11- UTI and Diuretics Flashcards
What are diuretics
Act on kidney to increase production of urine and eliminate water from body
What do diuretics do
Reduce plasma volume and CO
Reduce BP
Reduce edema and ascites
Act on tx on luminal membrane or renal tubular cells
Where do carbonic anhydrase inhibitors work
Inhibit carbonic anhydrase in PCT
Where do osmotic diuretics work
Whole tubule
Where do loop diuretics work
Loop of Henle
Where do K sparing diuretics work
DCT/CD
Where do thiazide and thiazide like diuretics work
DCT
How do CA inhibitors work
So HCO3 not produced in cell
So Na/HCO3 cotransporter can’t work
So high Na in cell
So less reabsorbed
How do osmotic Ds work
Freely filtered But no transporters so not reabsorbed Stay in lumen and pull in water Na spared Expand ECF initially, decrease blood viscosity, inhibit renin release, increase renal blood flow
How do Loop Ds work
Work on Na/K/2Cl
So less reabsorbed
Stay in lumen so water stays too
Potent
Emergency situations
How do K sparing Ds work
With diuretics there is lots of Na in lumen
So when gets to CD the ENAC works and reabsorbs Na and ROMK kicks out K due to Na/K turning
With K sparing = ENAC/ROMK not upregulated
How do Thiazide Ds work
Block Na/Cl Co
So less Na
Can induce high Ca as less Na in cell so favours Na/Ca antiporter so more Ca absorbed
Why does low K cause alkalosis
Cell swaps intracellular K for H so less H in blood = higher Ph
What are the defences of the UT against colonisation
Emptying of bladder
Immunological factors
Mucosal barriers
Urine acidity
Why do you get false negatives with collection bag
Peritoneal contamination
How long can you take to get samples to culture
4 Hours or refrigerate or boric acid
When does a dipstick indicate UTI
Leucocyte esterase Nitrates Blood Higher pH Protein- WBC
When is a dipstick useful
Under 65
Children to help rule out
When is a dipstick not useful
Over 65
Catheter
When is a dipstick not necessary
2-3 of dysuria, new nocturia, cloudy urine
When is a dipstick not necessary
2-3 of dysuria, new nocturia, cloudy urine
What is the role of culture
Investigate complicated infections
Epidemiology
Antibiotic susceptibility data
When do you do image urinary tract
Children with UTI
Septic patients to see renal involvement
Males: urethral valves
Females and children: vesico-ureteric reflux
When would you get sterile pyuria (WBC but not growth)
Prior abx Urethritis- STI Vaginal infections- postmenopausal vaginitis TB Appendicitis
Asymptomatic bacteriuria
High prevalence in elderly
Screen and treat in pregnancy
Risk of asymptomatic bacteriuria in pregnancy
Premature birth
Pyelonephritis
Treat UTI
Increased fluid
Analgesia
Treat underlying disorders
How to treat uncomplicated UTIs
3 day nitrofurantoin
Catheter - treat only if unwell
How to treat complicated
5-7 days nitrofurantoin, pivmecillinam, trimethoprim
Cefelexin in pregnancy
How to treat pyelonephritis/ septicaemia
7-10 days
Need systemic activity
IV Co-amoxiclav, Gen, cipro (7 days)
When to give prophylaxis
More than 3 episodes in a year
Good hygiene and behavioural measures taken
No treatable underlying condition
Abx chosen according to recent culture and susceptibility results
Breakthrough infections documents
Side effects of osmotic Ds
Headache, nausea, vomitting due to high Na
Extracellular volume expansion = oedema, HF
Do not use in chronic HF
Dehydration and high Na
Side effect of Loop D
Low electrolytes
Metabolic alkalosis
Side effect of Thiazide Ds
Hypercalcaemia low intracellular Na so more Na/Ca antiporter
When not to use K sparing Ds
Hyperkalemia
Liver disease
When to use K sparing Ds
Secondary hyperaldosteronism
CHF, hepatic cirrhosis, nephrotic syndrome
Hypertension in combination with others
When to use K sparing Ds
Secondary hyperaldosteronism
CHF, hepatic cirrhosis, nephrotic syndrome
Hypertension in combination with others
When to use osmotic Ds
Acute renal failure
Acute drug poisoning
Before surgery to reduce intracranial pressure
When to use loop Ds
Severe oedema
Hypercalcemia
Acute pulmonary oedema
Acute hyperkalaemia
When to use thiazide Ds
Essential hypertension
Mild heart failure
Osteoporosis
What is main complaint of UTI
Dysuria
What is a gram pos cocci that is coagulase neg
Staphylococcus epidermidis
What is Staphylococcus saprophyticus
Found in normal flora of female genital tract and perineum
Coagulase positive coccus
If nitrites negative
What is the first immunoglobulin to respond
IgM
What D normally added to loop to create potency
Thiazide when low GFR
What is a side effect of spironalactone
Gynecomastia as work on other steroid receptors
What drug reduces mortality by 30% in those with HF and LV dysfuntion
Spironolactone
