Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Gastrointestinal system > S7: IBD & distal tract pathology > Flashcards

S7: IBD & distal tract pathology Flashcards

1
Q

Describe the arterial supply of the large intestine

A

Midgut component – superior mesenteric artery
Ileocolic – caecum
Right colic – ascending colon
Middle colic – transverse colon
Hindgut component – inferior mesenteric artery
Left colic – descending colon
Sigmoid – descending colon
Superior rectal artery – upper 1/3 rectum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe the venous drainage of the large intestine

A

Midgut drains into the superior mesenteric vein
Hindgut drains into inferior mesenteric vein
Rectum:
Upper 1/3 drains into superior rectal vein
Middle and lower 1/3s drain into systemic venous system – site of portosystemic anastomosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe the longitudinal muscle of the large intestine

A

External longitudinal muscle is incomplete:

  • three distinct bands (teniae)
  • haustra are sacculations cause by contraction of teniae coli
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe water absorption in the colon

A 
Facilitated by ENaC 
Similar to principle cells of the late distal convoluted tubule 
Most absorption in proximal colon
Much tighter tight junctions:
-allows bigger gradient to form
-less back diffusion of ions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define inflammatory bowel disease

A

Group of conditions characterised by idiopathic inflammation of the GI tract
Affect function of the gut

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe Crohn’s disease

A

Affects anywhere in GI tract, but ileum involved in most cases
Transmural – affects whole gut wall
Skip lesions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe ulcerative colitis

A

Begins in rectum & can extend to involve entire colon
Continuous pattern
Mucosal inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe other symptoms which are common with inflammatory bowel disease

A

MSK pain – arthritis
Skin – erythema nodosum, pyoderma gangrenosum, psoriasis
Liver/biliary tree – primary sclerosing cholangitis
Eye problems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe macroscopic and microscopic features of Crohn’s disease

A

Macroscopic – skip lesions, hyperaemia, mucosal oedema, discrete superficial ulcers, deeper ulcers, transmural inflammation, fistulae & cobblestone appearance
Microscopic – granuloma formation (if this is found – definite diagnosis is Crohn’s)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe investigations for Crohn’s

A

Bloods – anaemia
CT/MRI – bowel wall thickening, obstruction & extramural problems
Barium enema/follow through – used less now
Colonoscopy – gross pathological changes can be seen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe pathological changes which occur in UC

A

Chronic inflammatory infiltrate of lamina propria
Crypt abscesses (neutrophilic exudate in crypts)
Crypt distortion – irregular shaped glands with dysplasia, darker crowded nuclei
Reduced number of goblet cells
Pseudopolyps can develop after repeated episodes
Loss of haustra

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe investigations for UC

A 
Bloods – anaemia & serum markers 
Stool cultures 
Colonoscopy 
Plain abdominal radiographs 
Barium enema 
CT/MRI – less useful for diagnosing uncomplicated UC
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is indeterminate colitis?

A

Even after diagnostic evaluation, 10% have disorders that cannot be classified

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe radiological features of Crohn’s

A

Barium follow through – sometimes see long strictures

String sign of kantour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe radiological features of UC

A

Featureless descending and sigmoid colon – lacking haustral markings & lead pipe colon
Continuous lesions without skipping
Whole colon
Mucosal inflammation – causes granular appearance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe surgical treatment for inflammatory bowel disease

A

Crohn’s – not curative, strictures/fistulas, as little bowel removed as possible
UC – curable (colectomy) -> inflammation not settling, precancerous changes & toxic megacolon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe the presentation of Crohn’s

A 
Multiple non-bloody loose stools/day
Weight loss 
Right lower quadrant pain 
15-30 year old  
Smoking makes it worse
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe the presentation of UC

A

Multiple bloody stools/day
Middle abdominal pain
20-30 year old
Smoking can help

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Define diarrhoea

A

Symptom and occurs in many conditions
Loose/watery stools
More than 3 times a day
Acute diarrhoea (less than 2 weeks)

20
Q

Describe the pathophysiology of diarrhoea

A

Unwanted substance in gut stimulates secretion and motility to get rid of it
Primarily down to epithelial function (secretion) rather than increased gut motility
Colon is overwhelmed and cannot absorb the quantity of water is receives in the ileum

21
Q

Describe diarrhoea due to osmotic causes

A

Gut lumen contains too much osmotic material (malabsorption)
Ingested material that is poorly absorbed
Inability to absorb nutrients
Will settle if you stop consuming offending substance
Other: too little absorption of sodium

22
Q

Describe diarrhoea due to secretory causes

A

Electrolyte transport is messed up
Too much secretion of ions
Cause of diarrhoea will affect the messenger systems that control ion transport -> infectious toxins
Diarrhoea continues in response to fasting

23
Q

Describe constipation

A

Suggestive if hard stools, difficulty passing stools or inability to pass stools
Straining, lumpy/hard stools, feeling of incomplete evacuation, feeling of obstruction or blockage & having fewer than three unassisted bowel movements a week
Risk factors: female, certain medications, low level of physical activity & increasing age

24
Q

Describe the pathophysiology of constipation

A

Normal transit constipation (often related to other psychological stressors)
Slow colonic transport
Defaecation – cannot coordinate the muscles of defaecation/disorders of the pelvic floor or anorectum

