Lower GI Tract Flashcards
Difference between malabsorption and maldigestion vs malassimilation
Defective mucosal uptake and transport of adequately digested nutrients vs impaired breakdown of nutrients(mainly in the small intestine), lumenal phase (eg pancreatic insufficiency).
Malassimilation refers to both
What is Zollinger- Elison syndrome
When tumours overproduce gastrin and therefore gastric acid, affecting functions of enzymes
What problems can affect fat solubilization
Decreased bile salts due to cholestasis or cirrhosis
Bile salt loss due to resection of ileum
Bile salt deconjugation due to bacterial overgrowth
What can affect Lumenal availability of nutrients and what nutrient in particular
- Bacterial consumption of nutrients (bacterial overgrowth) ⇒ B12 deficiency
- Decreased intrinsic factor (pernicious anaemia) ⇒ B12 deficiency
What are common causes of distruption of epithelial transport?
Damaged absorptive surface due to inflammatory diseases like coeliac’s or tropical sprue, Crohn’s. Or ischaemia
Infections like Giardia or SIBO
Lymphoma or amyloid infiltration
What is a post- mucosal cause of malabsorption
Problem with post-absorptive processing eg. lymphatic obstruction which affects fat transport. Neoplasms, TB and lymphangectasia are examples.
What are the clinical features of malabsorption
- Diarrhoea and weight loss despite adequate intake
- Bloating, tense abdomen, distention, cramps, borborygmi ⇒ Abnormal fermentation of nutrients by bacteria in colon
- Lethargy, malaise
- Symptoms often mild, non-specific
- Malabsorption can be global, or specific nutrients
- Malabsorption syndrome
What is malabsorption syndrome
steatorrhoea, distention, weight loss, oedema is a RARE presentation
What is a symptom of vascular insufficiency in gut
ntestinal angina
–Abdominal pain after a meal due to vascular insufficiency in gut ( which can also cause malabsorption)
What is one genetic disease that can cause malabsorption
Cystic fibrosis
What skin condition is associated with Coeliac’s
Dermatitis hepertiformis
What are the neurological symptoms of B12 deficiency
- Peripheral neuropathy
- Ataxia (posterior column) ⇒ Spinal cord damage
- Psychosis, dementia
What does microcytosis in malabsorption suggest
iron deficiency (common in coeliac, otherwise suspect GI blood loss)
What does macrocytosis in malabsorption suggest
B12 and folate deficiency( due to malabsorption??), but also common in coeliac, alcohol
What does elevated ALP in malabsorption suggest
Signs of metabolic bone disease, due to Vit D malabsorption
What are the tests for the three most commonest causes of malabsorption
- Tissue Transglutaminase (TTG) ⇒ Antibody test Coeliac disease
- Faecal elastase ⇒ Enzyme measurement in stools for Pancreatic enzyme insufficiency
- Glucose H2 breath test ⇒ SIBO
How to test for IBD
Faecal calprotectin
How to test for Bile acid malabsorption
7alpha-cholestenone or SeHCAT test ( for retention)
How to test for lactase deficiency
Lactose H2 breath test
causes of strictures in small bowel and what imaging is done for it
MRI ⇒ May find strictures which could be ischaemic, Crohn’s, Neoplastic, TB etc.
use of CT/ CT angiogram in lower GI
pancreatic disease, mesenteric ischaemia
What are causes of PEI
Chronic pancreatitis => alcohol is most common cause
May be autoimmune
Duct obstruction
Cystic fibrosis that causes thick sticky mucus that clogs the pancreatic ducts
SLE
Autoimmune pancreatitis
- Haemochromatosis ⇒ Rare- abnormal iron deposition in liver and pancreas
- Pancreatic resection ⇒ For cancer or pancreatitis
- Gastric resection ⇒ Can cause changes in acidity and impair enzyme function