Intestinal Disorders Flashcards
HLA associated with coeliac
HLA-DQ2
Describe Marsh criteria for Coeliac disease
- Lymphocytic infiltration
- Crypt hyperplasia
- Villous atrophy (C is the worst category)
- Flat strophic mucosa (may develop T-cell lymphoma)
Mucosa architecture is normal
Complications of coeliac disease
Osteoporosis (do DXA scans)
Autoimmune disease
NHL (T-cell)
Pneumococcus sepsis (hyposplenism)
Where is bile stored
Gallbladder
Describe what happens when bile acids reach the colon
Colonic bacteria dehydroxylates bile acids to secondary bile acids that stimulates water and electrolyte release = diarrhoea
Possible pathology of bile acid malabsorption
Overproduction of bile acids
Causes of bile acid malabsorption
TI disease (Crohn’s) or resection
Cholecystectomy
Idiopathic
How can we assess for BAM?
Measure turnover of radiolabelled bile acids
Measure serum metabolites
Quantification of excreted bile by seHCAT - retained fraction assessed with gamma cameras 7 days after po administration.
- <15% = BAM
Treatment of BAM
Cholestyramine
Colesevelam
1st line medical treatment of anal fissure
Topical diltiazem
Can give Botox
Surgery - literal sphincterotomy
How acquire strongyloidiasis?
Walking barefoot on soil
Asymptomatic in acute phase
Treatment of strongyloidiasis
Ivermectin
Symptoms associated with strongyloidiasis
Area of pruritis at site (migration of larvae) of entry
Diarrhoea
Abdominal pain
Weight loss
Complications of strongyloidiasis
Hyper infection syndrome = widespread dissemination of larvae into tissues = bloody diarrhoea, bowel perforation, gram -Ve sepsis
Rome 3 criteria in IBS
Symptoms improve with defecation
Onset associated with change in frequency of stool
Onset associated with change in form (appearance) of stool
Other supportive symptoms = abnormal stool frequency, defecation straining, urgency, bloating
What test should be performed before diagnosing a patient with IBS
FBC, ESR, CRP, TTG
NOT necessary to perform USS, flexi, TFTs, FOB, breath tests
Women >50 do Ca-125 (if >35 do USS)
How can you reduce the risk of radiation enteritis
Insert tissue expander to push loops of bowel out of radiotherapy field
Treatment of radiation enteritis
Sucralfate enemas
Hyperbaric O2
Loperamide
Describe the different types of radiation enteritis
Acute = within 6 weeks - direct mucosal damage
Chronic = years after - atrophy and fibrosis of epithelium due to obliterative arteritis = chronically ischaemic segment of bowel
What are the different causes of proctitis
HIV LGV - histology can resemble Crohn's Gonorrhoea Syphilius HSV
Type of bacteria in c diff
Gram +Ve bacillus
Describe different toxins in c diff
Toxin A - enterotoxin
Toxin B - cytotoxin
They produce inflammation = diarrhoea and possibly paeudomembranous colitis
Which toxin do some c diff strain NOT produce
Toxin A - so may get false negative if just test for toxin A
Describe different types of cytotoxin testing in c diff
- Cell culture cytotoxic assay - gold standard. If +Ve no further confirmatory tests are needed. Expensive
- Enzyme immune assay (EIA) - use reagents to detect toxin A and B. Quicker but more false negatives
- PCR - rapid. High sensitivity and specificity
What is the gold standard cytotoxic test in c diff
Cell culture cytotoxic assay
Gold standard diagnostic test in SBBO
Duodenal aspirates with cultures
These can identify asymptomatic patients
Normally, why is there very few bacteria in the small bowel
Ileocaecal valve
Acidity
Peristalsis
Risk factors for SBBO
Billroth 2 procedure as anatomy involves blind-end loop
Dysmotility (DM), strictures
Which antibiotics can cause and false negative result and why
Staph, strep viridins, enterococcus, pseudomonas
These bugs don’t produce hydrogen so get false negative result
Diagnosis of SBBO
Hydrogen breath test
Describe the role of hydrogen breath test
Some bacteria ferment carbohydrates and produce H+
Get double peak pattern:
- Metabolism by small bowel bacteria
- Colonic bacteria metabolism - more prolonged peak
Which hormone stimulate sensory neurones
Serotonin.
