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Kingdom of Bahrain Arabian Gulf University College of Medicine and Medical Sciences. General Surgery The Stomach. Ali Jassim Alhashli. Anatomy, Histology & Physiology of Stomach. Stomach is composed of 5 parts: Cardia . Fundus Body. Antrum . Pylorus. Blood supply of the stomach:
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Kingdom of BahrainArabian Gulf UniversityCollege of Medicine and Medical Sciences General Surgery The Stomach Ali Jassim Alhashli
Anatomy, Histology & Physiology of Stomach • Stomach is composed of 5 parts: • Cardia. • Fundus • Body. • Antrum. • Pylorus. • Blood supply of the stomach: • Lesser curvature: • Right gastric artery: from hepatic artery. • Left gastric artery: from celiac trunk. • Greater curvature: • Right gastroepiploic artery: from gastroduodenal artery. • Left gastroepiploic artery: from splenic artery. • Pylorus: gastroduodenal artery. • Fundus: short gastric arteries. • Innervation of the stomach: • Sympathetic: T5-T10. • Parasympathetic: • Anterior gastric wall: left vagus nerve (gives hepatic branch). • Posterior gastric wall: right vagus nerve (gives celiac branch).
Anatomy, Histology & Physiology of Stomach • Histology: • Cardia: glands secreting mucous. • Fundus: • Parietal cells: secreting HCl and intrinsic factor (which combines with vitamin B12 and facilitates its absorption in terminal ileum). Acid secretion is regulated by: • Gastrin. • Histamine (via H2-receptors). • Vagal stimulation (via M3-receptors). • Chief cells: secreting pepsinogen which is converted to pepsin by the acidic environment and digests protein. • Antrum: • G-cells: secreting gastrin which functions in: • Stimulation of gastric acid secretion. • Growth of gastric mucosa. • Stimulation of pepsinogen secretion. Gastrin secretion is stimulated by Gastrin-Releasing Peptide (GRP) + presence of amino acids in the stomach. It is inhibited by somatostatin.
GI Hormones • Immunological function of small bowel: • Secretion of IgA. • MALT (Mucosal Associated Lymphoid Tissue) is composed of: mucosal lymphocytes, lymphoid nodules, isolated lymphoid folicles in appendix and mesenteric lymph nodes.
Peptic Ulcer Disease (PUD) – Introduction • Definition of PUD = duodenal ulcer + gastric ulcer. • Risk factors for development of PUD: • Helicobacter pylori infection. • NSAIDs (due to inhibition of PG which acts as a protective barrier of gastric mucosa) and corticosteroids. • Smoking. • Burns (curling ulcer): due to due to sluggish blood flow to gastric mucosa. • Head trauma (cushing ulcer): due to increased vagal stimulation which in turn increases gastric acid production. • Family history of PUD. • Zollinger-Ellison syndrome. • Complications of PUD: • Bleeding (20%): • Occurs with posterior ulcers. • Gastric ulcer: left gastric artery. • Duodenal ulcer: gastroduodenal artery. • Signs and symptoms: dizziness, syncope, hematemesis/melena. • Perforation (7%): • Occurs with anterior ulcers. • Characterized by sudden, severe epigastric pain radiating to the right shoulder + air under diaphragm (with x-ray). • Valentino’s sign: RLQ pain/peritonitis as a result of succus collecting from a perforated peptic ulcer. • What is a Graham patch? Piece of omentum incorporated into the suture closure of perforation.
Peptic Ulcer Disease (PUD) – Duodenal Ulcer • It occurs mainly in males and discovered 2 decades earlier than gastric ulcer. In duodenal ulcer, there is increased acid production and the most common location is posterior wall in the first 2 cm of the duodenum. • Causes: • Almost always caused by H.pylori infection which is a urease-producing organism that damages gastric mucosa. • It can also be caused by NSAIDs/steroids. • Suspect that patient has Zollinger-Ellison syndrome when there are recurrent duodenal ulcers not responding to H.pylori treatment. • Signs and symptoms: • Burning epigastric pain which is relieved by food. • Nausea and vomiting. • Association with blood type (O). • Diagnosis: • Mainly a clinical diagnosis. • Endoscopy is done when there are alarming symptoms: bleeding/anemia, weight loss, dysphagia and recurrent vomiting. • Detection of H.pylori infection: can be done with serology (IgG) or urea-breath test (ingestion of C13/14 labeled urea). When treatment to eradicate H.pylori infection is given to the patient, follow-up is with detection of stool antigen. • Treatment: • Medical: • Stop smoking, NSAIDs and steroids + lifestyle modifications. • Proton-Pump Inhibitors (PPIs: omeprazole): 90% cure after 4 weeks. • H2-blockers (ranitidine): 85% cure after 8 weeks. • Antacids: symptomatic relief. • Eradication of H.pylori infection: • Triple therapy (for 2 weeks): amoxicillin, clarithromycin and PPI. • Quadraple therapy (for 2 weeks): bismuth, tetracycline, metronidazole and PPI. • Surgical: • Indicated when there is: hemorrhage, perforation or obstruction. • Procedure: highly selective vagotomy.
