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See Lawson's notes.

Case 1

  • Low Hb, Low MCV, low transferrin saturation, low ferritin, high ALP and GGT, high ESR and CRP.
  • Colicky = cramping pain that fluctuates in intensity
    • NB that biliary colic is severe and relatively constant - no exacerbations and remissions. Colick also indicates obstructed hollow viscous. Just turns out that biliary colic is more constant, not exacerbating/remitting
  • Pain: midgut (2nd part of duodenum up to 2/3 through transverse colon; mostly small bowel) is periumbilical pain; foregut is before midgut; hindgut is after midgut
    • Referral of pain from foregut and hindgut is less specifically localised
  • Diarrhoea is watery in this case, and the function of the colon is to absorb water. Normal ileal effluent is liquid. (Colectomy = ongoing diarrhoea = risk of dehydration).
    • Diarrhoea improving with fasting - not secretory (e.g. cholera and other infections can cause increased fluid output in stool)
  • Most forms of diarrhoea are at least partly responsive to fasting
    • Osmotic content of ingested food holds water in the lumen. If you get rid of food intake, you will therefore hold less water in the bowel. This is osmotic diarrhoea - virtually all causes of diarrhea have at least an osmotic component of diarrhoea
  • Diarrhoea present night and day
  • Commonest cause of diarrhoea in 35 year old woman - irritable bowel syndrome. This is because of functional disturbance in the gut
    • Colicky pain
    • Abdominal bloating
    • Diarrhoea or constipation or both
    • Affects 1 in 5
    • Tends to build up during the day, and remit at night - influence of stress/brain on gut function
      • Symptoms that persist through the night should trigger you to think about something else
    • Can be post-inflammatory bowel syndrome after waterborne food poisoning
    • No physically demonstrable pathology
    • No effective treatment
  • Crohn's disease has been climbing markedly in incidence
  • Travel, antibiotics, history of contacts
    • Looking for infectious causes
    • Antibiotics
      • Antibiotic-associated diarrhoea, since antibiotics can transiently affect the gastrointestinal flora
      • Pseudomembranous colitis - Clostridium difficile causes increased mucous secretions; due to antibiotic use and an imbalance of antibiotic microbiota; particularly in nursing homes
    • Travel - endemic locations for gut infections; relevant contacts
    • Food - dodgy take-out
  • Joint symptoms - pain swelling, worse early in the day
    • Inflammatory arthritis from Crohns more likely than OA
      • This is because of the swelling, and because degenerative arthritis gets worse throughout the day, while inflammatory arthropathies get better with walking
  • Crohn's has extraintestinal manifestations
    • Inflammatory arthritis: medium-large joints (ankles/knees/hips). Oligoarthritis (usually only 1-2 or a few joints)
    • Liver disease manifestations
    • Eye manifestations
    • Kidney stones, gallstones
    • Psoriasis
    • Skin: erythema nodosum (painful, tender, raised, red lumps, typically over the lower legs; they fade as they settle down to look like bruises), pyoderma gangrenosum
    • Some of these (like the arthritis) are active when the bowel disease is active - treat bowel will help everything else
    • pyoderma gangrenosum and liver manifestations run their own course independent of the bowel disease
    • mouth ulcers (apthous ulcers) occur in both ulcerative colitis and Crohn's. Typically have a hyperaemic border. Associated with activity of the disease.
