Case 28 from Dimity McCracken
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A 60yo man presented to ED with intractable vomiting & weight loss. His abdomen is distended.
He says he had “bleeding peptic ulcers” in the past, but this hasn’t been a problem for the last 6mths. A gastroscopy at that time showed 2 large duodenal ulcers (proximal D1). Otherwise his PMHx is unremarkable: hypertension, hypercholesterolaemia, osteoarthritis of L knee.
Routine bloods show hypokalaemia & a metabolic acidosis.
The ED staff organised a CT abdo.
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These are the axial images.
Here are the coronal views.
What are the CT findings?
What is your diagnosis?
What is the most likely cause?
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The CT scan shows:
- marked gastric distension from gastric outlet obstruction
- air-fluid levels (axial views)
- lumbar scoliosis
- bilateral hip prostheses
This is gastric outlet obstruction. The 2 most likely causes in this case are:
- stenosis from PUD, due to repeated scarring
- obstructing cancer
Gastric Outlet (Pyloric) Obstruction
Gastric outlet obstruction is any condition where there is a mechanical blockage preventing gastric emptying. It is separated most commonly into benign vs malignant causes. Previously benign causes were more common, but now only about 1/3 are benign (due to H.pylori eradication therapies & PPI’s). Peri-pancreatic malignancies are now most common.
Characteristic signs & symptoms (onset of symptoms depends on the aetiology of the obstruction):
- post-prandial vomiting (from the mechanical obstruction)
- initially a better tolerance of liquids than solids
- early satiety
- weight loss & malnutrition (a late sign).
- nausea & vomiting
- can lead to dehydration
- vomitus contents typically contains undigested food particles, even from days earlier
- increasing abdominal distension & gastric dilatation leads to loss of gastric contractility, which creates more food accumulation
- succussion splash
- epigastric pain is uncommon, & usually due to the underlying cause
Investigations need to exclude a functional problem ie. gastroparesis, since these require special treatments.
Treatment is urgent to prevent further malnutrition. Any delays in management tend to increase surrounding tissue oedema & risk needing more complicated corrective surgery.
These are usually separated into malignant & benign.
- pancreatic cancer (usually co-present with biliary obstruction)
- ampullary cancer
- duodenal cancer
- gastric cancer
- gastric lymphoma
- acute due to inflammation & oedema
- chronic due to fibrosis, scarring & remodelling
- pylori a risk factor for developing gastric outlet obstruction
- Pancreatitis & pancreatic pseudocysts causing duodenal obstruction
- gastric varices
- granulomatous disease (Crohn’s, sarcoid, TB)
- strictures (ie. alkali ingestion)
- pyloric stenosis
- congenital duodenal webs
- gallstone obstruction
- bezoars (more common in children)
- gastric volvulus
Nasogastric drainage of stomach is required prior to gastroscopy. This helps reduce the risk of aspiration.
Associated electrolyte abnormalities need to be corrected. Remember many of these patients will have had poor absorption, so refeeding syndrome may become a problem, perpetuating electrolyte abnormalities. High dose thiamine & multivitamins are recommended.
Gastroscopy to assist determining cause of obstruction, & in some cases treat this underlying cause.
Deal with the obstruction, which if not resolved by gastroscopy may need surgical intervention.
Regular PPI to reduce acid secretion, & potentially aid with ulcer healing if the obstruction is PUD related.
Ultimately the treatment required depends on the cause of the obstruction.
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Great pictures of gastric outlet obstruction from our friends at Radiopaedia
Cases of infantile & adult pyloric obstruction from FOAM EM RSS
A great summary of gastric outlet obstruction from Medscape
An unusual cause of gastric outlet obstruction: