Colon and Rectum Flashcards
What are the parts of the large colon?
Ascending, transverse, descending, sigmoid
What are the teniae coli?
Three bands that complete the longitudinal muscle layer.
They produce the haustral pattern
Describe the mucosa of the large intestine
Mucosa is lined with epithelial cells and goblet cells.
There are crypts but no villi so the surface is flat
Which muscles are contracted and relaxed in defecation?
Diaphragm and abdominal muscles are contracted
Pelvic floor and anal sphincter are relaxed
Which GI diseases can cause constipation?
Intestinal obstruction and pseudo-obstruction
Colonic disease (e.g. carcinoma, diverticula)
Aganglionitis (Hirschsprung’s, Chaga’s)
Painful anal conditions (e.g. fissures)
What investigation is indicated when there has been a recent change in bowel habit in association with other significant symptoms?
Colonoscopy or CT
What are the three categories of constipation, and which is the most common?
Normal transit time (most common)
Defecatory disorders
Slow transit
What is normal transit constipation?
Stool frequency is normal but people believe they have constipation due to passage of hard stools
Patients may have abdominal pain or bleeding
What investigation distinguished between normal and slow transit constipation?
Marker studies of colonic transit
What is defecatory disorder induced constipation?
Where contraction rather than relaxation of the puborectalis and external anal sphincter may prevent evacuation
What is the most common cause of a defecatory disorder?
Dysfunction of the anal sphincter and pelvic floor
Who predominantly experiences slow transit constipation?
Young women with infrequent bowel movements
What are the symptoms of slow transit constipation?
Infrequent urge to defecate
Bloating
Abdominal pain and discomfort
What treatment measure should be taken in normal and slow transit constipation?
Increase in fibre in the diet and increased fluid intake
What are examples of bulk-forming laxatives?
Dietary fibre
Methylcellulose
Sterculia
Ispaghula husk
What are some examples of stimulant laxatives?
Senna Glycerol suppository Bisacodyl Docusate sodium Sodium picosulphate
What are some examples of osmotic laxatives?
Lactulose
Macrogols
Phosphate enema
Citrate enema
How do stimulant laxatives work?
By stimulating motility and intestinal secretion
How do osmotic laxatives work?
By increasing fluids and electrolytes which stimulates contraction
Which type of laxatives are preferred?
Osmotic
What is megacolon?
A term for conditions where the colon is dilated
What can megacolon be secondary to?
Chronic constipation
Chaga’s disease
Which condition should be excluded in megacolon, and what is this condition?
Hirschsprung’s disease
An aganglionic section of the rectum causes constipation and subacute obstruction
What is minor and major incontinence?
Minor: inability to control flatus and liquid stool, causing soiling
Major: frequent and inadvertent evacuation of stool of normal consistency
What are some causes of incontinence?
Congenital abnormalities Anal sphincter dysfunction Rectal prolapse Faecal impaction with overflow diarrhoea Severe diarrhoea Neurological and psychological disorders
What are causes of anal sphincter dysfunction?
Structural damage
Pudendal nerve damage
Perianal descend
What us the initial medical management for incontinence?
Loperamide
What is ischaemic colitis caused by?
Occlusion of branches of the superior or inferior mesenteric artery
How does ishaemic colitis present?
Sudden onset abdominal pain
Passage of bright red blood per rectum (with or without diarrhoea)
May be signs of shock and CVD
Which is the most common part of the colon affected by ischaemic colitis?
The splenic flexure
Who most commonly experiences ischaemic colitis?
Elderly patients
Young women on the pill
Patients on nicorandil
Those with thrombophilia and vasculitis
What are the characteristic investigative features of ischaemic colitis, and which investigation is diagnostic?
Characteristic:
- Thumb-printing on AXR
- Epithelial cell apoptosis and lamina propria fibrosis on biopsy
Diagnostic: unprepared flexible signoidoscopy
Which signs on examination are symptoms of ischaemic colitis?
Abdomen may be distended and tender
Patients likely show signs of shock and may have lactic acidosis
Which investigations are done for suspected ischaemic colitis, and why?
