by kuc


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Where are iron, folate, and calcium all absorbed?
Proximal small intestine
Where is B12 absorbed?
Terminal ileum
What is the purpose of a GI barium study?
Visualise the GI mucosa
What are the common breath tests? [2]
Lactose-hydrogen BT (lactose intolerance), glucose-hydrogen BT (bacterial overgrowth)
What is an SeHCAT scan?
Selenium-75-homocholic acid taurine - nuclear medicine scan which assesses bile salt malabsorption
How is an SeHCAT scan carried out?
Radiolabelled bile salts are ingested, then scanned at 3h and 7 days. <15% at 7 days suggests bile acid malabsorption
Describe 3-day faecal fat collection
Patient given high fat diet. All stool is sampled over 3 days. > 18mm/day faecal fat suggests fat malabsorption or bile salt malabsorption
When is faecal elastase reduced? [2]
Chronic pancreatitis, pancreatic insufficiency
What is the purpose of a pancreolauryl test?
Assess pancreatic exocrine function.
Malabsorption - Common causes [3]
Coeliac disease, chronic pancreatitis, Crohn\\\'s disease
Name some rarer causes of malabsorption [8]
Decreased bile, pancreatic cancer, CF, Whipple\\\'s disease, tropical sprue, bacterial overgrowth, short bowel syndrome, drugs (metformin, neomycin, alcohol)
Malabsorption - Si [3]
Anaemia, oedema, hypovitaminosis
Malabsorption - Sy [3]
Diarrhoea, steatorrhoea, weight loss
Malabsorption - Bloods
High or low MCV, low Ca2+, low Fe, low B12/folate, ^INR
Malabsorption - Stool [2]
Sudan stain for fat globules; stool microscopy for infestation
Malabsorption - Ix
Bloods, stool, barium follow-through, breath hydrogen analysis, endoscopy + small bowel Bx, ERCP.
Malabsorption - functional testing [5]
24h faecal fat, faecal elastase, urinary D-xylose, 24h urinary protein (if low albumin), gut hormones
Coeliac disease - P
Gluten sensitivity leading to small intestinal enteropathy
Coeliac disease - Age distribution
Affects all ages, peak in 30s
Coeliac disease - Sy
Lethargy, weakness, diarrhoea, sub-fertility, weight loss
Coeliac disease - Si
Anaemia
Coeliac disease - diagostic tests
OGD + intestinal Bx (subtotal villous atrophy), coeliac antibodies (to gliadin, endomysium, and tTG)
Coeliac disease - malabsorption tests
FBC, iron, B12, folate, albumin, calcium
Coeliac disease - Rx
Lifelong gluten exclusion
Coeliac disease - Cx [4]
Small intestinal lymphoma/adenocarcinoma, osteopenia, dermatitis herpetiformis, hyposplenism
Achalasia - Definition
Motor disorder of oesophagus with aperistalsis and failure of lower oesophageal sphincter relaxation on swallowing
Achalasia - Pathophysiology
Degeneration of ganglionic cells of myenteric plexus disrupts peristaltic coordination. Cause is unknown. Trypanosoma cruzi infection in S. America produces similar syndrome.
Achalasia - Risk factors
Rarely associated with alacrimation and Addison\\\'s disease (Triple A syndrome)
Achalasia - Epi
Annual UK incidence is 1 in 100,000. All ages, but rare in children.
Achalasia - S
Intermittent dysphagia with solids and liquids, nocturnal regurgitation, cramping/retrosternal chest pain, weight loss
Achalasia - Ix
CXR (dilated oesophagus), barium swallow (beak-shaped, aperistalsis), manometry (sphincter resting pressure > 30mmHg), oesophagoscopy (exclude melignancy), blood (exclude Chagas\\\')
Achalasia - Rx [4]
Nifedipine, verapamil, or isosorbide mononitrate as needed; botulinum injection; endoscopic balloon dilatation of LOS; Heller\\\'s cardiomyotomy of LOS
Achalasia - Cx [4]
5% risk of malignancy. Aspiration pneumonia, malnutrition, weight loss.
Achalasia - Px
Good if treated
Carcinoid syndrome - Definition
Syndrome caused by systemic release of hormones from carcinoid (neuroendocrine) tumours
Carcinoid syndrome - Ae
Carcinoid tumours are slow-growing neuroendocrine tumours which secreting hormones such as 5-HT and also histamine, prostaglandins, bradykinin, and peptide hormones. Classic sites are appendix and small bowel.
Carcinoid syndrome - Risk factors
In 10 % of MEN type 1 patients
Carcinoid syndrome - Epi
Rare (annual UK incidence 1 in 1,000,000), Asymptomatic tumours are common.
Carcinoid syndrome - S +S [7]
Paroxysmal flushing, diarrhoea, abdominal cramp, ^gut motility, wheeze, sweating, palpatations
Carcinoid syndrome - Examination
Facial flushing, telangiectasia, wheeze. Right sided heart murmurs. Carcinoid crisis (tachycardia, hypotension)
Carcinoid syndrome - Ix
24h urine (5-HIAA levels), blood (^chromogranin B, fasting gut hormones), CT/MRI, radioisotope scan, investigate MEN-1
Carcinoid syndrome - Rx
Lifestyle: avoid alcohol, spicy food, strenuous exercise; Chronic: somatostatin analogue (e.g. octreotide); Supportive: ondansetron and cyproheptadine, rehydration, antiemetics, antidiarrhoea; Surgical resection
Carcinoid syndrome - Cx [4]
Electrolyte imbalance (2ary to diarrhoea), metastases, fibrosis of gut, tricuspid/pulmonary valve stenosis (RHF)
Carcinoid syndrome - Px
Mean survival 5 - 10 years
Coeliac disease - Ae
Sensitivity caused by gliadin component of gluten, triggering an immunological response in small intestine, causing mucosal damage and loss of villi
Coeliac disease - Risk factors
10 % of first-degree relatives affected. Associated with dermatitis herpetiformis. Genetic susceptibility with HLA-B8, DR3, and DQW2 haplotypes
Coeliac disease - Epi
Prevelance in UK is 1 in 2000, very rare in East Asia
Coeliac disease - S+S
May be asymptmatic. Abdominal pain and distention, steatorrhoea, diarrhoea. May be malaise, amenorrhoea, or failure to thrive
Coeliac disease - Examination
Signs of anaemia, malnutrition, and vitamin/mineral deficiency, itchy blisters of dermatitis herpetiformis
Coeliac disease - Ix [5]
Bloods, Stool (culture, faecal fat), D-xylose test, serology (IgA antigliadin, immunoglobulins), endoscopy
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