Inflammatory Bowel Disease
The inflammatory bowel diseases (IBD) are diseases in which parts of the digestive tract becomes spontaneously inflamed and ulcerated. These diseases are: Crohn’s disease, ulcerative colitis and indeterminate colitis. These are recurring relapsing conditions that can usually be controlled with medication. People with IBD continue to lead normal, active and productive lives.
The exact cause of IBD is unknown. It is thought that the immune system in genetically predisposed people react in an inappropriate way to environmental factors and causing the individual to develop IBD.
a. Genetic factors: Genes associated with IBD are not found in every IBD patients. Different genes have also been found in different ethnic populations. Likewise, having a suspected IBD gene does not mean that one will definitely develop IBD.
b. Environmental factors: Lifestyle and diet are thought to contribute to development of IBD. Smoking has been associated with Crohn’s disease. The presence of certain bacteria in the gut has been associated with IBD. It is thought that the composition of bacteria in the intestines is dependent on the diet, and the diet of Singaporeans has changed over the last 50 years as the country progressed from a developing to a developed economy.
c. Individual immune response: The over-reaction of the immune system plays a role in the development of IBD.
Symptoms are varied, comprising:
- Classical symptoms include diarrhoea, blood in the stool, weight loss, mouth ulcers and abdominal pain.
- Subtle symptoms include change in bowel habit, failure to thrive in babies, lagging developmental milestones in children, bloating and lethargy.
- Less common symptoms include anal fistulas, passing faeces or air in the urine.
a. Blood tests: Full blood count, renal panel, C-reactive protein, erythrocyte sedimentation rate (ESR), liver panel and vitamin B12/ folic acid/ iron levels in anaemia.
b. Stool tests: Stool culture, microscopy, Clostridium difficile PCR and stool calprotectin
i. Chest x-ray
ii. Abdominal x-ray
iii. Abdominal and/or pelvis CT scans
iv. Small bowel enteroclysis
v. CT/MRI enterogram
vi. Small bowel capsule endoscopy
d. Endoscopy to obtain tissue for biopsies
i. Colonoscopy and ileoscopy
ii. Oesophagogastroduodenoscopy (OGD)
iii. Small bowel enteroscopy
A. Treatment when disease is active:
Patients with IBD get recurrent flares of their condition. Common medicines used during flares include:
i. Steroids (e.g. prednisolone, budesonide, hydrocortisone) which are given intravenously, orally or topically (i.e delivered to the site of inflammation).
ii. High dose 5’aminosalicylic acids (5ASA) are used orally or topically.
iii. Immune suppressants such as: anti-tumour necrosis factor antibodies (eg infliximab/ Remicade or adalimumab/ Humira) and ciclosporin are used in challenging cases.
iv. Antibiotics have also been used for special cases (e.g perianal fistula)
v. Special diets (e.g. elemental/ polymeric diets) and infusion of nutrition (i.e. total parenteral nutrition) are sometimes used to treat Crohn’s disease patients.
vi. Patients with refractory disease (IBD not responding to treatment) and patients who develop complications may need surgery.
B. Maintenance treatment to prevent flare:
i. Long term 5ASA are used to prevent and decrease the severity of flares and cancer.
ii. Medicine that suppress the immune system such as azathioprine/6-mercaptopurine, methotrexate and anti-TNF antibodies, are good at preventing and decreasing the severity of flares.
iii. In a very select group of patients, good bacteria (probiotics) is useful.
IBD is a treatable illness that can be kept in remission.