GIT 3 Flashcards
Rebound gastric acid hypersecretion when PPI and Antacids withdrawn
↑Gastrin → induces hypertrophy of ECL and parietal cells → over stimulation of parietal cells with hyperfunctioning of unblocked ATPase
All antacids cause__
hypokalemia
Aluminium hydroxide adverse effects
CHOPS constipation Hypophosphatemia, Osteodystrophy, Proximal muscle weakness, Seizures
Octreotide: Long-acting somatostatin analog; inhibits secretion of various
splanchnic vasodilatory hormones
Sulfasalazine: A combination of ______ and _______. Activated by _______
sulfapyridine (antibacterial) and 5-aminosalicylic acid (anti-inflammatory).
colonic bacteria.
Metoclopramide promotes _____ but Does not influence _____
upper GI motility
colon transport time
Metoclopramide Drug interaction with _____ and ________
digoxin and diabetic agents.
Metoclopramide: Contraindicated in patients with __________
small bowel obstruction, Parkinson disease (due to D2-receptor blockade), ↓seizure threshold.
Orlistat: MECHANISM
Inhibits gastric and pancreatic lipase
___ is sometimes used for refractory chemotherapy induced diarrhea.
Octreotide
Weight loss medications
Stimulants (phentermine, benzphetamine, diethylpropion)
orlistat
Bupropion/natrexone
Sodium polystyrene resin:
exchanges intraluminal sodium for potassium ion and lowers serum potassium
In adenomatous polyps, _____ is most important risk factor for cancer
polyp size
↑risk >10mm
Greatest risk when >4cm
Familial adenomatous polyposis
Autosomal dominant mutation of APC tumor suppressor gene on chromosome ______. Mutations lead to _____ accumulation and uncontrolled cell proliferation.
5q22
ß-catenin
In FAP ____ is always involved
Rectum
in lynch syndrome ____ is always involved
proximal colon
Marker for intestinal origin of adenocarcinoma:
Cytokeratin 20
Molecular pathogenesis of colorectal cancer
Chromosomal instability pathway: mutations in APC
Microsatellite instability pathway: mutations or methylation of mismatch repair genes (eg, MLH1)
Congenital diaphragmatic hernia may occur due to congenital defect of ________
pleuroperitoneal membrane
Distal esophagus is attached circumferentially to diaphragm by ______ at __________
phrenoesophageal membrane
gastroesophageal junction
Bochdalek hernia is due to _____
failure of posterolateral diaphragmatic foramina to fuse
______ is not contained by femoral sheath
femoral nerve
Effect of prostaglandin and steroids on LES tone
Prostaglandins → ↓LES tone
Steroids inhibit prostaglandins → ↑LES tone
dysphagia, food impaction seen in _____
Endoscopic findings:
Eosinophilic esophagitis
Esophageal rings and linear furrows often seen on endoscopy
Schatzki rings Rings: location
at gastroesophageal junction
Mechanism of gastritis caused by H. Pylori
Gastric
duodenal
Gastric:
- Urea → Ammonium → Ammunium chloride → damage to mucosa
- Urea → Ammonium → ↑pH → gastrin release → ↑ acid
Duodenal:
antrum → D cells damage → ↓somatostatin → ↑gastrin → ↑acid → duodenal ulcer
Autoimmune gastritis: Autoantibodies to
H+/K+ ATPase on parietal cells and to intrinsic factor.
In gastricpresis damage to ——
- cells of cajal
2. NO secreting neurons that induce relaxation of fundus of stomach
Pain worse at night ——- ulcer
duodenal
Suspensory ligament of treitz:
suspends dudeno-jejunal flexure to posterior abdominal wall.
Celiac disease: HLA_____
DQ2, DQ8
Celiac disease is a _______ hypersensitivity reaction.
______ has no role in pathogenesis.
Type 4
antibodies. (only helpful for diagnosis)
↓mucosal absorption affecting duodenum and jejunum seen in
Celiac disease
Tropical sprue
Tropical sprue is associated with ______ due to ____ deficiency and, later, _____ deficiency.
megaloblastic anemia
folate , B12