This activates myenteric plexus and then cholinergic neurones release substance P + acetylcholine = contraction of smooth muscle behind area of stretch = peristalsis
How can we improve continence in DM
Biofeedback therapy
Clonidine for gastroparesis (but lots of SE)
Life cycle of giardia
Cyst ingested - excystation of trophozoites - organism released - sexual reproduction in gut - colonise in small bowel by adhering to mucosa - cytokine release - water and electrolyte loss - trophozoites encyst and pass in faeces
Symptoms of giardia
Diarrhoea Bloating Flatulence Abdominal pain Malabsorption Weight loss
Treatment of giardia
Tinidazole
How is giardia spread
Faecal-oral route
Diagnosis of collagenous colitis
Increase in collagen layer
Collagen band > 10micro-grams thick
Usually type 1 or 3 collagen
Diagnosis of lymphocytic colitis
Increase intraepithelial lymphocytes
> 20 lymphocytes per 100 epithelial cells
Treatment of microscopic colitis
Stop offending meds (NSAIDS, SSRIs, PPI) Loperamide Cholestyramine Aminosalicylates Budesonide - if severe
Is microscopic colitis associated with malignancy?
No
Associated with coeliac disease
Describe the screening involved for CRC in patients with acromegaly
Start screening age 40 or if raised ILGF-1
3 yearly screening - adenoma, raised ILGF-1
5 yearly if original colon negative
Hyperplastic polyp or normal ILGF-1 = 5-10year screening intervals
Which hereditary condition associated with bowel cancer is inherited in an AR fashion
MUTYH ASSOCIATED EITH POLYPOSIS (MAP)
100% will have colon cancer by age 60
Start screen age 25 years and perform every 2-3 years with dye spray
Mode of inheritance in HNPCC
AD
Describe the gene mutations in HNPCC
MSH2, MLH1, MSH6, PMS2
When to start screening in HNPCC
Age 25 or 5years less than 1st case of 1st degree relative
Repeat every 18/12 until age 70
Mutation in FAP
AD
APC mutation on 5q21
Endoscopy at 20 years and then every 5 years
Describe the types of polyposis syndrome
Juvenile polyposis syndrome
Peats-Jeghers syndrome
PTEN
Mutation in PJS
AD
serine threnonine kinase 11 (STK11) on chromosome 19
Diagnosis of PJS
> 2 polyps histologically or single polyp and a first degree relative with condition
Surveillance in PJS
OGD at 8 years, then 3 yearly if polyps found
Mechanism of action of prucalopride
5HT4 receptor agonist
For chronic constipation
Give when tried 2 classes of laxatives at highest tolerated doses for 6/12
What is the weakest independent risk factor for faecal incontinence
Forceps delivery
What is the pigment found in melanosis coli
What is the cause
Lipofuscin - brownish discolouration of colonic wall
Laxative abuse
Brown bowel syndrome - lipofuscin deposits at tunica muscularis
How can we measure colonic transit
Ingest radiopaque marker and perform AXR. 24 plastic markers, AXR on day 6. Normal transit time is <5 markers left
Radioisotopes and scintigraphy
Ingest of pressure and pH capsule and tracking its movement
How can we diagnose slow bowel transit
> 6 radio-opaque markers left throughout the colon
Diagnose dyssynergic defecation
> 6 markers in rectosigmoid region
Describe the causes of primary constipation
- slow transit - prolonged delay of transit time of stool
- dyssnergic defecation - difficulty expelling stool from rectum
- IBS-C = constipation and abdominal pain
Secondary causes of constipation
Drugs - opioids, anti-cholinergics Hypercalcaemia Cancer Stricture Fissure Hypothyroidism Parkinson's MS Psychiatric
Diagnosis and treatment of dyssnergic defecation
Anorectal manometry
Rx -biofeedback therapy
Describe B12 absorption
- cobalamin released from food by action of Pepsins in acid in stomach
- salivary R protein binds to free cobalamin protecting it from acid degradation
- in duodenum, pancreatic enzymes hydrolyse the R-protein, releasing cobalamin which binds to IF (secreted from parietal cells)
- complex taken up by cells in TI
LACK OF PANCREATIC ENZYMES CAN RESULT IN DEFECTIVE RELEASE OF COBALAMIN FROM R PROTEIN FOR IF BINDING
Does nicorandil cause colonic ulceration?
Yes
Infective colitis histology
Normal crypt architecture
Neutrophils
Crypt abscesses
Signs in VIPoma
Diarrhoea
Hypokalaemia
High stool weight and no reduction in stool weight on day 4 (the fasting day)
Why do patients get diversion colitis
Deficiency of short chain fatty acids which normally provide nutrients to the colonocytes
This causes reduced acetate, butyrate resulting in less absorption of Na and fluids
Y enterocolitica:
- cause
- mimics
- symptoms
- endoscopy findings
Gram negative bacilli/rod from contaminated pigs
Resembles Crohn’s - terminal ileitis
Diarrhoea, abdo pain, fever
Normal endoscopy findings
Typhoid fever:
- Cause
- Symptoms
- What is Faget’s sign?
4.
Salmonella typhi - more common in females (‘typhoid Mary)
Fever, headache, RIF pain, splenomegaly and rose spot on chest
When should chemoprophylaxis for diarrhoea be offered?
IBD pt
Liver/kidney/heart disease pt
Immunosuppressive
Can give rifampicin
Treatment of giardia
Tinidazole
Metronidazole
