B46. Gastritis

Question 1

What are the main causes of gastritis?

Answer 1

Things that disrupt any of the mechanisms that the stomach uses to protect itself from its own acid. Gastritis is essentially acidic damage of the stomach causing inflammation and direct damage.

An imbalance of increased acidic content and decreased mucosal defenses.

Defenses: Mucous layer, Bicarbonate secretion, Adequate blood supply.

• Reduced mucous synthesis and secretion, seen in elderly
• NSAID drugs, reduce prostaglandins, reduces bicarbonate secretion and decreases vasodilation, increasing acidity and decreasing blood flow.
• NSAIDs are also directly toxic to gastric mucosa and cause irritation on an empty stomach.
• H pylori infection
• Alcoholism can cause chronic gastritis
• Gastrin producing tumors causing excessive acid production, pancreatic gastrinomas
• Injestion of chemicals, bleach, acids.
• Chemotherapy and Radiation therapy
• Nasogastric tubes cause mechanical trauma and inflammation.

Question 2

Describe the histology of mild vs. moderate or sever gastritis

Answer 2

Mild acute gastritis involves mild edema and neutrophils in the epithelium.

More severe acute gastritis causes erosion of the mucosal epithelium, and neutrophil and inflammatory infiltration into the mucosa. May hemorrhage

Chronic gastritis involves lymphocytic and/or plasma cell infiltration of the mucosa, atrophy of the epithelium and glands.

Often H/ pylori infection is seen.

Question 3

What are the symptoms of acute gastritis?

Answer 3

Usually completely asymptomatic, and usually self resolving.

In severe cases, especially in alcoholics overlying a backround of chronic gastritis,

• epigastric pain
• nausea,
• gastric bleeding,
• vomiting of blood.
• Gastric bleeding may be severe enough to be life threatening.

Question 4

What are the 3 types of chronic gastritis and their causes?

Answer 4

3 types of chronic gastritis: Autoimmune, Bacterial, and Chemical

Autoimmune: Causes lesion of the body of the stomach, due to autoantibody production against the parietal cells Proton/Potassium ATPase pump. Death of the acid-secreting parietal cells. The lack of acid production by the stomach is called achlorhydria. These cells also secrete intrinsic factor, and their autoimmune death eventually causes pernicious anemia due to the loss of B12 absorption. Is about 10% of chronic gastritis cases

Bacterial: H. Pylori infection. This is the main cause of chronic gastritis. 90%. Increases stomach acid secretion. Causes antral gastritis at its preferred infection site. Low gastrin levels, but high acid levels. (gastrin normally drives acid secretion, but the infection drives it on its own). Eventually, the increased acidity of the stomach causes pangastritis with multifocal atrophic gastritis.

• H pylori increases the risk of:
• Peptic ulcers of the duodenum. (and to a lesser degree of the stomach, although these are more frequently due to NSAIDs).
• Gastric intestinal metaplasia with goblet cells, leading to –> Adenocarcinoma
• Intestinal MALT lymphoma

Chemical: Caused by chronic alcoholism. Leads to pangastritis and mucosal atrophy.

Question 5

What are the symptoms of chronic gastritis?

Answer 5

Usually asymptomatic, or periodic abdominal pain, nausea or vomiting.

Symptoms may appear due to a B12 deficiency and pernicious anemia. Subacute combined demyelination of the spinal cord, loss of sensation and ataxia, decreased reflexes.

Increased risk for intestinal metaplasia and gastric adenocarcinoma

Question 6

Where are the parietal cells of the stomach mainly located?

Answer 6

in the Body and the Fundus

Question 7

What are the clinical features of autoimmune gastritis?

Answer 7

Atrophy of the mucosa, particularly of the body and fundus

Achlorhydria with increased gastrin levels

Antral hyperplasia due to G-cell hyperplasia (gastrin producing cells are mostly in the antrum)

Megaloblastic/pernicious anemia.