GI Diseases Flashcards
Achalasia
failure of lower esophageal sphincter to relax due to loss of myenteric (Auerbach) plexus
High LES opening pressure and uncoordinated peristatlsis leads to progressive dysphagia to solids and liquids
Presents with: progressive dysphagia, chest pain, food regurgitation, aspiration (can lead to bronchopneumonia), bad breath
Alcohol may relieve due to relaxation of LES
Smaller valley in LES tone on monometry
Barium swallow shows dilated esophagus with distal stenosis
Increased risk of esophageal squamous cell carcinoma
Sjogren Syndrome
Autoimmune disorder characterized by destruction of exocrine glands (lacrimal and salivary)
Predominantly females of 40-60 years old
Findings: Xerophatlamia (decreased tear production and corneal damage)
Xerostomia (decreased saliva production)
Peresence of Anti-Ro and or anti-La (SS-A and B) Abs
Bilateral parotid enlargement
Complications: dental carries, MALT-lymphoma
Barretts Espohagus
Chronic GERD characterized by intestinal metaplasia (nonciliated columnar with goblet cells-G cells needed for diagnosis) replacing esophageal squamous mucosa
Endoscpic abnormality also needed for diagnosis
Complicated with ulcerations, stricture and bleeding
Increased risk of adenocarcinoma-more common in males and caucasians (atypia)
Higher esophageal/gastric junction
GERD
Symptoms: Heartburn, water brash, chest pain, postural related symptoms, nocturnal coughing, wheezing/asthma, Anemia (iron deficiency), GI bleeding, Dysphagia, painful swallowing
Pathogenesis: Decrease in lower esophageal sphincter tone
Transient: belching
Constant: hypotensive LES-caffeine, chocolates, fatty foods, alcohol, smoking, peppermint, gastric distension, drugs
Increased abdominal pressure
Histo: basal zone hyperplasia, elongation of lamina propria pappillae (upper 1/3 of epithelium), and inflammatory cells (eosinophils, neutrophils)
Hyperemia,
Treatment:
Mild symptoms: raise head in bed, avoid late night snacks, chewing gum, avoid tight clothing, lose weight, restriction of alcohol and elimination of smoking, antacids, H2 blockers
Severe symptoms: H2 Blockers or PPIs, metoclopramide, surgery (Nissen fundoplication)
Eosinophilic Esophagitis
Dysphagia
Children and infants have feeding difficulties
Do not respond to PPIs
History of Atopy: allergies, asthma, blood eosinophilia, food senstivities, allergic rhinitis
Endoscopy: linear furrowing and stacked circular rings
Eosinophils on histology
Treatment: elimination diets, topical glucocorticoids, esophageal dilatation
Esophagitis
irritants: corrosie chemicals, pills-doxycycline, hot liquids, heavy smoking, alcohol
Infectious: immunocompromised
Candida: psyodmembrane (yeast buds and hyphae)
HSV: punhced out ulcers
CMV: linear ulcers
Iatrogenic: cytotoxic chemotherapy, radiation, graft versus host disease
Crohns disease
Boerhaave syndrome
Transmural esophagitis
Distal esphageal rupture due to violent retching: surgical emergency
Esophageal air fluid leakage into mediastinal/pleura
Chest pain, fever, dyspnea and septic shock
Mallory-Weiss Syndrome
Mucosal lacerations at gastroesophageal junction due to severe vomiting (metabolic alkalosis),
Leads to hematemesis, epigastic pain
Alcoholics and bulimics
Associated with hiatal hernias
Chagas disease
Caused by trypanosoma cruzi-South America
dilated cardiomyopathy, megacolon, megaesophagus (achalasia)
Transmission: Reduviid bug, feces, deposited in painless bite
Diagnosis: blood smear
Treatment: benznidazole or nifuritimox
lactase deficiency
Malabsoprtion of lactose leads to bacterial fermentation and gas distension (H2, CO2 and methane)
Leads to osmotic diarrhea
Lactase functions on brush border
Primary: age dependent decline after childhood, common in Asian, African and Native American descent
Secondary: loss of brush border due to gastroenteritis (rotavirus), autoimmune,
Congenital: rare due to defective gene
Stool: decreased pH and breath shows increased H content with lactose tolerance test
Normal mucosa in biopsy
Symptoms: bloating, cramps, flatulence, osmotic diarrhea
