Gastrointestinal Flashcards
(182 cards)
1
Q
What layer of the trilaminar disc forms the inner linings of the digestive tract & respiratory system?
A
Endoderm
2
Q
What weeks of development does the embryo form the primitive gut?
A
4-8
3
Q
In weeks 4-8, what structure is the gut tube suspended from?
A
Dorsal mesentery
4
Q
What layer of the trilaminar disc forms the epithelium of the mouth & rectum?
A
Ectoderm
5
Q
What layer of the trilaminar disc forms the muscular & fibrous elements of the gut?
A
Mesoderm
6
Q
What layer of the trilaminar disc forms the inner epithelium and glands of the gut?
A
Endoderm
7
Q
Describe the 4 steps of the dilatation of the stomach & its rotation
A
- Fusiform dilatation of the caudal end of the gut tube. 2. Dilatation - greater dorsally than ventrally, forming the greater curvature. 3. Rotates 90 degrees clockwise around the longitudinal axis. 4. The greater curvature is now on the left, and the lesser curvature is on the right.
8
Q
Is the duodenum intraperitoneal or retroperitoneal?
A
Parts 2, 3, & 4 are retroperitoneal
9
Q
What process pulls the duodenum into a C-shaped loop in the embryo?
A
Rotation of the stomach
10
Q
The liver bud splits into cranial & caudal parts - what structures do each consist of?
A
Cranial - liver and bile duct. Caudal - gallbladder and cystic duct
11
Q
Which structures do the two pancreatic buds develop from - dorsal bud & ventral bud?
A
Dorsal bud - dorsal mesentery, ventral bud - bile duct
12
Q
What structure is formed when the ventral pancreatic bud moves to lie posteriorly & inferiorly to the dorsal bud?
A
Uncinate process of the pancreas
13
Q
What is annular pancreas?
A
When the ventral bud of the pancreas fails to rotate, and partially or fully encircles the duodenum.
14
Q
What structures does the foregut consist of?
A
The oesophagus to the first two parts of the duodenum
15
Q
What structures does the midgut consist of?
A
The last two parts of the duodenum to 2/3rds along the transverse colon
16
Q
What structures does the hindgut consist of?
A
The last 1/3rd of the transverse colon to the proximal 2/3rds of the rectum
17
Q
Stomach retro or intraperitoneal?
A
Intraperitoneal
18
Q
Jejunum and ileum retro or intraperitoneal?
A
Intraperitoneal
19
Q
Caecum and appendix retro or intraperitoneal?
A
Intraperitoneal
20
Q
Transverse colon retro or intraperitoneal?
A
Intraperitoneal
21
Q
Liver and gallbladder retro or intraperitoneal?
A
Intraperitoneal
22
Q
Sigmoid colon retro or intraperitoneal?
A
Intraperitoneal
23
Q
Ascending and descending colon retro or intraperitoneal?
A
Retroperitoneal
24
Q
Tail of pancreas retro or intraperitoneal?
A
Intraperitoneal
25
Spleen retro or intraperitoneal?
Intraperitoneal
26
Rectum retro or intraperitoneal?
Retroperitoneal
27
Head, neck & body or pancreas retro or intraperitoneal?
Retroperitoneal
28
Kidneys, suprarenal gland & ureters retro or intraperitoneal?
Retroperitoneal
29
Abdominal aorta retro or intraperitoneal?
Retroperitoneal
30
Inferior vena cava retro or intraperitoneal?
Retroperitoneal
31
What process results in the formation of the umbilical cord?
Liver growth reduces cavity space and causes intestinal loop herniation
32
What does the superior mesenteric artery act as a rotatory axis for?
90 degree anticlockwise rotation of the midgut
33
At what week does the coiling of the small intestine occur?
8 weeks
34
What is an omphalocoele/exomphalos?
Herniation of the bowels into the umbilical cord
35
What layer of the trilaminar disc forms the bladder & urethra?
Endoderm
36
What week does the cloaca separate into the rectum and urogenital sinus?
8 weeks
37
What investigations does new-onset unexplained dysphagia warrant? (3)
Endoscopy, barium swallow, MRI
38
What investigation does epigastric pain/vomiting warrant?
CT abdo
39
What investigations would you perform in suspected bowel obstruction? (2)
XR abdo, CT abdo
40
What investigations would you perform in suspected bowel perforation? (2)
XR chest, CT abdo
41
What investigation would you perform in a suspected swallowed foreign body?
