Stomach & Duodenum

Stomach & Duodenum Assistant Professor Dr. Ghassan Ali Al-Kizwini Consultant GIT Surgeon

Stomach & Duodenum LEARNING OBJECTIVES: the student should be able to • Describe gross and microscopic anatomy and pathophysiology of the stomach in relation to disease. • Decide on the most appropriate investigationof patients with complaints relating to the stomach and duodenum. • Recognize the critical importance of gastritis and Helicobacter pyloriin upper gastrointestinal disease. • Investigate and treat peptic ulcer disease and its complications. • Recognize the presentation of gastric cancer and understand the principles involved in its treatment. • Know causes of duodenal obstruction and the presentation of duodenal tumours.

Stomach & Duodenum Functions of the stomach: • Act as reservoir for the ingested food. • Breaks down foodstuffs mechanically and starts the process of digestion, before passing it to the duodenum Anatomy of the stomach & duodenum: Blood supply: Arteries: • Rt. gastric artery • Lt. gastric artery • Gastroduodenal artery • Rt. gastroepiploic artery • Lt gastroepiploic artery • Vasabrevia (short gastric arteries)

Stomach & Duodenum Anatomy of the stomach & duodenum: Blood supply: Veins: • Equivalent to the arteries. • Those on the lesser curve mainly drain into the portal vein. • Those on the greater curve mainly drain into the splenic vein Lymphatics: Are important in surgery of gastric cancer to assess tumour spread. Nerve supply: • Intrinsic nerves: Myenteric plexus of Auerbach Submucosal plexus of Meissner • Extrinsic nerve supply: Parasympathetic: Vagus nerve (CN X) Sympathetic: derived from the coeliac ganglia

Stomach & Duodenum Micro-anatomy of the stomach & duodenum: • Epithelial mucus secreting cells • Specialized cells Parietal cells Chief cells • Endocrine cells G-cells Enterochromaffin-like (ECL) cells D-cells (Somatostatin) Duodenal endocrine cells • The neurons

Stomach & Duodenum • Gastric acid secretion Hydrogen ions are produced by the parietal cell by the proton pump (Hydrogen-Potassium ATPase). • The role of Histamine, Vagus Nerve & Gastrin • H2-receptor antagonists • Proton Pump Inhibitors (PPIs)

Stomach & Duodenum Summary-The anatomy and physiology of the stomach ● The stomach acts as a reservoirfor food and commences the process of digestion ● Gastric acid is produced by a proton pump in the parietal cells, which in turn are controlled by histamine acting on the H2-receptors ● The histamine is produced by the endocrine gastric ECL cells in response to a number of factors, particularly gastrin and the vagus ● Proton pump inhibitors abolish gastric acid production, whereas H2-receptor antagonists only markedly reduce it ● The gastric mucous layer is essential to the integrity of the gastric mucosa

Stomach & Duodenum INVESTIGATION OF THE STOMACH AND DUODENUM • Flexible endoscopy • Contrast radiology • Ultrasonography • CT scanning and Magnetic Resonance Imaging • CT/ Positron emission tomography • Laparoscopy • Gastric emptying studies • Angiography • Tests for Helicobacter pylori

Stomach & Duodenum

Stomach & Duodenum • Helicobacter pylori • This organism has proved to be of major importance in the aetiology of a number of common gastroduodenal diseases such as chronic gastritis, peptic ulcerationand gastric cancer. • In 1980Warren and Marshall ingested the organism to confirm that it is the cause of gastritis that they succeed in causing in themselves. (received Nobel prize 2005)

Stomach & Duodenum Helicobacter pylori/ characteristics & pathological effects • Has the ability to hydrolyse urea, within the gastric mucosa resulting in the production of ammonia, a strong alkali. This will stimulate antral G cells to release of Gastrinvia a negative-feedback loop. • Infection with H. pylori leads to the disruption of the gastric mucous barrier by the enzymes produced by the organism. • Some strains of H. pylori produce cytotoxins, notably the Cag A and Vac A products. • H. pylori is now classed by the WHO as a class 1 carcinogen. • It is difficult to explain how the organism is involved in duodenal ulceration, since the normal duodenum is not colonized, but the increased Gastrin level 2ndary to increased production of Ammonia, and the modestly increased gastric acid secretion supports the responsibility for ulcer formation.

