34) Consequences of fluid loss from the GI tract Flashcards
What is hypovolaemia?
- Loss of blood volume
What is total body water balance?
- Water taken in = water excreted/lost
What are the sites of water loss?
- Skin
- Respiratory passage
- GI tract
- Urinary tract
- Menstrual flow
- Trauma
How is there a total balance of sodium chloride?
- The amount taken in is the same as the amount lost/excreted
How is NaCl taken in?
- In food
How is NaCl lost?
- Sweat
- Faeces
- Urine
How is water and NaCl excretion altered?
- Kidneys alter excretion to match gain with loss
How is water lost from the body?
- Defecatuion/ diarrhoea
- Vomiting
- Urination
- Ventilation
- Sweating
- Mensturation
How is water gained in the body?
- Drinking
- Metabolism
What is diarrhoea?
- Increased frequency of faeces where there is an increase in volume and fluidity
- There is a change in bowel movement
Why does diarrhoea occur?
- Failure of water absorption
- Increased secretion of water
What causes decreased absorption in the body?
- There is an increased number of osmotic particles leading to osmotic diarrhoea
- There is an increased rate of flow of intestinal contents (deranged motility diarrhoea)
- Abnormal increase in secretion of GI tract (secretory diarrhoea)
What is osmotic diarrhoea?
- Can be caused by decreased absorption of electrolytes and nutrients
- Can also be caused by disaccharidase deficiency or disaccharide malabsorption leading to the person feeling bloated, nausea and watery diarrhoea
What is secretory diarrhoea?
- ACh and other substances can act via increased concentration of Ca2+ to increase the rate of intestinal secretions
- Excessive use of laxatives and some infections can also cause secretory diarrhoea as they work through secondary systems where they increase cAMP causing increased Na+, Cl- and water loss
How to treat bacteria?
- Use water, electrolytes and glucose
What is travellers diarrhoea?
- When tourists who are not used to the place they visit may eat street food and other foods which may not be clean
- It is through these methods that they ingest bacteria and experience diarrhoea
What is inflammatory bowel disease?
- When there is a lot of movement leading chronic exudative diarrhoea (getting diarrhoea every few hours)
What is deranged motility diarrhoea?
- GI stasis may stimulate the overgrowth of some bacteria which may promote diarrhoea
- There is a lack of absorption as some agents promote secretion as well as motility
What are parasitic causes of diarrhoea?
- Parasites that are able to survive in anaerobic conditions and cause diarrhoea when ingested
- Treated by using metronidazole
What is dysentry?
- Painful, bloody, low volume diarrhoea
What are the causes of blood diarrhoea?
- Chronic disease
- Ulcerative colitis (inflammation of the bowel)
- Cancer
What are the major consequences of severe diarrhoea?
- We get hypovolaemia (blood volume drops)
- Metabolic acidosis as there is a loss of HCO3
What are the consequences of excessive vomiting?
- Increased salt and water loss
- Severe dehydration
- Circulatory problems
- Metabolic alkalosis due to loss of gastric acid (HCl)
- Death
What is lost in the vomit?
- Food
- Mucus with Na+, K+, Cl- and HCO3-
- Gastric acid
- Upper intestinal contents and bile
- Blood