XR
42
What investigations are used for staging of oesophageal cancer? (2)
CT, PET-CT
43
What muscle provides voluntary control of the oesophagus?
Cricopharyngeus/Upper oesophageal sphincter
44
What muscle types does the oeseophagus have? (2)
Striated muscle proximally, smooth muscle distally
45
What muscle provides involuntary control of the oesophagus?
Lower oesophageal sphincter
46
What layers does the oesophageal wall consist of, inner to outer? (5)
Mucosa -> submucosa -> circular layer muscularis -> longitudinal layer muscularis -> adventitia
47
What foods decrease LOS pressure (relaxes)? (6)
Chocolate, fatty foods, caffeine, citrus, garlic, tomato
48
What drugs decrease LOS pressure (relaxes)? (11)
Alcohol, anticholinergics, beta-agonists, calcium channel blockers, dopamine, nicotine, nitrates, progesterone, oestrogen, tricyclic antidepressants
49
What foods increase LOS pressure? (3)
Protein, carbohydrates, refluxed acid
50
What drugs increase LOS pressure? (5)
Alpha-agonists, beta-blockers, cholinergics, metoclopramide, domperidone
51
What do parietal cells secrete, and where are they?
HCl, gastric body
52
What do G cells secrete, and where are they?
Gastrin, gastric antrum
53
What do ECL (Enterochromaffin-like Cells) cells secrete, and where are they?
Histamine, gastric body
54
What do D-cells secrete, and where are they?
Somatostatin, whole stomach
55
Function of gastrin?
Stimulates HCl secretion via histamine release & direct parietal cell stimulation, stomach distension,
56
Function of histamine in the stomach?
Stimulates H2 receptors on parietal cells; stimulates HCl release
57
Function of somatostatin?
Inhibit secretion of gastrin, ghrelin, secretin, cholecystokinin (CCK), etc.
58
What is Zollinger-Ellison syndrome?
Excessive gastrin secretion (10x normal upper limit), resulting in a reduced gastric pH (more acidic!)
59
What is pyloric stenosis?
Congenital hypertrophic pyloric stenosis - obstruction that presents from 3-6wks old, with visible peristalsis & a palpable mass after feeding. Can be acquired - ulcer scar, antral tumour, tumours of the pancreatic head
60
What can cause acute gastritis? (5)
Irritants (smoking, alcohol), drugs (aspirin, NSAIDs, oral steroids), severe stress (burns, trauma, surgery, shock, sepsis), radiation, chemotherapy
61
Characteristics of acute 'stress' ulcers? (5)
Does not penetrate the muscularis propia, no scarring under ulcer, no endarteritis obliterans, heals by regeneration, can be anywhere and multiple
62
Characteristics of chronic 'peptic' ulcer?- (5)
Penetrates muscularis propia, scarring under ulcer, endarteritis obliterans (arterial occlusion), heals by repair with fibrous scar, single & usually antral
63
Complications of peptic ulcers? (4)
Perforation, haemorrhage, pyloric stenosis, malignant change
64
Characteristics of gastric vs duodenal ulcers? (4)
Gastric - slightly more common in males, no genetic factors, pain on eating, slightly older average age of onset. Duodenal - much more common in males, genetic factors very important, pain relieved by eating, slightly younger age of onset.
65
Primary malignant gastric neoplasia types? (3)
Adenocarcinoma, malignant gastrointestinal stromal, lymphoma
66
Risk factors for gastric neoplasia? (8)
Genetic, blood group type A, carcinogenic diet, pernicious anaemia, operated stomach, atrophic gastritis, adenomas, more common in males >50y/o.
67
Gastric lymphoma type & treatment?
Mucosa Associated Lymphoid Tissue (MALT), B-cell lymphoma, treated with abx.
68
What do chief cells secrete? (2)
Pepsinogen, leptin
69
What are the stages of gastric secretion?
Cephalic - thought or oral ingestion of food, vagus nerve. Gastric - food in stomach, distension, vagal stimulation. Intestinal - food in small intestine, gastrin, followed by enteric inhibitors.
70
What type of feedback loop is gastrin secretion?
Negative
71
Function of PGE2 in digestion?
Directly inhibits parietal cells.
