Stomach Flashcards
1
Q
Conditions of the stomach
A
- Congenital
- Diaphragmatic hernia - herniation of abdo viscera into thoracic cavity
- Congenital pyloric stenosis - persistent projectile vomiting - Acquired
- Gastropathy & acute gastritis
- Chronic gastritis
- Peptic Ulcer Disease
- Neoplasms
2
Q
Gastropathy vs acute gastritis
A
- Gastritis is a mucosal inflammatory process
- Neutrophils present: Acute Gastritis
- Neutrophils absent: Gastropathy
3
Q
Causes of acute gastritis (5)
A
- Reactive (chemical)
- alcohol, bile, corrosives, NSAIDs, corticosteroids, cigarette smoking - Chemotherapy/radiation-induced
- Vascular - portal HTN
- Stress-induced mucosal injury (local ischemia)
- shock, sepsis, severe trauma, post-MI (stress ulcers)
- severe burns (Curling ulcers)
- intracranial disease (Cushing ulcers) - Uremia
4
Q
Pathogenesis of acute gastritis (5)
A
- Increased acid secretion with back diffusion
- Decreased bicarb buffer production
- Reduced blood flow (decreased gastric perfusion & decreased prod of cytoprotective prostaglandins)
- Disruption of adherent mucus layer
- Direct damage to epithelium
- direct acting luminal agents - alcohol, bile salts
- chemo - reduces epithelial regeneration
5
Q
Effects & complications of acute gastritis (4)
A
- Asymptomatic, epigatric pain, indigestion, n/v
- Bleeding - hematemesis, melena)
- Erosions - loss of superficial epithelium
- Ulcers
6
Q
Features of chronic gastritis
A
- chronic inflammation leading to mucosal atrophy & intestinal metaplasia
- most commonly H. pylori-associated chronic gastritis
7
Q
Pathology associated with H. pylori (4)
A
- Chronic gastritis
- Peptic ulcer
- Gastric carcinoma
- Gastric lymphoma
8
Q
Histology of chronic gastritis (4)
A
- Active inflammation - neutrophils, lymphocytes, plasma cells, lymphoid aggregates
- Regenerative changes - mitoses in epithelium, loss of mucus vacuoles
- Intestinal metaplasia, goblet cells
- Atrophy - loss in glandular structures & specialised cells
9
Q
Effects & complications of chronic gastritis
A
- mostly asymptomatic
1. Peptic ulcer disease
2. Chronic atrophic gastritis
3. Malignancies - carcinoma, lymphoma
10
Q
Features of autoimmune gastritis (<10%)
A
- due to autoantibodies produced against gastric parietal cells & intrinsic factor (detected in serum & gastric secretions)
- associated with other autoimmune disorders - Hashimoto, DM, Graves
11
Q
Effects & complications of autoimmune gastritis (5)
A
- Defective gastric acid secretion - hypo/achlorhydria
- Endocrine cell hyperplasia - hypergastrinemia
- Disabled ileal vit B12 absorption - megaloblastic (pernicious) anemia
- Chief cell destruction - reduced serum pepsinogen conc
- Increased risk of adenocarcinomas, carcinoid tumour
12
Q
Other uncommon forms of gastritis
A
- Eosinophilic gastritis
- due to allergies, parasitic infections, immune disorders - Lymphocytic gastritis
- assoc w women, celiac disease - Granulomatous gastritis
13
Q
Definition of peptic ulcer disease
A
- chronic mucosal ulceration affecting duodenum, stomach
- penetrates muscularis mucosae & beyond
14
Q
Sites of peptic ulcers
A
- duodenum, 1st part (75%)
- stomach, lesser curve, antrum 20%
- lower esophagus in GERD, stomal ulcer, Merkel diverticulum, distal duodenum/jejunum
15
Q
Risk factors for peptic ulcers
A
- H. pylori infection
- Drugs - illicit eg cocaine, NSAIDs
- Smoking, alcohol
- Physiological stress - increases acid secretion
- Endocrine hyperplasia - stim parietal cell growth
- Zollinger-Ellison syndrome
16
Q
Pathogenesis of peptic ulcer disease
A
Imbalance between mucosal defences & damaging forces
- ureases generate free ammonia from endogenous urea - increases gastric pH
- proteases break down glycoprotein in gastric mucus
- phospholipase damage epithelial cells, release bioactive leukotrienes, damaged mucosa allows leakage of nutrients in
