Gastro Flashcards
Gastro-oesophageal junction 2 features
Epithelial transition: change in function
Gastric folds: allow stomach distention
Oesophagus motility measurement and regulation
Measured using manometry(peristaltic waves 40mmHg, resting LOS 20mmHg)
Mediated by inhibitory noncholinergic nonadrenergic neurons of myenteric plexus
Hypermotility(Achalasia) pathophysiology
Environmental trigger->inflammation
Fibrosis->neuron apoptosis
Loss of ganglion cells in LOS wall
Less NCNA activity->less inhibition so higher resting LOS pressure
Increased risk of oesophageal cancer
Achalasia causes
Chagas’ disease
Protozoa infection
Amyloid/sarcoma/eosinophilic oesophagitis
Achalasia treatment
Pneumatic dilation: circumferential stretching/tearing of muscle fibres
Heller’s myotomy:6cm oesophagus, 3cm stomach
Dor fundoplication: anterior fundus folded over oesophagis and sutured
Risks of surgery for achalasia
Perforation
Splenic injury
Division of vagus nerve
Hypomotility(scleroderma) pathophysiology
Autoimmune disease Neuronal defects->smooth muscle atrophy Distal peristalsis ceases Low resting LOS pressure CREST syndrome
Scleroderma treatment
Exclude organic obstruction
Improve peristaltic force with prokinetics
Corkscrew oesophagus pathophysiology and symptoms
Diffuse oesophageal spasm Disordered coordination Hypertrophy of circular muscle Dysphagia and chest pain 400-500mmHg
Corkscrew oesophagus treatment
Forceful pneumatic dilation of cardia
Oesophageal perforation symptoms
Pain
Fever
Dysphagia
Emphysema(uncommon)
Oesophageal perforation causes
Boerhaave’s(vomiting against a closed glottis)
Foreign body(batteries, sharp objects)
Trauma(neck, thorax)
3 protective mechanisms against GORD
Volume clearance by oesophageal peristalsis reflex
pH clearance by saliva
Oesophageal epithelium barrier properties
GORD risk factors
Smoking Chocolate Alcohol Sliding hiatus hernia Rolling hiatus hernia
GORD treatment
Lifestyle changes
PPIs
Dilation peptic strictures
Laparoscopic Nissen’s fundoplication
Stomach cells and secretions
Chief cell: pepsinogen
Parietal cell: acid
Gastritis causes
H. pylori Atrophic gastritis(autoimmune against parietal cell)->pernicious anaemia, G cell hyperplasia(carcinoma)
Gastric ulcer pathology
Lack of mucosal protection
Erosive haemorrhagic gastritis->acute ulcer->gastric bleed & perforation
H. Pylori secretions
VacA toxin: gastric mucosal injury
Urease: neutralise acid
Enzymes: mucinase, lipase, protease
Portal triad
Hepatic artery: O2 rich blood
Portal vein: process nutrients, detoxify blood
Bile duct: produce bile
Liver cells and function
Sinusoidal endothelial cells: fenestrated, movement of molecules
Kuppfer cells: macrophages
Hepatic stellate cells: damage->deposit collagen
Hepatocyte: metabolism and synthesis of albumin/clotting factors
Cholangiocyte: secrete HCO3 and H2O into bile duct
Enzyme for detoxification in liver
P450: modification followed by conjugation
Functions of bile
Cholesterol homeostasis
Lipid and soluble vitamin absorption
Excretion of waste
Pancreas exocrine cells
Acinar cells: low volume, enzyme rich, viscous
Ductal and centroacinar cells: high volume, bicarbonate rich, watery
Regulation of pancreas exocrine function
Vagus nerve(enzyme)
Cholecystokinin(enzyme)
Secretin(bicarbonate)
Small bowel cells
Enterocytes: columnar
Stem cells: pluripotent
Goblet cells: more abundant distally
