Stomach (Hertz) Flashcards
cardia produces
mucin (to protect the esophagus)
gastric body produces
acid and intrinsic factor
antrum produces
G cells there make gastrin
Acute Gastritis
Gastritis is a mucosal inflammatory process. When neutrophils are present, the lesion is referred to as acute gastritis. When inflammatory cells are rare or absent, the term gastropathy is applied
Hypertrophic gastropathy
is applied to a specific group of diseases exemplified by Ménétrier disease and Zollinger-Ellison Syndrome
things that disrupt stomach protective mechanisms
*Nonsteroidal antiinflammatory drugs (NSAIDs) inhibit cyclooxygenase- (COX) dependent synthesis of prostaglandins E2 and I2, which stimulate nearly all of the above defense mechanisms including mucus, bicarbonate, and phospholipid secretion, mucosal blood flow, and epithelial restitution while reducing acid secretion.
The gastric injury that occurs in uremic patients and those infected with urease-secreting *H. pylori may be due to inhibition of gastric bicarbonate transporters by ammonium ions.
- Reduced mucin and bicarbonate secretion have been suggested as factors that explain the increased susceptibility of older adults to gastritis.
- Decreased oxygen delivery may account for an increased incidence of acute gastritis at high altitudes.
Clinical Features
of gastropathy and acute gastritis
varies according to etiology, and the two cannot be distinguished on clinical grounds.
Patients with NSAID-induced gastropathy may be asymptomatic or have persistent epigastric pain that responds to antacids or proton pump inhibitors.
In contrast, pain associated with bile reflux is typically refractory to such therapies and may be accompanied by occasional bilious vomiting
Stress-Related Mucosal Disease
Stress ulcers are most common in individuals with shock, sepsis, or severe trauma.
Also Curling and Cushing ulcers.
Curling ulcers
Ulcers occurring in the proximal duodenum and associated with severe burns or trauma are called Curling ulcers.*
Cushing ulcers
Gastric, duodenal, and esophageal ulcers arising in persons with intracranial disease are termed Cushing ulcers and carry a high incidence of perforation.
Dieulafoy lesion
is caused by a submucosal artery that does not branch properly within the wall of the stomach. This results in a mucosal artery with a diameter of up to 3 mm, or 10 times the size of mucosal capillaries. Dieulafoy lesions are most commonly found along the lesser curvature, near the gastroesophageal junction. Erosion of the overlying epithelium can cause gastric bleeding that, while usually self-limited, can be copious. Bleeding is often associated with NSAID use and may be recurrent.
GAVE
is responsible for 4% of non-variceal upper gastrointestinal bleeding. It can be recognized endoscopically as longitudinal stripes of edematous erythematous mucosa that alternate with less severely injured, paler mucosa, and is sometimes referred to as *watermelon stomach. The erythematous stripes are created by ectatic mucosal vessels. Histologically, the antral mucosa shows reactive gastropathy with dilated capillaries containing fibrin thrombi. While most often idiopathic, GAVE can also be associated with cirrhosis and systemic sclerosis. Patients may present with occult fecal blood or iron deficiency anemia.
associated with NSAIDs*
Chronic Gastritis
The most common cause of chronic gastritis is infection with the bacillus H. pylori. Autoimmune gastritis, the most common cause of diffuse atrophic gastritis, represents less than 10% of cases of chronic gastritis, but is the most common form of chronic gastritis in patients without H. pylori infection.
Helicobacter pylori Gastritis
H. pylori infection most often presents as a predominantly *antral gastritis with normal or increased acid production
- Flagella, which allow the bacteria to be motile in viscous mucus
- Urease, which generates ammonia from endogenous urea and thereby elevates local gastric pH and enhances bacterial survival
- Adhesins that enhance bacterial adherence to surface foveolar cells
- Toxins, such as cytotoxin-associated gene A (CagA), that may be involved in disease progression
Comparison: H pylori vs autoimmune gastritis
H pylori- in antrum, neutrophils and subepithelial plasma cells are the inflammatory infiltrate, gastrin is normal to decreased, other lesions: hyperplastic/ inflammatory polyps. Serology: antibodies to H. pylori. Sequelae: peptic ulcer, adenocarcinoma, MALToma. Associations: low socioeconomic status, povery, residence in rural areas
Autoimmune: located in body of stomach. lymphocytes and macrophages as infiltrate. Acid production decreased, gastrin increased. Other lesions: neuroendocrine hyperplasia. Serology: atibodies to parietal cells (H+, K+, ATPase, intrinsic factor). Sequelae: atrophy, pernicious anemia, adenocarcinoma, carcinoid tumor. Associations: autoimmune disease, thyroiditis, diabetese mellitus, graves disease
Clinical features (and detection) of H pylori
In addition to histologic identification of the organism, several diagnostic tests have been developed including a noninvasive serologic test for antibodies to H. pylori, *fecal bacterial detection, and the urea breath test based on the generation of ammonia by the bacterial urease.
