In the laboratory, we look for the presence of pyuria
and 10 white cells per microlitre of mid-stream urine
in a counting chamber is the gold standard.
However, a counting chamber is not available that often.
So we can use just centrifuged urine
and look for 5 to 10 white cells per high power microscopic field.
We also had the dipstick leukocyte esterase test.
Leukocyte esterase is present in the granules of neutrophils.
So if the leukocyte esterase is positive,
then by inference, you can say there are white cells in the urine.
And the sensitivity and specifity are decent --
75-96% sensitive, 94-98% specific.
Once again, if a patient does not have microscopic hematuria
it's probably not coming from the urinary tract.
The source of the fever is somewhere else.
The urine culture in pylonephritis certainly should
have a least 10 to the 5th bacteria per mL.
And a poor man's culture is to look under the microscope
looking for microorganisms.
You can do it by Gram stain.
If you see 1 organism per microscopic field,
you can basically conclude
that there are at least 10 to the 5th organisms per mL of that infected urine.
When do we need to image people?
Well, for uncomplicated pylonephritis,
when the diagnosis is clear,
the patient's moderately ill,
we don't need to image them.
We need to image them for complicated pylonephritis,
when we suspect a structural urologic abnormality,
when we're not sure what's going on
and urinary tract infection pylonephritis is up high on the list,
if someone obviously is unusually,
severely ill with symptoms of urinary tract infection
and it would be prudent in an immuno-compromised patient to get imaging
because they may have not only urologic abnormalities
but they may have serious abscess
in the kidney or other organs in the abdomen.
Then obviously patients who fail to improve
from the choice of therapy we give them for pylonephritis.
or for males who have suffered recurrent infections.
What's the sequence of imaging?
we start looking with a plain film
and what we're looking for are calculi, stones
because that can be a reason
for either the first time or recurrent pylonephritis
and also we can detect some soft tissue masses.
Renal ultrasound is the next step,
and a renal ultrasound can tell you
not only the presence of pylonephritis
but perinephric abscess.
And if it's necessary,
a CT scan can show you intrarenal or perinephric abscess.
I think you can see the intrarenal abscess on this particular projection.
So how do we treat uncomplicated pylonephritis?
Well, we need to choose any microbials
that have good activity against the offending pathogen
and you will have a urine culture hopefully to go by.
So if Gram-negative bacteria are seen on a urine smear,
we'd assume E. coli.
And since it's a serious illness,
we're probably going to choose a fluoroquinolone,
ciprofloxacin or levofloxacin for 5-7 days.
We wouldn't give that to children, remember,
because of the adverse consequences of quinolones
on soft tissue like tendons.
TMP/SMX for 14 days
or plus or minus 1 dose of ceftriaxone or aminoglycoside
is often given.
Gram-positive cocci seen in chains on urine smear
or known in culture would get amoxicillin,
'cause we'd be thinking of the Enterococcus.
And like I mentioned, if you see Gram-positive cocci in clusters
or Staph aureus is growing --
I'd like to pause here and
those of you who have seen patients probaby say
"Isn't that funny that the patient would grow Staph
especially Staph aureus in the urine?
That's not a urinary tract pathogen.
What's that doing there?"
That's exactly the question I want all good physicians to ask
because that Staph aureus may have gotten there from the bloodstream.
In other words, the patient may have infective endocarditis,
a heart valve infection,
that then got into the blood stream and seeded the kidneys
producing a pylonephritis.
So the pylonephritis came from
some other source of staphylococcal bacteremia.
So if you have a patient with Staph aureus
that you think is causing the urinary tract infection,
draw blood cultures
and work the patient up for a serious staphylococcal infection elsewhere.
That's an important thing to think about.
But if you indeed had Staph aureus,
then you would consider,
"Is this methicillin-resistant staph?"
And you would consider linezolid
or TMP/SMX for 14 days.
Obviously, since it's an uncomplicated infection,
you would't necessarily need to hospitalize and
give them vancomycin for that length of time.
You can also start with parenteral therapy in patients who are quite ill.
And so for those who have Gram-negative rods causing the problem,
fluoroquinolones for 7 days
or extended-spectrum beta-lactam for 14 days.
For gram-positive cocci clusters its Ampicillin for 14 days.
For gram-positive cocci clusters as we talked about
now we would have to think about vancomycin for 14 days.
Now as far as the surgical management goes,
what we need to do is
we need to, first of all, identify whether there is anything to drain.
And we can do that with either ultrasound or CT,
and we can use both of those tools to identify abscesses and drain them.
And there's about 90% success rate with doing just that.
For complicated pyelonephritis you need to do imaging studies of the kidneys, like CT,
to determine the extent of pathology.
If there is a perinephric abscess, this should be drained.
If there is an obstruction, this should be relieved
either by cystoscopy or with other urologic measures.
Is is very important to carefully select the parenteral antibiotics
based on culture and sensitivity.