IBD & IBS Flashcards
What are IBS and IBD?
IBS (irritable bowel syndrome) is a benign relapsing functional bowel characterised abdominal pain or discomfort is associated with defecation or a change in bowel habit.
IBD (inflammatory bowel disease) is a range of inflammatory bowel disorders (Crohn’s disease and ulcerative colitis) of unknown aetiology although it is though to have an autoimmune element.
Describe the diagnostic criteria of IBS?
6 month history of:
- Abdominal pain/discomfort (associated with defecation or altered bowel habits)
- Bloating
- Change in bowel habit.
AND at least 2 of the following are present:
- Altered passage of stool (straining, urgency, incomplete evacuation).
- Abdominal bloating/distension
- Symptoms aggravated by eating.
- Passage of mucus in stool.
Note it is a diagnosis of exclusion you must 1st rule out more sinister causes: aka IBD
Describe the factors which may predispose to IBS?
Female gender 3:1
Stress
Antibiotic therapy
Can be a post parasitic infection IBS.
Describe common presenting symptoms of Crohn’s disease and ulcerative colitis?
Chronic diahorrea aka >6 weeks which may be bloody or contain mucous.
May be associated with weight loss and abdominal pain.
Systemic symptoms include: malaise, anorexia and fever. Relapsing and remitting diseases.
Extra GI features
UC: blood, mucus, urgency, tenesmus
Crohns: weight loss, abdominal cramping
List the pathophysiological + histological differences between UC and Crohns?
UC
- Starts in the rectum and goes proximally. Colon only.
- Proctitis if affects rectum alone. Doesnt usually affect anus
- Only affects mucosa - causes severe ulceration and pseudopolyps
- Crypt abscesses and goblet cell depletion, can loose horstra
Crohns
- May affect any part of the GI tract, skip lesions
- Ulceration of the mucosa is transmural (extends through the whole to the serosa)
- Terminal ileum and proximal colon are most commonly affected.
- Bowel narrowed due to thickened wall, deep ulcers described as ‘rose thorn’ or ‘cobblestone’.
- Fistula and stenosis common.
- Can cause lymphoid hyperplasia
- Granulomas are present in 2/3 of cases.
Describe the extra-intestinal features of IBD?
Eyes: conjunctivitis/ episcleritis/ uveitis
Joints: arthralgia
Skin: erythema nodosum, pyoderma gangrenosum
VTE
Liver: AI hepatitis, 1y sclerosing cholangitis + cholangiocarcinoma (UC), gallstones (crohns)
Amyloidosis
Kidney stones
Describe the complications of crohn’s and UC?
Crohn’s:
- Strictures (may cause obstruction)
- Fistulae (between bowel and: other loops of bowel,bladder, vagina, skin)
- Perforation: generalised peritonitis.
- Haemorrhage.
- Abscess formation
- In crohn’s colitis increased risk of colonic ca.
- Absorptive: Iron, folate and B12 deficiency (ileal involvement).
Steroid related complications:
- Immuno-compromised
- Osteoporosis
- Cushingoid
- Hyperglycaemia
UC:
- Toxic Megacolon
- Twice the risk of colorectal ca
- Haemorrahage
- Complications post surgery: Pouchitis (ileal pouch used as a false rectum following removal.
Describe the investigations you would do for a patient suspected of having IBD?
Bloods:
- FBC (anaemia). Also test serum iron/b12/folate if anaemic
- CRP and ESR should be raised
- LFT may be abnormal (albumin can be low in acute disease)
- Can do pANCA (usually +ve in UC not CD)
Stool sample:
- Culture (exclude other causes of colitis)
- Faecal calproctein (detects inflammation the bowel)
Imaging:
- UC: Sigmoidoscopy/Colonoscopy + biopsy
- Crohns: CT with oral contrast, colonoscopy if colonic involvement
- Acute: AXR key in acute UC disease, dont conoloscopy if severe acute
Which medications are used for inducing remission in Crohn’s disease? (1st, 2nd and 3rd line)
1st line corticosteroids: Prednisolone Po (mild) or Hydrocortisone IV (severe)
2nd line aminosalicylates: Sulfalsazaine, mesalazine (mild) , thioprines: Azothioprine (severe)
3rd line: Infliximab
4th line: Methotrexate
Which medications are used for inducing remission in Ulcerative Colitis? (1st, 2nd and 3rd line)
1st line Aminosalicylates: Sulfasalazine oral or Mesalazine oral or topical (enemas, liquids) and suppositories.
