5.4. Intestinal Disease - Crohn's Disease (IBD) Flashcards
What is the Aetiology of Crohn’s Disease?
This is unknown, but it is clear that there is an interaction between several co-factors
What co-factors are thought to cause Crohn’s Disease
- Genetic Susceptibility - This is a Complex Polygenic Disease
- Environmental Factors
- Intestinal Microbiota - The number of Mucosal Adherent Bacteria is Increased
What are the Risk Factors which make up the Genetic Susceptibility to Crohn’s?
- Family History - the largest independent risk factor
- People with mutations of the (Chromosome 16) NOD2 gene - expressed on the Epithelial/Endothelial Cells, and Macrophages
What are the Risk Factors which make up the Environmental Factors for the Susceptibility of Crohn’s?
- Smoking
- NSAID
- Hygiene
- Nutritional Factors
- Phsychological Factors
- Appendectomy
How is Smoking associated with the Aetiology of Crohn’s Disease?
It has been shown to exacerbate the disease
How are NSAID’s associated with the Aetiology of Crohn’s Disease?
This is associated with the Onset and Flaring of the disease
How is Hygiene associated with the Aetiology of Crohn’s Disease?
Good Domestic Hygiene has been shown to be a risk factor - A constantly clean environment may not expose the Intestinal Immune System to (Non-)Pathogenic Organisms
How is Nutrition associated with the Aetiology of Crohn’s Disease?
- Some foods are suggested to play a role but none have been proven
- Breast feeding may provide protection against the developing within offspring
How are Psychological Factors associated with the Aetiology of Crohn’s Disease?
Chronic Stress / Depression increase relapses in patients
How is having had an Appendectomy associated with the Aetiology of Crohn’s Disease?
This increases the Risk of the Disease
What are the Risk Factors which make up the Intestinal Microbiota for the Susceptibility of Crohn’s?
- Intestinal Dysbiosis
- Pathogenic Organisms
- Bacterial Antigens
- A Defective Chemical Barrier
- An Impaired Mucosal Barrier
- Butyrate
How is Intestinal Dysbiosis associated with the Aetiology of Crohn’s Disease?
There is an Altercation in the Bacterial Flora of those with Crohn’s:
- There are Higher Concentrations of Bacteroides and E. Coli
- There are Lower Concentrations of F. Prausnitzii
How are Pathogenic Organisms associated with the Aetiology of Crohn’s Disease?
There is an increase in E. Coli (Intestinal Dysbiosis) adherence to the Ileal Epithelial Cells, which has been shown to be related to Invasion of the Mucosa, of people with Crohn’s Disease exacerbations
How are Bacterial Antigens associated with the Aetiology of Crohn’s Disease?
There is an increase of Bacteria which exert their influence by Ligands, which interact with Host-Pattern Receptors in Crohn’s Disease exacerbations
How is a Defective Chemical Barrier associated with the Aetiology of Crohn’s Disease?
Evidence suggests a decrease in Human Intestinal Defensin “Alpha-Defensin-1” (HD-1) as well as a lack of induction of other Defensins can lead to Crohn’s Disease exacerbations
How is a Impaired Mucosal Barrier associated with the Aetiology of Crohn’s Disease?
This can explain the presence of unusual and potentially pathogenic bacteria, which can lead to Crohn’s Disease exacerbations
What is Butyrate?
A type of fatty acid which helps with Intestinal Function
How is a Butyrate associated with the Aetiology of Crohn’s Disease?
- A Sulphate-Producing Bacteria which increases Luminal Levels of Hydrogen Sulphide
- This decreases Butyrate Oxidation in the Colonic Mucosa
- This leads to Mucosal Inflammation which can precede Crohn’s Disease exacerbations
What is the Pathology of Crohn’s Disease?
This is a Chronic Inflammatory Condition