- neutrophils affected by H. pylori release myeloperoxidase
- H. pylori damages epithelial/endothelial cells, bacterial platelet activating factor promotes thrombotic occlusion of mucosal capillaries
- other antigens recruit inflam cells to the mucosa
- chronically inflamed mucosa is more susceptible to acid injury
17
Q
Features of gastric ulcers
A
- gastric body/fundus
- impaired mucosal defence - motility defects, mucosal ischemia, mucosal inflammation
- mucosal atrophy
18
Q
Features of duodenal ulcers
A
- most common
- excessive acid-pepsin secretion that overwhelms impaired mucosal defences
- epigastric pain relieved by food
- increased gastric acid secretion, decreased duodenal bicarbonate secretion
19
Q
Morphology of peptic ulcer
A
G:
- round to oval, sharply demarcated, punched out defect
- mucosal margin may overhang base slightly, variable depth, smooth & clean base
- scarring & puckering of wall - stellate appearance
M:
- surface zone of fibrinopurulent exudate
- acidophilic layer of necrotic tissue
- zone of granulation tissue
- zone of dense scar tissue
- interruption of muscularis propria & mucosae
20
Q
Effects & complications of peptic ulcer (5)
A
- Epigastric burning pain, relived by food (DU), alkali (antacids), worse when hungry & at night
- Bleeding (15-20%) - mild & chronic - iron def anemia, severe & acute - hematemesis
- Perforation (5%) - with consequent acute peritonitis
- Obstruction (2%) - due to edema, scarring & strictures
- Gastric adenocarcinoma
21
Q
Neoplasms & precancerous lesions of the stomach
A
- Polyps
- Adenocarcinoma
- Neuroendocrine cell tumours - carcinoid tumours
- Gastrointestinal stromal tumours (GIST)
- Gastric lymphomas
22
Q
Polyps of the stomach
A
- Hyperplastic polyps
- benign, common, reaction to chronic inflammation, precedes chronic gastritis
- surface erosions may cause bleeding - Fundic gland polyps
- causes: sporadic or familial
- associated w reduced acidity or hypergastrinemia leading to oxyntic glandular hyperplasia
23
Q
Definition of gastric adenocarcinoma
A
malignant neoplasm showing GI epithlial glandular differentiation
24
Q
Risk factors of gastric adenocarcinoma (5)
A
- General
- age >55, M, Japan, Korea, E Europe, Latin America - Body - obesity
- Lifestyle
- smoking, diet (preserved food), working in coal, metal, rubber industries - Genetics eg Lynch syndrome, HNPCC
- Others - H. pylori infection
25
Q
Types of gastric adenocarcinoma
A
G: patterns of growth
- Exophytic
- Flat/depressed
- Excavated
M:
- Intestinal type - papillary, tubular, mucinous
- Diffuse type - signet ring cell, undifferentiated
26
Q
Clinical features of gastric adenocarcinoma
A
- often asymptomatic, non specific symptoms, late detection, poor prognosis
- early gastric cancer - invasive, invades no deeper than submucosa
- prognosis depends on depth of invasion, extent of nodal & distant mets
- treatment - surgical resection +/- adjuvant chemo & radiation
27
Q
Growth & spread of gastric adenocarcinoma
A
- pylorus & antrum > cardia, lesser curvature > greater curvature, distal > proximal
- invades esophagus, duodenum, omentum, colon, pancreas, spleen
- death due to widespread seeding of peritoneum & liver/lung mets
- also mets to adrenals, peritoneum, ovary spleen, supraclavicular nodes (Virchow’s node, Trousseau’s sign)
- extensively infiltrated gastric wall - rigid, thickened - linitis plastica
28
Q
Gastric neuroendocrine tumours (Carcinoids)
A
- derived from enterochromaffin-like cells (ECL) in gastric mucosa
- assoc w chronic atrophic gastritis, MEN type I, Zollinger-Ellison syndrome
- results in a hypergastrinemic state - ECL cell hyperplasia - presumed precursor lesion
29
Q
Gastrointestinal stromal tumours (GIST)
A
- can occur as polypoidal intramural tumour masses
- ulcerate overlying GI mucosa
- most frequent sarcoma of GIT
