Week 4 Flashcards
What is the gastroileal reflex stimulated by and what does it involve?
Stimulated by gastric distension
Involves opening of the ileocaecal valve
What is absorbed and secreted by the large intestine?
Water, sodium and chloride ions are absorbed
Potassium, bicarbonate and mucus are secreted
Carbohydrates not absorbed in the S.I can be absorbed in the L.I but first must be converted. What does this involve?
Colonic flora ferment the carbohydrates to short-chain fatty acids which can then be absorbed
Is the internal anal sphincter under control of the brain or the spinal cord?
Spinal cord
What does RELAXATION of the skeletal muscle of the external anal sphincter cause?
Defecation
What does CONTRACTION of the skeletal muscle of the external anal sphincter cause?
Delays defecation
What are some of the roles of colonic bacteria within the bowel?
Increase intestinal immunity
Promote motility
Activate some drugs
Synthesis vitamin K2 and free fatty acids
What are the two main important drug classes used for IBD?
Steroids and immunosuppressants
What two conditions fall under IBD?
Crohn’s Disease and Ulcerative Colitis
What is a polyp?
A protrusion above an epithelial surface
What is an adenoma?
Benign tumours composed of epithelial cells
What is an adenocarcinoma?
A malignant epithelial tumour
Injecting what substance can prevent bleeding when removing a polyp?
Adrenaline
Why must all adenomas be removed?
They are dysplastic and are pre-malignant - it would only take a few more mutations for a cancer to develop and thus they need to be removed to prevent this from happening
Are left or right sided colorectal cancers more common?
Left- sided
Why can there be spread to the liver from a colorectal cancer?
The merging of the systemic with the portal venous system allows metastasis to be directed towards the liver
Name two types of inherited cancer syndromes
HNPCC (hereditary non polyposis coli)
FAP (familial adenomatous polyposis)
What are causes of diverticular disease?
Low fibre diet
Increased intraluminal pressure
What is diverticulitis?
Inflammation of the diverticulae
What are some of the complications of diverticular disease?
Inflammation Rupture/ Perforation - peritonitis/ sepsis Abscess Fistula Stricture Massive bleeding
What is the most common fistula that can occur from the large intestine? What can this cause?
Colovesical fistula (bladder and L.I communicate) - Can cause recurrent UTI's and flatus (bubbles) in the urine
What is a fistula?
A pathological communication between two epithelial surfaces
What classification is used to stage acute diverticulitis?
Hinchey Classification
What is the name of the surgery used in the management of complex diverticulitis?
Hartmann’s procedure
Who gets ischaemic colitis?
Elderly patients
Arteriopaths (patients with artery disease)
What are some of the causes of rectal bleeding?
Haemorrhoids
Diverticular disease
Cancer
Large polyps
What are some of the possible causes of large bowel obstruction?
Colorectal cancer
Hernias
Volvulus
Strictures
What are the symptoms of large bowel obstruction?
Constipation
Distension
Pain
Vomiting
What is a sigmoid volvulus?
When the sigmoid colon twists on its mesentery causing the lumen to be blocked off and the vasculature to be pinched off - can cause infarction and gangrene
What is meant by a ‘pseudo obstruction’?
When there is no real mechanical/ physical obstruction - can be due to hypoxia/ biochemistry
What are the histopathological clues of ischaemia?
Withering of crypts
Pink, smudgy lamina propria
Few chronic inflammatory cells
What are the histopathological clues of antibiotic-induced pseudomembranous colitis?
Patchy yellow membrane exudates on the mucosal surfaces
What are the histopathological clues of collagenous colitis?
Increased thickness of sub epithelial collagen
thickened basement membrane
What are the histopathological clues of lymphocytic colitis?
Increased intraepithelial lymphocytes
No thickening of the basement membrane
What two conditions come under the term ‘Microscopic Colitis’?
Collagenous Colitis and Lymphocytic Colitis
What kind of history would be important in considering a diagnosis of radiation colitis?
History of prostate/cervical cancer, treated with radiotherapy
What are two causes of irritable bowel syndrome?
Disorders of intestinal motility
Visceral hypersensitivity
What can exaggerate the symptoms of IBS?
Stress
Menstruation
Gastroenteritis
What investigations are done for IBS?
FBC ESR/ plasma viscosity CRP Antibody testing for coeliac disease Lower GI tests if >50 years or there is a FH of colorectal cancer
What classes of drugs can be used for the treatment of IBS?
Anti-diarrhoeals
Anti-spasmodics
Anti-depressants
Laxatives
Which disease has a higher risk of malnourishment - Crohn’s or Ulcerative colitis?
Crohn’s
- As the disease can affect anywhere in the GI tract from the mouth to the anus
A BMI of 30 - 35kg/m2 reduces life expectancy by how many years?
A BMI of >40kg/m2 reduces life expectancy by how many years?
2-4 years
10 years
What are the alarm symptoms for dyspepsia which require urgent referral for endoscopy?
Chronic GI bleeding Weight loss (unintentional) Persistent vomiting Dysphagia Iron deficiency anaemia Epigastric mass Patient >50 years with persistent dyspepsia
List 3 medications which can cause dyspepsia
NSAIDs
Aspirin
Corticosteroids
What are the three types of jaundice?
Prehepatic
Intrahepatic
Posthepatic
List some possibilities to include in the differential diagnosis of dysphagia
Cancer Ulcers GORD Achalasia Oesophagitis Extrinsic pressure Oesophageal spasm Benign strictures and tumours
What are the investigations for dysphagia?
History and examination
Endoscopy (OGD)
Bacillus Serus can cause food poisoning. What food is it usually associated with?
Starchy foods - particularly poorly temperature controlled rice
What is the most common organism to cause food poisoning?
Campylobacter
Which organisms which cause food poisoning can cause bacteraemia in immunosuprressed patients?
Campylobacter and Salmonella
What organism which can cause food poisoning do reptiles carry a lot of?
Salmonella Enteritidis
What organism which is a cause of food poisoning can cause cell death of red blood cells and renal cells?
E.Coli 0157
What substance does E.coli 0157 produce?
Verotoxins
What can cause Haemolytic Ureamic Syndrome (HUS)?
E.Coli 0157
What are the symptoms of HUS?
Anaemia signs and symptoms Fever Vomiting and diarrhoea Abdominal pain Blod in stools Low/ no urine output
Why must antibiotics not be given to patients with suspected E.coli/ HUS?
As antibiotics can actually cause E.coli to produce more verotoxins, which worsens the condition
Which virus is the most common cause of vomiting and diarrhoea in children under 3 years old?
Rotavirus
Which virus involves sudden onset of explosive diarrhoea and vomiting, is highly infectious and causes large outbreaks?
Norovirus