Paneth cells: engulf bacteria/protozoa
Enteroendocrine cells: columnar
Small bowel motility
Segmentation: circular muscles
Peristalsis: sequential contraction
Migrating motor complex
Proteases activation in small bowel
Enterokinase activates trypsinogen
Trypsin activates other proteases
Carbohydrate absorption
Glucose:
SGLT-1(apical)
GLUT-2(basolateral)
Fructose:
GLUT-5(apical)
Calcium absorption
Duodenum and ileum
Absorbed by IMcal
Ca binds to calbindin
Ca leaves cell by Na-Ca antiporter or Ca ATPase
Iron absorption
Heme iron absorbed by HCP-1
Fe2+ absorbed by DMT-1
Fe enters blood by ferroportin and travels as transferrin
Vit B12 absorption
B12 binds to intrinsic factor from parietal cells
Absorbed in distal ileum
Enteric nervous system
Myenteric plexus: senses distention, controls motility
Submucosal plexus: senses chemicals, controls secretions
Hirschsprung’s disease
Congenital absence of myenteric and submucosal plexus
Affected segment is contracted, unaffected part proximal to it is dilated
Reuires surgery
Gut hormones and cells
Gastin: G cells(acid)
Secretin: S cells(alkali)
CCK: I cells(gall bladder contraction)
GIP: K cells(insulin)
GLP-1: L cells(satiety)
Somatostatin: D cells(universal inhibitor)
Pancreatic polypeptide: PP cells
Peptide YY: L cells
Hepatocellular cancer tests/investigations
Hepatocellular cancer: ultrasound and alpha feto protein(AFP) for high risk patients
Types of oesophageal cancers
Squamous cell carcinoma: upper 2/3
Adenocarcinoma: lower 1/3, acid reflux
Oesophageal cancer symptoms
Dysphagia
Weight loss
Elderly
More commonly male
Oesophageal/gastric cancer diagnosis
Oesophagogastroduodenoscopy(OGD), biopsy to diagnose
CT chest and abdo to stage
PET to check for metastasis
Oesophageal cancer treatment
Curative: neoadjuvant, oesophagectomy
Palliative: palliative chemo, steroids, stent
Gastric cancer symptoms (ALARMS55)
Anaemia Loss of weight/appetite Abdominal mass Recent onset of progressive symptoms Melaena/haematemesis Swallowing difficulty 55 years old
Gastric cancer treatment
OG junction: oesophagogastrectomy
Close to OG junction: total gastrectomy
Far from OG junction: subtotal gastrectomy
Colorectal cancer risk factors
Previous cancer
Family history
Smoking
Obesity
Colorectal cancer aetiology and type of carcinoma
Adenocarcinoma
Most common GI cancer
More often in descending/sigmoid colon or rectum
Colorectal cancer presentation and symptoms
Bowel obstruction causing tenderness
Bone pain/hepatomegaly if metastasis
Abdominal mass
Right sided/caecal: iron deficiency anaemia, diarrhoea
Left sided/sigmoid: PR bleed, mucus
Rectal: PR bleed, mucus, tenesmus
Colorectal cancer investigations
DRE<12cm reached by finger Rigid sigmoidoscopy FIT: faecal occult blood Colonoscopy CT colonoscopy(non-invasive) MRI pelvis for rectal cancer
Colorectal cancer management
Ascending/transverse: resection and primary anastomosis
Left sided: Hartmann’s procedure, primary anastomosis, palliative stent
Pancreatic cancer aetiology
Highly lethal
Late presentation
Male more common
Pancreatic cancer risk factors
Chronic pancreatitis
T2DM
Smoking
Family history
Most common type of pancreatic cancer
Pancreatic ductal adenocarcinoma(PDA)
Pancreatic cancer presentation
Jaundice Weight loss Pain GI bleed Acute pancreatitis If at body/tail, more advanced
Pancreatic cancer investigations
CA19-9 >200u/mol