Gastric biopsy specimens can also be analyzed by the *rapid urease test, bacterial culture, or bacterial DNA detection by PCR.
Effective treatments for H. pylori infection include combinations of antibiotics and proton pump inhibitors. Individuals with H. pylori gastritis usually improve after treatment, although relapses can occur after incomplete eradication or reinfection, which is common in regions with high endemic colonization rates.
Autoimmune Gastritis- what do we find?
Autoimmune gastritis accounts for less than 10% of cases of chronic gastritis. In contrast to H. pylori–associated gastritis, autoimmune gastritis typically spares the antrum and is associated with hypergastrinemia*
-Antibodies to parietal cells and intrinsic factor that can be detected in serum and gastric secretions
-Reduced serum pepsinogen I concentration
-Endocrine cell hyperplasia
Vitamin B12 deficiency
-Defective gastric acid secretion (achlorhydria)
Autoimmune Gastritis- cellular stuff
Autoimmune gastritis is associated with loss of parietal cells, which are responsible for secretion of gastric acid and intrinsic factor
CD4+ T cells directed against parietal cell components, including the H+,K+-ATPase, are considered to be the principal agents of injury in autoimmune gastritis
Autoantibodies to parietal cell components, most prominently the H+,K+-ATPase, or proton pump, and intrinsic factor are present in up to 80% of patients with autoimmune gastritis
diagnosis, clinical features of autoimmune gastritis and pernicious anemia
Because of the slow onset and variable progression, patients are generally diagnosed only after being affected for many years; the median age at diagnosis is 60.
Pernicious anemia and autoimmune gastritis are often associated with other autoimmune diseases including Hashimoto thyroiditis, insulin-dependent (type I) diabetes mellitus, Addison disease, primary ovarian failure, primary hypoparathyroidism, Graves disease, vitiligo, myasthenia gravis, and Lambert-Eaton syndrome
Clinical presentation may be linked to symptoms of anema. Vitamin B12 deficiency may also cause atrophic glossitis, in which the tongue becomes smooth and beefy red, epithelial megaloblastosis, malabsorptive diarrhea, peripheral neuropathy, spinal cord lesions, and cerebral dysfunction.
neuro features of autoimmune gastritis
Neuropathic changes include demyelination, axonal degeneration, and neuronal death. The most frequent manifestations of peripheral neuropathy are paresthesias and numbness.
The spinal lesions result from demyelination of the dorsal and lateral spinal tracts, giving rise to a clinical picture that is often referred to as subacute combined degeneration of the cord.
It is associated with a mixture of loss of vibration and position sense, sensory ataxia with positive Romberg sign, limb weakness, spasticity, and extensor plantar responses.
Complications of Chronic Gastritis
Peptic ulcer disease (PUD) refers to chronic mucosal ulceration affecting the duodenum or stomach. Nearly all peptic ulcers are associated with H. pylori infection, NSAIDs, or cigarette smoking. The most common form of peptic ulcer disease (PUD) occurs within the gastric antrum or duodenum as a result of chronic, H. pylori-induced antral gastritis, which is associated with increased gastric acid secretion, and decreased duodenal bicarbonate secretion
Epidemiolog of Peptic Ulcer Disease
Epidemiology. The incidence of PUD is falling in developed countries along with reduced prevalence of H. pylori, infection. However, a new group of duodenal PUD patients older than 60 years of age has emerged as a result of increased NSAID use
PUD results from imbalances between mucosal defense mechanisms and damaging factors that cause chronic gastritis