Urgent CT to exclude perforation
Un prepared flexible sigmoidoscopy for diagnosis
Biopsy showing characteristic features
Colonoscopy after recovery to exclude stricture formation
What investigation should be done in ishcaemic colitis if the patient has underlying CVD?
Screening for thrombophilia and vasculitis
What is the management for ischaemic colitis?
Symptomatic treatment
If peritonism or imminent perforation - surgery
What is diverticulosis?
The presence of diverticula
What is diverticulitis?
Inflamed diverticula
What is diverticular colitis?
Crescentic inflammation on the folds in areas of diverticulosis
How does diverticulitis occur?
Faeces obstructs the neck of the diverticulum, causing stagnation and allowing bacteria to multiply and produce inflammation
What complications can diverticulitis lead to?
Bowel perforation Abscess formation Fistulae Haemorrhage Generalised peritonitis
Are diverticula most often asymptomatic and discovered incidentally, or symptomatic and discovered due to symptoms?
Asymptomatic and discovered incidentally
What are the symptoms of diverticular disease?
Intermittent LIF pain or discomfort
Erratic bowel habit
What is the investigation of choice for diverticular disease?
Colonoscopy or virtual colonoscopy
Barium enema combined with flexible sigmoidoscopy can also be used
What does the term diverticular disease refer to?
The presence of diverticula, with or without inflammation
What is the management of diverticular disease?
Uncomplicated diverticular disease is managed with a well balanced fibre diet and smooth muscle relaxants if required
What are the pathological features of acute diverticulitis?
Altered gut motility
Increased luminal pressure
Disordered colonic micro-environment
How does acute diverticulitis present?
Severe pain in LIF
Fever
Constipation
What are signs of acute diverticulitis that can be found on examination?
Tenderness, guarding and rigidity on the left side of the abdomen
Sometimes a palpable tender mass in LIF
What investigations are done in acute diverticulitis?
Blood tests (ESR and CRP raised)
CT colonogrpahy
Ultrasound (less sensitive than CT)
What will a CT colonography find in acute diverticulitis?
Colonic wall thickening
Diverticula
Often pericolic collections and abscesses
What is the management of a mild attack of acute diverticulitis?
Oral antibiotics
What is the management for acute diverticulitis if there is systemic upset, significant abdominal pain or co-morbidity?
Bowel rest
IV fluids and antibiotics
When might acute diverticulitis require surgery
Repeat attacks
What results when a diverticulum forms a fistula into the bladder or vagina?
Bladder: dysuria or pneumaturia
Vagina: discharge
When might intestinal obstruction occur as a complication of diverticular disease?
After repeated attacks of acute diverticulitis
What are haemorrhoids?
Lumps inside, or around the anus
What does it mean when a haemorrhoid is classed as primary, second degree or third degree?
1 - internal
2 - prolapsing
3 - prolapsed
What can haemorrhoids cause?
Rectal bleeding, discomfort and pruritus ani
What is pruritus ani?
Itchy bottom
What is the most common cause of rectal bleeding?
Haemorrhoids
What is a likely sign of haemorrhoids?
Bright red blood on toilet paper
How is diagnosis of haemorrhoids made?
Inspection, rectal exam and proctoscopy
What is the management of mild haemorrhoids?
Just advice about avoiding constipation
Suppositories containing a local anaesthetic and steroids are helpful
What is the management of severe haemorrhoids?
Rubber band ligation or injection of a sclerosant
Haemorrhoid artery ligation operation
What is an anal fissure?
A tear in the skin-lined lower anal canal distal to the dentate line, which produces pain on defecation
How is diagnosis done for anal fissures?
History, confirmed on perianal exam
PR exam often nor possible because of pain and sphincter spasm
In sever cases proctoscopy and sigmoidoscopy should be done to exclude other disease
What is the treatment for anal fissures?
Local anaesthetic gel and stool softeners
Botulinum toxin in chronic fissures or lateral subcutaneous internal sphincterotomy
How do fistula in ano usually present, and when do they heal?
Present as abscesses and heal after abscess is incised
How can rectal prolapse, intussusceptions and solitary rectal ulcer syndrome be treated?
Treating underlying pathology
