U10C2 Crohn’s Flashcards

Question 1

Q

Features of Crohns (CHRISTMAS mnemonic)

Question 2

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What is the Pathophysiology of crohn’s?

Question 3

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What is the progression of crohn’s?

Question 4

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What are the 4 phases of defection?

Answer

A

Basal Phase:
This is the resting phase when the rectum is filling with feces.
The internal and external anal sphincters are contracted to prevent involuntary passage of feces.

Pre-Expulsive Phase:
As the rectum fills, stretch receptors in its walls are activated.
Nerve signals from the stretch receptors initiate the defecation reflex.
Smooth muscle contractions in the rectum intensify, preparing for expulsion.

Expulsion Phase:
The defecation reflex causes the internal anal sphincter to relax, facilitating the movement of feces toward the anus.
The external anal sphincter, a voluntary muscle, relaxes when a person chooses to defecate.
Coordinated contractions of rectal muscles and increased intra-abdominal pressure result in the expulsion of feces through the anus.

Termination Phase:
Once feces are expelled, the rectum begins to return to a more quiescent state.
The internal anal sphincter resumes its contraction to prevent continuous leakage.
The external anal sphincter regains tone, providing voluntary control over bowel movements

Question 5

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What are the 4 types of diarrhoea?

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Secretory diarrhoea is caused by decreased absorption or increased secretion of electrolytes and water
Osmotic diarrhoea is characterised by a substance such as lactose or gluten drawing water into the bowel down the concentration gradient - this occurs frequently in malabsorption syndromes such as lactose intolerance or coeliac disease or from ingestion of osmotically active substances like magnesium sulphate which are common ingredients in laxatives
Inflammatory diarrhoea will occur in IBD such as Crohn’s disease or ulcerative colitis as well as certain invasive intestinal infections like C. difficile
Functional diarrhoea such as IBS - the aetiology is unknown but may involve alterations in the microbiome of the intestine

Question 6

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How is Crohn’s managed and treated?

Answer

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Anti-inflammatory meds
Enteral feeding (mostly for children)
Antibiotics
Immunosuppressants eg. Mercaptopurine
Steroids eg. Prednisolone
Anti TNFa agents eg. Adalimumab
Surgery

Question 7

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What are the diagnostic tests for crohn’s

Answer

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Serum full blood count — anaemia may be due to blood loss, malabsorption, or malnutrition; an increased platelet count may suggest active inflammation.
Serum inflammatory markers such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) — may be raised if there is active inflammation or an infectious complication.
Serum urea and electrolytes — to assess for electrolyte disturbance and signs of dehydration.
Serum liver function tests, including albumin — a low serum albumin may indicate protein-losing enteropathy.
Serum ferritin, vitamin B12, folate, and vitamin D levels — may be nutritional deficiencies due to malabsorption or intestinal losses.
Coeliac serology — to exclude coeliac disease.
Stool microscopy and culture, including Clostridium difficile toxin — to exclude infective gastroenteritis or pseudomembranous colitis. Note: the diagnosis of a pathogen does not exclude a diagnosis of Crohn’s disease, as a first episode may be triggered by enteric infection.
Faecal calprotectin (a faecal white cell marker, for adults) — if raised may suggest active inflammation
Biopsy- of ileum, colon and rectum, taken during colonoscopy. Features: granulomas, many immune cells that have invaded lamina propria, ulcers and erosion, crypt abscess, branching of crypts
Barium follow through- usually of small bowel, cannot eat or drink for 6 hours before, X-rays taken at regular intervals, can take 2-6 hours. Features: mucosal ulcers, thickened folds, pseudodiverticula, string sign