Dual phase CT & MRI checks resectability
Laparoscopy and PET for occult metastasis
Types of liver cancer
Hepatocellular carcinoma
Cholangiocarcinoma
Gall bladder cancer
Secondary liver metastasis
Pancreas protective mechanisms against autodigestion
Inactive pro-enzymes
Trypsin inhibitor
Enzymes only activated in duodenum
Acute pancreatitis causes(GETSMASHED)
Gall stones Ethanol Trauma Steroids Mumps/other viruses Autoimmune(SLE) Scorpion/snake bite Hypercalcaemia, hyperlipidaemia ERCP Drugs: steroids, azothioprine, NSAIDs, diuretics
Acute pancreatitis types
Oedematous pancreatitis
Haemorrhagic pancreatitis
Necrotic pancreatitis
Acute pancreatitis symptoms
Epigastric pain radiating to back Nausea and vomiting Fever Haemodynamic instability(hypotension, tachycardia) Peritonism Haemorrhagic: Grey-Turner’s sign(flank bruising) Cullen’s sign(umbilical bruising)
Acute pancreatitis investigations
Blood test-> high amylase X ray Ultrasound-> gall stones ERCP->remove gall stones MRCP->gall stone pancreatitis
Acute pancreatitis severity(PANCREAS)
PO2<8kPa (hypoxia) Age>55 Neutrophil>15 (neutrophilia) Calcium<2mmol/L (hypercalcaemia) Renal: urea>16mmol/L (renal failure) Enzymes: AST>200iu/L, LDH>600iu/L Albumin<32g/L (hypoalbuminuria) Sugar>10mmol/L (hyperglycaemia)
Score of 3 or more is severe
CRP>200 is severe
Acute pancreatitis management
Airway, breathing, circulation
Fluid resuscitation
Analgesia
Pancreatic rest
Determine underlying cause
HDU if severe
Acute pancreatitis complications
Hypocalcaemia
Hyperglycaemia
ARDS
Renal failure
Pancreatic necrosis
Haemorrhage
Pancreatitis infected necrosis treatment
Antibiotics
Percutaneous drainage
Chronic pancreatitis complications
Insulin dependent DM
Steatorrhoea
Chronic pancreatitis symptoms
Pain Malabsorption Weight loss Diabetes mellitus Thrombosis Obstructive jaundice
Chronic pancreatitis treatment
Surgical resection
Total pancreatectomy
Distal pancreatectomy
Causes of jaundice
Prehepatic: haemolysis, massive transfusion
Posthepatic: gallstones, tumours
Intrahepatic: low BR uptake, low conjugated BR, low secreted BR, cholestasis, liver failure
Acute liver failure causes
Toxins
Inflammation
Pregnancy
Drugs
Chronic liver failure causes(cirrhosis)
Inflammation Alcohol Drugs Cardiovascular causes Autoimmune
Liver failure complications
Hypoglycaemia Coagulopathy & bleeding Encephalopathy Vulnerable to infection Renal failure
Hormone affected in liver failure
Secondary hyperaldosteronism causing hypokalaemic alkalosis
Effect of low albumin in liver failure
Ascites
Liver failure treatment
Encephalopathy: reduce protein intake
Hypoglycaemia: dextrose
Hypocalcaemia: calcium gluconate
Renal failure: haemofiltration
Resp failure: ventilation
Hypotension: albumin, vasoconstriction
Infection: antibodies
Bleeding: vit K, FFP, platelets
Visceral vs parietal abdominal pain
Visceral: autonomic, dull/cramping/burning
Parietal: somatic, well-localised, sharp/ache
Character of abdominal pain
Inflammation: constant pain thats worse when moving
Obstructive: colicky, fluctuates in severity, moves to relieve pain
Abdominal pain radiation
Kidney: groin
Stomach/pancreas/duodenum: back
Gall bladder: right and back
Regulation of hunger in brain(which nucleus and which neurons)
Arcuate nucleus
Excitatory: NPY/Agrp neurons
Inhibitory: POMC neurons
Act on paraventricular nucleus
Hormones in appetite
