Week 4/5 - C - Non malignant colon - Diverticulosis (complications), Colitis (ischaemic, antibiotic, microscopic), angiodysplasia

Question 1

DIVERTICULAR DISEASE Defintions What is a diverticulum (diverticula = plural)? What is diverticulosis? What is diverticular disease vs diverticulitis?

Answer 1

A diverticulum is mucosal herniation through the muscular gut wall usually at sites of entry of perforating arteries Divertulosis means that diverticula are present Diverticular disease implies that the present diverticula are symptomatic Diverticulitis refers to inflammation of the diverticula

Question 2

Where do diverticula most commonly occur? What are risk factors for diverticular disease?

Answer 2

Diverticula most commonly occur within the sigmoid colon (left iliac fossa) Risk factors include increasing age and a low fibre diet

Question 3

Why is it thought that a low fibre diet may lead to diverticulosis? (the presence of diverticula)

Answer 3

It is thought a low fibre diet can cause high intraluminal pressures forcing the mucosa to herniate through the muscle layers of the gut at weak points adjacent to penetrating vessels

Question 4

What are the clinical features of diverticular disease? (diverticulosis that is symptomatic)

Answer 4

Diverticulosis can present in a number of ways: painful diverticular disease: * altered bowel habit +/- colicky left sided abdominal pain which is relieved by defecation * Nausea and flutulence may also be present

Question 5

What are the different complications of diverticular disease?

Answer 5

Inflammation - diverticulitis (may be due to an infection) Rupture Abscess Fistulae formation Haemorrhage - massive bleeding Post infective stricture

Question 6

How is acute diverticular disease diagnosed?

Answer 6

Acutely unwell surgical patients should be investigated in a systematic way. * Plain abdominal films and an erect chest x-ray will identify perforation (free air) and maybe obstruction An abdominal CT scan will help to identify whether acute inflammation is present but also the presence of local complications such as abscess formation. -> the imaging modality of choice

Question 7

What are the diagnostic options for patients who present in clinic for diagnosing diverticular disease?

Answer 7

Clinical history + usually one of the following three * Colon/sigmoid oscopy * Barium enema * CT scan - the usual investigation of choice

Question 8

What is the treatment of diverticulosis? (asymptomatic diverticula usually as an incidental finding) What is the treatment of diverticular disease? What may be considered for treatment if there are complications?

Answer 8

For both diverticulosis and diverticular disease - Increased dietary fibre intake If there are complications Diverticulitis, rupture, abscess, fistulae, haemorrhage, strictures They will require antibiotics and / or surgery

Question 9

How does diverticulitis present?

Answer 9

Same features as diverticulosis altered bowel habit +/- colicky left sided abdominal pain which is relieved by defecation Nausea and flutulence may also be present but also Pyrexia Raised WCC Tender colon +/- localised peritonism

Question 10

What is the treatment of diverticulitis?

Answer 10

If there is suspected mild, uncomplicated diverticulitis, depending on clinical judgement: prescibe co-amoxiclav The need for surgery is reflected by the degree of infective complications usually seen by investigations

Question 11

Investigations carried out into the diagnosis of diverticular disease / the complications What were the usual investigations carried out in thh acute setting again?

Answer 11

Abdominal xray / chest xray - can help diagnose pneumoperitoneum due to rupture, also can diagnose obstruction CT scan - best to confirm acute diverticulitis and can identiffy extent of complications eg abscess, fistulae, perforation

Question 12

What is the classification system for acute diverticulitis? State the stages (hinchey classification for acute diverticulitis)

Answer 12

Stage 0 - clinically mild diverticulitis - oral antibiotic Stage 1 - confined pericolic inflammation or abscess formation Stage 2 - walled off or pelvic abscess Stage 3 - generalised purulent peritonitis Stage 4 - generalised faecel peritonitis

Question 13

What are the features of colonic perforation? What are the features of a colonic abscess?

Answer 13

Colonic perforation - ileus, peritonitis +/- shock Abscess - usually presents with a swinging fever, localised signs

Question 14

What is the treatment options for complex diverticulitis? * Abscess formation * Haemorrhage * Fistulae * Perforation

Answer 14

Percutaneous drainage of large abscesses. Haemorrhage - colonoscopic haemostasis For patients with severe or diffuse peritonitis - * emergency colectomy, * a Hartmann’s procedure, * or colectomy with primary anastomosis may be necessary

Question 15

There are different causes of inflammation of the large bowel - known as acute or chronic colitis What are the different causes?

Answer 15

Acute colitiis can be due to * Ischaemic colitis * Infective colitis - gastroenteritis * Antibiotic associated colitis Chronic * Ischaemic colitis * Ulcerative colitis * Crohn’s colitis

Question 16

What are the symptoms of both acute and chronic colitis?

Answer 16

Symptoms include Dirrhoea +/- blood Abdominal cramps Dehydration Sepsis Weight loss, anaemia

Question 17

What are the different methods to diagnosis acute and chronic colitis?

Answer 17

Plain Xray Sigmoidoscopy + biopsy Stool cultures / stool toxins Barium enema

Question 18

What is the management of colitis in the acute step? Once infective/ischaemic colitis has been ruled, what may you consider for the diagnosis?

Answer 18

Management of colitis in the acute phase is IV fluids Once infective/ischaemic colitis has been ruled out, may think towards chronic causes such as ulcerative/crohns - will need immunosuppression (IV steroids short term)

Question 19

Who does ischemic colitis occur in? What is affected here and what is the presentation?

