What is the purpose of foveolar cells in the cardia of the stomach?
they secrete mucin which coats food to prevent it from physically touching and harming the gastric epithelium as in the case of acute gastritis
What are the most common peptic ulcers?
-stress ulcers, commonly affecting critically ill pts. with shock, sepsis, burns, etc.
Curling ulcers, occuring in the proximal duodenum in association with burns
Cushing ulcers, arising in the stomach, duodenum, or esophagua of persons with intracranial disease
How are intestinal ulcers associated with intracranial disease as in Cushing ulcers?
thought to be caused by direct stimulation of vagal nuclei, causing gastric acid hypersecretion
T or F. The symptoms and signs of chronic gastritis are less severe but more persistent than those of acute gastritis
T. Again, N/V may occur with abdominal discomfort, but hematemesis is uncommon, unlike acute gastritis
What is the msot common cause of chronic gastritis?
H. pylori. In pts without H. pylori, autoimmune gastritis is the most common cause
T or F. The incidence of H. pylori infection correlates most closely with sanitation and hygiene during a person's childhood
T. Infection is often pediatrically acquired
How does H. pylori infection present?
Most often as an antral gastritis with high acid production, despite hypogastrinemia
What are the virulence factors of H. pylori?
-urease, which generates ammonia from urea to elevate the local pH
-adhesions to foveolar cells
-toxins via CagA that may be involved in ulcer or cancer development
T or F. Autoimmune gastritis typically spares the antrum and induce HYPERgastrinemia
What is autoimmune gastritis?
Abs to parietal cells and intrinsic factor in the body of the stomach which results in:
-reduces serum pepsinogen I levels
-antral endocrine cell hyperplasia
-vit B12 deficiency
Why is autoimmune gastritis associated with hypergastrinemia?
loss of parietal cells and thus acid stimulates production of gastrin in the antrum G cells
How does pernicious anemia present (as in the case of autoimmune gastritis)?
The symptoms of pernicious anemia come on slowly. Untreated, it can lead to neurological complications, and in serious cases, death. Many of the signs and symptoms are due to anemia itself, when anemia is present.
Symptoms may consist of the triad of tingling or other skin sensations (paresthesia), tongue soreness (glossitis), and fatigue and general weakness.
It presents with a number of further common symptoms, including depressive mood, low-grade fevers, diarrhea, dyspepsia, weight loss, neuropathic pain, jaundice, sores at the corner of the mouth (angular cheilitis), a look of exhaustion with pale and dehydrated or cracked lips and dark circles around the eyes, as well as brittle nails, and thinning and early greying of the hair.
Because PA may affect the nervous system, symptoms may also include difficulty in proprioception, memory changes, mild cognitive impairment (including difficulty concentrating and sluggish responses, colloquially referred to as brain fog), and even psychoses, impaired urination, loss of sensation in the feet, unsteady gait, difficulty in walking, muscle weakness and clumsiness.
Anemia may also lead to tachycardia (rapid heartbeat), cardiac murmurs, a yellow waxy pallor, altered blood pressure (low or high), and a shortness of breath (known as "the sighs"). The deficiency also may present with thyroid disorders.
Peptic ulcer disease is most often associated with what?
H. pylori infection or NSAID use
Although more than 70% of PUD cases are associated with H. pylori infection, only 5-10% of these pts. develop ulcers. Gastric hyperacidity is fundamental to the development of PUD, either driven by H. pylori, parietal cell hyperplasia, or elevated gastrin release as in ZE Syndrome
What is Zollinger-Ellison Syndrome?
characterized by multiple peptic ulcerations in the stomach, duodenum, and even jejunum caused by hyper-gastrin release by a tumor and subsequent acid production
What are some risk factors for PUD?
-cigs, which imapir mucosal blood flow and healing
-hyperPTH and chronic kidney failure
Why do hyperPTH and chronic kidney failure increase the risk of PUD?
hypercalcemia stimulates gastrin production
Peptic ulcers are most common where?
4x more common in the proximal duodenum than in the stomach
Note that most peptic ulcers are solitary
Describe the pain of PUD
it tends to occur 1-3 hrs after meals during the day, is worse at night, and is relieved by alkali or food
Describe hyperplastic and inflammatory polyps in the stomach
These represent about 75% of all gastric polyps, commonly occurring between the age of 50-60, and usually arising on a background of chronic gastritis that initiates the injry followed by reactive hyperplasia. If associated with H. pylori, these regress after tx.
T or F. Hyperplastic and inflammatory polyps in the stomach are often multiple
T. Typically ovoid in shape, small, and covered by a smooth surface
The frequency with which dysplasia develops in inflammatory or hyperplastic polyps correlates with _____
size (1.5+cm= bad risk)
Describe fundic gland polyps
These occur sporadically and in persons with FAP but do NOT have neoplastic potential
Fundic gland polyps are more likely with the use of PPIs. Why?
Acid inhibition stimulates gastrin production and subsequent glandular hyperplasia
What is the most common malignancy of the stomach?
T or F. PDU does not increase the risk of gastric cancer
T. But partial gastrectomies increase the risk
What mutations are common in gastric cancers?
majority of gastric cancers are not hereditary, but CDH1 mutations leading to loss of E-cadherin are associated with those that are (usually the diffuse type)
FAP pts. with APC mutations are more likely to get intestinal-type gastric cancer
Sporadic intestinal type gastric cancer is assoicated with mutations in B-catenin, MSI, and hypermethylation
What infections raise the risk of gastric adenocarcinomas?
The _____ classification seperates gastric cancers into intestinal and diffuse types
Describe intestinal type gastric cancers
they tend to be bulky and contain abundant mucin in gland lumen
Describe diffuse type gastric cancers
marked by a signal ring cell morphology and are infiltrative so that they can stimulates a desmoplastic rxn that stiffens the gastric wall and may cause diffuse rugal flattening and rigid, thickened wall that imparts a 'leather bottle' appearance termed linitis plastica
What are the most powerful prognostic indicators for gastric cancer?
depth of invasion and the extent of nodal and distant METs at the time of daignosis
How do gastric cancers behave?
local invasion into the duodenum, pancreas, and retroperitoneum is common
What is the prognosis of gastric cancer?
90% after surgical resection in early lesions even with lymph node mets, but poor in advanced cancer (which the majority are discovered in)
What are some other common tumors of the stomach besides adenocarcinomas?
T or F. Lymphomas like to go to the stomach
T. The most common of which are indolent extranodel marginal zone B cell lymphomas, or MALTomas
What are carcinoid tumors?
Tumors arising from neuroendocrine organs (e.g. the endocrine pancreas) and neuroendocrine-differentiated GI epithelia (e.g. G-cells), the majority of which occur in the small intestine (lungs are also common)
How do carcinoid tumors present?
Present in the 60s-70s and symptoms are determined by the hormones produced. For exm, the carcinoid syndrome is caused by vasoactive substances secreted by the tumor that cause cutaneous flushing, sweating, bronchospasm, colicky abdominal pain, diarrhea, and right-side valvular fibrosis
T or F. Carcinoid syndrome is strongly associated with METs
T. Confined to intestines= first pass will degrade any vasoactive substances
What is the most important prognostic factor for GI carcinoid tumors?
Describe foregut carcinoid tumors
these are found within the stomach, duodenum proximal to the ligament of Treitx, and esophagus, and rarely METs are are curable.
Describe midgut carcinoid tumors
arise in the jejunum and ileum and are often multiple and tend to be aggressive.
Describe hindgut carcinoid tumors
these arise in the appendix and colorectum and are typically discovered incidentally. Appendical carcinoids tend to be benign while colorectal tumors tend to produce polypeptide hormones and may manifest with abdominal pain and weight loss
What is a GIST?
The most common mesenchymal tumor of the abdomen (and 50% of these occur in the stomach) (leiomyomas and leiomyosacromas can also occur but are rare)
What mutations are common in GIST?
gain of function of the gene encoding c-KIT (and some PDGFRA)
T or F. gastric GISTs are less agressive than those arising in the small intestine
T. Prognosis correlates with tumor size, mitotic index, and location
How can GIST pts. with unresectable (the mainstay tx), recurrent, or MET disease be tx?
Imatinib, an oral tyrosine kinase inhibitor of c-KIT and PDGFRa (resistance WILL develop)