Block 7 (GI) - L1 to L3 Flashcards
True or false - the tongue and the major salivary glands are part of the oral cavity.
False - the major salivary glands are NOT part of the oral cavity.
The ___ protects the airway during swallowing to avoid aspiration.
Epiglottis
What are the 3 major exocrine salivary glands (in order from largest to smallest) and what do they secrete?
- Parotid
- Submandibular
- Sublingual
Saliva (enzymes + mucus)
Describe the composition of the saliva secreted from each of the 3 major glands.
- Parotid: purely serous
- Submandibular: mixed (serous>mucinous)
- Sublingual: mixed (mucinous>serous)
The parotid gland drains via the ___ duct.
Stensen
The submandibular gland drains via the ___ duct.
Wharton
The sublingual gland drains via the ___ ducts, which terminate in the submandibular duct.
Bartholin and Rivunus
What comprises the salivary unit?
Acinus and draining duct system
Which of the salivary glands is the only one to have intraparenchymal lymph nodes?
Parotid
What is sialadenitis?
Inflammation of the salivary glands
Discuss acute sialadenitis.
Typically caused by an ascending bacterial infection (S. aureus, S. viridans) and secondary to sialolithiasis and reduced saliva flow.
Typically unilateral
What are obstructive causes of chronic/recurrent sialadenitis?
- Stenosis
- Chronic sialolithiasis
- Mucus retention
What are non-obstructive causes of chronic/recurrent sialadenitis?
Sjogren’s syndrome, sarcoidosis, TB
What are the symptoms of sialadenitis?
- Swelling and pain in the affected gland
- Fever (acute)
- Dry mouth
- Fibrosis leading to a hard salivary gland
What is the most common cause of acute, painful bilateral parotid swelling?
Mumps sialadenitis
What population is most affected by mumps?
Children
What causes mumps?
Paramyxovirus
What are conditions associated with mumps?
Orchitis (can lead to sterility), pancreatitis, or aseptic meningitis
___ is elevated when the salivary gland or pancreas is involved in mumps.
Serum amlyase
What is the treatment for mumps?
Supportive
What is the most common benign salivary gland neoplasm?
Pleomorphic adenoma (60% of parotid, submandibular, and minor salivary gland neoplasms)
Discuss the epidemiology of pleomorphic adenoma.
Adults: F>M, peaks in 4th/5th decades
Children (5-15): M>F
Describe the tumor of a pleomorphic adenoma.
Painless, slow-growing, well-circumscribed mass
Composed of glandular/ductal epithelial structures and myoepithelial cells with variable morphology present within a mesenchymal stroma
How is a pleomorphic adenoma treated?
Surgical excision
What is the second most common benign salivary gland tumor (most commonly involving the parotid gland)?
Warthin tumor (papillary cystadenoma lymphomatosum)
Describe the appearance of a Warthin tumor.
Biphasic tumor composed of bilayered oncocytic cells forming cysts and papillary fronds within a dense lymph node-like stroma (tram track)
Cyst fluid is brown and viscous, like used motor oil
Discuss the epidemiology of the Warthin tumor.
M>F, 6th and 7th decades
Smoking is an associated etiologic factor
How is a Warthin tumor treated?
Surgical excision
What is the most common malignant salivary gland tumor in children and adults?
Mucoepidermoid carcinoma
Discuss the epidemiology of mucoepidermoid carcinoma.
F>M (mean age - 47)
Describe the composition of a mucoepidermoid carcinoma.
Painless, fixed, slow-growing mass
Mucus cells, intermediate cells, and epidermoid cells with variable cystic/solid components
What is the treatment for a mucoepidermoid carcinoma?
Surgical excision +/- neck dissection
What prevents reflux of gastric contents and acid back into the esophagus?
Lower esophageal sphincter (LES)
Describe the different mucosa in the esophagus and the stomach.
Esophagus: squamous mucosa
Stomach: glandular mucosa
Separated by GEJ
What are the layers of the esophagus?
- Epithelium
- Lamina propria
- Submucosa
- Muscularis mucosa
- Muscularis externa
What is atresia?
Rare congenital defect composed of a discontinuous segment of esophagus associated with a terminal blind pouch proximally and a lower blind pouch distally
What is typically associated with atresia?
Fistula between the trachea and the lower discontinuous segment
How does a baby with atresia present?
Regurgitation shortly after birth with poor feeding
What are complications of atresia?
Aspiration +/- pneumonia, paroxysmal suffocation, and fluid/electrolyte disturbances
What is achalasia?
Failure of the LES to relax due to degeneration of the myenteric plexus with muscle denervation and increase LES resting tone
What are the symptoms of achalasia?