Answer 19

Ischaemic colitis tends to occur in elfderly people / arterioapths It is usually due to low flow in the inferior mesenteric artery territory This may lead to inflammation, ulceration and haemorrhage. * Therefore causing left sided abdominal pain, often bloody diarroea also

Question 20

What typically causes the ischaemia to the inferior mesenteric artery in ischaemic colitis?

Answer 20

Mostly the result of a thromboembolism. Commonly the embolism is caused by atrial fibrillation, valvular disease, myocardial infarction, or cardiomyopathy. Non-occlusive diseaseIn ie in hemodynamically unstable patients (i.e. shock)may compromise the mesenteric circulation

Question 21

What is seen on AXR in ischaemic colitis? Why is it seen?

Answer 21

‘thumbprinting sign’ may be seen on AXR commonly at the splenic flexure to due ischaemia “watershed” areas, at the borders of the territory supplied by SMA/IMA- such as the splenic flexure and the rectosigmoid junction. Watershed areas are most vulnerable to ischemia when blood flow decreases, as they have the fewest vascular collaterals.

Question 22

What imaging technique is used for diagnosing ischaemic colitis? What is gold standard for diagnosing ischaemic colitis and ruling out other causes?

Answer 22

Contrast enhanced imaging (ideally with an arterial phase) is the modality of choice. Gold standard for diagnosing ischaemic colitis is lower GI endoscopy- * Ischemic colitis has a distinctive endoscopic appearance; endoscopy can also facilitate alternate diagnoses such as infection or inflammatory bowel disease. Biopsies can be taken via endoscopy to provide more information.

Question 23

What is the treatment of ischaemic colitis?

Answer 23

Management - usually supportive with fluid replacement and antibiotics - surgery may be required in a minority of cases if conservative measures fail. Indications would include generalised peritonitis, perforation or ongoing haemorrhage

Question 24

What is antibiotic induced colitis? What is the pathogenesis of the infection?

Answer 24

Antibiotic induced colitis is associated with C.difficile formation - watery bloody dirrhoea and abdo pain * C.diff is part of the normal gut flora * Broad spectrum antibiotic use disrrupts the normal gut flora * This enables C.diff to produce spores and toxins. * The toxins (toxin A (enterotoxin) and toxin B (cytotoxin)) damage the gut leading to the symptoms * The spores are resistant to normal alcohol disinfectants and facilitation of person-to-person spread occurs

Question 25

What can form in the gut in severe cases of this? What are the associated drugs?

Answer 25

In severe C.diff infection, a pseudomembrane can form on the gut wall - viscous collection of inflammatory, fibrin and necrotic cells 4C antibiotics Clindamycin (lincosamide) Co-amoxiclav Cephalosporins (eg ceftriaxone) Ciprofloxacin (fluoroquinolones)

Question 26

What is the management of a C.difficile infection?

Answer 26

Non-severe disease - oral metronidazole Severe disease - oral vancomycin * Very severe/non responder - vancomycin + IV metronidazole Recurrent - fidomaxicin

Question 27

What two conditions make up the term microscopic colitis? What is the presentation of these conditions (same for both) and why is it referred to as microscopic?

Answer 27

Microscopic Colitis is the umbrella term for both lymphocytic collitis and collagenous Although they look different under the microscope, symptoms and treatment are the same Both conditions are characterized by the presence of * persistent non-bloody watery diarrhea, * normal appearances on colonoscopy (hence the name microscopic) and * characteristic histopathology findings of inflammatory cells

Question 28

What is the difference between lymphocytic and collagenous colitis on biospy?

Answer 28

Lymphocytic colitis (LC) – where the inner lining has more white blood cells (lymphocytes) than usual. (normal basement membrane) Collagenous colitis (CC) – where the inner lining has a thicker layer of a collagen (thickened basement membrane)

Question 29

What is the treatment of microscopic colitis?

Answer 29

Lymphocytic and collagenous colitis have both been shown in randomized, placebo-controlled trials to respond well to budesonide, a glucocorticoid.

Question 30

What is colonic angiodysplasia? What is the main symptoms due to this?

Answer 30

Angiodysplasia is a vascular deformity of the gastrointestinal tract which predisposes to bleeding and iron deficiency anaemia. It is a common cause of otherwise unexplained gastrointestinal bleeding and anemia (bleeding can be either red or dark depending on where the vascular deformity is)

Question 31

Which patients is angiodysplasia typically seen in? Where in the colon is affected?

Answer 31

Typically affects elderly patients Lesions are often multiple, and frequently involve the cecum or ascending colon, although they can occur at other places

Question 32

What condition does angiodysplasia have an association with? (it forms a syndrome known as Heyde’s syndrome)

Answer 32

Heyde’s syndrome is a syndrome of gastrointestinal bleeding from angiodysplasia in the presence of aortic stenosis

Question 33

Diagnosis is often very difficult as the lesions can be notoriously hard to find How is it diagnosed?

Answer 33

Diagnosis is typically made via colonoscopy (mesenteric angiography can be attempted if acutely bleeding)

Question 34

What is the treatment of colonic angiodysplasia?

Answer 34

Endoscopic ablation treatment is an initial possibility, where cautery or argon plasma coagulation (APC) treatment is applied through the endoscope. If multiple bleeding sites, antifibrinolytics such as tranexamic acid may be tried Embolisation and finally surgery may be required if treatment continues to fail