Intestinal Problems 1, 2 and 3 - Intestinal failure, pathology of small bowel, malabsoprtion Flashcards
What is intestinal failure?
The inability to maintain adequate nutrition or fluid status via the intestines - can result from a number of things such as obstruction, dysmotiltiy, surgical resection, congenital defect, or disease associated with loss of absorption and is characterised by the inability to maintain protein-energy, fluid, electrolyte, or micronutrient balance
How can IF be classified in terms of time frame?
Acute short term = days/ weeks/ months e.g. mucositis post chemotherapyChronic long term e.g. short gut syndrome
How many different types of IF are there?
3
What types of IF are classified as acute short term?
Types 1 and 2
What types of IF are classified as chronic long term?
Type 3
What is type I intestinal failure?
Self-limiting short term postoperative or paralytic ileus (usually on wards, sometimes HDU/ ITU)
What is type 2 intestinal failure?
Prolonged, associated with sepsis and metabolic complications. Often related to abdominal surgery with complications (mainly HDU/ ITU or wards)
What is type 3 intestinal failure?
Long term but stable - home parenteral nutrition often indicated (usually seen in wards to home)
How malnourished will a patient with type I intestinal failure be?
Normal/ moderately malnourished
Treatment of a patient with type I intestinal failure? (7)
Replace fluids, correct electrolytesParenteral nutrition if unable to tolerate food/ fluids for greater than or equal to 7 days post opAcid suppression: PPIOctreotide (reduces GI secretions)Alpha hydroxycholecalciferol to preserve MgIntensive multi-disciplinary inputAllow some diet/ enteral feeding
What does parenteral nutrition rely on?
Venous access e.g. PICC line, tunnelled catheter (central line), vascuport (portacaf) - US guided placement
Parenteral nutrition complications?
Nutrient toxicityLiver diseaseMetabolic disturbancePhyscho-social effectsInappropriate usageSepsisSVC thrombosisLine fractureLine leakageLine migrationMetabolic bone disease
How long do patients with type 2 IF usually have it for?
Weeks/ months
What type of feeding should patients with type 2 IF usually receive?
Parenteral +/- some enteral feeding
What are some examples of causes of type 2 intestinal failure?
Usually a surgical complication but can be due to crohns, coeliac disease, malignancy, ischaemia, radiation, etc.
What is the treatment of choice for patients with chronic IF? (type III)
Home parenteral nutrition
What is another 3 treatment options for patients with type 3 intestinal failure, apart from parenteral nutrition?
Intestinal transplantation (specific indications, long term survival lower than HPN)Bowel lengthening (not validated yet in adults)GLP2 (teduglutide) treatment for SBS
What are examples of conditions that can cause type 3 intestinal failure?
Short gut syndromeCrohns diseaseNeoplasiaVascularMechanicalRadiation enteritisDysmotiity
What length must the bowel be to be classified as short bowel syndrome?
Less than 200cm - insufficient length of small bowel to meet nutritional needs without artificial nutritional support
What length of bowel is indicative that the patient requires HPN for their short bowel syndrome?
Less than 50cm of small bowelAlthough patients usually need it before due to a poor quality of life e.g. 100cm of small bowel
Do patients who go on HPN usually get weaned off it eventually/
Very rarely - there are usually dependent for life
What is the advantages of intestinal transplantion compared to HPN?
Transplantation = survival 5 years = 50-60% and the patient requires a stoma, risk of immunosuppression but eatingHPN = 5 year survival 80% but not eating
What are the main indications of small bowel transplant compared to HPN?
Loss of venous accessLiver disease (usually combined with a liver transplant)Last resort
Do palliative patients tend to get sent home with HPN?
Not usually - look at individual cases
What are the 2 causes of ischaemia of the small bowel?
Mesenteric arterial occlusionNon occlusive perfusion insufficiency
What are the 2 causes of mesenteric arterial occlusion?
Mesenteric artery atherosclerosisThromboembolism from the heart e.g. A fib
What are 4 causes of non occlusive perfusion insufficiency?
ShockStrangulation obstructing venous return e.g. hernia adhesionDrugs e.g. cocaineHyperviscosity
Is bowel ischaemia usually acute or chronic?
Usually acute but can be chronic
What part of the small bowel is most sensitive to the effects of hypoxia?
The mucosa - most metabolically active part
In non-occlusive ischaemia, when does most of the tissue damage occur?
After reperfusion
How is acute ischaemia classified?
By degree of infarction caused - mucosal infarct, mural infarct or transmural infarct (depending on the length of time of the ischaemia)
What are the 3 types of outcomes of acute ischaemia depending on the length of time the ischaemia has been present for?
RegenerationStrictureGangrene
What type of outcome does mucosal infarct usually have?
Regeneration - mucosal integrity restored
What type of outcome does mural infarct have?
Repair and regeneration = fibrous stricture
What type of outcome does transmural infarct have?
