Nutrition Disorders: Malabsorption Flashcards
What is malabsorption?
- a disorder that occurs when people are unable to absorb nutrients from their diets
- this can contribute to clinical outcomes
Does malabsorption take place predominantly with macro or micro nutrients?
- can be both
- can be one specific macro or micro nutrient or everything
What part fo the GIT does the majority of absorption take place?
- small intesintes
- duodenum, jejunem and ileum
Is malabsorption long or short term?
- can be both
- short term = coeliacs flair up
- long term = bowel resection
Where in the pancreas do endocrine secretions come from?
- islets of langerhans (generally in tail of pancreas)
- insulin and glucagon secreted directly into blood
Where in the pancreas do exocrine secretions come from?
- acinar cells (generally in the head of the pancreas)
- pancreatic enzymes and juice are secreted
Malabsorption can be caused by a number of factors. Alterations to secretions in the GIT is one of these, what can happen if enzyme secretions into the GIT are low?
- low enzyme secretion
- a-amylase = low carbohydrates digestion
- pancreatic lipase = low fat digestion
- proteolytic enzymes = low protein digestion
Malabsorption can be caused by a number of factors. Alterations to secretions in the GIT is one of these, what can happen if there are intraluminal (GIT fluid secretions) factors?
- low gastric or pancreartic juice secreted
- enzymes work at specific pHs
- high pH in duodenum due to low acid called achlorhydria
- low pH in duodenum causing Zollinger - Ellinson syndrome.
Malabsorption can be caused by a number of factors. Alterations to secretions in the GIT is one of these, what can happen if there are bile salt deficiencies causes by liver disease?
- lack of fat digestion
What are the 4 main causes of malabsorption?
1 - alterations to gastric secretions.
2 - alterations in gastric structure/absorptive capacity.
3 - alteration in gastric motility.
4 - reduction in blood flow
What is autosomal recessive disease?
- autosomal = non sex chromosomes
- 2 copies of abnormal gene are required to cause disease
Cystic fibrosis is an autosomal recessive disease. What can this do to the GIT?
- blockage of ducts of pancreas due primarily to low Cl-
- can then cause high Na+ and H2O in cells
- causes thick pancreatic juice that blocks pancreatic ducts
In a patient with cystic fibrosis, what are some of the nutritional considerations?
- low energy intake
- impaired nutrient absorption (fat, proteins and carbs)
- low fat soluble vitamin absorption (ADEK)
How can bowel resection contribute towards malabsorption?
- reduced absorbative capcity
- reduced secretions into the GIT
How can bowel inflammation contribute towards malabsorption?
- GIT walls are damaged and inflammed (IBS and pancreatitis)
- secretions and absorption are low
What is coeliac disease?
- immune system disease
- immune system attacks GIT wall when gluten is eaten
- malabsorption can occur
In coeliac disease the GIT walls are damaged when the immune system attacks the walls when gluten is eaten? What does this do this do to the villi and cause as a secondary effect?
- causes villous atrophy
- nutrients can not be absorbed
Coeliac disease is an auto immune disease that damages the GIT, specifically causing villous atrophy. How can this be treated?
- remove gluten from the diet
In coeliac disease which mineral is specifically important to monitor?
- calcium
What is inflammatory bowel disease (IBD), and what are the 2 main diseases of IBD?
- chronic inflammation of the GIT
- crohn’s disease and ulcerative colitis
Inflammatory bowel disease is a chronic condition characterised by inflammation of the mucosal surface. What are the common symptoms of IBD?
- reduced quality of life
- abdominal pain, diarrhoea with and without blood and mucus
- urgency and tenesmus (needing to go but no stool)
- weight loss
- fatigue
In inflammatory bowel disease they are often advised to take a routine multivitamin, why is this?
- vitamin and mineral deficiencies are common
- minerals iron, zinc, copper, beta carotene and folate
- vitamins B12, B6, E,C,D
In inflammatory bowel disease parts of the inflammaed bowel can be removed. If an ileal resection or bacterial overgrowth occurs in Crohns disease, what vitamin and nutrient deficiency can this cause?
- B12 and lactase deficiency
In inflammatory bowel disease osteoperosis is common, why?
- low calcium absorption
- low activity levels due disease
Microcytic anaemia is caused by iron deficiency. This can be caused by a low intake, but is more likely to be due to malabsorption. How can inflammatory bowel disease contribute to microcytic anaemia and normacytic anaemia?
