Bile acid malabsorption is found in a number of conditions. For example, it can be caused by diseases of the small intestine, such as Crohn's disease, and it is seen in people who have had an operation to remove or bypass their small intestine. However, sometimes it occurs when the small bowel appears normal; the reason for bile acid malabsorption in this situation is not known.
Although not life threatening, bile acid malabsorption can have a big effect on lifestyle and quality of life because the increased need to pass motions may limit the person's ability to travel and leave the house. Advice Information for the public About this information Licensing medicines What is bile acid malabsorption?
Colesevelam has been shown to be effective if treatment with cholestyramine is not successful. Other medicines that are used to treat any cause of diarrhoea can also be used to treat bile acid diarrhoea. See the separate leaflet called Diarrhoea Medicine for more details. Most people with bile acid diarrhoea in which cause is unknown idiopathic bile acid diarrhoea respond very well to treatment with a bile acid binder medicine.
However, you may need to continue taking the medicine for a long time years in order to stop the diarrhoea. Bile acid diarrhoea may be caused by an underlying condition affecting the bowel. The outcome prognosis will then depend on the underlying bowel condition. Camilleri M ; Bile Acid diarrhea: prevalence, pathogenesis, and therapy.
Gut Liver. Aliment Pharmacol Ther. Epub Mar 6. Can J Gastroenterol. Camilleri M ; Advances in understanding of bile acid diarrhea. Expert Rev Gastroenterol Hepatol. Epub Nov Watson L, Lalji A, Bodla S, et al ; Management of bile acid malabsorption using low-fat dietary interventions: a useful strategy applicable to some patients with diarrhoea-predominant irritable bowel syndrome?
Clin Med Lond. Hi Everyone, I have been unwell for 11 days now and off work 8 days. My symptoms started with central abdominal pain which the following day, had then moved to the right hand side. My abdominal Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions.
Egton Medical Information Systems Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions. In this series.
In this article Understanding the gallbladder and bile What is bile acid diarrhoea? What causes bile acid diarrhoea? How common is bile acid diarrhoea? What are the symptoms of bile acid diarrhoea? How is bile acid diarrhoea diagnosed? The selenium homocholic acid taurine SeHCAT test is a nuclear medicine investigation considered to be the gold standard for the diagnosis of bile acid malabsorption BAM.
Many studies demonstrate that it could be effective in the clinical workout of chronic diarrhea due to different conditions. However, there is no general agreement regarding its cutoff value and the test is not widely available.
The aim of this review is to discuss the advantages and disadvantages of the SeHCAT test in clinical practice. It is characterised by watery diarrhea often postprandial , bloating, urge for defecation, and faecal incontinence at times.
BAM may occur in many different pathological conditions, which sometimes overlap Figure 1. BAM is often caused by a surgical resection or a structural impairment of the ileum i. Currently available therapies are BASs like cholestyramine, colestipol, and colesevelam.
Obeticholic acid could be a promising drug for BAM: it is an agonist of the farnesoid X receptor FXR , which increases fibroblastic growth factor 19 FGF synthesis and decreases bile acid BA synthesis by hepatocytes [ 3 , 5 ]. BAs excreted into the intestinal lumen are mainly reabsorbed in the ileum by a specific receptor, the apical sodium-dependent bile acid transporter ASBT , and return to the liver via the portal venous system Figure 2.
BAs entering the enterohepatic circulation are primary acids synthesised from cholesterol in the hepatocytes. They are actively secreted across the canalicular membrane and carried into the bile to the gallbladder, where they are concentrated in the fasting state. Also, genetic mutations of TGR5, a G-protein-coupled receptor that functions as a cell surface receptor for BAs and regulates basal and cholinergic-induced secretion in the colon and colonic transit, can predispose to BAM [ 9 ].
Another important cause of BAM may be a deficiency in FGF, a hormone produced in the enterocytes that regulates hepatic BA synthesis via a negative feedback mechanism [ 4 , 10 ].
Walters et al. Genetic variations in the proteins involved in the feedback regulation of BA synthesis, specifically the klothoB gene and fibroblast growth factor 4 gene Figure 2 , are rare causes of BAM.
An accelerated small-bowel transit, bypassing active BA transport in the ileum, has been hypothesised as a cause of BAM in idiopathic [ 12 ] and postradiation cases [ 13 ]. The 14C-glycocholate breath and stool test has a limited clinical use because it is cumbersome and time-consuming [ 14 , 15 ]. Determination of serum C4 levels using a relatively simple chromatographic method is potentially applicable to most patients, but it requires further clinical validation.
It varies according to a circadian rhythm, and false-positive results are reported in patients with liver disease or in those treated with statins. The assessment of the hour faecal output of BAs is cumbersome and not widely available. An enzymatic assay indirectly measures faecal BAs, but it tends to underestimate total BAs [ 18 ].
Moreover, when it is used to measure BA concentrations in small-bowel fluid or in ileostomy effluent, it is not reliable [ 19 ]. A possible diagnostic option could be an empiric trial with BASs. In patients with symptom improvement, the treatment may be stopped and, if the BAM symptoms reappear after seven days, the test is considered positive.
BAM diagnosis with a cholestyramine trial is less expensive and immediately available. Unfortunately, this is not supported by any quantitative data but only by the presence or the absence of a clinical improvement referred by the patients.