Gangrene - patient death if not resected
Complications of ischaemia of the small bowel? (10)
FibrosisStrictureChronic ischaemiaMesenteric anginaObstructionGangrenePerforationPeritonitisSepsisDeath
What is Meckel’s diverticulum?
A tubular structures, 2 inches long, 2 foot above the IC valve in 2% of people due to incomplete regression of vital-intestinal duct (may contain heterotopic gastric mucosa)
Symptoms of a meckels diverticulum?
May cause bleeding, perforation or diverticulitis which mimics appendicitis - commonly asymptomatic, incidental finding
Are primary or secondary tumours of the small bowel more common?
secondary (metastases) - ovary, colon, stomach
What type of primary tumours of the small bowel are found? (3)
LymphomasCarcinoid tumoursCarcinomas
What are carcinoid tumours?
Slow growing neuroendocrine tumours - different to carcinomas which are epithelial
What type of lymphomas are found in the small bowel?
Non hodgkins (rare) e.g. maltomas (B-cell - mucosa-assocaited lymphoid tissue)Enteropathy associated t-cell lymphomas (associated with coeliac disease)
What type of bowel cancer is associated with coeliac disease?
T-cell lymphomas (also carcinoma of the small bowel)
How are lymphomas of the small bowel treated?
Surgery and chemotherapy
What is the commonest site of carcinoid tumours of the bowel?
Appendix
What is the appearance of carcinoid tumours?
Small, yellow, slow growing, local invasive
What symptoms do carcinoid tumours cause?
Intussusception, obstructionProduce hormone like substancesIf metastases to liver occur, a carcinoid syndrome occurs producing diarrhoea and flushing
What is carcinoma of the small bowel associated with?
Rare - Crohns disease and coeliac disease
What does carcinoma of the small bowel look like?
Identical to colorectal carcinoma in appearancePresents lateMetastases to lymph nodes and liver occur
What causes vomiting, abdominal pain, RIF tenderness and increased WCC?
Appendicitis
What causes acute appendicitis? (5)
UnknownFaecoliths (dehydration)Lymphoid hyperplasiaParasitesTumours (rare)
Pathology of acute appendicitis? (5)
Acute inflammation (neutrophils)Mucosal ulcerationSerosal congestion, exudate (yellow surface)Pus in lumenAcute inflammation must involve the muscle coat
Complications of appendicitis? (5)
PeritonitisRuptureAbscessFistulaSepsis and liver abscess
What causes coeliac disease?
An abnormal reaction to a constituent of what flour, gluten, which damages enterocytes and reduces absorptive capacity
What are 3 things that coeliac disease is strongly associated with?
HLA-B8Dermatitis herpetiformisChildhood diabetes
What is the component of gluten that is suspected to be the toxic agent that causes coeliac disease?
Gliadin - abnormal immune reaction to this in coeliacs
What mediates the immune reaction to gliadin in coeliac disease?
T-cell lymphocytes which exist within the small intestinal epithelium “intraepithelial lymphocytes”
What is the normal life span of an enterocyte?
About 72 hours
What causes the fat duodenal mucosa in coeliac disease?
Increasing loss of enterocytes due to intestinal epithelial lymphocyte mediate damage = loss of villous structure, loss of surface area and a reduction in absorption
What part of the bowel are legions worse in in coeliac disease?
Proximal bowel so duodenal biopsy is very sensitive - even if the bowel looks normal
What antibodies may be present in the serum = coeliac disease? (3)
Anti-TTGAnti-endomesialAnti-gliadin
Why do patients with coeliac disease sometimes get steatorrhoea?
Malabsorption of fats
Why do patients with coeliac disease sometimes get gallstones?
Reduced intestinal hormone production leads to reduced pancreatic secretion and bile flow (CCK) leading to gallstones
What are the effected of malabsorption caused by coeliac disease? (5)
Loss of weightAnaemiaAbdominal bloatingFailure to thriveVitamin deficiencies
Complicaitons of coeliac disease apart from malabsorption effects? (4)
T-cell lymphomas of GI tractIncreased risk of small bowel carcinomaGall stonesUlcerative-jejenoilitis
What is malabsorption?
Defective mucosal absorption - caused by defective luminal digestion, mucosal disease, structural disorders
What are 5 common causes of malabsorption?
Coeliac diseaseCrohns diseasePost infectionsBiliary obstructionCirrhosis
What are 5 uncommon causes of malabsorption?
Pancreatic cancerParasitesBacterial overgrowthDrugsShort bowel
What 2 questions should be asked when presented with someone who has malabsorption?
What is being malabsorbed? (protein, dat, carbohydrate, vitamins and minerals)What is this reason for this?
What are digestive causes of protein malabsorption? (4)
Partial or total gastrectomy = poor mixingExocrine pancreatic insufficiencyTrypsinogen deficiencyCongenital deficiency of intestinal enterokinase (produced in the duodenum)
What are absorptive causes of protein malabsorption?