Peptic Ulcer Disease (PUD) – Gastric Ulcer • There is decreased acid production and damage to mucosal protective mechanisms (↓ mucous and bicarbonate production). • Causes: • H.pylori infection. • NSAIDs/ steroids. • Smoking. • Signs and symptoms: • Burning epigastric pain which is increased by food. Therefore, patient will avoid eating and this will result in weight loss. • Nausea and vomiting. • Association with blood type (A). • Diagnosis: • When clinically suspected, you have to do endoscopy and take a biopsy because here there is a risk of gastric adenocarcinoma and you want to rule it out. • Treatment: depends on classification of gastric ulcers
Gastritis • Definition: It is acute or chronic inflammation of gastric lining. • Causes: “GNASHING” • G: Gastric reflux. • N: Nicotine. • A: Alcohol. • S: Stress. • H: H.pylori. • I: Ischemia. • N: NSAID’s. • G: Glucocorticoids. • There are 2 types: • Type-A (fundal): autoimmune destruction of parietal cells of the stomach resulting in pernicious anemia and achlorhydria. • Type-B (antral):H.pylori infection. • Diagnosis: endoscopy. • Treatment: same as medical treatment for PUD. • Complications: • Gastric atrophy. • Gastric metaplasia: with increased risk of MALT lymphoma and gastric adenocarcinoma.
Post-Gastrectomy Complications • Dumping syndrome: • It results from unregulated movement of gastric contents to small intestine. • There are 2 types: • Early dumping syndrome: 5-15 minutes post-prandially; due to high osmolar load reaching small intestine. • Late dumping syndrome: 2-4 hours postprandially; due to hypoglycemia. • Signs and symptoms: flushing, sweating, tachycardia/palpitations, nasuea/vomiting, diziness/syncope and diarrhea. • Treatment: • Small, frequent meals (low in carbohydrates and fat). • Avoid excessive fluid intake. • Alkaline reflux gastritis: • Presents with: postpradial pain + bilious vomiting. • Treatment: Roux-en-Y gastrojejunostomy. • Nutritional deficiencies: vitamin B12 deficiency anemia and iron deficiency anemia. • Afferent loop snydrome. • Postvagotomy diarrhea.
Gastric Outlet Obstruction • Causes: • Tumors of the stomach or head of the pancreas. • Ulcers (especially duodenal ulcers). Notice that chronic ulcers can result in scarring and edema which obstruct the lumen. • Symptoms: • Early: abdominal distention, gastric reflux and early satiety. • Late: vomiting, dehydration, hypokalemichypochloremic metabolic alkalosis with paradoxical aciduria, weight loss. • Diagnosis: • Barium meal. • Endoscopy. • Treatment: • NG tube (for gastric decompression). After 7 days → truncalvagotomy and gastrojejunostomy.
Upper GI Hemorrhage • Definition: bleeding which occurs proximal to ligament of Treitz. • Differentials: • Esophagus: • Mallory-Weiss syndrome: post-emetic (mucosal tear) in gastroesophageal junction which resolves spontaneously. • Boerhaave syndrome: post-emetic (rupture) in posterolateral aspect (left) of the esophagus near gastroesophageal junction. • Esophagitis. • Esophageal varices (in patient suffering from liver cirrhosis and portal hypertension). • Esophageal cancer. • Stomach and duodenum: • PUD (gastric or duodenal ulcers). • Gastritis. • Gastric cancer. • Signs and symptoms: • Hematemesis (bright red blood or coffee ground). • Melena (black, tarry stool occurs when bleeding is more than 60 cc). If there is profuse upper GI bleeding, patient can present with hematochezia (bright red blood per rectum). • Signs of hypovolemic shock (hypotension and tachycardia). • Diagnosis: • CBC: check Hb and Hct; blood type and cross-match. Check for coagulation profile. • NG tube aspirate. • Endoscopy. • Rate of bleeding ≥ 0.5 ml/minute: bleeding scan. • Rate of bleeding ≥ 1 ml/minute: arteriography. • Treatment: IV fluids + blood products then search for the cause.
Bariatric Surgery • Definition: weight reduction surgery for morbidly obese patients. • How to calculate BMI (Body Mass Index)? • BMI = weight (kg) / height (m)2 • What are the indications for bariatric surgery? • BMI ≥ 35 with other diseases (such as diabetes or hypertension). • BMI ≥ 40 with or without other diseases but there has to be a participation in a dietary program with no results. • What are the medical conditions which are associated with morbid obesity: • Diabetes mellitus. • Hypertension. • Coronary Artery Disease. • Obstructive sleep apnea. • Mention the types of bariatric surgery: • Restrictive: reducing quantitiy of food which you can eat • Gastric sleeve resection. • Band placement. • Malabsorptive: liming absorption by bypassing duodenum and small intestine: • Gastrojejunostomy.
