Page | 1
Essential Notes for Gastroenterology
Created by: Dr Chen
, Page | 2
Contents
Pathophysiology of abdominal pain................................................................................................................................4
Suspected upper GI cancer (NICE)...................................................................................................................................5
Referral guidelines (NICE)................................................................................................................................................7
Upper GI bleed................................................................................................................................................................8
Dysphagia...................................................................................................................................................................... 12
Gastro-oesophageal reflux disease (GORD)...................................................................................................................13
Oesophageal cancer......................................................................................................................................................16
Hiatus hernia................................................................................................................................................................. 18
Eosinophilic oesophagitis..............................................................................................................................................19
Mallory-Weiss syndrome – Defined as longitudinal tear of mucosa of lower oesophagus...........................................21
Achalasia – Definition: Oesophageal motility disorder impaired peristalsis and relaxation of lower oesophageal
sphincter....................................................................................................................................................................... 23
Food bolus obstruction / Steakhouse syndrome...........................................................................................................25
Scleroderma – It is a result of systemic sclerosis which leads to fibrosis of oesophagus stiffness regurgitation .........26
Oesophageal carcinoma................................................................................................................................................27
Dyspepsia / Indigestion.................................................................................................................................................28
Functional GI disorders / Disorders of gut brain interaction.........................................................................................30
Gastritis......................................................................................................................................................................... 31
Peptic ulcer (gastric and duodenal) - Definition of peptic ulcer: Open sores in lining of stomach or duodenum..........32
Caustic substance ingestion...........................................................................................................................................34
Gastro-oesophageal varices..........................................................................................................................................35
Acute gastritis – Definition: Inflammation of lining of stomach. Starts from antrum....................................................37
Chronic gastritis – Definition: Inflammation of ENTIRE gastric mucosa.........................................................................38
Gastric carcinoma..........................................................................................................................................................39
Gastroenteritis..............................................................................................................................................................40
Travelers diarrhoea.......................................................................................................................................................42
Diarrhoea without blood...............................................................................................................................................43
Diarrhoea with blood....................................................................................................................................................44
Clostridium difficile........................................................................................................................................................46
GI parasites.................................................................................................................................................................... 48
Giardiasis....................................................................................................................................... 48
Amoebiasis.................................................................................................................................... 48
Nematodes.................................................................................................................................... 49
Platyhelminthes (Annelids) / Cestodes.........................................................................................50
, Segmented worm (Annelid)..........................................................................................................50
Page | 3
Porphyria....................................................................................................................................................................... 51
Crohn’s Disease.............................................................................................................................................................52
Ulcerative Colitis............................................................................................................................................................55
Coeliac disease..............................................................................................................................................................58
Irritable Bowel Syndrome..............................................................................................................................................60
Small bowel bacterial overgrowth syndrome................................................................................................................62
Dumping syndrome.......................................................................................................................................................64
Pancreatic cancer..........................................................................................................................................................65
Peritonitis – Definition: Inflammation of the serosal membrane that lines the abdominal cavity and organs..............67
Plasma autoantibodies and associated GI disease........................................................................................................69
Liver Failure................................................................................................................................................................... 70
Cirrhosis......................................................................................................................................................................... 75
Budd Chiari syndrome...................................................................................................................................................83
Drug induced liver problems.........................................................................................................................................84
Paracetamol overdose...................................................................................................................................................87
Alcoholic Fatty Liver Disease.........................................................................................................................................88
Alcoholic hepatitis.........................................................................................................................................................89
Non alcoholic Fatty Liver Disease (NAFLD)....................................................................................................................91
Jaundice......................................................................................................................................................................... 94
Bile acid malabsorption.................................................................................................................................................98
Pyogenic liver abscess...................................................................................................................................................99
Ascites......................................................................................................................................................................... 100
Autoimmune Hepatitis (AIH).......................................................................................................................................101
Primary Biliary Cholangitis (PBC).................................................................................................................................104
Primary Sclerosing Cholangitis (PSC)...........................................................................................................................108
ANCA associated vasculitis..........................................................................................................................................110
Hereditary Haemochromatosis (HH)...........................................................................................................................111
1-antitrypsin (A1AT) deficiency....................................................................................................................................114
Wilson’s disease / Hepatolentricular degeneration....................................................................................................116
Viral Hepatitis..............................................................................................................................................................118
Liver Tumours..............................................................................................................................................................124
Hepatocellular carcinoma (HCC)..................................................................................................................................125
Cholangiocarcinoma....................................................................................................................................................126
Carcinoid syndrome:...................................................................................................................................................127
Bile duct and Gallbladder Cancers...............................................................................................................................129
Splenomegaly..............................................................................................................................................................130
Hepatomegaly.............................................................................................................................................................131
, Gilbert’s disease..........................................................................................................................................................132
Page | 4
Dubin-Johnson syndrome............................................................................................................................................133
Whipple's disease........................................................................................................................................................134
Obesity: bariatric surgery............................................................................................................................................136
Zieve syndrome...........................................................................................................................................................137
Pathophysiology of abdominal pain
Types of pain:
1. Visceral pain
a. Generalised dull pain
b. Mediated by sympathetic nervous system
c. The visceral peritoneum and the viscera are insensitive to mechanical,
thermal or chemical stimulation, and can therefore be handled, cut or
cauterized painlessly. However, they are sensitive to tension, whether due
to overdistension or traction on mesenteries, visceral muscle spasm and
ischaemia.
