The Colon Flashcards
(97 cards)
0
Q
What is a sigmoid volvulus?
A
Sigmoid colon twisting around itself
1
Q
What are haustra?
A
Visible tonic contractions of teniae coli
2
Q
What are the branches of the sup. mesenteric artery?
A
Jejunal and ileal arteries Inf. pancreaticoduodenal a. Middle colic a. Right colic a. Ileocolic a.
3
Q
What are the branches of the inf. mesenteric artery?
A
Left colic a.
Sigmoid arteries
Sup. rectal a.
4
Q
What is the main anastomosis prevent bowel ischaemia?
A
Marginal artery (of Drummond)
5
Q
What is the blood supply of the distal half of the anal canal?
A
Middle rectal a. (Branch of internal iliac a.)
Inf. rectal a. (Branch of pudendal a.)
6
Q
Clinical presentation of portal hypertension?
A
Caput medusae - dilated collateral epigastric veins
Oesophageal/Rectal varices
7
Q
What is the vertebral level of the pelvic cavity?
A
L5
8
Q
What is the levator ani?
A
Pelvic floor muscle
9
Q
At what vertebral level does the sigmoid colon become the rectum?
A
S3
10
Q
When does the anal canal start?
A
Anterior to the tip of the coccyx
11
Q
Where does the rectal ampulla lie?
A
Immediately sup. to levator ani
12
Q
What is the role of the levator ani muscle?
A
Supports pelvic organs
- Tonic contractions prevent prolapse
- Increased contractions during coughing/sneezing
13
Q
What is the levator ani supplied by?
A
Nerve to levator ani
14
Q
What is the puborectalis muscle?
A
A muscle wrapped around anal canal
15
Q
What is the nerve supply to the rectum and anal canal?
A
SNS - T12-L2 - Synapse at inf. mesenteric ganglia - periarterial plexuses PNS - S2-S4 - Via pelvic splanchnic nerves Visceral afferents - Enter at S2-S4 - Run along PNS fibres Somatic motor - Leave in pudendal nerve (S2-S4) - Also in levator ani nerve (S3 and S4)
16
Q
What makes diverticular disease complicated?
A
Inflammation Rupture Abscess Fistula Massive bleed
17
Q
What is diverticular disease related to?
A
Low fibre diet
High intralumenal pressure
18
Q
Symptoms of colitis?
A
Diarrhoea (+/- blood) Abdo cramping Dehydration Sepsis Weight loss Anaemia
19
Q
Clinical features of small bowel ischaemia and infarction
A
Severe, poorly localised pain
Elderly
Arteriopaths
20
Q
What is the Rome III criteria for IBS?
A
Recurrent abdo pain/discomfort for >3 days per month for 3 months and two or more of the following:
- Improvement on defecation
- Onset associated with change in stool frequency
- Onset associated with change in stool form
21
Q
What symptoms are present in IBS?
A
Bloating Urgency Tenesmus PR mucus Nocturia Stress aggravation
22
Q
Treatment of IBS
A
Regular meal times
Decreased fibre intake
Plenty of fluids (but not caffeine)
Try 4 weeks of probiotics
23
Q
Common causes of small bowel obstruction
A
Adhesions
Hernias
Malignancy
24
What are the non-infectious causes of diarrhoea?
```
GI bleed
Ischaemia
Diverticulitis
Endocrine disorder
Drugs
Toxins (fish)
Withdrawal
```
25
Infectious causes of bloody diarrhoea?
Campylobacter
Shigella
E. coli 0157
Amoebiasis
26
Treatment of campylobacter infection?
Clarithromycin
| Azithromycin
27
Key features in the examination of infectious diarrhoea
```
Fever
Rashes
Dehydration
- Pulse
- Mental state
- BP
Abdo tenderness
PR exam
```
28
What two causative agents is stool microscopy used to diagnose for?
Giardia
| Amoeba
29
What organisms does stool culture test for in blood diarrhoea?