Leptin: deficiency/resistance causes obesity. Acts on hypothalamus
Ghrelin: stimulates NPY/Agrp, inhibits POMC
Peptide YY: inhibits NPY, stimulates POMC
Secondary polydipsia causes
Medications Dehydration Diabetes mellitus Acute kidney failure Conn’s syndrome Addison’s disease
Eating disorders
Anorexia nervosa: avoid eating
Bulimia nervosa: eat then purge
Pica: eating non-food items
Rumination syndrome: food brought back from stomach
Obesity treatment
Bariatric surgery
BMI>40 or >35 with comorbidities
Gastric bypass and sleeve gastrectomy
Remission of diabetes and OSA
Reduced ghrelin, raised peptide YY,GLP1
Immunological barrier in mucosal defense
MALT: mucosa associated lymphoid tissue
GALT: gut associated lymphoid tissue
What is MALT
Lymphoid mass in submucosa, containing lymphoid follicles surrounded by high endothelial venule(HEV)
What are Peyer’s patches
Organised GALT in submucosal distal ileum
Lymphoid follicles covered in follicle associated epithelium(FAE)
Naive B and T cells
Antigen uptake by M cells
Antigen sampling by transepithelial dendritic cells
Gut B cell adaptive response
Naive B cells express IgM, switch to IgA after antigen exposure
Mature B cells secrete IgA and populate lamina propria
Cholera transporter, symptoms, diagnosis and treatment
Secretes cholera enterotoxin Causes CFTR to secrete chloride Severe dehydration & watery diarrhoea Diagnose with stool sample culture Treat with oral rehydration
Infectious diarrhoea viruses
Rotavirus: young children
Norovirus: closed communities
Infectious diarrhoea bacteria
Campylobacter(curved bacteria)
6 pathotypes of E. coli
Clostridium difficile
Severe C. diff infection criteria
WCC>15
Creatinine>150
Types of IBD
Crohn’s disease: non-continuous, cobblestone, transmural, non-caseating granulomas
Ulcerative colitis: continuous, ulcerations, mucosa only
Both are autoimmune
Types of artificial nutritional support
Enteral nutrition: superior to parenteral, NGT/NJT/NDT depending on gastric feed
Parenteral nutrition: nutrients directly into venous blood using central venous catheter
Complications of enteral nutrition
Mechanical: misplacement, blockage
GI: aspiration, ulceration
Complications of parenteral nutrition
Mechanical: pneumothorax, haemothorax
Catheter related infections
What is refeeding syndrome
Biochemical shift and clinical symptoms when reintroducing nutrition
Symptoms of refeeding syndrome
Hypokalaemia
Hypophosphataemia
Thiamine deficiency
Salt and water retention
Arrythmia, tachycardia
Encephalopathy, coma, seizures
Respiratory depression
Bowel ischaemia presentation
Sudden onset crampy abdo pain
Bloody, loose stool
Fever, septic shock
Bowel ischaemia large vs small(cause, onset and name)
Small occlusive, large atherosclerotic Large more gradual and mild Small more painful Small: acute mesenteric ischaemia Large: ischaemic colitis
Bowel ischaemia investigations
FBC: neutrophilic leukocytosis
VBG: lactic acidosis
CT abdo/pelvis: vascular stenosis
Endoscopy for mild/moderate large b
Bowel ischaemia conservative management
Only for ischaemic colitis IV fluid Anticoagulants Bowel rest Broad spectrum antibiotics
Bowel ischaemia surgery
Exploratory laparotomy: resect necrotic bowel, embolectomy, mesenteric artery bypass
Endovascular revascularisation(patients without signs of ischaemia): balloon angioplasty/thrombectomy
Acute appendicitis presentations