- microcytic anaemia = inflammed GIT causing low absorption
- normocytic anaemia = chronic internal blood loss
Gastric ressection can be performed for a number of reasons. What are the most common impairments that may occur?
- impaired motility
- reduced secretion of a intrinsic factor, enzymes and HCl
- rapid gastric emptying (‘dumping’)
What is intestinal failure?
- term used to describe a variety of diseases or injuries to the small intestine that can result in surgery and resections
- impair ability to absorb adequate nutrients and water
- patients eat but do not absorb causing malnourisment and dehydration
If a patient has a large bowel resection, which is responsible for the reabsorption of H2O and electrolytes, what can happen?
- diarrhoea as H2O is not absorbed
- vitamin B12 and biles acids can be affected
If a patient has a large bowel resection, this can reduce the reabsorption of H2O and electrolytes. Is this permanent or can the body adapt?
- 6-8 weeks following surgery ileum appears to adapt and losses decrease but still remain at ~400-600mls per day
What is dumping syndrome?
- impaired gastric motility
- symptoms where food leaves the stomach too quickly
Dumping syndrome is a symptom where food leaves th stomach too quickly and enters the duodenum. What can this cause in the duodenum?
- chyme is not adequately prepared to allow efficient absorption
- malabsorption of fluids and nutients occurs
Dumping syndrome can be classified as early or late dumping, what are these?
1 - early dumping = occurs soon after eating
- causes sweating, dizziness, faintness, rapid weak pulse and hypotension
2 - late dumping = prolonged
- causes weakness, cold, faintness and sweating ~2 hours after a meal
How can impaired blood flow cause malabsorption?
- impaired transport mechanisms
- impaired fat transport e.g. congenital lymphangiectasia.
- impaired monosaccharide transport e.g. congenital primary malabsorption of glucose and galactose
- vascular disease
If pancreatic disease is present, for whatever cause, what can happen to a patient?
- endocrine insufficiency
- exocrine insufficiency (fats and vitamin D are big concerns)
Pancreatic disease can cause exocrine insufficiency. Patients are prescribed enzymes such as creon, when mjust these prescriptions be taken?
- with meals
What are the key diagnostic criteria that can all be used or used in isolation for malabsorption?
- diarrhoea or change in stool consistency (MAIN ONE)
- abdominal distension (MAIN ONE)
- fatulence or wind (MAIN ONE)
- loss of weight in adults or growth failure in children
- hypoproteinaemia (low serum albumin / prealbumin)
- iron deficiency anaemia or low serum ferritin
What is steatorrhea?
- increased fat content in stools
- a clinical features of fat malabsorption
- also common in exocrine pancreatic insufficiency (EPI), celiac disease, and tropical sprue
Why can fat malabsorption be a big cause of energy intake?
- fats have highest calories/gram so big loss in energy intake
How can fat malabsorption be accentuated by low fat products?
- patients are scared of having steatorrhea
- they swithc to low fat products to avoid this
- this further accentuates fat malabsorption
In patients with fat malabsorption what are treatment options?
- increase calorie intake
- multivitamin supplement (specifically fat soluble)
What is the most common cause of carbohydrate malabsorption?
- lactose malabsorption
- patients may lack the lactase enzyme
- unable to digest lactose into galactose and glucose
What carbohydrate malabsorption, specifically lactase deficiency cause?
- lactose remains in the GIT causing osmotic diarrhoea.
- bacteria ferment lactose resulting in symptoms such as abdominal distension, flatulence and explosive watery diarrhoea
There are a lot of common nutritional deficiencies in the UK that results from malabsorption. What are 2 of the most common causes of malabsorption?
1 - disease of the GIT
2 - ressection of the GIT
- both cause can chronic diarrhoea and / or self imposed dietary restriction
There are a lot of common nutritional deficiencies in the UK that results from malabsorption. What are older and young children specifically at risk of following acute episodes of diarrhoea?
- dehydration with loss of fluid and electrolytes
There are a lot of common nutritional deficiencies in the UK that results from malabsorption. What patients with alcoholic liver disease specifically at risk of?
– thiamine (B1) deficiency
- vitamin D deficiency
There are a lot of common nutritional deficiencies in the UK that results from malabsorption. What are patients with inflammatory bowel disease specifically at risk of?
- iron, B12, vitamin D, vitamin K, folic acid, selenium, zinc, vitamin B6, and vitamin B1 deficiencies
