Lecture 31 Flashcards
How are functional gut disorders defined?
Constellation of symptoms but without overt pathology. There is not structural or tissue abnormality.
What causes functional gut disorders?
Due to disturbed function:
1) Disturbed motility.
2) Visceral hypersensitivity.
3) Brain-gut dysfunction.
4) Psychosocial factors.
Why is there not a specific diagnostic test for functional gut disorders?
Due to there being no overt pathology, there is no diagnostic test. There’s no biochemical abnormality with conventional testing, no histological or radiological features.
What can functional gut disorders affect?
Any part of the gut: oesophagus, stomach, SI and LI.
What are examples oesophagus GI disorders?
1) Globus - sensation of lump stuck in the throat.
2) Functional heartburn - symptoms of reflux without evidence of GORD or a motility disorder.
What are examples of stomach GI disorders?
1) Functional dyspepsia - upper abdomen pain or discomfort without structural abnormality e.g. no ulcer, pancreas or gallbladder pathology.
2) Functional vomiting/cyclical vomiting syndrome - recurrent vomiting; no diagnostic abnormalities and no psychiatric cause.
What are examples of bowel GI disorders?
1) Irritable bowel syndrome - abdominal discomfort/bloating associated with defaection and altered bowel habit i.e. constipation/diarrhoea or both.
2) Functional abdominal pain - recurrent or continuous abdominal pain unrelated to defaecation and without disturbed bowel habit; no diagnostic abnormalities.
How can you diagnose functional GI disorder?
1) Symptom complex - analogous to diagnosis of migraine.
2) Symptoms of functional gut disorders can be similar to those with serious pathology.
3) Diagnosis of functional gut disorders is a “diagnosis exclusion”.
4) Always consider other GI diagnoses first before making a diagnosis of functional gut disorder.
What is irritable bowel syndrome characterised by?
Swinging bowel habit - from constipation to diarrhoea.
What are the symptoms of irritable bowel syndrome?
1) Swinging bowel habit.
2) Abdominal pain, which is relieved with defaection.
3) Associated symptoms:
- urgency (incomplete evacuation),
- passage of mucus,
- abdominal bloating and
- excess flatus.
When can irritable bowel syndrome occur?
May occur after gastroenteritis (post-infective IBS). Usually people who don’t have a history of IBS.
What is the Rome III criteria for IBS?
IBS is a functional disorder characterised by abdominal pain or discomfort and changes in still frequency or consistency.
Describe further the Rome III criteria for IBS?
1) At least 3 days per month in the last three months.
2) Onset of symptoms at least 6 months prior to diagnosis.
3) Must be associated with 2 or 3 of the following:
- improves with defecation.
- Onset of pain coincides with changes in stool frequency.
- Onset of symptoms is accompanied by changes in the form or appearance of the stool.
What are the associated symptoms of IBS?
1) Fatigue.
2) Other functional GI symptoms:
- functional dyspepsia.
- Early satiety, post-prandial fullness.
- Nausea, vomiting.
3) Backache, headache.
4) Urinary symptoms.
5) Dysmenorrhea, dyspareunia.
6) Palpitations.
7) Poor sleep quality.
What are symptoms that can alert to other possible pathologies?
1) Older patient (over 50, even 40+).
2) Short history.
3) Nocturnal diarrhoea/nocturnal pain.
4) Rectal bleeding.
5) Anaemia or iron deficiency.
6) Weight loss.
7) Vomiting.
8) Family history of colon cancer.
How common is IBS?
5-12% men.
5-18% women.
But if not strictly based on criteria, more common than this.
It is early onset - early 20-30s.
Describe altered gut motility in IBS?
1) Frequency and duration of contractions are either long or short depending on constipation or diarrhoea.
2) Transit time (time for food to meet back passage) is increased or reduced depending on constipation or diarrhoea.
3) Exaggerated response to meal ingestion/stress. Need to go to the toilet.
Simple terms - Exaggerated with diarrhoea, reduced with constipation.
Describe visceral hypersensitivity?
1) Balloon distension of colon causes pain in 50-60% of IBS patients compared with 10% of controls. IBS recognise pain at lower threshold of distension compared to controls.
2) People with IBS describe distension as unpleasant or painful.
What is the mechanism of peripheral sensitisation in visceral hypersensitivity?
In patients with post-infective IBS, there may be a degree of sensitisation. There was an acute gastroenteritis, which causes inflammation, this will lead to up regulation of nociceptors. This will lead to increased sensitivity to painful stimuli and non-painful stimuli perceived as pain.
What is the mechanism of central sensitisation in visceral hypersensitivity?
Central sensitisation is where the pain may radiate beyond the gut e.g headaches.
Describe spinal cord - gate control theory?
Pain messages from the periphery and have to enter the spinal cord before entering the brain. Some people with IBS, at the level of spinal cord becomes altered. If the gate is open - reaches the brain. If the gate is closed it doesn’t reach the brain. People with IBS there may be an increased focus on unpleasant stimuli - due to brain focussing on processing pain stimuli.
What are the effect of stress on IBS.
The communication between the gut and brain is bi-directional (both ways). Brain can influence motor, sensory, secretory and immune functions of GI tract.
