Common GI Tract disorders Flashcards
What is Diarrhoea?
- Defined as passage of >200g faeces per day
- Increases in faecal mass of 500 – 1000g /day require attention
- Needs to be more severe to result in dehydration
What are the results of Diarrhoea physiologically?
- Lower GI losses results in loss of bicarbonate - metabolic acidosis
- Dehydration - increased Urea
- Electrolyte disturbances – especially decreased K+ and Mg2+, decreased HCO3
What are the different types of Diarrhoea?
- Osmotic: Due to solution of high osmotic potential, generally salt or sugar. Water is drawn from the body to equilibrate the chyme. Can also be due to malabsorption
- Secretory: Increased secretion or reduced absorption of water and ions e.g. enterotoxins (such as cholera) open membrane channels leading to export of water, Na, K and HCO3 into the intestine
- Inflammatory: Damage to intestinal mucosa e.g Ulcerative Colitis/Crohn’s disease or infective e.g Shigella (Dysentary)
What results from Vomiting physiologically?
One of the most common causes is gastroenteritis leading to upper GI losses
- Loss of acid – increased bicarbonate
- Decreased chloride - metabolic alkalosis
- Dehydration can result in low K (2°Hyperaldosteronism)
What can causes Upper GI bleeds?
- Peptic ulcer
- Oesophageal varices
- Gastric erosions
- Gastric cancer (rarely )
What is the results of Upper GI bleeds physiologically?
- Red blood cells released and reabsorbed
- Increased potassium (from intracellular release)
- Increased urea from protein metabolism
- Raised urea:creatinine ratio
What is Irritable Bowel Syndrome?
- Bowel disorder with no detectable organic cause
- Signs and symptoms include cramping, abdominal pain, bloating, gas and diarrhoea or constipation
- Does not cause changes to the bowel tissue, does not increase risk of colorectal cancer
- Diagnosis of exclusion
What is Inflammatory Bowel Disease?
- Similar symptoms to IBS
- Caused by chronic inflammation of the digestive tract
- Crohn’s Disease and Ulcerative colitis
What are features of Crohns Disease?
- Age of onset between 15-35 years of age
- Symptoms: Abdominal pain, Diarrhoea, Weight Loss and Fatigue, Bloody stool, malnutrition
- Can affect any part of GI tract from mouth to anus
- Most commonly starts in terminal ileum
What are features of Ulcerative Colitis?
- Age of onset between 15-35 years of age
- Symptoms: Stool Urgency, Fatigue, Increased Bowel Movements, Mucous In Stools, Nocturnal Bowel Movements, Abdominal pain
- Restricted to colon and rectum
What are some biochemical tests for Inflammatory Bowel Disease?
- Faecal calprotectin identifies patients who require colonoscopy
- CRP/ESR can give an indication of the level of inflammation
- Nutritional assessment
What is Coeliac Disease?
Gluten sensitive enteropathy
- Wheat protein contains gliadin. Gliadin metabolised by tissue transglutaminase
- In Coeliac disease, an autoimmune reaction happens. Upon exposure to Gliadin, there is an immunological response to Tissue transglutaminase.
How is Coeliac Disease screened?
- Screened by ELISA (TTG)
- Histology to confirm
How is Bowel Cancer screened biochemically?
- National screening programme for men and women aged 60 to 74
- Offered test ever 2 years
- Uses Faecal Immunochemical Test (FIT)
- Detects small amounts of faecal occult blood
What is intestinal failure?
- Defined as intestinal failure when the ability of intestine to absorb fluids and nutrients threaten’s the health of patient
- Intestines have considerable reserve capacity
- Maybe short term while awaiting surgery on the small intestine
What are the types of Pancreatitis?
Acute
- Abdo pain, nausea & vomiting
- At worst can lead to multi-organ failure!
- Amylase, Lipase & CRP
- U&E, LFT, Calcium, Blood gases
Chronic
- Follows acute
- Most commonly due to alcohol (in UK)
- Faecal elastase
Hereditary
What is Pancreatic Insufficiency, lab tests and the treatment?
- Usually due to long term damage to organ
- Lab Tests
- Faecal enzymes (e.g elastase)
- Treatment
- Supplementation (Creon- protease, amylase, lipase)
- Insulin (for DM)
What are complications of Pancreatic Insufficiency?
- Malabsorption
- Malnutrition
- Vitamin deficiencies
- Weight loss
- Fatty stools (steatorrhoea)
- Diabetes
What are the types of patterns demostrated in Liver Function Tests?
Hepatocellular pattern:
- Disproportionate elevation in the serum aminotransferases compared with the alkaline phosphatase
- Serum bilirubin may be elevated
- Tests of synthetic function may be abnormal
Cholestatic pattern:
- Disproportionate elevation in the alkaline phosphatase compared with the serum aminotransferases
- Serum bilirubin may be elevated
- Tests of synthetic function may be abnormal
Isolated hyperbilirubinemia
- Elevated bilirubin level with normal serum aminotransferases and alkaline phosphatase
What are causes of Cholestasis?
Obstruction of bile flow
- Pregnancy
- Gallstones
- Pancreatic carcinoma
Non-obstructive causes
- Drug induced- e.g ampicillin/erythromycin
- Inherited
- Primary Biliary Cirrhosis, Primary SclerosingCholangitis – inflammatory conditions
- Total Parenteral Nutrition
What is Acute Hepatitis?
- Damage to hepatocyte characterised biochemically by short term increased in transaminases and then rising bilirubin as excretory capacity if reached
- Usually caused by viral infection (Hep A, B, C, D and E, EBV, CMV) or toxins (e.g. alcohol, drugs)
- Great variation in severity and time course
What is Chronic Hepatitis?
- >6 months of Hepatitis
- Autoimmune, Hep B and C and alcohol very commonx
What are features of Autoimmune Hepatitis?
Autoimmune hepatitis:
- Onset ~45yrs
- Association with other autoimmune diseases
- More common in women
- Antinuclear and anti smooth muscle antibodies often very high
- Raised IgG
What are Gallstones formed from?
- 80% Mainly comprised of cholesterol
- 20% ‘pigment stones’ of calcium bilirubinate/polymers containing calcium & copper
What is Cholecystitis?
Cholecystitis is inflammation of the gall bladder
What is Cholagitis and how does it present?
- Inflammation of common bile duct (usually infection e.g bacterial but can occur due to roundworm/fluke)
- Typical presentation: ‘Charcot’s triad’; 1:fever/chills/rigor, 2:upper right quadrant pain & 3:jaundice’
- Biliary obstruction which can be complete or intermittent
- Mixed hepatocellular & cholestatic picture
What are biochemical features Primary Sclerosing Cholangitis?
- 60+% cases are pANCA Ab +ve
Strongly associated with IBD (85%UC, 15% Crohn’s)
What is Steatosis?
- In certain metabolic conditions and alcoholism, fat is laid down in the liver. This leads to an inflammatory response
- Collagen deposition occurs and this leads to cirrhosis in 10-30% of patients within 10 years (NASH)
What are some features of Liver and Pancreatic Cancers?
Symptoms: Weight loss, Painless jaundice
- Liver (& bone) carcinoma often secondary due to metastases
- Endocrine tumours of pancreas such as insulinoma, glucagonoma, VIPoma
- Hepatocellular carcinoma
What is Cirrhosis?
- Late stage of scarring of liver
- End stage liver failure
