Surgical resection is the principal therapy for gastric cancer, as it offers the only potential for cure. A subtotal gastrectomy is usually performed for tumours of the distal stomach. Subtotal gastrectomy is the treatment of choice for middle and distal-third gastric cancer as it provides similar survival rates and better functional outcome compared to total gastrectomy, especially in early-stage disease with favourable prognosis. D2 dissections are recommended by the National Comprehensive Cancer Network over D1 dissections. A pancreas-and spleen-preserving D2 lymphadenectomy is suggested, as it provides greater staging information, and may provide a survival benefit while avoiding its excess morbidity when possible. Patients that undergo D2 lymphadenectomy as a standard part of surgical resection of gastric adenocarcinoma generally have better stage-for-stage overall survival figures compared to patients undergoing less extensive lymphadenectomies.
After partial gastrectomy, some patients report disorders such as reflux esophagitis and alkaline gastritis, as well as dumping syndrome, delayed gastric emptying and malabsorption, which are defined as functional dyspepsia. Duodenogastric reflux is recognized to be a major cause of clinical symptoms after resection.
Roux-Y reconstruction seems to be effective in reducing bile reflux into the stomach, compared to Billroth I and II procedure, and conversion to this procedure has been reported in patients with symptomatic uncontrolled reflux disease.

Iatrogenic perforation of the gastrointestinal tract
related to diagnostic or therapeutic endoscopy is
a rare but severe adverse event, associated with
significant morbidity and mortality

Conservative treatment may be suitable for patients with limited oesophageal injury and contained leakage. Such patients include those suffering endoscopic iatrogenic perforation, as the patient is likely to be fasted and the diagnosis made promptly. They must remain nil by mouth, with appropriate antibiotic cover, and proton pump inhibitor therapy, total parenteral nutrition, and continued observation. Similarly, medical treatment might be suitable for cases of inoperable malignant stricture, that is, palliation.

Iron deficiency anaemia (IDA) is the most common form of anaemia worldwide and can be due to inadequate intake, decreased absorption (e.g., atrophic gastritis, inflammatory bowel disease), increased demand (e.g., during pregnancy), or increased loss (e.g., gastrointestinal bleeding, menorrhagia) of iron. Prolonged deficiency depletes the iron stores in the body, resulting in decreased erythropoiesis and anaemia.
Symptoms are nonspecific and include fatigue, pallor, lethargy, hair loss, brittle nails, and pica. Diagnostic lab values include low haemoglobin, microcytic, hypochromic red blood cells on peripheral smear, and low ferritin and iron levels. Once diagnosed, the underlying cause should be determined. Patients at risk for underlying gastrointestinal malignancy should also undergo a colonoscopy.
Iron deficiency anaemia is treated with oral (most common) or parenteral iron supplementation. Severe anaemia or those with concomitant cardiac conditions may also require blood transfusions. The underlying cause of IDA should also be corrected. IDA may manifest as Plummer-Vinson syndrome (PVS): triad of postcricoid dysphagia, upper oesophageal webs, and iron deficiency anaemia

Duodenal ulcers are more common than gastric ulcers and unlike gastric ulcers, are caused by increased gastric acid secretion. Duodenal ulcers are commonly located anteriorly, and rarely posteriorly. Anterior ulcers can be complicated by perforation, while the posterior ones bleed. The reason for that is explained by their location. The peritoneal or abdominal cavity is located anterior to the duodenum. Therefore, if the ulcer grows deep enough, it will perforate, whereas if a posterior ulcer grows deep enough, it will perforate the gastroduodenal artery and bleed.
Patients with duodenal ulcers will usually have a history of epigastric pain that occurs several hours after eating. The pain is often improved by eating food.

Ulcer bleeding stops spontaneously in about 80% of patients. Only a small percentage require specific measures to stop bleeding. surgery remains the most definitive method of controlling ulcer haemorrhage, and is indicated when endoscopic haemostasis fails to control the bleeding, or when rebleeding occurs. The morbidity and mortality of emergency surgery for ulcer bleeding is high. In principle, the operation performed should be the minimum compatible with permanent haemostasis. The choice of operations is determined by the site and size of the ulcer as well as the experience and preference of the surgeon. Most bleeding duodenal ulcers may be managed by underrunning the bleeding vessel together with vagotomy and pyloroplasty.

Dysphagia that is episodic and nonprogressive and varies between solids and liquids is more likely to represent a motility disorder. It may also associated with retrosternal chest pain.

Motility disorder is a condition where the nerves and muscles in the gastrointestinal tract are not working together correctly, which cause difficulty in the digestive process. These conditions include chronic intractable constipation, gastroesophageal reflux disease (GERD), chronic intestinal pseudo-obstruction, gastroparesis, Hirschsprung’s disease, and oesophageal achalasia, among other disorders.

In addition to imaging studies, these conditions are usually evaluated with manometry studies which measure the pressure in different areas of the gastrointestinal tract.

A gastrinoma is a gastrin-secreting tumour that can occur in the pancreas, although it is most commonly found in the duodenum. Duodenal wall gastrinomas have been identified in 40-50% of patients. These duodenal wall tumours are frequently small and multiple. Sporadic tumours occurring in the pancreas tend to be solitary and have a greater malignant potential as compared to duodenal gastrinomas.

