Phys · gastrointestinal
Malabsorption and Small Bowel Disease
Also known as malabsorption · coeliac disease · tropical sprue · Whipple disease · small intestinal bacterial overgrowth · bile salt malabsorption · short bowel syndrome · refractory coeliac disease · enteropathy-associated T-cell lymphoma · protein-losing enteropathy
Consultant-physician-depth guide to malabsorption and small bowel disease — the three-level pathophysiology (luminal maldigestion, mucosal absorption, and transport), the mucosal causes (coeliac disease with anti-tTG IgA and anti-endomysial serology, duodenal Marsh classification, gluten-free diet, refractory coeliac, dermatitis herpetiformis, and selective IgA deficiency), tropical sprue, Crohn disease, eosinophilic gastroenteritis, amyloidosis, and Whipple disease (Tropheryma whipplei), the digestive causes (chronic pancreatic exocrine insufficiency, bile salt malabsorption, and SIBO), the structural causes (short bowel syndrome, blind loop, fistula, strictures), and the structured investigation pathway (FBC anaemia type, albumin and alpha-1-antitrypsin clearance, coeliac serology, faecal calprotectin and elastase, SeHCAT, hydrogen breath test, OGD with biopsy, capsule endoscopy, CT or MR enterography). Structured for FRACP DWE and DCE preparation.
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Red flags
- Refractory coeliac disease or new symptoms in a treated coeliac patient — exclude enteropathy-associated T-cell lymphoma
- Microcytic iron deficiency anaemia from coeliac disease may be the sole presenting feature
- Selective IgA deficiency causes false-negative anti-tTG IgA — always check total serum IgA
- Whipple disease with neurological involvement — oculomasticatory myorhythmia is pathognomonic and demands prolonged CSF-penetrating antibiotics
- Short bowel syndrome with high-output stoma — dehydration and electrolyte disturbance can be rapidly fatal
Malabsorption and Small Bowel Disease
[1]Meet the patient
A 48-year-old woman is referred for fatigue and iron deficiency anaemia — haemoglobin ninety-two, MCV seventy-six, ferritin six. Her colonoscopy is normal, with no source of bleeding found. She has no gastrointestinal symptoms beyond mild bloating, but she has lost five kilograms over six months and her DEXA shows osteoporosis.[1]
The two questions that unlock her diagnosis are the two that unlock every malabsorption workup: what is the anaemia type? (microcytic means proximal small bowel, macrocytic means terminal ileum or diffuse mucosa), and where in the three-level pathway is the defect? (luminal, mucosal, or transport). Iron deficiency without bleeding is coeliac disease until proven otherwise — test the serology and the total IgA before you reach for the scope.[1]
References10ShowHide
- [1]Ludvigsson JF, Bai JC, Biagi F, et al. Diagnosis and management of adult coeliac disease: guidelines from the British Society of Gastroenterology Gut, 2014.PMID 24917550
- [2]Rubio-Tapia A, Hill ID, Kelly CP, et al. ACG clinical guidelines: diagnosis and management of celiac disease Am J Gastroenterol, 2013.PMID 23609613
- [3]Malamut G, Cellier C Refractory Celiac Disease Gastroenterol Clin North Am, 2019.PMID 30711206
- [4]Delabie J, Holte H, Vose JM, et al. Enteropathy-associated T-cell lymphoma: clinical and histological findings from the international peripheral T-cell lymphoma project Blood, 2011.PMID 21566094
- [5]Schneider T, Moos V, Loddenkemper C, et al. Whipple's disease: new aspects of pathogenesis and treatment Lancet Infect Dis, 2008.PMID 18291339
- [6]Bures J, Cyrany J, Kohoutova D, et al. Small intestinal bacterial overgrowth syndrome World J Gastroenterol, 2010.PMID 20572300
- [7]Walters JR, Pattni SS Managing bile acid diarrhoea Ther Adv Gastroenterol, 2010.PMID 21180614
- [8]Jeppesen PB, Gilroy R, Pertkiewicz M, et al. Randomised placebo-controlled trial of teduglutide in reducing parenteral nutrition and/or intravenous fluid requirements in patients with short bowel syndrome Gut, 2011.PMID 21317170
- [9]Jeppesen PB Pharmacologic options for intestinal rehabilitation in patients with short bowel syndrome JPEN J Parenter Enteral Nutr, 2014.PMID 24615689
- [10]Pimentel M, Lembo A, Chey WD, et al. Rifaximin therapy for patients with irritable bowel syndrome without constipation N Engl J Med, 2011.PMID 21208106