d. Irritation of foregut structures (the lower oesophagus to the second part of
the duodenum) is usually felt in the epigastric area.
e. Pain from midgut structures (the second part of the duodenum to the splenic
flexure) is felt around the umbilicus.
f. Pain from hindgut structures (the splenic flexure to the rectum) is felt in the
hypogastrium.
2. Somatic pain
a. Well localised sharp pain
b. The parietal peritoneum covers the anterior and posterior abdominal walls,
the undersurface of the diaphragm and the pelvic cavity.
c. Its nerve supply is derived from somatic nerves supplying the abdominal wall
musculature and the skin (T5–L2). The exception to this is the diaphragmatic
portion, which is supplied centrally by afferent nerves in the phrenic nerve
(C3–C5), and peripherally in the lower six intercostal and subcostal nerves.
d. The parietal peritoneum is sensitive to mechanical, thermal or chemical
stimulation, and cannot be handled, cut or cauterized painlessly reflex
contraction of the corresponding segmental area of muscle, causing rigidity of the abdominal wall (guarding) and
hyperaesthesia of the overlying skin.
e. When the diaphragmatic portion of the parietal peritoneum is irritated peripherally, there will be pain, tenderness and
rigidity in the distribution of the lower spinal nerves, but when it is irritated centrally, pain is referred to the cutaneous
distribution of C3, 4 and 5 (i.e. the shoulder area.)
Causes of pain:
- Inflammation
o Infection
o Non-infective e.g. chemical, ischaemic, trauma, immune
- Perforation
- Obstruction
Peritonitis pathophysiology
- May be classified according to extent (either localized or generalized)
- Generalized peritonitis common causes
Essential Notes for Gastroenterology
Created by: Dr Chen
, Page | 2
Contents
Pathophysiology of abdominal pain................................................................................................................................4
Suspected upper GI cancer (NICE)...................................................................................................................................5
Referral guidelines (NICE)................................................................................................................................................7
Upper GI bleed................................................................................................................................................................8
Dysphagia...................................................................................................................................................................... 12
Gastro-oesophageal reflux disease (GORD)...................................................................................................................13
Oesophageal cancer......................................................................................................................................................16
Hiatus hernia................................................................................................................................................................. 18
Eosinophilic oesophagitis..............................................................................................................................................19
Mallory-Weiss syndrome – Defined as longitudinal tear of mucosa of lower oesophagus...........................................21
Achalasia – Definition: Oesophageal motility disorder impaired peristalsis and relaxation of lower oesophageal
sphincter....................................................................................................................................................................... 23
Food bolus obstruction / Steakhouse syndrome...........................................................................................................25
Scleroderma – It is a result of systemic sclerosis which leads to fibrosis of oesophagus stiffness regurgitation .........26
Oesophageal carcinoma................................................................................................................................................27
Dyspepsia / Indigestion.................................................................................................................................................28
Functional GI disorders / Disorders of gut brain interaction.........................................................................................30
Gastritis......................................................................................................................................................................... 31
Peptic ulcer (gastric and duodenal) - Definition of peptic ulcer: Open sores in lining of stomach or duodenum..........32
Caustic substance ingestion...........................................................................................................................................34
Gastro-oesophageal varices..........................................................................................................................................35
Acute gastritis – Definition: Inflammation of lining of stomach. Starts from antrum....................................................37
Chronic gastritis – Definition: Inflammation of ENTIRE gastric mucosa.........................................................................38
Gastric carcinoma..........................................................................................................................................................39
Gastroenteritis..............................................................................................................................................................40
Travelers diarrhoea.......................................................................................................................................................42
Diarrhoea without blood...............................................................................................................................................43
Diarrhoea with blood....................................................................................................................................................44
Clostridium difficile........................................................................................................................................................46
GI parasites.................................................................................................................................................................... 48
Giardiasis....................................................................................................................................... 48
Amoebiasis.................................................................................................................................... 48
Nematodes.................................................................................................................................... 49
Platyhelminthes (Annelids) / Cestodes.........................................................................................50
, Segmented worm (Annelid)..........................................................................................................50
Page | 3
Porphyria....................................................................................................................................................................... 51
Crohn’s Disease.............................................................................................................................................................52
Ulcerative Colitis............................................................................................................................................................55
Coeliac disease..............................................................................................................................................................58
Irritable Bowel Syndrome..............................................................................................................................................60
