10. GI malignancies & Imaging Flashcards
Whats the likely further surgical intervention if a appendiceal tumour is:
Less than 1cm
More than 2cm
Appendicectomy
Right hemicolectomy
Whats the most common type of appendiceal tumour?
Carcinoid
Whats the common metastatic location for appendiceal tumour?
Liver
Once metastasised, what characteristic symptom of appendiceal tumours might a patient suffer from?
Carcinoid syndrome:
Flushing, diarrhoea, heart valvular lesions, cramping, telangiectasia, peripheral oedema, wheezing, cyanosis, arthritis, pellagra
Describe the patterns & spread of caecal adenocarcinoma
Direct spread thru bowel wall
Lymphatic spread to mesenteric nodes
Via portal venous sys to liver
4 risk factors for dev adenocarcinoma of large bowel
Low residue diet
Slow transit time
High fat intake
Genetic disposition
Why might a patient with caecal adenocarcinoma is not suffering obstructive symptoms
Contents of colon still watery/fluid
In which part of colon is a tumour more likely to produce obstructive symptoms?
More distal portions: stool more formed
What is tenesmus & how can a tumour produce this symptom?
Sensation of incomplete defacation, so continually trying to empty bowel
Tumour in rectum can elicit stretch response
What are the common locations for colonic cancer & typical assocated symptoms?
Caecum/ascending colon (30%): anaemia
Sigmoid (25%): obstructive symptoms, overt bleeding
Rectum (20%): tenesmus, overt bleeding, pain
Descending colon (15%)
Transverse (10%)
Whats the location of pathology for a patient with central/right sided abdo pain, vomiting & blood mixed in stools
Embryological mid gut
What is intussusception & what symptoms does it cause?
Pathological process: one section of bowel invaginates into adjoining distal piece of bowel
Quickly leads to intestinal obstruction
Causes colicky pain, nausea, vomiting, lethargy
Red currant jelly stools can occur when ischaemia of bowel sloughs of & causes bleeding of bowel mucosa
What types of malignant tumours can affect the small bowel
Adenocarcinomas: most prevalent at proximal small bowel
Lymphoma of small bowel
Gastro-intestinal stromal tumours
Carcinoid tumours
3 possible diagnoses of:
Mild generalised abdo pain for a few days
diarrhoea
vomiting
Mild diffuse tenderness ln palpation of abdomen
Decreased bowel sounds
Dehydration
Food poisoning
Gatroenteritis
Early appendicitis
Small bowel obstruction
List 3 features of a plain X ray that determine small intestine evident?
Central position
Transverse mucosal bands (valvulae conniventes)
Size of dilated loops (smaller diameter than large bowel)
Why might 2 xrays showing small bowel obstruction present differently?
Supine vs erect xray
Erect allows gas filled loops to appear in upper abdomen: air/fluid levels appear
More distal small bowel obstructions appear with more fluid levels
Whats your initial treatment of someone with small bowel obstruction
Nil by mouth & NG tube (to reduce gastric aspirate & encourage passing of flatus)
IV fluids
Antibiotics (to cover predominantly gram negative anaerobes)
What imaging modality might be used to image small bowel obstruction
Erect X ray
CT abdo (superior to Xray in complete obstruction): reveals site of obstruction & potential signs of bowel ischaemia But low sensitivity for low grade/incomplete obstruction
What might have occurred if a patient with small bowel obstruction develops abdominal guarding & temperature
What is the treatment
Perforated bowel
Developing peritonitis
Surgical intervention
Antibiotics
What are the causes of small bowel obstruction in the following areas:
Extrinsic
Bowel wall lesions
Intra-luminal
Adhesions, hernias, volvus
Tumours, CD (thickening of bowel wall)
Foreign bodies, food bolus, meconium (CF), gallstones, intussusception
What are the causes of large bowel obstruction (most - least prevalent)
Malignancies
Diverticular disease
Volvulus
What features on a plain X ray help differentiate between small & large bowel obstruction
Position of dilated loops (SBO more central, LBO more peripheral)
Size of dilated loops (SBO >3cm 5cm)
Number of loops (SBO-many, LBO-few)
Bowel markings (small- valvulae go all the way across, large-haustra only partially across)
What features of the history can differentiate btw small & large bowel obstruction?
Small: early onset vomiting & before constipation, colicky pain more frequent (2-3m)
Large: later onset vomiting & after constipation, colicky pain less frequent (5+min)
What mechanisms lead to the signs/symptoms of pancreatic cancer: Pale stools Dark urine Jaundice Weight loss Back pain
Compression of common bile duct: build up of bile, normally broken down in colon to stercobilinogen (gives faeces colour)
Reabsorption of bilirubin from blocked bile duct back into bloodstream. Bilirubin soluble from conjugation
Hyperbilirubinaemia from blocked flow of bile
Bile & pancreatic enzyme release into duodenum aids absorption & digestion fats
Effects from cancer associated anorexia
Retroperitoneal position of pancreas
