Consequences of Fluid Loss Flashcards
What are the sites of water loss?
→Skin →Respiratory passageways →GIT →Urinary tract →Trauma →Menstrual flow
What is the daily NaCl intake?
→ 10.5g in food
What 2 things cause water to be gained?
→ Drinking
→metabolism
What is diarrhoea and what is the criteria for it?
→Increased frequency with increased volume and fluidity of feces
→>3 unformed stools per 24 hrs
Why does diarrhoea occur?
→Failure of water absorption
→Increased secretion of both
What are the causes of decreased absorption?
→Increased number of osmotic particles
→Increase in rate of flow of intestinal contents (deranged motility diarrhoea)
→Abnormal increase in secretions of GIT (secretory diarrhoea)
What is the cause of osmotic diarrhoea?
→decreased absorption of electrolytes and nutrients
→Disaccharidase deficiency
→drug induced
→malabsorption of galactose
What increases the rate of secretion in secretory diarrhoea?
→ACh, substance P, 5-HT and neurotension act via an increase in Ca2+
What causes secretory diarrhoea?
→Excessive laxative use, defects in digestion and absorption (infections eg. Cholera)
→Enterotoxin stimulates adenylate cyclase increases cAMP causes Na+ and Cl- and water loss.
What causes traveller’s diarrhoea?
→ Bacteria
What causes chronic exudative diarrhoea?
→ Inflammatory bowel disease
What causes deranged motility diarrhoea?
→ lack of absorption
→some agents promotes secretion as well as motility
Why can GI stasis promote diarrhoea?
→stimulating bacterial growth
What are the two parasites that cause diarrhoea?
→Entamoeba histolytica
→Giardia lamblia
What condition does entamoeba cause and what is the treatment for it?
→asymptomatic dysentery
→ Metronidazole
What does giardia cause?
→Steatorrhea and abdominal pain
→Maldigestion and malabsorption of lipids, CHOs, vitamin A, vitamin B12, folic acid
What does dysentery cause?
→painful
→ bloody
→low volume diarrhoea
What are the consequences of severe diarrhoea?
→loss of water, nutrients, Na+, K+ and HCO3-
→Decreased blood volume (hypovolaemia)
→Metabolic acidosis - due to 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