Summary of Chris Fraser’s “Gastroenterologist’s perspective – how does GI physiology help in the diagnosis and management of medical patients”
(BSG Conference, 2016)
by Andres Vales, Clinical Physiologist at The Functional Gut Clinic
Dr. Chris Fraser is a consultant gastroenterologist at the Royal Infirmary of Edinburgh with specialist interests in functional disorders.
He started by explaining how the diagnosis of functional disorders are becoming more and more common in modern gastro clinics with many patients never reaching a resolution of symptoms. Heartburn, bloating, urgency and straining are classic symptoms that persist despite the patient trying many different medications and attempting substantial lifestyle modifications, inevitably ending up with a very poor quality of life. However good work is being done to understand the underlying physiology with advances being made in the diagnosis of reflux, gut microbiome disorders and incontinence/constipation. This, along with the involvement of other modalities such as dietetics and biofeedback in the treatment pathway, mean that tricky ‘functional’ patients can be given the chance of a cure.
Dr. Fraser highlighted key aspects of the diagnostic pathway that are often overlooked but can provide essential information. A thorough patient history and careful examination of the patient is vital with blood and stool tests as routine where consideration should be given for latent coeliac disease in adults even in only mildly elevated TTG levels. A simple PR exam can reveal a lot and a flexible sigmoidoscopy can quickly rule out IBD with these options being considered before deciding to send for a colonoscopy.
A series of case studies were then reviewed with insight into how physiology was used to get a diagnosis:
Oesophageal dysmotility – Achalasia may be considered as a text book diagnosis with set treatment pathways and prognosis. However an example of how oesophageal physiology can be used to augment the diagnosis was given where a Barium swallow suggested type I but high resolution manometry confirmed type II which gave the patient a better prognosis and treatment options. Another patient was reviewed with pathological supine GORD and hypomotility however an extended high resolution manometry study with bread swallows showed a good improvement in contractility. In patients like this Dr. Fraser suggested that the Stretta procedure, where radiofrequency energy is applied to the LOS and cardia, has been shown help symptoms whilst having little effect on bolus outflow and so can be a useful option for patients where the benefit of fundoplication is uncertain.
SIBO/Colonic mal-fermentation - Commonly patients experienced bloating, abdominal pain and altered bowel habit for many years without investigation. One patient had coeliac disease and so symptoms were overlooked as they were thought to not be following a strict enough GFD. In these types of patients a lactulose breath test was used to reveal SIBO with some being methane producers highlighting the importance of measuring for this gas during breath testing. Lactulose is nonabsorbable in the small bowel and so is also useful for investigating colonic fermentation where excessive breath values in the 100’s of parts per million towards the end of the study may suggest that a FODMAP diet can be useful to reduce gas production in the large bowel. Used in conjunction with lactose and fructose mal-absorption tests, this diagnosis can greatly help a dietician to create an individualised diet for the patient with many improving simply with antibiotics and a dietetics referral. Another test which can be used to look at the gut microbiome is the SmartPill wireless motility capsule. By measuring pH, pressure and temperature simultaneously, the capsule can provide a transit profile of each individual section of the gut as well as whole gut transit and has compared well against radiopaque marker studies making the test useful for those with suspected gastric emptying, as well as those with constipation. The pH measurement of the bowel can supplement the lactulose breath test as colonic bacterial fermentation produces short-chain fatty acids. In excessive fermentation this increased production can lower caecal pH and the increased irritation it causes has been linked with IBS in terms of increasing pain and decreasing contractility.
Anorectal physiology – the case studies showed that on occasion symptoms such as diarrhoea and constipation were, after a detailed consultation, found to also be occurring with straining, tenemus, rectal urgency or vaginal fullness during evacuation. Anorectal physiology including a defecating proctogram were essential in revealing issues such as hyposensate megarectum, prolapses and intussusception. Treatment could then go ahead with sessions of biofeedback therapy and tailored diet modifications being effective in an array of different disorders.
Overall the ‘functional’ patient can present with vague symptoms however paying attention to them when taking a history and not being afraid of investigating the different areas of the gut using the methods covered above can lead to a positive diagnosis. With this in mind Dr. Fraser underlined the need for strong physiology services in gastroenterology.