72
What can cause too little acid secretion in the stomach? (3)
Inflammation & gastric atrophy (autoimmune gastritis, H. Pylori gastritis), iatrogenic (drugs, fundoplication-related dysphagia, vagotomy), associated with infectious diarrhoea/gastric adenocarcinoma
73
Causes of acute epigastric pain? (9)
Acute pancreatitis, perforated peptic ulcer, peptic ulcer, acute cholecystitis, biliary colic, acute cholangitis, mesenteric vascular disease, perihepatitis, supradiaphragmatic pathology
74
Causes of dyspepsia? (5)
Functional (sensitisation), GORD, peptic ulcer, oesophageal cancer, gastric cancer
75
Risk factors for gastric cancer? (4)
Age, smoking, atrophic gastritis, H. Pylori
76
Risk factors for GORD? (2)
Smoking, BMI
77
Risk factors for peptic ulcers? (3)
H. Pylori, NSAIDs/aspirin, smoking
78
Risk factors for oesophageal cancer? (4)
Smoking, BMI, Barrett's oesophagus, age
79
What are the NICE referral guidelines for suspected oesophageal cancer? (5)
Dysphagia, OR >55y/o AND weight loss, with any of the following: upper abdo pain, reflux, dyspepsia
80
Tests for H. Pylori? (7)
Urea breath test, faecal antigen, serology, biopsy - urease, histology, culture, PCR
81
1st line treatment for H. Pylori? (3)
One to two weeks - PPI BD + amoxicillin 1g BD + clarithromycin 500mg BD
82
2nd line treatment for H. Pylori? (5)
Esomeprazole 40mg BD + 2 or 3 of: amoxicillin 1g BD / levofloxacin 500mg OD / metronidazole 400mg TDS / tetracycline 500mg QDS
83
3rd line for H. Pylori? (2)
Endoscopy & biopsy (for antibiotic sensitivities)
84
Treatment for functional dyspepsia? (8)
H. Pylori eradication, PPI, prokinetics, amitriptyline/imipramine, buspirone, mirtazepine, sulpiride, behavioural interventions (diaphragmatic breathing, psychological)
85
What is linitis plastica?
'Leather bottle stomach' - diffuse gastric cancer
86
What investigation is used in staging gastric cancer alongside CT contrast?
Staging laparoscopy
87
Curative treatment for gastric cancer? (2)
Perioperative chemotherapy & gastrectomy, or straight to gastrectomy if >80y/o and/or significant comorbidities
88
Palliative treatment for gastric cancer? (4)
Best supportive care, stent (e.g. pyloric stent for obstruction), drain (e.g. ascites), palliative chemotherapy
89
What is the standard chemotherapy regime in curative treatment for gastric cancer? (2)
3 cycles before gastrectomy, then 3 cycles of adjuvant chemotherapy (75% dose) after surgery
90
What anastomosis is made in gastrectomy surgery?
Oesophago-jejunal. Maintain & anastomose section of duodenum with ampulla of Vater.
91
Which form of oesophageal cancer is most common in the West?
Adenocarcinoma
92
Which form of oesophageal cancer is most common worldwide?
Squamous cell carcinoma
93
Risk factors for oesophageal SCC? (5)
Alcohol, smoking, chewing betel nut, frequent consumption of very hot drinks, achalasia
94
Risk factors for oesophageal adenocarcinoma? (6)
GORD, obesity, older males, hiatus hernia, smoking, Barrett's oesophagus
95
Where is oesophageal adenocarcinoma most commonly located?
Oesophagogastric junction
96
What is the cell type lining the oesophagus until the Z-line?
Pale pink stratified squamous epithelium
97
What cell type lines the stomach?
Salmon coloured columnar epithelium
98
Red flags for oesophageal cancer? (6)
Progressive dysphagia (cancer until proven otherwise), self-adapted liquid diet, weight loss, food regurgitation, persistent reflux not responding to tx with PPI, food bolus obstruction
99
What is the name of the current standard chemotherapy for oesophageal cancer, and what is its mode of delivery?
FLOT chemotherapy, PIC line
99
Why are barium swallows not helpful in oesophageal cancer?
Does not tell if benign or malignant, gastroscopy would be required for biopsy.
99
What investigations are used to stage oesophageal cancer? (4)
CT, CT-PET, endoscopic ultrasound, staging laparoscopy
100
Management for oesophageal adenocarcinoma?
3 cycles chemo, surgery, 3 cycles adjuvant chemo (75% dose)
101
Management for oesophageal SCC?
CROSS regime - chemoradiotherapy
102
What surgery is performed for oesophageal cancer?
Ivor-Lewis oesophagectomy
103
What structures remain in the Ivor Lewis oesophagectomy?
Top 3rd of the oesophagus, anastomosed to the bottom 2/3rds of the stomach.
104
What structure slings around the lower oesophageal sphincter, and when the stomach emerges past creates a hiatus hernia?