Small bowel bacterial overgrowth syndrome................................................................................................................62
Dumping syndrome.......................................................................................................................................................64
Pancreatic cancer..........................................................................................................................................................65
Peritonitis – Definition: Inflammation of the serosal membrane that lines the abdominal cavity and organs..............67
Plasma autoantibodies and associated GI disease........................................................................................................69
Liver Failure................................................................................................................................................................... 70
Cirrhosis......................................................................................................................................................................... 75
Budd Chiari syndrome...................................................................................................................................................83
Drug induced liver problems.........................................................................................................................................84
Paracetamol overdose...................................................................................................................................................87
Alcoholic Fatty Liver Disease.........................................................................................................................................88
Alcoholic hepatitis.........................................................................................................................................................89
Non alcoholic Fatty Liver Disease (NAFLD)....................................................................................................................91
Jaundice......................................................................................................................................................................... 94
Bile acid malabsorption.................................................................................................................................................98
Pyogenic liver abscess...................................................................................................................................................99
Ascites......................................................................................................................................................................... 100
Autoimmune Hepatitis (AIH).......................................................................................................................................101
Primary Biliary Cholangitis (PBC).................................................................................................................................104
Primary Sclerosing Cholangitis (PSC)...........................................................................................................................108
ANCA associated vasculitis..........................................................................................................................................110
Hereditary Haemochromatosis (HH)...........................................................................................................................111
1-antitrypsin (A1AT) deficiency....................................................................................................................................114
Wilson’s disease / Hepatolentricular degeneration....................................................................................................116
Viral Hepatitis..............................................................................................................................................................118
Liver Tumours..............................................................................................................................................................124
Hepatocellular carcinoma (HCC)..................................................................................................................................125
Cholangiocarcinoma....................................................................................................................................................126
Carcinoid syndrome:...................................................................................................................................................127
Bile duct and Gallbladder Cancers...............................................................................................................................129
Splenomegaly..............................................................................................................................................................130
Hepatomegaly.............................................................................................................................................................131
, Gilbert’s disease..........................................................................................................................................................132
Page | 4
Dubin-Johnson syndrome............................................................................................................................................133
Whipple's disease........................................................................................................................................................134
Obesity: bariatric surgery............................................................................................................................................136
Zieve syndrome...........................................................................................................................................................137
Pathophysiology of abdominal pain
Types of pain:
1. Visceral pain
a. Generalised dull pain
b. Mediated by sympathetic nervous system
c. The visceral peritoneum and the viscera are insensitive to mechanical,
thermal or chemical stimulation, and can therefore be handled, cut or
cauterized painlessly. However, they are sensitive to tension, whether due
to overdistension or traction on mesenteries, visceral muscle spasm and
ischaemia.
d. Irritation of foregut structures (the lower oesophagus to the second part of
the duodenum) is usually felt in the epigastric area.
e. Pain from midgut structures (the second part of the duodenum to the splenic
flexure) is felt around the umbilicus.
f. Pain from hindgut structures (the splenic flexure to the rectum) is felt in the
hypogastrium.
2. Somatic pain
a. Well localised sharp pain
b. The parietal peritoneum covers the anterior and posterior abdominal walls,
the undersurface of the diaphragm and the pelvic cavity.
c. Its nerve supply is derived from somatic nerves supplying the abdominal wall
musculature and the skin (T5–L2). The exception to this is the diaphragmatic
portion, which is supplied centrally by afferent nerves in the phrenic nerve
(C3–C5), and peripherally in the lower six intercostal and subcostal nerves.
d. The parietal peritoneum is sensitive to mechanical, thermal or chemical
stimulation, and cannot be handled, cut or cauterized painlessly reflex
contraction of the corresponding segmental area of muscle, causing rigidity of the abdominal wall (guarding) and
hyperaesthesia of the overlying skin.
e. When the diaphragmatic portion of the parietal peritoneum is irritated peripherally, there will be pain, tenderness and
rigidity in the distribution of the lower spinal nerves, but when it is irritated centrally, pain is referred to the cutaneous
distribution of C3, 4 and 5 (i.e. the shoulder area.)
Causes of pain:
- Inflammation
o Infection
o Non-infective e.g. chemical, ischaemic, trauma, immune
- Perforation
- Obstruction
Peritonitis pathophysiology
- May be classified according to extent (either localized or generalized)
- Generalized peritonitis common causes
