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Bowel disorders
Published in Henry J. Woodford, Essential Geriatrics, 2022
Normally up to 95% of bile salts are reabsorbed by the enterohepatic circulation. Reduced absorption can lead to bile acid diarrhoea. The risk is increased after cholecystectomy. Selenium homocholic acid taurine (SeHCAT) testing is the most commonly used investigation.24 Retention of a radio-labelled substrate is measured after seven days. Low retention suggests bile salt malabsorption. Treatment is through a low-fat diet and a trial of a bile acid sequestrant (e.g. colestyramine).
Nuclear Medicine Imaging and Therapy
Published in Debbie Peet, Emma Chung, Practical Medical Physics, 2021
David Towey, Lisa Rowley, Debbie Peet
Bile acid malabsorption is a chronic condition that affects a patient’s digestive system. The process can be measured using a SeHCAT study. SeHCAT (23-seleno-25-homotaurocholic acid, selenium homocholic acid taurine, or tauroselcholic acid) is a drug used to diagnose bile acid malabsorption. The patient is given a low activity 75Se capsule to swallow. The capsule is broken down in the digestive system, and the radiopharmaceutical is actively absorbed by the intestines and re-excreted by the bile duct. Over 7 days, the pharmaceutical is expected to pass around this loop around 35 times, and if malabsorption is present, the level of SeHCAT within the patient will reduce considerably. The amount of SeHCAT in the patient is measured at 4 hours post-administration and again 1 week later.
Irritable Bowel Syndrome
Published in Peter Sagar, Andrew G. Hill, Charles H. Knowles, Stefan Post, Willem A. Bemelman, Patricia L. Roberts, Susan Galandiuk, John R.T. Monson, Michael R.B. Keighley, Norman S. Williams, Keighley & Williams’ Surgery of the Anus, Rectum and Colon, 2019
Recent evidence indicates that about 28% of patients with IBS-D may have bile acid diarrhoea (BAD).31 The most common cause of BAD is believed to be overproduction of bile acids, leading to a larger than normal pool of bile acids that saturate the transport capacity for bile acids in the distal ileum and leads to increased spill-over of bile acids to the colon. An increased amount of bile acids in the colon will stimulate electrolyte and water secretion and give rise to diarrhoea. The loss of bile acids can be measured using a radiolabelled synthetic bile acid 75Se-homocholic acid-taurine (SeHCAT). The measured entity with the SeHCAT-test is whole body retention of the tracer after seven days. Retention of <10% indicates significant loss of bile acids to faeces. The exact fraction of tracer that should remain after normal losses of bile acids is somewhat controversial, but >15% is often considered normal. Newer methods for assessment of bile acid diarrhoea include measurements of the serum level of 7α-hydroxy-4-cholesten-3-one, which reflects the rate of bile acid synthesis, and the serum level of the protein-hormone fibroblast growth factor 19 (FGF19), which is secreted by enterocytes of the small bowel for the control of bile acid synthesis in the liver.
The era of lenalidomide maintenance therapy in multiple myeloma: settings for achieving best outcomes
Published in Expert Review of Clinical Pharmacology, 2022
Meghana Kesireddy, Sarah A. Holstein
Long-term therapy with lenalidomide can cause bile-salt malabsorption leading to severe episodes of diarrhea (due to increased accumulation of bile acids in the small bowel) as well as urgency and cramping. In a case series of 12 patients, the median number of months of lenalidomide exposure before diarrhea onset was 6 months (range 1–15 months) [52]. While a formal diagnosis can be made using selenium homocholic acid taurine (SeHCAT) scanning, a trial of a bile acid binder such as colestipol or colesevelam can provide rapid benefit if lenalidomide-induced bile salt malabsorption is the cause of the diarrhea. In the case series, following official diagnosis of bile acid malabsorption, 50% of patients reported normalization of their bowel habits after initiating colesevelam while others reported a decrease in stool frequency and/or improvement in stool consistency. In addition, none of the patients required dose reduction or discontinuation of lenalidomide due to diarrhea [52]. Two patients had resolution of diarrhea after reduced dietary fat intake (to 20% of total calories).
Colesevelam – a bile acid sequestrant for treating hypercholesterolemia and improving hyperglycemia
Published in Expert Opinion on Pharmacotherapy, 2022
Oluwayemisi Esan, Adie Viljoen, Anthony S. Wierzbicki
Sclerosing cholangitis (primary biliary cirrhosis) [88] or cirrhotic liver disease are associated with hypercholesterolemia and a higher CVD risk. The BA binding properties of BAS are useful for management of pruritus and hyperlipidemia for these indications and in bile salt malabsorption syndromes [89,90]. A formal trial is proposed in 50 adults with bile acid malabsorption (BAM) [91]. Patients will be randomized to either treatment with the BAS colesevelam or the GLP-1 agonist liraglutide for 6 weeks with a primary endpoint of change in daily stool frequency. Secondary endpoints include changes in 75selenium-homotaurocholic acid test (SeHCAT) scans, fecal bile acid content and gut microbiome composition.
Clinical evaluation and treatment of chronic bowel symptoms following cancer in the colon and pelvic organs
Published in Acta Oncologica, 2019
Helene Mathilde Larsen, Mette Borre, Peter Christensen, Asbjørn Mohr Drewes, Søren Laurberg, Klaus Krogh, Janne Fassov
Bile acid malabsorption was treated with cholestyramine. If this was without effect or poorly tolerated, colesevelam was given. One patient not responding to cholestyramine and colesevelam was treated with colestipol. A few of the first patients seen in our clinic (n = 6) were treated with bile acid sequestrants empirically without a prior SeHCAT scan.