Moreover, evaluating the clinical response to BASs may give false positive for a placebo effect or false negative for poor compliance with the therapy [ 21 ]. Furthermore, the lack of specificity—since cholestyramine may inactivate some diarrhea etiological agents such as the Clostridium difficile toxin [ 22 , 23 ], the possible adverse events associated with BASs e.
This test was first performed in [ 27 ], and the protocol currently used was developed by Brydon et al. The SeHCAT test is currently available in twelve European countries and in Canada, but not in the USA; it is relatively expensive and it is usually available only at third-level centers.
The absorbed dose for the small intestine and gallbladder is 3. The absorbed dose for the small bowel increases in patients who have undergone cholecystectomy and who have severe liver damage. In comparison, the radiation dose given during an abdominal CT scan is approximately 5. There are different gamma camera measurement methods—whole-body count and static abdomen acquisition with or without collimators Figure 3. The total body or abdominal acquisition is performed with the detector of the gamma camera at the maximum opening of the gantry.
Care should be taken with abdominal acquisition, as it requires identical patient positioning inside the camera between the first and the second scan [ 31 ]. Collimation removal improves test sensitivity and accuracy, although, depending on the model of the gamma camera, it may be necessary to pay attention to possible crystal damage.
Abdominal counts are corrected for background BG counts and for decay; selenium has a relatively long half-life days. The percentage of abdominal or whole-body retention is calculated according to the following formula [ 32 ]:.
Figure 4 shows the selenium retention in a graphical format, which includes a cutoff line for abnormality for days 0— Therefore, it seems reasonable to consider this the optimal cutoff level [ 34 ]. In addition, Wedlake et al. BAM severity could allow the clinician to predict the response to therapy and is a starting point for evaluating clinical improvement.
Moreover, a positive diagnosis can have a positive psychological impact on the patient, leading to a better compliance with BAS therapy.
Patients with a confirmed diagnosis are more motivated to start and continue a treatment with BASs, which are not palatable and can potentially induce some adverse events [ 40 ].
The diagnosis of BAM in patients with chronic diarrhea has a great clinical relevance: since a positive SeHCAT test does not exclude other organic causes of diarrhea, patients should also undergo other tests as clinically indicated.
This is particularly true in patients treated with many different drugs, where the cause of diarrhea may be difficult to diagnose. Prolonged BAS treatment may lead to malabsorption of fats and liposoluble vitamins A, D, and K , increasing the risk of osteoporosis and possible coagulation abnormalities. For this reason, patients with coagulation defects or those taking oral anticoagulant therapy should undergo a SeHCAT test to obtain a precise diagnosis and to evaluate the benefit-risk ratio of BAS administration, as well as patients assuming life-saving drugs whose absorption could be potentially modified by BASs.
It is common to find CD patients with persistent diarrhea despite having normal inflammatory and disease activity indexes. Diarrhea is one of the most frequent symptoms during chemotherapy or radiotherapy, and BAM could be involved in its pathophysiological mechanism [ 47 ]. In a study by Phillips et al. It was mild in A SeHCAT test scan should be considered by the gastroenterologist treating cancer patients with diarrhea [ 13 ].
An interference from nonhydrolysed triglycerides, which also impairs absorption, like in chronic pancreatitis and pancreatic disease i. The pathophysiological mechanism is linked to the lack of BA reservoir and the consequent inability of the gut to absorb their excessive output. A study by Sciarretta et al.
In fact, some studies have shown that BAS can improve diarrhea in many different pathological conditions, also in patients without BAM. In particular, cholestyramine, which is a strong anion-exchange resin that can bind with bacterial toxins and mycotoxins in the colon [ 46 ], was effective in improving diarrhea also in patients with microscopic colitis without associated BAM, as reported by Fernandez-Banares et al.
It was also able to reduce the risk of developing Clostridium difficile -associated diarrhea due to its capacity of binding to toxins A and B [ 22 ]. This pharmacological effect could work in the cholecystectomized patient with a multifactorial diarrhea. This suggests the existence of other factors associated with BAM and, above all, a healing role rather than a symptomatic one for this drug.
This syndrome is defined by the presence of abnormal gallbladder function and chronic postprandial diarrhea responding to BASs [ 53 ].
Hepatobiliary nuclear scintigraphy using Tcm-DISIDA with cholecystokinin DISIDA with CCK injection has to be performed to estimate the gallbladder ejection fraction, in accordance with the standard calculation of gallbladder contraction 30 minutes after CCK injection, to establish the possible relationship of gallbladder dysfunction and chronic diarrhea.
However, the poor function of the gallbladder seems to be the common primary factor in this syndrome. However, up to now, its cost and the lack of an agreed standard cutoff have strongly limited its wider acceptance and availability in everyday clinical practice. More widespread use of the SeHCAT test should provide further information to help understand the pathophysiologic mechanisms underlying chronic diarrhea afflicting many different patients and ensure that they are offered a treatment that is selected on the basis of a reliable clinical test and not on simple empirical observations.
The authors declare that there is no conflict of interest regarding the publication of this paper. This is an open access article distributed under the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Article of the Year Award: Outstanding research contributions of , as selected by our Chief Editors. Read the winning articles. Journal overview. Special Issues. Academic Editor: Fabiana Zingone. Received 17 Apr Revised 24 Jul Accepted 29 Aug Published 26 Nov Abstract Bile acid malabsorption BAM causing chronic diarrhea may be due to organic as well as functional disorders, and some of them were included under the general label of diarrheic-type irritable bowel syndrome IBS-D.
Figure 1. Venn diagram of different causes of chronic diarrhea related to BAM.
0コメント