Salmonella
Campylobacter
Shigella
30
How do we test for E. coli and C. diff?
Stool toxins
31
How do we test for norovirus?
PCR
32
How is the severity of a C. diff infection calculated?
One or more of:
- Pseudomembranous colitis/toxic megacolon/ileus/colonic dilation >6cm
- WCC >15cells/mm3
- Creatinine > 1.5xbaseline
33
Risk factors for a C. diff infection?
Antibiotics
PPIs/H2RAs
Age >65
Chemo/Renal disease/IBD
34
Therapy for Pseudomembranous colitis
```
Metronidazole (non-severe)
PO vancomycin (if severe)
```
35
Clinical features of UC?
```
Bloody diarrhoea
Urgency
Tenesmus
Incontinence
LIF pain
```
36
How do we assess UC?
```
CRP
Albumin
AXR
Endoscopy
Histology
```
37
What signs of UC can be seen on an AXR?
No stool distribution
Thumb printing (mucosal oedema)
Toxic megacolon
38
What are the extra intestinal manifestations of UC?
```
Arthritis
Uveitis
Deranged LFTs
Primary sclerosing cholangitis
- Itch
- Rigors
```
39
Symptoms of CD?
```
Cramps
Diarrhoea
Wgt loss
Mouth
- Painful ulcers
- Swollen lips
- Angular stomatitis
```
40
How do we asses CD?
```
Clinical exam
- Wgt loss
- RIF mass
- PR signs
Bloods
- CRP
- Albumin
- Platelets
- Vitamin B12
- Ferritin
```
41
Drug therapy for UC?
5ASA (Mesalazine)
Steroids
Immunosuppressants
Anti-TNF
42
Drug therapy for CD?
Steroids
Immunosuppressants
Anti-TNF
43
What are the side effects of 5ASA?
Diarrhoea
| Idiosyncratic nephritis
44
Side effects of Azathioprine?
Pancreatitis
Leukopaenia
Hepatitis
Lymphoma
45
What are the types and examples of Anti-TNF drugs?
Chimeric
- Infliximab (IV infusion)
Humanised
- Adalimumab (SC injection)
46
When is Anti-TNF therapy recommended?
```
If long term immunosuppression is needed:
- Surgery
- Support
In refractory or fistulating disease
If a current infection is excluded
```
47
What do I cells secrete and where do they secrete it?
CCK
| Duodenum and jejunum
48
What do S cells secrete and where do they secrete it?
Secretin
| Duodenum
49
What do M cells secrete and where do they secrete it?
Motilin
| Duodenum and jejunum
50
What do K cells secrete and where do they secrete it?
Glucagon-like insulinotropic peptide
| Duodenum and jejunum
51
What do L cells secrete and where do they secrete it?
Glucagon-like peptide 1
52
What is the migrating motor complex and what affects it?
```
Peristalsis between meals
Inhibited by
- Feeding
- Vagal tone
Triggered by
- Motilin
Suppressed by
- Gastrin
- CCK
```
53
What surgical operations can be carried out for Crohn's disease?
Resection
| Stricturoplasty
54
What operations can be carried out in UC?
Protocolectomy +
- End ileostomy
- Ileorectal anastomosis
55
Features of a colostomy
Usually left
Usually flush
Stool
56
Features of an ileostomy
Usually right
Usually sprouted
Usually effluent
57
Surgeries available for colonic Cancer?
```
Right hemicolectomy
Transverse colectomy
Left hemicolectomy
Sigmoid colectomy
Subtotal colectomy
```
58
What are the available surgeries for rectal Cancer?
Abdominal-perineal excision of the rectum (APER)
| Anterior resection
59
What is the commonest cause of food poisoning?
Campylobacter
60
How is a campylobacter infection treated?
Ciprofloxacin
| Erythromycin
61
How is salmonella typed?
Via O-antigens and slide agglutination
62
How is salmonella food poisoning treated?