Crural diaphragm
105
What is classed as a small hiatus hernia?
<2cm
106
What is classed as a large hiatus hernia?
>5cm
107
Symptoms of reflux? (9)
Heartburn, chest pain, regurgitation, sensitivity to certain foods (especially cold), acid brash (metallic taste in back of mouth), worse leaning forwards & lying flat, worse at night, cough, dental issues
108
Initial management of reflux (no red flag symptoms)?
Trial PPIs full dose for 4-8 weeks.
109
Lifestyle changes for GORD? (7)
Weight loss, adjusting head of bed/sleep angle, dietary (e.g. fizzy drinks, alcohol, spicy food, etc.), smoking cessation, stress reduction, eat 3h before bed, reduce caffeine intake
110
2nd line treatment for GORD?
H2 receptor antagonists
111
What surgery is performed in refractory GORD?
Nissen fundoplication
112
What does a Nissen fundoplication involve?
Taking the fundus 360 degrees around the LOJ and suturing together to form an artificial sphincter.
113
What does the first tier of obesity management involve? (2)
Tier 1 = universal interventions - environmental & population wide services, identifying & reinforcing healthy eating and physical activity messages.
114
What does the second tier of obesity management involve? (3)
Tier 2 = lifestyle interventions, diets, pharmacotherapy - multicomponent weight management services, identification & primary assessment.
115
What does the third tier of obesity management involve? (1)
Tier 3 = specialist services - MDT, specialist assessment.
116
What does the fourth tier of obesity treatment involve? (1)
Tier 4 = surgery - preoperative assessment, bariatric medical & multidisciplinary team.
117
What three types of bariatric surgery are available?
Sleeve gastrectomy, Roux-en-Y gastric bypass, laparoscopic adjustable gastric band (LAGB)
118
What does a sleeve gastrectomy involve?
Removal of fundus & significant portion of body, with the pylorus remaining.
119
What does a Roux-en-Y gastric bypass involve?
Two anastomoses - gastrojejunostomy & a jejuno-jejunostomy. The stomach is bypassed, with food & bile mixing in the common channel in the jejunum.
120
What does a laparoscopic adjustable gastric band involve?
A port is made, leading to an inflatable band which separates the stomach into a smaller portion and a larger portion.
121
What is Ludwig's angina?
Infection of hypoglossal tissue - oedema & exudate cause the tongue to be pushed up and back. May become an emergency. Stridor, bull-neck, pain, dysphagia, fever
122
Presentation of strep throat? (7)
Fever, rapid-onset sore throat, pain on swallowing, grey-yellow tonsillar exudate. No cough, runny nose, don't lose voice
123
Presentation acute epiglottitis? (8)
Severe sore throat, difficulty swallowing, high fever, malaise, rapid development, tenderness of neck, stridor, most common in children
124
Management of acute epiglottitis? (5)
High dose abx (cefotaxime, chloramphenicol), corticosteroids (reduce oedema), sit patient upright, oxygen, emergency tracheostomy
125
Bilirubin blood test & normal value?
Breakdown product of RBCs, isolated rise can be benign (Gilbert's), total <21umol.
126
ALP blood test & normal value?
Alkaline phosphatase, raised in bile duct blockage/pressure, bone disease, low vitamin D. 30-130.
127
ALT blood test & normal value?
Alanine transaminase, released by damaged cells (direct hepatocyte damage). 10-60 male, 10-40 female.
128
AST blood test & normal value?
Aspartate aminotransferase, long term hepatocyte damage (helpful in indicating fibrosis), <50 male, <35 female
129
GGT blood test & normal value?
Gamma glutamyl transferase, rises with alcohol, rises with ALP in bile duct blockage. <55 male, <38 female.
130
Features of Crohn's disease on imaging? (7)
Skip lesions, ulcers, fistulas, fissures & oedema (cobblestoning), stenosis, wall thickening, inflammatory masses & abscesses
131
Indications for imaging the large intestine? (4)
Change in bowel habit, PR bleeding, iron deficiency anaemia, palpable mass
132
What are polyps of the large intestine classed as?
Premalignant adenomas, progressing to carcinoma
133
Causes of small bowel obstruction? (6)
Adhesions, hernias, Crohn's, malignancy, intussusception, gallstone (ileus)
134
What are taeniae coli?
3 bands of smooth muscle, making up the longitudinal muscle layer at the muscularis of the large intestine (except at terminal end)
135
What are the folds of the small bowel called (seen on AXR)?
