An ulcer that penetrates deeper than the mucosa can breach a blood vessel, the wall of the stomach or duodenum, or an adjacent organ, and it can also scar the outlet of the stomach. Bleeding is the most common of these events, and it is the one that most often brings a silent ulcer to medical attention.
Bleeding
Ulcer bleeding presents as haematemesis (vomiting blood, which may be fresh or resemble coffee grounds) or melaena (black, tarry stool from digested blood), and a large bleed can also cause haematochezia or the signs of shock. The first priority is to assess the severity of the bleed and resuscitate the patient. A very low-risk patient, identified by a Glasgow-Blatchford score of 0 to 1, may be managed as an outpatient, but most patients are admitted. Hospitalised patients are transfused at a restrictive threshold of 7 g/dL rather than a higher one, because a higher threshold does not improve outcomes and may cause harm.
Endoscopy is both diagnostic and therapeutic. It is generally performed within 24 hours of presentation, and endoscopic haemostasis is the definitive treatment for an ulcer that is actively spurting or oozing, or that has a non-bleeding visible vessel. Several methods work — bipolar electrocoagulation, heater probe and absolute ethanol injection are recommended — and clips, argon plasma coagulation and haemostatic powder are further options; active bleeding and recurrent bleeding after an initial successful treatment each have their own preferred techniques. After haemostasis, high-dose PPI therapy is given for 3 days, followed by twice-daily oral PPI for the first 2 weeks. If bleeding recurs, endoscopy is repeated, and if endoscopic treatment fails, transcatheter arterial embolisation is used.
Perforation
Perforation causes the sudden onset of severe, generalised abdominal pain with tenderness and rigidity — a board-like abdomen — as the acid and contents of the stomach leak into the peritoneum. Free air under the diaphragm on an upright chest radiograph, or on a CT scan, supports the diagnosis. Duodenal perforation most often affects the anterior wall. Treatment is usually surgical repair, though some patients can be managed with endoscopic closure and antibiotics.
Penetration
In penetration the ulcer erodes into an adjacent structure rather than through the whole wall. The most common organ involved is the pancreas, and the pain changes character: instead of epigastric pain it becomes constant and radiates to the back. The liver, biliary tract and colon can also be involved. Penetration often responds to acid suppression, but it may need surgery if it does not.
Gastric outlet obstruction
Long-standing ulceration close to the pylorus can narrow the gastric outlet through inflammation and scarring, so that the stomach empties poorly. The patient develops early fullness, nausea and vomiting of undigested food, often with weight loss. The obstruction is treated first by decompression and acid suppression, with endoscopic balloon dilation or surgery (or both) for a fixed narrowing.
Malignancy
Malignancy is different in kind from the other complications. A gastric ulcer can itself be malignant, which is why it is biopsied rather than assumed benign. H. pylori infection is the most important cause of gastric adenocarcinoma and of gastric MALT lymphoma, and eradicating the infection reduces the risk of gastric cancer; the link between the infection and these tumours is why H. pylori is tested for and treated in the first place.