Stomach & Duodenum Helicobacter pylori/ Detection • Tests using the organism’s obligate urease activity include: • the 13C and 14C breath tests • the CLO test (Campylobacter Like Organism test) performed on gastric biopsies. • The organism can also be detected histologically using the Giemsa or the Warthin–Starry stains, and cultured using appropriate media. • Serological tests to detect previous or current infection

Stomach & Duodenum Helicobacter pylori/ Eradication • Hypochlorhydria produced by proton pump inhibitors combined with antibiotics is effective in eradicating the organism. • Commonly used eradication regimes include a proton pump inhibitor and two antibiotics, such as metronidazole and amoxycillin. • High eradication rates (of 90%) can be achieved with combinations that include the antibiotic clarithromycin, although future resistance will become a problem.

Stomach & Duodenum Gastritis • Describes any histologically confirmed inflammation of the gastric mucosa. • According to the underlying aetiology, gastritis is classified into: • Autoimmune gastritis • H. pylori gastritis • Reflux gastritis • Erosive gastritis • Stress gastritis • Ménétrier’s disease • Lymphocytic gastritis • Eosinophilic gastritis • Granulomatous gastritis • Acquired immunodeficiency syndrome (AIDS) gastritis • Phlegmonous gastritis

Stomach & Duodenum Peptic Ulcer • What is an “Ulcer”? ..&..Is it really “Peptic ” ?!!! • Site: common sites include the first part of the duodenum and the lesser curve of the stomach. • Acute and Chronic peptic ulcer: it is really a spectrum of disease from the superficial gastric and duodenal ulceration, frequently seen at endoscopy, to deep chronic penetrating ulcers. • The cause: high gastric acid output…!!!, genetic factor…., social stress…, H. pylori, NSAIDs, cigarette smoking. • Does duodenal differs from gastric ulcer regarding incidence, pathology, clinical presentation, the risk of malignancy, diagnosis or treatment?

Stomach & Duodenum Other sites for peptic ulcers • Pre-pyloric gastric ulcer • Pyloric channel ulcers Both carry the risk of malignancy and biopsy is essential. • Stomal ulcers occur after a gastroenterostomy

Stomach & Duodenum Clinical features of peptic ulcers • Gastric and duodenal ulceration cannot be really differentiated depending on symptoms or clinical features. • Pain: epigastric, often gnawing قضم, حفر, نخر and may radiate to the back. • Periodicity: Symptoms may disappear for weeks • Vomiting • Alteration in weight • Bleeding: all peptic ulcers may bleed. Chronic bleeding presents with microcytic anemia • Clinical examination: is either –ve or may reveal epigastric tenderness, unless complications develops like gastric outlet obstruction or perforation.

Stomach & Duodenum Investigation of the patient with suspected peptic ulcer • Gastroduodenoscopy: (certain technical details; like taking biopsies, CLO test, J maneuver, ..etc.) Treatment of peptic ulceration/ Principles • The majorityof uncomplicated peptic ulcers are treated medically. • Surgical treatment of uncomplicated peptic ulceration is now seldom performed. • Surgical treatment is now mainly used for complications. • H. pylori eradication therapy.

Stomach & Duodenum Medical Treatment • Modifications to the patient’s lifestyle. • Drugs: A. Antisecretory drugs • H2-receptor antagonists • Proton Pump Inhibitors (PPIs) • Both drug categories don’t cause serious side-effects. • Relapse is common after stopping them. • Drugs: B. Eradication therapy: • If a patient has a peptic ulcer and H. pylori is the principal etiological factor (essentially the patient not taking NSAIDs) • It is more economical than prolonged courses of antisecretory drugs and definitely safer than surgery. • A PPI + 2 antibiotics for 10-14 days followed by 4 weeks course of PPI alone will achieve this target. • A patient on NSAIDs, should not be prescribed an eradication therapy • Zollinger–Ellison syndromeshould be treated with proton pump inhibitors unless the tumour can be managed by surgery.

Stomach & Duodenum Surgical treatment of uncomplicated peptic ulceration • Duodenal Ulcer Surgeries/ types 1. Vagotomies: • Truncal Vagotomy & Drainage procedure* • Selective Vagotomy & Drainage procedure* * (Pyloroplasty or Gastro- Jejunostomy) • Highly Selective Vagotomy 2. Gastrectomies: • Distal Gastrectomy & Gastro- duodenostomy (Billroth 1 operation) • Distal Gastrectomy & Gastro- jejunostomy (Billroth 11 or Polya operation) 3. Mixed: • Vagotomy & Antrectomy 4. Drainage only • Gastro- jejunostomy alone

Stomach & Duodenum

Stomach & Duodenum