Transcript Check the pee

Check the pee
Lab rounds Aug 7th, 2008
Kristian Hecht
Case 1
• 22y female 3 day hx of dysuria, frequency and
urgency. Afebrile.
• Urine dip: +leuks, +nitrite, +RBC’s
• Urinalysis:
RBC
20
0-5/hpf
WBC
30
0-5/hpf
Epithelial
Few
0/hpf
Bacteria
Many
0/hpf
Casts
None
0/hpf
Case 1
• 22y female 3 day hx of dysuria, frequency and
urgency. Afebrile.
• Urine dip: +leuks, +nitrite, +RBC’s
• Urinalysis: RBC
20
0-5/hpf
WBC
30
0-5/hpf
Epithelial
Few
0/hpf
Bacteria
Many
0/hpf
Casts
None
0/hpf
Dipsticks in UTI
• Multisticks measure Sp. gravity, pH,
glucose, nitrites, protein, leuks, rbc’s, bili,
ketones
• Leuks and nitrites are the most useful in
suspected UTI
Dipsticks
• WBC’s measured indirectly measuring
leukocyte esterase activity
• LE contained in neutrophils and
macrophages
• Sp 80-90%
• Sn 75-96%
• False –ve’s: high glc, high prot,
tetracycline, keflex
Dipsticks
• Nitrites produced by most Gm –ve
uropathogens
• Not produced by Pseudomonas or
Enterococcus
• Diet must contain nitrates to be +ve
• Sn <50%
• Sp >90%
Dipsticks
• In children <12y, when compared to
microscopy, urine dips were equally as
accurate Pediatrics 104:54, 1999
• Less accurate in children <2y
• In adults with a typical UTI hx, some
advocate for empiric tx with no further
investigation based on a +ve dip
Microscopy
• Urine spun at 2000rpm for 5 min
• Sediment is resuspended in remaining
urine and examined + gram staining
• WBC’s
– >5/hpf in females, >2/hpf in males
• Bacteria
– >15/hpf
Case 2
• 18y f, 3d hx of dysuria, frequency and urgency
• Dipstick +ve leuks, -ve for nitrite
• Micro:
RBC
1
0-5/hpf
WBC
30
0-5/hpf
Epithelial
0
0/hpf
Bacteria
0
0/hpf
Casts
None
0/hpf
Microscopy
• WBC’s
– False negatives: dilute urine, leukopenia,
partial treatment
• Bacteria
– Negative if: C. trachomatis, N. gonorrhea,
HSV, S. saprophyticus
– False –ve if: dilute urine, low bacterial load
Case 2 con’t
• Further hx indicates recent unprotected
intercourse with a new partner 10d ago
• Swabs taken
• Teachable moment seized
Urine Culture
•
•
•
•
Provides definitive diagnosis
>105 CFU/mL considered positive
correlated with 95% likelyhood of infection
>104 CFU/mL correlated with only 50%
likelyhood
Urine Culture
• False +ve cultures are common due to
contamination from uropathogens on the
perineum and foreskin
• Many studies show that urine culture is
only useful when the diagnosis is
uncertain or when there are host factors
that make pathogen identification
important
Groups in Which Urine Culture is Indicated
1. Children
2. Adult men
3. Immunocompromised patients
4. "Treatment failure" (recently completed course of antibiotics with persistent urinary
symptoms)
5. Patients with symptoms in excess of 4 to 6 days
6. Elderly patients at risk for bacteremia
7. Toxic-appearing patients with signs and symptoms suggestive of pyelonephritis or
bacteremia
8. Pregnant women
9. Patients with known chronic or recurrent renal infection
10. Patients with known anatomic urologic abnormalities
11. Patients in whom urinary tract obstruction is suspected (e.g., stones, benign prostatic
hypertrophy)
12. Patients with serious medical diseases, including diabetes mellitus, sickle cell anemia,
cancer, or other debilitating diseases
13. Patients with alcoholism, drug dependence
14. Recently hospitalized patients
15. Patients taking antibiotics
16. Patients recently instrumented (e.g., cystoscopy, catheterization)
Case 3
• 75y male unresponsive, tachycardic,
hypotensive, afebrile
• Had complained of flank pain 24h ago
• Hx of BPH and mild UTI’s in past
Case 3
• While working this pt up for presumed
urosepsis a urine was sent off…
• Micro
pH
6.0
RBC
10
0-5/hpf
WBC
2
0-5/hpf
Epithelial
Mod - Necrotic
renal tubular cells
0/hpf
Bacteria
Few
0/hpf
Casts
Many – epithelial
casts
0/hpf
Crystals
Many - Oxalate
mono/dihydrate
0/hpf
Case 3
• A neighbor comes by the ICU the next day
and mentions that the pt had seemed
depressed lately.
• Pt also asked to borrow some antifreeze
for his car 3 days ago…
Crystals
• Crystals may be normally found in urine
based on diet, concentration and pH
– Urate, oxalate
• Pathologic crystals
– Cholesterol – indicates marked proteinuria
– Cystine – familial cystinuria
– Drugs (Acyclovir, Amoxil, Cipro, Indinavir)
• Can be implicated in cases of ATN
Casts
• Form when urinary ‘Tamm-Horsfall’
proteins precipitate with low pH or incr.
concentration
• Cellular debris can become entrapped in
this precipitate
• May help differentiate causes of acute
renal failure and renal disease
RBC cast
Granular cast
Waxy cast
Casts
• Acute tubular necrosis
– necrotic renal tubular epithelial cells (RTEC)
– RTEC casts
• Proliferative/Necrotic GN/vasculitis – erythrocytic
casts
• Rhabdomyolysis – myogolbin casts
• Calcium oxalate crystals – ethylene glycol
Casts
• Nephrotic syndrome
– Proteinuria, lipuria with RTEC and fatty casts
• Degree of hematuria can indicate underlying cause
(mininmal change, membranous, focal
segmental…)
• Nephritic syndrome
– Mod/Severe dysmorphic hematuria
• RTEC casts and/or waxy casts
Other Casts
• Hyaline – prerenal azotemia, normal
• Granular – renal disease of any cause
• Leukocytic – Pyelonephritis/acute
interstitial nephritis
Take home goodies
• Think about STI’s when the microscopy
doesn’t fit with the story/dip
• Don’t culture everyone
• Crystals and casts can be useful in
differentiating causes of ARF
Thanks!