hartnup Disease
Autosomal recessive disorder
Deficiency of neutral amino acid transporters in proximal renal tubular cells and on enterocytes
Leads to neutral aminoaciduria and decreaed absorption from the gut
Results in: photosensitivity, skin rashes, ataxia (wax and wane), Niacin (Vit. B3 deficiency)-pellagra like sypmtoms
Treat with: high protein diet, and nicotinic acid
Celiacs disease
Immune mediated damage of small bowel villi due to gluten exposure
Associated with HLA-DQ2 and DQ8
Gluten present in wheat and grains-gliadin is pathogenic Gliadin is deaminated by tissue transglutaminase and presented to MHC class II cells leading to helper T cell damage
Clinical:
children: abdominal distension, diarrhea, and failure to thrive, delayed puberty, growth failure
Adults: chronic diarrhea and bloating, anemia, difficulty gaining weight
Small herpes like vesicles on skin (dermatitis hepetiformis)
Due to IgA deposition at the tips of the dermal papillae
labs:
IgA Abs to endomysium, tTG, or gliadin
Duodenal biopsy reveals flattened villi, hyperplasia of crypts, and increased interaepithelial lymphocytes
Damage is most prominent in duodenum and jejunum
Small bowel carcinoma and T cell lymphoma are late complications
Crohn’s Disease
Chronic inflammation of transmural layers of intestine (any part mostly ileum and colon) and skip lesions
Symptoms: right lower abdominal pain, fevers, weight loss
Inflammation can lead to abscesses, fistula, scarring/obstruction and rectal fissures, peri anal disease, non caseating granulomas, palpable mass, leukocytosis
Endoscopy: apthous ulcers, longitudinal ulcers, cobble-stoning, fat creeping, colon and small bowel obstruction
Complications: malabsorption of fats and gallstones (don’t reasorb bile salts)
Systemic manifestations: migratory polyarthritis, erythema nodosum, ankylosing spondylitis, pyoderma gangrenosum, uveitis, oxalate kidney stones, anemia, gallstones
Smoking may cause disease, appendectomy my be risk, oral contraceptives slightly increase risk, more genetic
Treatment: Corticosteroids, azothioprine, methotrexate, infliximab, adalimumab
Responds to antiobiotics and recurs after surgery
Ulcerative Colitis
Chronic and continuous Inflammation of the mucosal layer of the COLON
Involves the RECTUM with no skip lesions
Symptoms: abdominal pain, tenesmus, passage of mucus and gross bloody diarrhea
Endoscopy: mucosal friability and distorted vascular pattern, pesuodpolyps formed from islands of remaining regenerating mucosa, loss of haustra
Complications: pyoderma gangrenosum, erythema nodosum, primary sclerosing cholangitis, ankylosing spodnyltis, apthous ulcers, uveitis
Increased colon cancer and toxic megacolon risk
Smoking may prevent disease, appendectomy may be protective
Treatment: ASA perparations (sulfasalazine), 6-mercaptopurine, infliximab, colectomy
Osmotic Diarrhea
Little or no passive electrolyte absorption in gut, cannot sustain osmotic gradient
3.5 ml water retained in lumen for each additional mOsm
Increased stool osmotic gap=290-2(Na+K)
Greater than 50 mOsm/kg
Causes:
Laxatives: Mg, SO4, PO4, PEG
Non-absorbable sweeteners: mannitol sorbitol, aspartame, erythritol (sugar free products)
CHO maldigestion: disaccharidase deficiency, pancreatic exocrine insufficiency
Malabsorption: celiacs
Non inflammatory secretory diarrhea
mechanism: enterotoxin, adherence of superficial invasion
Location: proximal small bowel
Illness: watery diarrhea
Stool exam: no leukocytes
Exudative (inflammatory) diarrhea
Mechanism: invasion, cytotoxin
Location: colon
Illness: dysentery/inflammatory diarrhea
Stool exam: fecal leukocytes (PMNs),, sometimes RBCs
Entamoeba histolytica
Ameboe Bloody diarrhea (dysentery), liver abscess with exudate, RUQ pain
Histology shoes flask shaped ulcer if submucosal abscess of colon ruptures
Transmission: cysts in water
Diagnosis: serology and/or trophozoites (with RBCs in the cytoplasm) or cysts with up to 4 nuclei in stool
Treatment: metronidazole, iodoquinol for asymptomatic cyst passers
Chronic Mesenteric Ischemia