Odynophagia
Impaired peristalsis with progressive dysphagia
What is seen when a Barium swallow is done to detect achalasia?
“Bird’s beak” deformity and proximal dilation
What is the etiology of achalasia?
Unknown, but autoimmune or viral etiologies are suspected
What are some causes of secondary achalasia?
- Trypanosoma cruzi infection (Chagas disease)
- Mass effect from extraesophageal tumors
- Diabetes, sarcoidosis, amyloidosis
Achalasia is associated with an increased risk of ___.
Carcinoma (especially squamous cell carcinoma)
What is scleroderma?
Autoimmune mediated chronic connective tissue disorder; can be localized or systemic (two types of systemic - CREST or systemic sclerosis)
What are the symptoms of CREST?
- Calcinosis (calcium deposits in skin)
- Raynaud’s phenomenon (spasm of blood vessels in response to cold or stress)
- Esophageal dysfunction (acid reflux and decrease in motility of esophagus)
- Sclerodactyly (thickening and tightening of the skin on the fingers and hands)
- Telangiectasis (dilation of capillaries causing red marks on the surface of the skin)
What GI involvement is seen in scleroderma?
- Progressive dysphagia due to damage of esophageal tissues and fibrosis; can lead to acid reflux and secondary Barrett’s
- Aspiration
What is Plummer-Vinson Syndrome?
Triad of dysphagia, iron deficiency anemia, and esophageal webs; +/- glossitis and stomatitis/angular cheilitis
What is the epidemiology of Plummer-Vinson Syndrome?
Rare, typically affects middle-aged women
What is a hiatal hernia?
Herniation of the GEJ and/or proximal stomach into the chest cavity as a result of the separation or widening of the diaphragmatic crura
What is the cause of a hiatal hernia?
Exact cause unknown, but thought to be associated with increased abdominal pressure (obesity, pregnancy)
What are the two types of hiatal hernia?
- Sliding: GEJ and proximal stomach are pulled up into the mediastinal space
- Rolling: proximal stomach herniates through the crura
What are complications of a hiatal hernia?
Strangulation/obstruction +/- perforation, bleeding, GERD
What is a Mallory-Weiss tear?
Longitudinal mucosal lacerations or tears occuring at the GEJ in association with severe retching and vomiting (people with bulimia and alcohol use disorder)
What is a predisposing factor for a Mallory-Weiss tear?
Hiatal hernia
What is Boerhaave Syndrome?
Distal esophageal transmural rupture in association with violent retching
What can be seen on CT in Boerhaave Syndrome?
Pneumomediastinum (air in the mediastinum), sometimes a hemomediastinum - this is a surgical emergency
What are esophageal varices?
Dilated submucosal veins in the lower 1/3 of the esophagus, GEJ, and proximal stomach; appear as mucosal bumps on endoscopy
What causes esophageal varices?
Portal HTN leads to diversion of portal blood flow through the veins of the stomach and into the plexus of the lower esophageal veins
Esophageal varices are common in patients with ___.
Cirrhosis
What are some causes of esophagitis?
- GERD
- Infection (fungal, HSV, CMV)
- Eosinophilic Esophagitis
- Other (ingestion of caustics, pills/medications, chemo)
What are the general symptoms of esophagitis?
- Chest pain/heartburn (retrosternal burning pain)
- Dysphagia (difficulty swallowing)
- Odynophagia (pain with swallowing)
- Hematemesis
- Coughing and hoarseness
What is GERD and what are its causes?
Reflux of gastric acid contents into the esophagus, leading to mucosal inflammation and injury
- Incompetent LES
- Hiatal hernia
- Delayed gastric emptying/increased gastric volume
What are complications of GERD?
- Ulcerations and bleeding
2. Barrett’s esophagus
What is seen on histology in GERD?
- Variable inflammation
- Basal cell hyperplasia
- Elongation of vascular papillae
How does fungal esophagitis appear?
Limited to the epithelium, appears at white mucosal plaques
How does esophagitis with Herpes simplex virus appear?
Virus vesicles form in the epithelium, squamous cell becomes infected, can also cause ulcers in the subepithelial layers
How does esophagitis with CMV appear?
Deep linear ulcers, infecting deeper stromal or vascular endothelial cells, viral “owl eye nuclear inclusions”
What are the three M’s of HSV esophagitis?
- Multinucleation of cells
- Molding of nuclei
- Margination of chromatin
What is eosinophilic esophagitis?
Formation of esophageal rings and linear furrows +/- white mucosal discolorations due to chronic inflammation secondary to food allergen exposure
What are typical causes of pill esophagitis?