Anorexia, nausea, vomiting
McBurnery’s point Blumberg’s sign: rebound tenderness Rovsing sign: LLQ->RLQ Psoas sign Obturator sign
Acute appendicitis investigations
FBC: neutrophilic leukocytosis, CRP
CT scan gold standard
USS for pregnant/child, MRI if USS inconclusive
Acute appendicitis conservative management
IV fluids
Analgesia
Antibiotics
Percutaneous drainage if abscess
Acute appendicitis surgery
Laparoscopic or open surgery
Laparoscopic: cost, pain, hospital stay length, infection rate
Small bowel obstruction presentations
Colicky central pain Early vomiting Early high pitched bowel sounds Dehydration Abdominal tenderness
Large bowel obstruction presentations
Colicky central pain Early constipation Early & significant abdominal distention Early high pitched bowel sounds Dehydration Abdominal tenderness
Small bowel obstruction causes
Adhesions
Neoplasia
Incarcerated hernia
Crohn’s
Large bowel obstruction causes
Colorectal carcinoma
Volvulus
Diverticulitis
Faecal impaction
Important points of bowel obstruction
Diagnose using symptoms
Check for hernia
Strangulating or simple
Bowel obstruction investigations
FBC: high CRP&WCC if strangulated U&E: imbalance VBG(vomiting):hypoCl,hypoK,M alkalosis VBG(strangulated): M acidosis(lactate) Erect AXR: S bowel 3cm dilation, L bowel 6cm dilation, caecum 9cm CT abdo
Bowel obstruction conservative management
Nil by mouth Fluid resuscitation Analgesia, anti-emetics Faecal impaction: stool evac Sigmoid volvulus: rigid sigmoidoscopic decompression SBO: oral gastrogaffin for adhesion
Bowel obstruction surgery
Exploratory laparoscopy/laparotomy
Bowel resection with primary anastomosis/stoma formation
GI perforation presentations
Sudden pain with distention Guarding rigidity, rebound tenderness Nausea, vomiting, constipation Fever, tachycardia, hypotention Little to no bowel sounds
GI perforation investigations
FBC: leukocytosis High urea, creatinine VBG: M acidosis(lactate) Erect CXR: free subdiaphragmatic air CTAP: pneumoperitoneum, GI content
GI perforation conservative management
Nil by mouth, NG tube
Broad spectrum antibiotics
PPIs
Analgesia, anti-emetics
GI perforation surgery
Exploratory laparoscopy/laprotomy Primary closure of perforation Resect perforated segment Culture abdominal fluid, peritoneal lavage Biopsy if malignancy
Biliary colic symptoms
Postprandial RUQ pain with radiation to shoulder
Nausea
Acute cholangitis symptoms
Charcot’s triad:
Jaundice
RUQ pain
Fever
Acute cholecystitis symptoms
Acute, severe RUQ pain
Fever
Murphy’s sign
Biliary colic investigations
Normal bloods
USS: cholelithiasis
Acute cholecystitis investigations
Elevated WCC/CRP
USS: thick gall bladder wall
Acute cholangitis investigations
Raised LFT/WCC/CRP
Blood MC&S positive
USS: biliary dilation
Biliary colic management
Analgesia
Anti-emetics
Elective cholecystectomy
Acute cholecystitis management
Fluid
Antibiotics
Analgesia
Early/elective cholecystectomy
Acute cholangitis managenent
Fluid
Antibiotics
Analgesia
ERCP to clear bile duct or stent
CNS mutations causing obesity
POMC deficiency
MC4R loss of function mutation
Hormone in anorexia
Serotonin
Bowel obstruction AXR signs
Small bowel: ladder distension
Large bowel: coffee bean sign
3 areas for oesophageal perforation
Cricopharyngeal constriction (OGD related) Aortic and bronchial constriction Diaphragmatic constriction