Predominantly involving the small intestine
Involves clot in SMA (a. fib), atherosclerosis or low flow state
Postprandial epigastric pain and food aversion
pain due to lack of blood supply with mucosal celsl most susceptible followedc by submucosa and muscularis (total infarction of bowel in 4-6 hours if no collateral)
preservation of crypts where stem cells can initiate regeneration of mucosa
In embryo leads to atresia
In adult leads to atrophy
Incarcerated: trapped
Strangulate: no flow or no movement
Diagnosis: arteriogram
Ischemic enteritis/colitis
Loss of sufficient blood for good function but not enough decrease in flow to cause tissue death (but often doesn’t)
Symptoms: pain over affected site and bloody diarrhea
Most common sites:
Splenic flexure and sigmoid colon due to watershed areas relying on circulation through marginal arteries
Cure: increase flow
Reperfusion injury
If flow restored before death of cells than further injury generated by free radical production and may result in multiorgan failure
Generation of free oxygen radicals and release of inflammatory mediators including complement and TNF
Acute Gastritis
Disruption of mucosal barrier leads to inflammation
Can be caused by stress, NSAIDs (decrease PGE2 leading to decreased gastric mucosa protection) alcohol, uremia, burns (decreased plasma volume sloughing of gastric mucosa-Curling ulcer) and brain injury (increased vagal stimulation leading to Increased ACh and increased H+-Cuhsing ulcer)
stress: shock, extensive burns, sepsis, severe trauma, and intracranial injury/surgery
Neutrophil infiltrate with multiple defects in stomach
Chronic Gastritis-Type A
In fundus/body
Autoimmune disorder characterized by autoAbs to parietal cells (upper glandular layer)
Pernicious anemia: fatigue, lower extremity parasthesias, megaloblastic RBCs
Acholrhydia
Associated with other autoimmune disorders
Chronic gastritis-Type B
In antrum
Most common type
Caused by H. Pylori infection
Increase risk of MALT lymphoma and gastric adenocarcinoma
Decreased somatostatin producing cells (delta cells) leads to increased acidity not matched by duodenum leading to duodenal ulceration and gastric metaplasia
Tropical Sprue
Similar to celiac sprue
Affects small bowel
Responds to antibiotics
Recent visitors to tropics
Can cause diarrhea, steatorrhea, weight loss, weakness, and vitamin and mineral deficiencies
Whipple disease
Infection with tropheryma whipplei (gram+)
PAS+
Foamy macrophages in intestinal lamina propria, mesenteric nodes, Cardiac symptoms, arthralgias, and neurologic symptoms
Most often in older men
Treat with antibiotics
Can cause diarrhea, steattorrhea, weight loss, weakness, and vitamin and mineral defeiciencies
Abetalipoproteinemia
decreased synthesis of apolipoprotein B leading to inability to generate chylomicrons leading to decreased secretion of cholesterol, VLDL into bloodstream leading to fat accumulation in enterocytes
clear or foamy cytoplasm
Presents in early childhood with failure to thrive, steatorrhea, acanthocytosis, ataxia, night blindness
LOF of MTP gene (functions as chaperone proteins of proper folding of apoB)
Appendicitis
Acute inflammation of appendix due to obstruction by fecalith (in adults) or lymphoid hyperplasia (children) nematodes, carcinoids, foreign bodies
Retained mucus causes appendicular wall to distend leading to impaired venous outflow which causes hypoxia and bacterial invasion
Initial periumbilical pain migrates to McBurney point
nausea, fever, may peforate leading to peritonitis
+obturator, psoas and Rovsing signs
Differential: diverticulitis (elderly), ectopic pregnancy (use B-hCG)
Treatment: appendectomy
Diverticulum
Blind pouch protruding from the alimentary tract that communicates with the lumen of the gut
Most diverticula are acquired and are false (lack or have attenuated musscularis externa)
Most often in sigmoid colon
Due to increased intraabdominal pressure due to straining during constipation
Diverticulosis
Many false diverticula of the colon, commonly sigmoid
Common >60 y.o.
