Nephrolithiasis/Pyelonephritis PBL Flashcards
Bactrim
not used if previously taken in what time period?
last 3 months
What causes urgency in UTIs?
urinary reflex
(parasympathetic)
Sx present in pyelnephritis not present in lower UTI
systemic Sx
fevers, chills
constitutional Sx
3 things that matter to Dx UTI
dysuria
leukocyturia (greater than trace)
nitrates in urine
Why can nitrofurantoin not be used to treat pyelonephritis?
nitrofurantoin is only effective to treat infections when it is concentrated in the urine
*not concentrated enough in the kidney
*concentrated enough in the ureter and lower urinary tract
Preferred imagine modality for evaluation of nephrolithiasis
CT
ultrasound isn’t sensitive at all
X-ray isn’t sensitive or specific
intravenous pyelography only evaluates urinary tract stuff
3 Abx used for lower UTI
bactrim (sulfamethoxaxole + trimethoprim)
ciprofloxicin (in men)
nitrofurantin
Pyelonephritis Tx
and mechanism
fluoroquinolones
MOA: topo II inhibitor
Adverse: Ca2+ kelation, can exacerbate stone formation
Abx in pyelonepritis when resistant to flouroquinolones?
ceftriaxone or aminoglycoside
What is the difference in Tx approaches between uncomplicated cystitis and pyelonephritis?
cystitis = empiric Tx
pyelonephritis = suceptibility testing
Cystitis more common cause
E. coli
Staph saprophyticus is more common is women who are
sexually active
Struvite stones are caused by what organisms?
urease-positive organisms
Proteus vulgaris, Klebsiella
Pyelonephritis Tx
cipro (fluoroquinolone) empirically
sensitivity-speific once culture comes back
Causes of staghorn calculus
ammonium magnesium phosphate crystals
(from urease-positive infections)
cysteine stones
(in children, inborn error of cysteine metabolism)
Nitrofurantoin
MOA
Tox
TU
MOA: reduced to reactive intemediates, inactivates ribosomal proteins and other macromolecules
Tox: pulmonary fibrosis with repeated use, in elderly populations
TU: only lower UTI, needs to be concentrated by kidney for lower urinary tract. adequate concentrates not reached in kidney to treat pyelonephritis
Sulfamethoxizole
MOA
Tox
TU
MOA: dihydropteroate synthase inhibitor, folate pathway
Tox: hypersensitivity, hemolytic anemia in G6PD deficiency
TU: lower UTI
Trimethoprim
MOA
Tox
TU
MOA: dihydrofolate reductase inhibitor
Tox: megaloblastic anemia, leukopenia, granulocytopenia
TU: lower UTI
Ciprofloxicin
Class
MOA
Tox
TU
Class: fluoroquinolones
MOA: topo II inhibitor (DNA gyrase)
Tox: chelation (no antacids/milk), tendon rupture (not for athletes), cartilage damage (not for children)
TU: upper and lower UTIs, some strains resistant
Co-therapy when UTI resistant against cipro
ceftriaxone
or
aminoglycocide
Phenazopyridine
MOA
Tox
TU
MOA: unknown
Tox: red urine (it’s an azo dye used in clothing manufactoring)
TU: analgesic effect on urinary mucosa, used for UTI pain relief that must be concurrent w/ antimicrobial therapy
Preferred imagine modality for suspected nephrolithiasis
non-contract CT
*most sensitive and specific
*allows for visualization of surrounding structures
ultrasound when CT not availabl
plain film and intravenous pyelography may also be used
Most common causative organism in UTI
E. coli
Gram -
facultative anaerobe
rod-shaped
Second most common causative organism in UTI in sexually active women
Staph saprophyticus
Gram +
What type of bacteria are most commonly causing UTIs?
enteric
