Bowel Obstruction and CRC Flashcards
What are the three groups that we use when considering the possible causes of intestinal obstruction? Give an example of each (Formative Q)
- Intraluminal - tumours, gallstone ileus, meconium ileus, diaphragm disease
- Intramural - crohn’s disease, diverticulitis, tumours, hirschprung’s disease
- Extraluminal - adhesions, volvulus, tumour
What are the four cardinal symptoms in a patient with an acute bowel obstruction? (Formative Q)
- Absolute constipation
- Vomiting
- Abdominal pain
- Abdominal distention
What is the most common type of colorectal cancer? What examination must be performed in suspected colon cancer? (Formative Q)
Adenocarcinoma
A digital rectal examination must be performed as around 30% of colon cancer can be palpated with the finger
What is an intraLUMINAL obstruction? Examples?
- blockage of lumen within intestines
- Tumour: carcinoma, lymphoma
- Diaphragm disease
- Meconium ileus (paediatric disease)
- Gallstone ileus
What is an intraMURAL obstruction? Examples?
- walls abnormality within the bowel that causes obstruction
- Inflammatory: Crohn’s, diverticulitis
- Tumours: growing within the wall, causing stenosis
- Neural: Hirschsprung’s disease
- Strictures
What is an extraluminal obstruction? Examples?
- Something external that is pressing and distorting shape of the intestinal lumen.
- Adhesions: fibrous bands of tissues between bowels usually caused by previous surgery
- Volvulus - common in sigmoid where it twists on itself
- Peritoneal Tumour (e.g. within momentum)
Sx and signs of bowel obstruction
(1. ) Abdo Pain: Can be colicky, poorly localised
(2. ) N&V
(3. ) Constipation
(4. ) Abdominal distention
(5. ) Inc sounds then absent bowel sounds
(6. ) tachycardia, dehydrated (low BP, poor urine output)
Paralytic ileus - pathophysiology, causes (3), signs (3).
- Intestinal blockage in the absence of physical obstruction. Blockage due to failure of peristalsis.
- Causes = Drugs, post-operative, trauma, intraabdominal sepsis
- Signs = Painless distension, vomiting, absent or minimal bowel sounds
Gastric Outlet Obstruction - causes (3), signs and Sx, Ix
- Causes = Chronic peptic ulcer, gastric cancer, advanced pancreatic cancer
- Presentation = N+V, satiety, pain, dehydration, malnutrition, weight loss, failure to thrive
- Investigations = Blood, CT, Endoscopy
Small bowel obstruction - causes, signs, Ix
- Causes = Adhesion hernia (most common), IBD, malignancy, volvulus
- Presentation = Colicky pain but can be constant, N+V, Constipation, diarrhoea, abdo distension, Inc bowel sounds
- Investigations: Bloods and Radiology
Large bowel obstruction - causes, signs, Ix
- Causes = Malignancy, diverticular strictures, volvulus
- Presentation = Abdominal distention, pain, constipation, nausea, vomiting, Tenderness, hyper resonant abdomen with normal or diminished bowel sounds
- Investigations = Bloods and Radiology
Aetiology and RF of CRC
Environmental and genetic factors play a role in carcinogenesis. CRC develops from an accumulation of mutations. Most common in rectum and sigmoid.
- Environmental = Red meat, saturated animal fat diet, IBD, adenomas, acromegaly, smoking, alcohol, sedentary lifestyle
- Genetic = HNPCC (genetic predisposition), FAP (inherited)
- Sporadic CRC (70%) - Malignant transformation of benign polyps.
Staging and survival rate of CRC
TMN Staging is used. . T=tumour, N=Node, M = metastases. (0=no spread, 1-4 = spread present with inc severity)
- Stage 1 = T1 or T2,N0,M0
- Stage 2 = T3 or T4,N0,M0
- Stage 3 = N1 or N2
- Stage 4 = M1
Survival rate
- Stage 1 =>90%
- Stage 2 = ~65%
- Stage 3 = ~35%
- Stage 4 = <5%
Sx and signs of CRC (8.)
Depends on the site of carcinoma in the bowel
(1. ) Fresh rectal bleeding (left colon) or occult blood (right colon)
(2. ) Anaemia
(3. ) Altered bowel movement
(4. ) Colicky abdominal pain
(5. ) Mucus discharge
(6. ) Weight loss
(7. ) Palpable mass
(8. ) Hepatomegaly from metastases
Ix of CRC
- Colonoscopy and biopsy
- CT colonography
- If unable to perform colonoscopy - CT scan
- Performed after CRC diagnosis for staging, investigations and metastases