NSAID’s, bisphosphanates, antibiotics, potassium
What is Barrett’s Esophagus?
Complication of long-standing GERD; chronic acid reflux injury leads to intestinal metaplasia
Discuss the epidemiology of Barrett’s Esophagus.
Occurs in ~10% of symptomatic patients, 40-60 y/o, M>F
Describe the gross and histologic appearance of Barrett’s Esophagus.
Gross: salmon colored metaplastic epithelium
Histology: intestinal metaplasia and goblet cell metaplasia
Barrett’s Esophagus is the single most important risk factor for ___.
Adenocarcinoma
What is the most common benign esophageal tumor?
Leiomyoma
What are the molecular abnormalities associated with squamous cell carcinoma?
- p53 point mutations
2. P16/INK4a mutation
Describe the histology of squamous cell carcinoma.
Infiltrating islands of malignant squamous cells, keratin pearls, abnormal keratinization
Where does esophageal squamous cell carcinoma tend to occur? Adenocarcinoma?
Sq: proximal 2/3 of esophagus
Ac: distal 1/3 of esophagus + GEJ
What are some mutations associated with adenocarcinoma?
- p53
- Amplification of c-ERB-B2, cyclin D1, cyclin E
- RB gene
- Allelic loss of cyclin dependent kinase inhibitor p16/INK4a
- Hypermethylation of p16/INK4a
- Increased epithelial expression of TNF and NF-kB
(Stepwise)
What is omphalocele?
Persistent herniation of the bowel into the umbilical cord COVERED by peritoneum and amnion of cord - failure of abdominal wall to return to body cavity during development
What is gastroschisis?
Malformation of abdominal wall causing exposure of abdominal contents, not covered by peritoneum
What is pyloric stenosis?
Congenital hypertrophy of smooth muscle of pylorus
How does pyloric stenosis present?
Projectile vomiting in first 2-6 weeks of life, visible peristalsis, olive-like mass in abdomen
Pyloric stenosis is more common in ___ (M or F).
Males
What is the pH of the stomach?
1
What are the 4 parts of the stomach?
- Cardia
- Fundus
- Body
- Antrum
What are the cells contained in each of the 4 parts of the stomach?
- Cardia - foveolar cells
- Fundus and Body -
parietal cells and chief-cells - Antrum - G-cells and mucin-secreting cells
What is the differential diagnosis of upper abdominal pain?
- Gastritis
- Peptic ulcer disease
- GERD
- Biliary colic
- IBS
- Pancreatitis
What are the symptoms of gastritis?
- Nausea
- Epigastric pain
- Vomiting
- Hematemesis
What are the normal damaging forces in the stomach?
- Gastric acidity
2. Peptic enzymes
What are the normal defensive forces in the stomach?
- Surface mucus secretion
- Bicarbonate secretion into mucus
- Mucosal blood flow
- Apical surface membrane transport
- Epithelial regenerative capacity
- Elaboration of prostaglandins
What are possible injuries to the stomach?
- H. pylori infection
- NSAIDs
- Aspirin
- Cigarettes
- Alcohol
- Gastric hyperacidity
- Duodenal-gastric reflux
What are possible causes of impaired defenses in the stomach?
- Ischemia
- Shock
- Delayed gastric emptying
- Host factors
What causes stress-related gastric injury?
Local ischemia in patients with critical illness/injury
What are three examples of stress-related gastric injury?
- Stress ulcers (patients in shock, sepsis, severe trauma)
- Curling ulcers
- Cushing ulcers
What are Curling ulcers?
Ulcers located in the proximal duodenum, seen in patients with severe burns or trauma
What are Cushing ulcers?
Ulcers located in the stomach, duodenum, or esophagus, seen in patients with intracranial disease
Describe the features of acute gastritis.
Transient process involving nausea, vomiting, and epigastric pain.
Superficial, erosive, ulcerative, may have hemorrhage
Often an impairment of protective systems (NSAIDs, ingestion, direct injury)
How is acute gastritis treated?
Stress ulcer prophylaxis with PPI or H2 blockers in at-risk patients
Treatment with acid blocking agents
Treat underlying condition
What are the features of chronic gastritis?
Similar symptoms as acute, but hematemesis is uncommon
Symptoms less severe, but more persistent
Most common cause is H. pylori infection; other causes include autoimmune, radiation injury, chronic bile reflux, mechanical injury
How is H. pylori visualized?
- Methylene blue stain
2. Warthin-Starry silver stain
H. pylori is a Gram ___ bacteria.
Negative
What are the four modes of virulence of H. pylori?
- Flagella
- Secretion of urease
- Adhesins
- Toxins
How is infection with H. pylori treated?