Caused by increased intaluminal pressure with focal weakness in colonic wall
Associated with low fiber diets
Asymptomatic or vague discomfort
Common cause of hematochezia
Diverticulitis
Inflammation of diverticula causing LLQ pain, fever, leukocytosis
May peforate leading to peritonitis, abscess formation or bowel stenosis
Give antibiotics
Stool occult blood is common with or without hematochezia
May cause colovescial fistula (fistula within bladder) leading to pneumaturia
Zenker Diverticulum
Pharyngoesophageal false diverticulum
Herniation of mucosal tissue at Killian triangle between the thyropharyngeal and cricopharygneal parts of the inferior pharyngeal constrictor
Due to cricopharyngeal muscle dysfunction occurs due to diminshed relaxation of pharyngeal muscles during swallowing
More force needed to move bolus downward
more intense contraction increase pressure leading to herniation
Presents with: dysphagia, obstruction foul breath from trapped foods, recurrent pneumonia
palpated lateral neck muscles
Common in elderly males
Intussusception
Telescopin of bowel segment into distal segment, commonly at ileocecal junction
Compromised blood supply leads to intermittent abdominal pain often with currant jelly stools (blood and mucus)
Can cause ischemia and subsequent necrosis
majority in children (idiopathic or associated with enteric or respiratory infection)
Abdominal emergency
Diagnosis: barium enema
Volvulus
Twisting of portion of bowel around its mesentery
Can lead to obstruction and infarction
Can occur throughout GI tract
Midgut volvulus more common in infants and children
Sigmoid volvulus more common in elderly
Intestinal atresia and stenosis
Atresia: lumen is completely occluded
Stenosis: lumen is narrowed
Failed recanalization or ischemia
Clinical: polyhydramios and billous vomiting (proximal)
Normal amniotic fluid levels, abdominal distension, later vomiting and failure to pass meconium (distal)
SMA syndrome
Third portion of duodenum compressed due to decreased angle between SMA and aorta
Occurs due to decreased mesenteric fat (bariatric surgery, anorexia), severe burns, prolonged bed rest, pronounced lordosis, dehabilitating illness, scoliosis surgery
High pitched bowel sounds and billous vomiting
Gastric Ulcer
Pain is greater with meals
H. Pylori in 70%
Mechanism: Decreased mucosal protection against gastric acid
Other causes: NSAIDs
High risk of MALT lymphoma or gastric adenocarcinoma
Often occurs in older patients
Duodenal Ulcer
Pain decreases with meals-weight gain
H. Pylori infection in 100%
Mechanism: decreased mucosal protection or increased gastric acid secretion
Other causes: Zollinger-Ellison syndrome, NSAIDs
Generally benign
Hypertrophy of brunner glands
Treat with: metronidazole, tetracycline, amoxacillin, or clarithromycin
with proton pump inhibitor
Irritable Bowel Syndrome
Diagnosis: at least 12 weeks total time in preceding 12 months with pain/discomfort that has 2/3 of
1. Relieved with defecation
2. Onset associated with change in frequency in stool
3. Onset associated with change in appearance of stool
Clinical: diarrhea, constipation or both
Visceral hypersensitivity
Symptoms that support diagnosis:
1. Abnormal stool frequency
2. Abnormal stool form
3. Abnormal stool passage
4. Passage of mucus
5. Bloating or feeling of abdominal distention
Patyhophys: changes in 5- hydroxytryptamin signaling (overactivity)
Overactivation of anterior cingulate cortex, PFC and amygdala in response to rectal distension (involved in attentional processes, threat perception and response selection)
