Nephrolithiasis/Pyelonephritis PBL

Question 1

Bactrim

not used if previously taken in what time period?

Answer 1

last 3 months

Question 2

What causes urgency in UTIs?

Answer 2

urinary reflex

(parasympathetic)

Question 3

Sx present in pyelnephritis not present in lower UTI

Answer 3

systemic Sx

fevers, chills

constitutional Sx

Question 4

3 things that matter to Dx UTI

Answer 4

dysuria

leukocyturia (greater than trace)

nitrates in urine

Question 5

Why can nitrofurantoin not be used to treat pyelonephritis?

Answer 5

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

Question 6

Preferred imagine modality for evaluation of nephrolithiasis

Answer 6

CT

ultrasound isn’t sensitive at all

X-ray isn’t sensitive or specific

intravenous pyelography only evaluates urinary tract stuff

Question 7

3 Abx used for lower UTI

Answer 7

bactrim (sulfamethoxaxole + trimethoprim)

ciprofloxicin (in men)

nitrofurantin

Question 8

Pyelonephritis Tx

and mechanism

Answer 8

fluoroquinolones

MOA: topo II inhibitor

Adverse: Ca2+ kelation, can exacerbate stone formation

Question 9

Abx in pyelonepritis when resistant to flouroquinolones?

Answer 9

ceftriaxone or aminoglycoside

Question 10

What is the difference in Tx approaches between uncomplicated cystitis and pyelonephritis?

Answer 10

cystitis = empiric Tx

pyelonephritis = suceptibility testing

Question 11

Cystitis more common cause

Answer 11

E. coli

Question 12

Staph saprophyticus is more common is women who are

Answer 12

sexually active

Question 13

Struvite stones are caused by what organisms?

Answer 13

urease-positive organisms

Proteus vulgaris, Klebsiella

Question 14

Pyelonephritis Tx

Answer 14

cipro (fluoroquinolone) empirically

sensitivity-speific once culture comes back

Question 15

Causes of staghorn calculus

Answer 15

ammonium magnesium phosphate crystals

(from urease-positive infections)

cysteine stones

(in children, inborn error of cysteine metabolism)

Question 16

Nitrofurantoin

MOA

Tox

TU

Answer 16

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

Question 17

Sulfamethoxizole

MOA

Tox

TU

Answer 17

MOA: dihydropteroate synthase inhibitor, folate pathway

Tox: hypersensitivity, hemolytic anemia in G6PD deficiency

TU: lower UTI

Question 18

Trimethoprim

MOA

Tox

TU

Answer 18

MOA: dihydrofolate reductase inhibitor

Tox: megaloblastic anemia, leukopenia, granulocytopenia

TU: lower UTI

Question 19

Ciprofloxicin

Class

MOA

Tox

TU

Answer 19

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

Question 20

Co-therapy when UTI resistant against cipro

Answer 20

ceftriaxone

or

aminoglycocide

Question 21

Phenazopyridine

MOA

Tox

TU

Answer 21

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

Question 22

Preferred imagine modality for suspected nephrolithiasis

Answer 22

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

Question 23

Most common causative organism in UTI

Answer 23

E. coli

Gram -

facultative anaerobe

rod-shaped

Question 24

Second most common causative organism in UTI in sexually active women

Answer 24

Staph saprophyticus

Gram +

Question 25

What type of bacteria are most commonly causing UTIs?

Answer 25

enteric