25
Q

Describe treatments for constipation

A 
Psychological support
Increased fluid intake 
Increased activity 
Increased dietary fibre
Fibre medication
Laxatives
26
Q

Describe the anatomy of the appendix

A

Diverticulum off the caecum
Separate blood supply to caecum - ileocolic branch of SMA
Can be different locations of the appendix – retro-caecal, pelvic, sub-caecal & para-ileal

27
Q

Describe the pathophysiology of appendicitis

A

Blockage of appendiceal lumen creates a higher pressure in the appendix
Causes venous pressure to rise (causing oedema in walls of appendix) – makes it harder for arterial blood to supply appendix -> ischemia in walls of appendix & bacterial invasion follows
Alternative explanation: viral/bacterial infection causes mucosal changes that allow bacterial invasion of appendiceal walls

28
Q

Describe the symptoms of appendicitis

A 
Poorly localised peri-umbilical pain 
Anorexia 
Nausea/vomiting 
Low grade fever 
After 12-24 hours, pain is felt more intensely in right iliac fossa (if appendix is retro-caecal or pelvic may not get this pain – might get supra-pubic pain, right sided rectal/vaginal pain instead)
29
Q

Describe the signs of appendicitis

A

Appear slightly ill
Slight fever/tachycardia
Generally lie quite still as peritoneum is inflamed
Localised right quadrant tenderness
Rebound tenderness in right iliac fossa (relatively specific)

30
Q

Describe diagnosis and treatment of appendicitis

A

Blood tests
History/physical examination – if classic, this may be enough
In non-classical presentations – CT scan will show distended appendix that doesn’t fill with contrast
Treatment – open appendicectomy or laparoscopic appendicectomy

31
Q

Describe diverticulosis

A

Asymptomatic
Occurs in colon
Outpouchings of mucosa and submucosa herniate through the muscularis layers
Occurs along where nutrient vessels penetrate the bowel wall
Thought to be caused by increased intra-luminal pressure

32
Q

Describe acute diverticulitis

A

Diverticula become inflamed or perforate +/- bleeding and abscess formation
Pathophysiology is similar to that involved in appendicitis
Uncomplicated – inflammation and small abscesses confined to colonic wall
Complicated – larger abscesses, fistula & perforation

33
Q

What is diverticular disease?

A

The patient experiences pain but there is not inflammation or infection

34
Q

Describe the symptoms and signs of acute diverticulitis

A

Symptoms: abdominal pain at the site of inflammation, fever, bloating, constipation & haematochezia
Signs: localised abdominal tenderness, distension, reduced bowel sounds & signs of peritonitis

35
Q

Describe the diagnosis and treatment for acute diverticulitis

A

Diagnosis – blood tests, USS, CT scan

Treatment – antibiotics, fluid resus, analgesia & surgery if perforation or large abscesses need to be drained

36
Q

Describe the anatomy of the rectum

A

Continuous band of outer longitudinal muscles
Curved shape anterior to sacrum
Parts of it are covered in peritoneum
Temporary storage of faeces prior to defaecation

37
Q

Describe the blood supply to the rectum

A

Arterial supply – several arteries that form a plexus -> superior, middle & inferior rectal arteries
Venous drainage – portal drainage through superior rectal vein & systemic drainage through internal iliac vein

38
Q

Describe the anatomy of the anal canal

A

Narrowed portion of the GI tract that continues from the rectum
Starts at the proximal border of the anal sphincter complex
Puborectalis sling changes the direction of anatomy -> anal canal points posteriorly
Contains the dentate line
-above: visceral pain receptors, columnar epithelium
-below: somatic pain receptors, stratified squamous epithelium

39
Q

Describe the anal sphincter complex

A

Internal involuntary sphincter – thick circular smooth muscle, under autonomic control
External anal sphincter – striated muscle
-nerve supply from pudendal nerve

40
Q

What are the anal cushions?

A

Anus contains a complex venous plexus, which is divided into 3+ areas of tissues = anal cushions
Play a role in anal continence

41
Q

What are haemorrhoids?

A

Symptomatic anal cushions
Internal haemorrhoids – caused by loss of connective tissue support, above dentate line (relatively painless, bleed bright red/pruritis)
External haemorrhoids – swelling of the anal cushions which may then thrombose, below dentate line (very painful)

42
Q

Describe the treatment for haemorrhoids

A

Increased hydration/high fibre diet
Avoid straining
Rubber band ligation
Surgery

43
Q

Describe anal fissures

A

Linear tear in the anoderm – passing of hard stool, pain on defecation & haematochezia (blood in stool)
Underlying causation – high internal anal sphincter tone & reduced blood flow to anal mucosa
Treatment – hydration, dietary fibre, analgesia, warm baths & medication trying to relax the internal anal sphincter

44
Q

List common causes of haematochezia

A 
Diverticulitis 
Angiodysplasia 
Colitis 
Colorectal cancer 
Anorectal disease 
Upper GI bleeding
45
Q

Describe melaena

A

Black tarry stools – offensive smelling
Due to haemoglobin being altered by digestive enzymes and gut bacteria
Common causes – upper GI bleeding -> peptic ulcer disease, variceal bleeds, upper GI malignancy
Uncommon causes – gastritis & Meckel’s diverticulum

Gastrointestinal system (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions