Radiology Case 28

Here are the coronal views.

What are the CT findings?

What is your diagnosis?

 This is gastric outlet obstruction. The 2 most likely causes in this case are:

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
  • high aspiration risk
• 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.

Causes

These are usually separated into malignant & benign.

Malignant causes:

• pancreatic cancer (usually co-present with biliary obstruction)
• ampullary cancer
• cholangiocarcinoma
• duodenal cancer
• gastric cancer
• adenocarcinoma
• GIST
• gastric lymphoma
• metastases

Benign causes:

• PUD
  • 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

Management

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.