Stomach Flashcards
Gastroschisis
Congenital malformation of the anterior abdominal wall leading to exposure of the abdominal contents
omphalocele
Persistent herniation of bowel into umbilical cord
- due to failure of herniated intestines to return to the body cavity during development
- contents are covered by peritoneum and amnion of the umbilical cord
Pyloric stenosis
Congenital hypertrophy of pyloric smooth muscle –> more common in males
Classically presents two weeks after birth as:
- projectile non-bilious vomiting
- visible peristalsis
- olive like mass in the abdomen
Treatment is myotomy
Acute gastritis
Acidic damage to the stomach mucosa –> due to imbalance between mucosal defenses and acidic environment
Defenses include
- mucin layer –> produced by foveolar cells
- bicarbonate secretion by surface epithelium
- normal blood supply –> provides nutrients and picks up leaked acid
Risk factors
- severe burn (curling ulcer) –> hypovolemia leads to decreased blood supply
- NSAIDs –> decreased PGE2
- heavy alcohol consumption –> toxic to mucosa
- chemo –> kills rapidly turning over cells
- increased intracranial pressure (cushing ulcer) –> increased stimulation of bagus nerve leads to increased acid production
- shock –> multiple (stress) ulcers may be seen in ICU patients due to decreased blood flow
Acid damage results in superficial inflammation, erosion (loss of superficial epithelium) or ulcer (loss of mucosal layer)
Chronic gastritis
Chronic inflammation of the stomach –> non-erosive
- divided into two types based on underlying etiology
1. chronic autoimmune gastritis
2. chronic h pylori gastritis
Chronic autoimmune gastritis
Due to autoimmune destrcution of gastric parietal cells –> located in the stomach body and fundus
- associated with antibodies against parietal cells and/or intrinsic factor –> useful for dx, but pathogenesis is mediated by T cells (type 4 hypersensitivity)
Clinical features
- atrophy of mucosa with intestinal metaplasia
- achlorhydria with increased gastrin levels and antral g cell hyperplasia
- megaloblastic (pernicious) anemia due to lack of intrinsic factor
- increased risk for gastric adenocarcinoma (intestinal type)
Chronic h pylori gastritis
Due to H pylori induced acute and chronic inflammation –> most common form of gastritis (90%)
- h pylori ureases and proteases along with inflammation weaken mucosal defenses –> antrum is most common site
- presents with epigastric abdominal pain –> increased risk for ulceration(peptic ulcer disease), gastric adenocarcinoma (intestinal type) and MALT lymphoma
Treatment involves triple therapy
- resolves gastritis/ulcer and reverses intestinal metaplasia
- negative urea breath test and lack of stool antigen confirm eradication of h pylori
Peptic ulcer disease
Solitary mucosal ulcer involving proximal duodenum (90%) or distal stomach (10%)
Duodenal ulcer is almonst always due to h pylori (>95%), rarely may be due to ZE syndrome
- presents with epigastric pain that improves with meals
- diagnostic endoscopic biopsy shows ulcer with hypertrophy of brunner glands
- usually arises in anterior duodenum –> when present in posterior duodenum, rupture may lead to bleeding from the gastroduodenal artery or acute pancreatitis
Gastric ulcer –> usually due to h pylori (75%), other causes include NSAIDs and bile reflux
- presents with epigastric pain that worsens with meals
- ulcer is usually located on the lesser curvature of the antrum
- rupture carries risk of bleeding from left gastric artery
Differential diagnosis of ulcers
Includes carcinoma
- duodenal ulcers are almost never malignant –> duodenal carcinoma is extremely rare
- gastric ulcers can be caused by gastric carcinoma (intestinal subtype)
- –> benign peptic ulcers = usually small ( malignant ulcers = large and irregular with heaped up margins
Biopsy required for definitive diagnosis
Gastric carcinoma
Malignant proliferation of surface epithelial cells (adenocarcinoma)
- divided into intestinal and diffuse types
- presents late with weight loss, abdominal pain, anemia and early satiety
- rarely presents as acanthosis nigricans (thickening and darkening of skin, esp. in axillary region) or leser-trelat sign (dozens of severated keratoses all over skin that arise suddenly)
Spread to lymph nodes can involve the left supraclavicular node (virchow node)
- distant metastasis most commonly involves liver
- mets to periumbilical region = sister mary joseph nodule –> seen with intestinal type
- mets to ovaries bilaterally = krukenberg tumor –> seen with diffuse type
Intestinal type gastric carcinoma
More common, presents as large, irregular ulcer with heaped up margins –> most commonly involves lesser curvature of the antrum (similar to gastric ulcer)
Risk factors
- intestinal metaplasia (eg due to h pylori and autoimmune gastritis)
- nitrosamines in smoked foods (japan)
- blood type A
Diffuse type
Characterized by signet ring cells that diffusely infiltrate the gastric wall –> desmoplasia results in thickening of he stomach wall = linitis plastica
- not associated with h pylori, intestinal metaplasia, or nitrosamines