2nd line corticosteroids: Prednisolone or IV hydrocortisone.
3rd line Calineurin Inhibitors: Tacrolimus or Ciclosporin can be added in severe disease which is unresponsive.
4th line: Anti TNF
Which are the medications used for maintaining remission in Crohn’s disease? (1st, 2nd and 3rd line)
1st line Thiopurines: Azathioprine and Mecaptopurine
Take several months to work so not effective for acute flares. Need to check TPMT level before starting.
2nd line: Methotrexate given once weekly.
Take several months to start so also not suitable for acute flares.
3rd line Anti TNF drugs: Infliximab or Adalimumab
Immunosupressant and can increase Ca risk.
Note: can be used to induce remision in both UC and Crohn’s but reserved as a last resort.
Which are the medications used for maintaining remission in Ulcerative Colitis? (1st and 2nd line)
1st line Aminosalicylates: Mesalazine or balsalazide
2nd line Thiopurines: Azathioprine or Mecaptopurine.
When are antibiotics indicaed in IBD?
Never indicated for UC.
Can be used in fistulising Crohn’s
Oral metronidazole can be used in Crohn’s anal disease.
Which medication can be used to control diahorrea caused by reduced absorption of bile salts?
Cholestyramine
Categorise the following medication into whether they are used for Crohn’s, UC or both: aminosalicylates, steroids, methotrexate, anti TNF, thiopurines, calcineurin inhibitors and antibiotics?
UC:
Calineurin Inhibitors (tacrolimus and ciclosporin)
Crohn’s:
Methotrexate
Antibiotics
(Anti TNF)
Both:
Aminosalicylates
Steroids
Thiopurines (Mercaptopurine/azathioprine)
(Anti TNF) mostly used in Crohn’s
Describe the indication and type of surgery in UC?
Indication:
- Progressing disease which is not well controlled by medication.
- Toxic Megacolon (emergency).
- Dysplasic changes.
Surgery: usually curative but extreme:
Emergengy: subtotal colectomy and end ileostomy (stoma can be reversed + pouch added), Pan proctocolectomy and end ileostomy (cant be reversed)
Elective: Pan proctocolectomy and stoma, or subtotal colectomy and ileoanal pouch formation
Describe the indications and types of surgery in Crohn’s disease?
Indications:
- Symptomatic crohn’s with failed medical treatment
- Complications such as fistulae, strictures or perforations.
Medication may be given beforehand to reduce inflammation.
Surgery
- Involve limited resection of affected bowel. Patients will often have a stoma when there is an increased risk of failed bowel anastomoses these are known as Hartmann’s procedures.
- Hemicolectomy (partial removal of bowel)
- Small bowel resection.
Describe some of the theories regarding the pathophysiology of IBS?
GI motility: no predeominant pattern of motor activity but motor abnormalaties are present in some patients. Such as:
- increased frequency of contractions
- prolonged transit time in constipation predominant IBS
- exagerated motor response to cholecystokinin in diaorhoea predominant IBS
Visceral hypersensitity:
- Increased sensation in response to stimulus
Other theories such as food sensitivities and bowel flora are being investigated.
What are the relationship between smoking and Crohns/UC?
In Crohns smoking is a risk factors whereas in UC it is protective.
Describe the management for IBS
Relaxation advice, exercise and diet advice (lots of water, regular mealtimes, limit tea/ coffee and high insoluble fibre food)
FODMAP if this unseccesful
Antispasmodics e.g. mebeverine if painful
Laxatives if constipation (avoid laculose), Loperamide if diarrhoea
2nd line: TCA, 3rs line SSRI
If these unsuccesful after one year: CBT referral
What investigations should be done in IBS
Coeliac disease: TTG/ anti=endomysial antibodies
IBD: CRP/ESR, faecal calprotectin, FBC (anaemic)
How does a patient with toxic megacolon present?
Fever, tachycardia, dehydration, abdominal pain and tenderness, blood stained stool
Will have high WCC and electrolyte abnormalities (low potassium)