Valvulae conniventes
136
What are the folds of the large intestine called (seen on AXR)?
Haustra
137
What are epiploic appendages?
Fat-filled sacs of visceral peritoneum found on the taeniae coli
138
How many rectal valves are there?
3
139
What is the purpose of the rectal valves?
To separate gas and faeces, preventing simultaneous flatus and faeces passage
140
How long is the rectum?
20cm
141
How long is the anal canal?
3.8-5cm
142
What type of muscle makes up the internal anal sphincter?
Smooth involuntary
143
What type of muscle makes up external anal sphincter?
Skeletal voluntary
144
What cell type makes up the anal canal surface?
Stratified squamous epithelial mucosa
145
What purpose do anal canals serve?
Mucus secretion to facilitate defecation
146
What is is the band marking the junction between hindgut & external skin called?
Dentate/pectinate line
147
What innervates above the dentate line?
Visceral sensory fibres - fairly insensitive.
148
What innervates below the dentate line?
Somatic sensory fibres - very sensitive.
149
What cells secrete mucus in the digestive tract?
Goblet
150
How frequently do the haustra contract & for how long?
Every 30 minutes, lasting approximately 1 minute
151
Which reflex increases gastric motility, and in response to what?
Gastrocolic reflex, stomach distension & breakdown products in the small intestine
152
What process produces gas in the colon?
Saccharolytic fermentation
153
What is faeces composed of? (6)
Undigested food residue, unabsorbed digested substances, bacteria, old epithelial cells, inorganic salts, water
154
Defecation reflex is caused by what?
Faeces in the anal canal gives choice of relaxing or keeping it temporarily closed. Parasympathetic reflex mediated by the spinal cord.
155
What is the definition of dysentery?
Severe diarrhoea with blood or mucus
156
What is gastroenteritis?
Inflammation of the stomach & intestinal mucosa
157
What is the leading cause of gastroenteritis?
Food poisoning
158
What type of viruses are responsible for 90% of cases of acute viral gastroenteritis? (2)
Norovirus, rotovirus
159
What is protozoan diarrhoea usually related to? (2)
Travel, part of an outbreak
160
What microbes are commonly associated with raw seafood (3)
Norwalk-like virus, Vibrio sp, hepatitis A
161
What microbes are commonly associated with raw eggs? (1)
Salmonella sp
162
What microbes are commonly associated with undercooked meat or poultry? (4)
Salmonella sp, Campylobacter sp, STEC, Clostridium perfringens
163
What microbes are commonly associated with unpasteurised milk or juice? (4)
Salmonella sp, Campylobacter sp, STEC, Yersinia enterocolitica
164
What microbes are commonly associated with unpasteurised soft cheese? (5)
Salmonella sp, Campylobacter sp, STEC, Y. enterocolitica, S. aureus
165
What microbes are commonly associated with homemade canned goods?
Clostridium botulinum
166
What microbes are commonly associated with fruits & vegetables? (5)
Cyclospora, C. perfingens, B. cereus, EHEC, STEC
167
What microbes are commonly associated with water? (3)
Cholera, Vibrio sp, giardia
168
What bacteria causes Guillain-Barre & bloody diarrhoea?
Campylobacter jejuni
169
EHEC (Enterohaemorrhagic E. Coli) causes what problems? (3)
Bloody diarrhoea, haemolytic-uraemic syndrome, neurological complications. Toxin damages vascular endothelial cells.
170
Salmonella typhi causes what disease?
Enteric fever/typhoid
171
Salmonella enterica causes what disease?
Loads of types of food poisoning differentiated by O & H antigens
172
Properties of viral stools? (4)
Watery diarrhoea, no pus, no blood, self-limiting
173
Properties of bacterial stools - toxigenic? (2)
Large volume, watery or greasy
174
Properties of bacterial stools - invasive (3)
Extreme urgency of defecation, small volume of stool, contains pus & blood.
175
Symptoms of botulism? (2)
Visual disturbances, potentially life-threatening descending paralysis
176
How do enterotoxins cause diarrhoea? (4)
Increase chloride ion permeability of the apical membrane of intestinal mucosal cells, pores activated, chloride leakage into lumen, sodium & water movement results. Causes secretory diarrhoea within a few hours.
177
How is C. Diff diagnosed?
Detection of GDH/glutamate dehydrogenase
178
Characteristics of C. Diff on colonoscopy?
Inflamed colon mucosa with raised, yellowish plaques/nodules.
179
What is C. Diff also commonly referred to as?
Pseudomembranous colitis
180