Ciprofloxacin
63
What can cause haemolytic ureamic syndrome?
E. coli 0157
64
Presentation of HUS?
```
Symptoms
- Abdo pain
- Fever
- Pallor
- Petechiae
- Oliguria
Signs
- High WCC
- High urea
- Low platelets
- Low Hb
```
65
What causes enteric Fever?
Salmonella typhi
| Salmonella paratyphi
66
What conditions result in both Fever and jaundice?
```
Pre-hepatic:
- Malaria
- HUS
- Sickle cell crisis
Intra-hepatic:
- Hep A and E
- Leptospirosis - Weils diseases
- Malaria
- Enteric Fever
- Typhus
- Viral haemorrhagic Fever
Post-hepatic:
- Ascending cholangitis
- Helminths
```
67
What is Chagas' disease?
Trypanasoma cruzi infection
Results in PNS denervation of
- Colon
- Oesophagus
68
What is the causative organism of rectal gonorrhoea?
Neisseria gonorrhoea
69
Treatment of rectal gonorrhoea?
Cephalosporin
Chlamydia treatment
STI screen
70
What is the cause of rectal chlamydia?
Chlamydia trachomatis
71
Which is milder, rectal gonorrhoea or chlamydia?
Chlamydia
72
How do we treat rectal chlamydia?
Azithromycin
| Doxycycline
73
What is telangiectasia visible in?
Radiation colitis
74
What is the histological appearance of Crohn's disease?
Patchy and segmented
Transmural (entire thickness)
Non-caseating granulomas
75
What is the histological appearance of Ulcerative Colitis?
```
Diffuse
Crypt branching
Irregular crypts
Cryptitis
Massive inflammatory cell influx
```
76
True or false. Crohn's disease can cause toxic megacolon (acute fulminant colitis).
False. UC can cause toxic megacolon
77
What is the initial treatment of diverticulitis?
IV fluids
Rest
IV antibiotics
78
Which of a proximal or distal small bowel obstruction causes distension?
Distal
79
How do we diagnose meckels diverticulum?
Technicium Tc 99m scan (detects ectopic gastric mucosa)
80
What is the empirical treatment for diarrhoea and at least one other symptom?
Ciprofloxacin 500mg BD for 3-5 days
81
If rapid bowel clearing is needed, would a bulk or osmotic laxative be used?
Osmotic
82
What type of laxative is methylcellulose?
A bulk laxative
83
Examples of osmotic laxatives?
Lactulose
Sorbitol
Glycerin (Sodium Stearate) suppositories
84
Examples of stimulant purgatives?
Bisacodyl
Senna
Sodium picasulfate
85
What is oral dorcusate sodium?
Faecal softener
86
What are some mechanisms of sodium reabsorption?
```
Sodium/Glucose co-transport
Sodium/Amino acid co-transport
Sodium/H+ exchange
Parallel Sodium/H+ and Chloride/Bicarbonate exchange
Epithelial sodium channels (ENaC)
```
87
Are sodium co-transporters regulated by cAMP or calcium ions?
Nope
88
What effect does aldosterone have on epithelial sodium channels?
Increased rate
89
Which is greater, chloride secretion or chloride absorption?
Absorption
90
What is the role of CFTR?
Chloride conductance - secretory diarrhoea
91
What bacterial infection causes secretory diarrhoea and how?
Cholera
Toxin inhibits GTPase resulting in increased cAMP and CFTR stimulation.
Chloride hypersecretion
92
What is rigler's sign?
Gas outside of the bowel wall in toxic megacolon
93
What bacteria have short (1-6hr) incubation periods?
Staph aureus
| Bacillus cereus
94
What bacteria have 12-48hr incubation times (medium)?
Salmonella
| Clostridium perfringens
95
How long is the incubation period for Campylobacter and E. coli 0157?
2-14 days
96
What is the incubation period of enteric Fever?
7-18 days