Adenocarcinoma (95%): • Incidence increases with advanced age (< 60 years). It is more common among males and blacks. In addition, it is considered to be the leading cause of cancer-related deaths in Japan. • Risk factors: • Familial adenomatouspolyposis. • Chronic atrophic gastritis. • H. pylori infection. • Smoked food. • Smoking. • Pathological types: • Polypoid (25-50%). • Ulcerative (25-50%): with sharp margins. • Superficial spreading (3-10%): involves mucosa and submucosa only; has the best prognosis. • Linitisplastica (7-10%): involves all the layers; extremely poor prognosis. • Histologic types: • Intestinal: well-differentiated, distal, progressing to cancer slowly, secondary to environmental factors, usually 1 mass identified. • Diffuse: poorly-differential, proximal, aggressive, congenital, characterized by generalized gastric hypertrophy. • Signs and symptoms: • Constant epigastric pain which increases with food. • Hematemesis. • Melena. • Weight loss and anorexia. • Blumer’s shelf: metastasis to pelvic cul-de-sac; felt by digital rectal examination. • Krukenberg’s tumor: metastasis to ovaries. • Virchow’s node: metastasis to left supraclavicular lymph node. • Sister Mary Joseph’s nodule: periumbilical metastatic nodule. • Irish’s node: left axillaryadenopathy from gastric cancer. Malignant Tumors
Adenocarcinoma (continued): • Diagnosis: • Best: upper GI endoscopy with biopsy. • Endoscopic ultrasound. • Abdomino-pelvic CT-scan: for staging. • Staging (TNM): • Tumor: • Tx: tumor cannot be assessed. • T0: no evidence of tumor. • Tis: carcinoma in situ. • T1: involving submucosa. • T2: reaching muscularispropria. • T3: subserosal, not reaching adjacent structures. • T4: involving adjacent structures. • Nodes: • Nx: lymph nodes cannot be assessed. • N0: no evidence of lymph node involvement. • N1: 1-2 regional lymph nodes. • N2: 3-6 regional lymph nodes. • N3: ≥ 7 regional lymph nodes. • Metastasis: • Mo: no distant metastasis. • M1: distant metastasis. • Treatment (gastrectomy with lymph node disection + chemotherapy/radiation): • Proximal and midbody tumors: total gastrectomy. • Antrum tumor: distal subtotal gastrectomy. • Prognosis: tumor markers (not specific) → CEA and CA 19-9 Malignant Tumors
Gastric lymphoma (4%): • Most are non-Hodgkin B-cell type. Risk is increased with H.pylori infection. • Signs and symptoms (non-specific): abdominal pain, bleeding/anemia, nausea/vomiting and weight loss/anorexia. • Diagnosis: • Upper endoscopy with biopsy. • Bone marrow aspiration and gallium bone scan (for metastasis). • Treatment: • Low-grade MALT: treat H.pylori infection. • High-grade MALT or non-MALT: radiation/chemotherapy ± surgical resection (which is preserved for those with perforation or hemorrhage). • GIST (1%) Gasto-Intestinal Stromal Tumor: • Arising from cells of Cajal, submucosal, slow growing. • Stomach is the most common site. • Expression of c-kit (CD 117) which has tyrosine kinase activity. • Treatment: surgical removal + imatinib (inhibits tyrosine kinase receptor). Malignant Tumors
Menetier’s disease: • Definition: it is hypertrophic gastropathy in which glandular cells will replace parietal and chief cells resulting in protein deficiency. • Signs and symptoms: • Middle-aged male who presents with epigastric pain, anorexia/weight loss, diarrhea and hypoproteinemia. • Diagnosis: • Endoscopy with biopsy. • Barium swallow: shows thickened rugae. • Treatment: • Anticholinergics and H2-blockers to reduce protein loss. • High-protein diet. • Dieulafoy’s lesion: • Definition: mucosal end artery which causes pressure necrosis, erodes into the stomach and ruptures. • Signs and symptoms: recurrent, massive, painless hematemesis. • Diagnosis: upper GI endoscopy. • Treatment: endoscopic sclerosing therapy or electrocoagulation. • Gastric volvulus: • Definition: twisting of the stomach around its long axis. This is associated with paraesophageal hernia. • It is characterized by Brochardt’s triad: • Inability to vomit. • Difficulty in passing NG tube. • Intermittent, severe epigastric pain and distention. • Diagnosis: upper GI contrast study. • Treatment: • Surgical repair of associated paraesophageal hernia. • Gastropexy: fixation of stomach to anterior abdominal wall. Benign Lesions