PPI + antibiotics
How is chronic gastritis caused by autoimmune processes different from that caused by H. pylori?
Autoimmune - spares the antrum
H. pylori - primarily affects the antrum
What happens in autoimmune chronic gastritis?
Ab to parietal cells and IF lead to Vitamin B12 deficiency (and pernicious anemia), as well as decreased pepsinogen I levels (due to loss of chief cells). This leads to impaired gastric acid secretion (achlorhydria). Gastrin release increases and antral G cells undergo hyperplasia.
What are the symptoms of peptic ulcer disease?
Epigastric burning or aching pain occurring 1-3 hours after eating, worse at night, relieved by alkali or food; may also have nausea, bloating, belching
What are the most common causes of peptic ulcer disease?
H. pylori or NSAIDs
Where is peptic ulcer disease most common in the body?
Proximal duodenum and antrum
Food ___ pain with duodenal ulcers; pain ___ with gastric ulcers.
Decreases; increases
How is peptic ulcer disease treated?
Eradicate H. pylori, remove offending agent, surgery for bleeding or perforation
What is the key issue in peptic ulcer disease?
Gatric hyperacidity
What is Zollinger-Ellison Syndrome?
Multiple ulcerations in GI tract due to hypersecretion of gastrin by a tumor
What are other risk factors for peptic ulcer disease?
NSAIDs, smoking, high-dose corticosteroids, alcoholic cirrhosis, COPD, chronic renal failure, hyperparathyroidism, psychological stress
What are the 5 common neoplasms of the stomach?
- Gastric polyps
- GIST
- Lymphoma
- Carcinoid tumor
- Gastric adenocarcinoma
What is a polyp?
Nodule or mass that projects above the level of the surrounding mucosa, due to hyperplasia, inflammation, ectopia, or neoplasia
Which type of polyp makes up 75% of polyps?
Inflammatory and hyperplastic polyps
Which type of polyp occurs more in males (versus evenly in M/F)?
Gastric adenoma
Which type of polyp has no neoplastic potential?
Fundic gland polyp
Where are fundic gland polyps located? Gastric adenomas?
Fundic gland polyp: body and fundus
Gastric adenoma: antrum
How does gastric adenoma appear on histology?
Intestinal-type epithelium with variable degrees of dysplasia
Which polyp is sporadic or associated with familial adenomatous polyposis?
Fundic gland polyp
Carcinoid tumors arise from neuroendocrine tumors; in the stomach, they arise from ___.
G-cells
Location determines the prognosis of a carcinoid tumor - which location is most aggressive?
Midgut
What is a GIST (gastrointestinal stromal tumor)?
Mesenchymal neoplasm of the interstitial cells of Cajal (pacemaker cells of gut peristalsis)
75-80% of people with GIST have a gain-of-function mutation in the gene encoding ___.
Tyrosine kinase c-KIT
How is GIST treated?
Surgical resection if possible + Imatinib (inhibits tyrosine kinase activity); resistance to this drug does exist
Where is gastric adenocarcinoma most common in the world?
Eastern Asia
What are the early and late symptoms of gastric adenocarcinoma?
Early: nausea, dyspepsia, dysphagia
Late: weight loss, anorexia, bowel habit changes, anemia, hemorrhage
What are risk factors for gastric adenocarcinoma?
- Geography
- Low SES
- Multifocal mucosal atrophy and intestinal metaplasia in the setting of chronic gastritis
- History of partial gastrectomy for PUD
- Blood type A
What are some causes of gastric adenocarcinoma?
- H. pylori infection
- Epstein Barr Virus
- Mutations of CHD1 causing loss of E-cadherin function and mutations in APC genes (familial adenomatous polyposis)
What are the 2 categories of gastric adenocarcinoma in the Lauren classification?
- Intestinal
2. Diffuse
Describe the structure and epidemiology of intestinal gastric adenocarcinoma.
Bulky, glandular structures, exophytic mass or ulcerated tumor
Mean age 55, M>F (2:1), incidence higher in high-risk areas
Describe the structure and epidemiology of diffuse gastric adenocarcinoma.
Infiltrative growth, discohesive cells with large mucin vacuoles (signet ring cells)
Linitis plastica (gross)
M=F, incidence the same regardless of geography
What is a Virchow node?
Metastatic gastric adenocarinoma in the left supraclavicular node
What is a common location of distant metastases of gastric adenocarcinoma?
Liver
What is a Sister Mary Joseph nodule?
Metastatic gastric adenocarinoma in the periumbilical region (intestinal type)
What is a Krukenberg tumor?
Metastatic gastric adenocarinoma in bilateral ovaries (diffuse type)