  • Bowel appearance
    • Fat wrapping, where fat is actually on the surface of the bowel (rather than on the mesentery - related to inflammation)
    • Skip lesions
    • Thick bowel - feel the bowel is thicker than normal
      • Due to transmural inflammation
  • This is different to ulcerative colitis
    • Inflammation is mucosal or submucosal, but definitely not into the underlying layers
    • No skip lesions
  • Pathological changes in Crohn's disease
    • Flattening of the villi
    • Chronic inflammatory change - lymphocytes, all layers of bowel, possible fibrosis
    • Granulomas - very specific, but not sensitive (their absence doesn't rule out the diagnosis)
    • Note: Crypt branching is a feature of ulcerative colitis
  • Pain in right iliac fossa mass
    • Abscess - transmural inflammation can penetrate right through bowel wall, causing a perforation either to another organ (enterovagina, enterorectal, to small bowel, or enterocutaneous), or forming an abscess on the serosal surface
      • Not an abscess - in abscess the fever is high spiking fevers due to a periodic bacteraemia; and bacterial products result in pyrogenic response
      • Each time she takes corticosteroids the mass goes away
      • Phlegmon: Omentum, pieces of bowel etc tangled up in an inflammatory mass that is palpable and tender. It is related to transmural inflammation and the fact that abdominal viscera are freely mobile, that will try to wall-off an area of inflammation. Phlegmon gets better if you can get rid of the inflammation. Common in Crohn's
  • In these patients, perforation tends to be localised, and doesn't cause peritonism
  • Smoker - exacerbates Crohn's. She's pregnant and smoking but doesn't want to take medications in case they harm pregnancy LOL
    • The best thing people with Crohn's can do to make their Crohn's better is to quit smoking
      • Changing diet, exercise, weight etc won't change it.
      • Quitting smoking is as effective as any single medication.
  • Smoking is protective against ulcerative colitis, so patients will notice that when they quit smoking their ulcerative colitis may improve
  • Mesalazine = antiinflammatory agent (oral, PR) that is specifically acting in the gut. Not very good in Crohn's disease (since Crohn's is transmural not mucosal)
  • Asothioprine = immunosuppressive - purine analogue, gets bound into DNA, causing apoptosis in activated lymphocytes (a major part of pathogenesis of Crohn's disease). This is a good drug in Crohn's, but has a lot of side effects
  • Low Hb, microcytic anaemia (iron deficiency, thalassemia trait (homozygous is rarer))
  • Low ferritin is diagnostic of iron deficiency
    • Ferritin is an acute phase protein - therefore can be elevated with inflammation
      • Causes of low ferritin: iron deficiency, a rare genetic defect
    • Serum level can be in normal range despite deficiency
    • Definitive diagnosis of iron deficiency is a bone marrow biopsy - if none, iron deficiency
  • ESR is elevated, CRP is elevated
  • LFTs
    • ALP is made in the liver and bone
      • But if ALP and GGT are elevated together it is indicative of cholestasis - can be at liver lobule or microcellular level (Primary sclerosing cholangitis - in small bile ducts; associated with inflammatory bowel disease)
        • Not just obstruction - because that could be macro e.g. pancreatic cancer or
  • Platelets elevated - inflammation (acute phase reaction), bleeding also causes acute platelet increase
  • Stool culture
    • You're looking at immunosuppression as treatment - so you want to rule out infection first
    • Patients with underlying active IBS are more likely to get superimposed infection
  • You have to be quite concerned about disease if you do a colonoscopy during pregnancy
    • Shows colitis and ileitis - very severe disease
  • Options
    • Quit smoking
    • Patient education - don't assume she knows everything about it even though she's had it for 8 years
      • Apologise for seeming like you're condescending
      • But you really need to know if they understand
      • Be careful about judgements you make of people described as noncompliant
    • All medications are classed for safety scale in pregnancy A, B, C, D, X (from best to worst)
      • Treatments for IBD (azathioprine) are class D drugs but recent evidence suggests they don't really affect the baby
        • Specifically for IBD, there are no adverse effects (can have LBW and prematurity, but these are both also seen with the disease)
        • Treatments for IBD outweigh the risks to the foetus
        • Uncontrolled Crohn's disease causes miscarriage - it's actually better to have the drug
        • Start this conversation long before people become pregnant
  • Drugs you don't use in pregnancy - methotrexate. But you can use azathioprine and corticosteroids.
  • TNF inhibitors also work well (monoclonal antibodies) - very expensive but might be needed in this patient. Costs $40k/year.
  • Ulcerative colitis and Crohn's disease can't coexist, but Crohn's disease can masquerade as ulcerative colitis.
    • Acute treatments are the same (flares)
    • Longer term - drugs don't work as well in ulcerative colitis, but you have a better surgical option in ulcerative colitis - surgery is curative