Enterochromafffin cell release 5HT in GI tract
SERT clears serotining from synpases in the brain (low SERT expression in IBS)
Stress exacerbates IBS
above pectinate line hemorrhoids
internal hemorrhoids-not painful due to visceral innervation
arterial supply from superior rectal artery (branch of IMA)
Venous drainage is superior rectal vein leading to inferior mesenteric vein then to portal system
Lymphatic drainage to deep nodes
Adenocarcinoma also here
Below pectinate line hemorrhoids
receive somatic innervation via inferior rectal branch of pudendal nerve and are painful
arterial supply via inerior rectal artery (branch of pudendal artery)
venous drainage via inferior rectal vein leading to internal pudendal vein leading to internal iliac vein then to IVC
squamous cell carcinoma also happens here
Anal fissure
tear in anal mucosa below the pectinate line
pain while pooping, blood on toilet paper,
located midline posteriorly due to poor perfusion
associated with constipation and low fiber diets
May have skin tag
diaphragmatic hernia
abdominal structures enter the thorax-in infants as a result of defective development of pleuroperitoneal membrane
most commonly a hiatal herniates upward through the esophageal hiatus
Sliding hiatal hernia
most common
gastroespogeal junction is displaced above (hourglass stomach)
Paraesophageal hernia
gastrogesophageal junction is normal
fundus protrudes into the thorax
indirect inguinal hernia
goes through internal (deep ring) then external (superficial ring) and into scrotum
lateral to inferior epigastric artery
occurs in infants due to failure of processes vaginalis to close ( can form hydrocele)
or due to internal inguinal ring to close
lower border=inguinal ligament
medial border=inferior epigastric vessels
covered by all 3 layers of spermatic fascia
Direct inguinal hernia
Protrudes through the inguinal (hesselback triangle)
bulges directly through abdominal wall medial to inferior epigastric artery
Goes through external (superficial) inguinal ring only
Covered only by external spermatic fascia (external oblique)
Caused by weakness of transversalis fascia
lower border=inguinal ligament
medial border=rectus abdominus muscle
lateral border=inferior epigastric muscles
Femoral hernia
protrudes below inguinal ligament through femoral canal below and lateral to pubic tubercle
femoral canal becomes lax with age
Upper thigh, groin or pelvic discomfort
Leading cause of bowel incarceration (leading to nausea, vomiting, abdominal pain)
medial border: pubic tubercle and lacunar ligament
lateral border: femoral artery, vein and nerve
posterior border: Cooper’s ligament
Diffuse Esophageal Spasm
Non peristaltic esophageal contractions
Can be painful
Corkscrew esophagus on barium esphogogram
Symptoms: intermittent dysphagia and occasional chest pain
Chest pain associated with exertion and not relieved by rest
Menetrier disease
Gastric hypertrophy with protein loss, parietal cell atrophy, and increased mucous cells
Precancerous
Rugae of stomach are so hypertrophied they look like brain gyri
Ulcer Complications
Hemorrhage:
gastric=posterior
lesser curvature of stomach-bleeding from left gastric artery
posterior wall of duodenum=gastroduodenal artery
Duodenal=anterior
Perforation: duodenal
may see free air under the diaphragm with pain referred to shoulder
Toxic megacolon
Abdominal pain and distension
Fever, diarrhea and shock (decrease BP and increase HR)
Due to complete cessation of neuromuscular activity is first step in pathogenesis
Can perforate leading to death
Barium contrast and colonscopy are CI due to risk of perforation