Coeliac diseaseTropical sprueMethionine malabsorption syndrome and blue diaper syndromeShort bowel syndromeJejunoilial bypassHarasnup disease (defects in neutral AA transporters)Cystinuria I-IIIOculocerebral syndrome of lowe
What are fats delivered in post-absorption?
Lymphatics
What are digestive causes of fat malabsorption?
Less time to mix- gastric resection, autonomic neuropathy, amyloidosisDecrease in micelle formation - decreased bile acid synthesis/ secretion - cirrhosis, biliary obstruction, CCK deficiency, small intestinal bacterial overgrowthDecreased lipolysis - chronic pancreatitis, CF, pancreatic tumours, low luminal pH, excessive calcium ingestion, co-lipase deficiency
What are absorptive causes of fat malabsorption?
Decreased chylomicron formation and/ or mucosal absorption - coeliac disease, + other rarer causes
What are post-absorptive causes of fat malabsorption?
defective lymphatic transport - primary intestinal lymphangiectasia, lymphoma, whipple disease, trauma
What is a digestive cause of carbohydrate malabsorption?
Severe pancreatic insufficiency (alpha-amylase deficiency)
What is an absorptive cause of carbohydrate malabsorption?
Primary or acquired lactase deficiency: post-infecitohs lactase deficiency, coeliac disease, crohns disease, other deficiency
Causes of vitamin B12 malabsorption?
Atrophic gastritis (impaired peptin/ acid secretion)Deficiency of gastric intrinsic factorPancreatic insufficiencyIleal crohn disease/ resection
Cause of folic acid malabsorption?
Diseases affecting the proximal small bowel e.g. coeliac, whipple, tropical sprueAlcoholism
Causes of fat soluble vitamins malabsorption?
Anything that disrupts fat absorption will result in one/ more deficiency
Causes of calcium malabsorption?
Selective deficiency can occur with renal disease/ hyperparathyroidism, inborn defect in vitamin D receptorDisease that reduce intestinal surface area and/ or cause formation of insoluble calcium soaps with long chain fatty cards e.g. coeliac, bile acid deficiency
Cause of magnesium malabsorption?
Anything causing a reduced mucosal surface area and/ or luminal binding by malabsorbed fatty acids
What causes iron malabsorption?
Most often GI bleeding, or mucosal surface area decrease
What causes zinc malabsorption?
Acrodermatitis enteropathica
What causes copper malabsorption?
Menkes disease
What is the primary blood test for coeliac disease?
IgA anti-tissue transglutaminase test (biopsy confiramtive)
How is lactose malabsorption confirmed?
Lactose breath hydrogen testOral lactose intolerance test (treated with lactose free diet)
What is tropical sprue?
Tropical sprue is a malabsorptive disease of the small bowel, characterised by inflammation and villous flattening in the small intestine usually due to colonisation of the intestine by an infectious agent or alterations in the intestinal bacterial flora induced by exposure to another environmental agent
How is tropical sprue diagnosed?
Biopsy
How is tropical sprue treated?
TetracyclineFolic acid
What is whipple disease?
Whipple disease is a rare bacterial infection that most often affects your gastrointestinal system. Whipple disease interferes with normal digestion by impairing the breakdown of foods, such as fats and carbohydrates, and hampering your body’s ability to absorb nutrients.Whipple disease also can infect other organs, including your brain, heart, joints and eyes.It caused by infection by Tropheryma whipplei
How is whiles disease diagnosed?
Demonstration of T. while in involved tissue by microscopy
When do patients with Crohns disease get very severe malabsorption?
When they have extensive ill involvement, many resections, enterocolic fistulas and strictures causing small intestinal bacterial overgrowth
What is a risk factor for infection with the parasite Giardia lamblia?
Travel to areas where the water supply may be contaminated, swimming in ponds
Diagnosis of Giardia lamblia infection?
Stool examination for ova and parasites (3 separate stool samples increase the yield of positive examinations)
Treatment of Giardia lamblia?
Metronidzole for 1 week
Symptoms of small bowel bacterial overgrowth?
Diarrhoea, steatorrhoea, macrocytic aneamia (B12)
Causes of small bowel bacterial overgrowth?
Diverticula, fistulas and strictures related to Crohns disease, bypass surgeries functional stasus
Treatment of small bowel bacterial overgrowth?
Low cobalamin and high folate levelsAerobic and/ or anaerobic colonic-type bacteria in a jejunal aspirate Best established by a schilling test
Treatment of a small bowel bacterial overgrowth?
Surgical correction of an anatomical blind loopTetracyclines for 2-3 weeks
What causes easy bruising?
Vitamin C deficiency - scurvyVitamin K deficiency
What is acrodermatits enteropathica?
An autosomal recessive condition that causes impaired zinc uptake - premolar rash - need lifelong zinc supplements
