Fluid and electrolyt Fluid and electrolyte balance week 4 gi

Question Answer
jejunum length 2.5m
ileum length 3.5m
colon length 5m – divided into 5 segments
daily oral intake 2000mL
daily gastric juice secretions 2500mL
daily bile secretions 500mL
daily pancreatic juice 1500mL
daily intestinal secretions 1000mL
daily water turnover 9000mL
daily water excretion 100mL
where are most water and nutrients absorbed ileum and jejunum
where does insensible loss occur through the skin
what is the membrane of enterocytes dotted with? Ion channels which actively transport electrolytes in and out
what are the tight junctions of enterocytes permeable to? water and other molecules with a molecular weight less than 300Da
name four types of membrane transporters ATP-driven pump, ion channel, co-transporter: symporter, exchange carrier: antiporter
what do sodium cotransporters transport? amino acids, peptides, bile salts, vitamins
what does sodium drive the absorption of? water
what does the sodium gradient provide the energy for? active transport of many minerals, vitamins, and metabolites
what's an SGLT1 transporter? sodium dependent glucose linked transporter
what's a GLUT2 transporter? facilitated glucose transporter, a transmembrane carrier protein that enables protein facilitated glucose movement across cell membranes
what's GLUT2 the principal transporter for? transfer of glucose between liver and the blood, and has a role in renal glucose reabsorption
what counteracts electrolyte uptake? chloride-driven colonic electrolyte secretion counteracts electrolyte uptake
what do endotoxins released by Vibrio cholerae (cholera toxin) and Escherichia coli (heat stable enterotoxin) activate? Activate intracellular cAMP/PKA and activate CFTR on the apical plasma membrane leading to massive chloride secretion
what's CFTR? cystic fibrosis transmembrane conductance regulator
what's normal stool weight about 200g/24hr
what does the volume of the shit have to be to be classified as diarrhoea? volume greater than 200ml
give four things that cause diarrhoea secretory agonists, inflammation, non-absorbable solutes, failure to digest or absorb nutrients
name the three types of diarrhoea Secretory, inflammatory, and osmotic (malabsorptive)
which two types of diarrhoea have a high volume? secretory and osmotic (malabsorptive)
what to do with absorption and secretion is secretory diarrhoea? Decreased absorption and increased secretion
Give some causes of secretory diarrhoea Acute infections, failure of bile salt absorption, malabsorption of fat, laxative abuse, carcinoid syndrome, zollinger-ellison syndrome
give some causes of inflammatory diarrhoea inflammatory bowel disease, Crohn disease, ulcerative colitis, infectious disease: Shigella, salmonella, irritable colon
which type of diarrhoea has a low volume? inflammatory
what to do with secretion is inflammatory diarrhoea? Increased secretion and propulsive activity of the bowel
what to do with absorption is osmotic (malabsorptive) diarrhoea? Decreased intestinal absorption
What can cause osmotic (malabsorptive) diarrhoea? laxatives, antacids, acarbose (alpha-glucosidase inhibitor), orlistat (lipase inhibitor), digestive enzyme deficiencies (lactase), pancreatic insufficiency, inflammatory disease, short bowel syndrome
Name three things that can cause acute watery diarrhoea, and thus dehydration V. cholera, e.coli. rotavirus
what can cause bloody diarrhoea (dysentery) shigella
what can dynsentery cause? intestinal damage and nutrient loss
How can you treat diarrhoea in children? fluid replacement to prevent dehydration (oral rehydration salts, ORS), zinc supplements (decrease severity and duration), continue feeding, use appropriate fluids available at home and increased fluids in general
what can prevent diarrhoea? Rotavirus and measles vaccinations, early breastfeeding and vitamin A supplementation, hand washing with soap, improved water quality, community-wide sanitation promotion
what should the speed of fluid replacement depend on? age, renal function and cardiovascular status
what do you need to measure when examining a patient with diarrhoea? electrolyte profile, blood gases, glucose, albumin, urea, creatinine, plasma osmolality, check water balance chart
what's osmolality and what does it control? measurement of the solute concentration of a solution, it controls the movement of water – high osmolality draws water into a compartment, low osmolality means water moves out of a compartment
what does high osmolality mean in terms of hydration level of the cell? cellular dehydration
what does low plasma osmolality mean in terms of cellular hydration? cellular overhydration and oedema (build up of fluid in the body which causes the affected tissue to become swollen)
what does increased osmolality in the blood cause to happen in normal people? stimulates secretion of ADH, which results in increased water reabsorption, more concentrated urine, and less concentrated blood plasma
what sort of oral rehydration solution is better in any situation? isosmotic
Give three types of intravenous solutions blood products, colloids, and crystalloids
describe colloids large molecular weight, consists of albumin, haemaccel, hydroxyethyl starch (HES)
Describe crystalloids water plus electrolytes, consists of saline, dextrose, ringer-lactate Hartmann's solution (mixture of sodium chloride, sodium lactate, potassium chloride, and calcium chloride in water)
why shouldn't you use sodium bicarbonate unless in an emergency? because it is very hypoosmotic – however, there is a bicarbonate solution that is isosmotic, which is useful in patients with bicarbonate loss
what is hypoosmotic saline? Kind of 'half strength', but there are risks associated with using it
what percentage of colloids given intravenously stay in the vascular bed and why is this important? initially nearly 100% – important in resuscitation
what percentage of saline stays in vascular bed? 25%
what percentage of dextrose stays in vascular bed? 10%
what can you use 5% dextrose for? for fluid therapy but not when it comes to fluid feeding
how quickly does dextrose enter cells and why is giving it clever Dextrose solution very quickly enters cells.Dextrose is quickly metabolised by cells so all that will remain is water so giving dextrose is a clever way of giving wate
what is the standard postoperative fluid regimen? saline and dextrose given in a ratio of 2:1 – not that useful in patients that have lost electrolytes though
what is produced during lactate metabolism? a substantial amount of bicarbonate
what might normal saline contribute to? metabolic acidosis
what might ringer-lactate increase? cerebral oedema
List five factors that affect the rate of fluid replacement age, cardiovascular status, renal function, time it took to develop, severity of existing dehydration
when giving an infusion what is the standard fluid size? give a standard 500mL bag and just prescribe how long it should run for – e.g. run for 2 hours for emergency rehydration, 6 hours as the standard regimen, and 8 hours for slow rehydration
where is the main output of potassium? through kidney excretion
what must happen to concentrated potassium solution before use? must be diluted
what's the maximum concentration of potassium for peripheral administration 40mmol/L
what's the maximum rate for potassium administration? 10mmol/hour: faster only if cardiac monitoring/central line are available (up to 20mmol/hour)
what can low potassium levels cause? muscle weakness and heart rhythm disturbances
what can too much potassium cause? dangerous heartbeat irregularities and even sudden death

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