the relief of GOO against the malignancy's type and
extent, as well as the patient's anticipated long-term prognosis
 As a guiding principle, undertake major tumor resections in the
absence of metastatic disease(in fit pts)
 In patients with largely metastatic disease, determine the degree of
surgical intervention for palliation in light of the patient's realistic
prognosis and personal wishes

20. THE CHALLENGES HERE
 The commonest cause is chronic PUD
 Diagnostic challenge in terms of a CT scan, though
can still be done
 Laboratory challenge in determining the metabolic
anomalies
 Best to use Ringer’s for resuscitation as potassium is not
easily available

21. SUMMARY
 In poor resource countries, the best diagnostic
modality still remains to be clinical ( non- bilious
vomitus within an hour of taking a meal, gastric
peristalsis and succution splash)
 the availability of PPIs and eradication therapy for
H.pyroli has made the incidence of malignancy to be
on the rise as the cause of GOO