Primary tumours also occur in a variety of ectopic sites, including the body of the stomach, jejunum, peripancreatic lymph nodes, splenic hilum, omentum, liver, gallbladder, common bile duct, and the ovary. Over 50% of gastrinomas are malignant and can metastasize to the regional lymph nodes and the liver. One fourth of gastrinomas are related to multiple endocrine neoplasia (MEN) type I and are associated with hyperparathyroidism and pituitary adenomas.

The symptoms in 90-95% of patients with gastrinomas are similar to the symptoms of common peptic ulcer disease. Usually, persistent abdominal pain exists that is less responsive to medical treatment.
Sometimes, symptoms may relate to a complication of peptic ulcer disease, such as bleeding (e.g., melena, hematemesis), gastric outlet obstruction (e.g., vomiting), and perforation (e.g., peritoneal irritation).
Other symptoms include gastroesophageal reflux, diarrhoea, steatorrhea, and weight loss, all of which are secondary to acid hypersecretion. Vitamin B-12 malabsorption, which is not correctable by oral intrinsic factor, may also be observed.

Somatostatin receptor scintigraphy (SRS) is very useful to identify the primary lesions preoperatively. SRS is the most sensitive non-invasive method for localizing the primary tumours and metastases. It also is helpful for detecting the presence of liver or bone metastasis.

Oesophageal dysphagia occurs when there is a difficulty with the passage of solid or liquid material through the oesophagus, specifically the region between the upper and lower oesophageal sphincter. It results from either abnormal motility of this segment of the oesophagus or obstruction.
Common causes of dysphagia:
Gastro-oesophageal reflux—waterbrash, regurgitation, due to dysmotility or stricture
Achalasia—classically hold-up relieved by carbonated beverages
Motility disorders—may be associated with central chest pain, systemic disease (scleroderma, dermatomyositis)
Oesophageal cancer—progressive, weight loss
Head and neck cancer—pain, dysphagia, otalgia, >90% smokers, often excess alcohol consumption
Pharyngeal pouch—slowly progressive, regurgitation, gurgling
Web—able to swallow only small amounts, “can’t swallow tablets”
Stroke
Neurodegenerative disorders—parkinsonism, motor neurone disease, multiple sclerosis, myasthenia gravis
Presbyphagia

Endoscopy has the advantage of potentially yielding a histological diagnosis. The overall rate of oesophageal perforation after flexible endoscopy involving oesophageal instrumentation, biopsy, or dilatation is 2.6%

Oesophageal manometry remains the investigation of choice in suspected motility disorders. Manometry can classify oesophageal dysmotility into rare specific disorders such as achalasia and diffuse oesophageal spasm or more common non-specific motility disorders that do not respond directly to drug treatment but may improve if related reflux or psychiatric disturbances are treated. The symptoms of non-specific motility disorders may have an uncertain relation to the manometric abnormalities

Management is based on the history, findings of the clinical investigations, and prognosis for the individual patient. The underlying disorder is treated, but the impact of dysphagia on nutrition and hydration will compromise any intervention unless managed effectively. Poor physical condition from malnutrition or dehydration will lead to a suboptimal rehabilitation process, in both duration and completeness of recovery and inadequate management of dysphagia contributes to this. A malnourished person is at risk of decompensation of the swallow, leading to dysphagia. The clinical swallow assessment is used to determine safely modified diets that reduce malnutrition and dehydration. This may range from nil by mouth with total enteral support to full oral route or a balance of the two. Enteral feeding is essential to maintain nutritional status when oral feeding is suspended, even if only for a short time. Prompt involvement of a dietitian is thus essential.

Upper gastrointestinal (GI) bleeding is usually defined by a bleeding source proximal to the ligament of Treitz although some may also include a bleeding source in the proximal jejunum. Upper GI bleeding emergencies are characterized by hematemesis, melena, haematochezia (if the bleeding is massive and brisk) and evidence of hemodynamic compromise such as dizziness, syncope episodes and shock. The most commonly used endoscopic haemostatic interventions include epinephrine (adrenaline) injection, thermal coagulation and endoscopic clipping at the ulcer site to constrict, compress and/or destroy the bleeding vessel. Injection of 30 mL diluted epinephrine (1:10 000) can effectively prevent recurrent bleeding with a low rate of complications. The optimal injection volume of epinephrine for endoscopic treatment of an actively bleeding ulcer (spurting or oozing) is 30 mL.

Achalasia is an oesophageal motor disorder characterized by aperistalsis of the oesophageal body and lack of relaxation of the lower sphincter in response to swallows.
Achalasia cardia is one of the common causes of motor dysphagia. Pathophysiologically, achalasia cardia is caused by loss of inhibitory ganglion in the myenteric plexus of the oesophagus. In the initial stage, degeneration of inhibitory nerves in the oesophagus results in unopposed action of excitatory neurotransmitters such as acetylcholine, resulting in high amplitude non-peristaltic contractions (vigorous achalasia); progressive loss of cholinergic neurons over time results in dilation and low amplitude simultaneous contractions in the oesophageal body (classic achalasia).