ICL 1.9: Urinalysis Flashcards
1
Q
what is the normal color of urine?
A
straw colored
2
Q
what does it mean if urine is colorless?
A
- dilute urine
- low specific gravity
- tubular diseases
3
Q
what does it mean if urine is milky?
A
infections = PMNs
4
Q
what does it mean if urine is yellow-green?
A
bilirubin
5
Q
what does it mean if urine is red?
A
- vitamins/food items (beets)
- Hb
- myoglobin (rhabdomyalsis or crush injury)
6
Q
what does it mean if urine is black?
A
- melanin (melanoma)
- homogentistic acid
- alkaptonuria = spill homogentistic acid in the urine which is black
7
Q
what kind of urine sample do you want for screening?
A
the specimen that was voided 1st thing in the morning is the best
8
Q
what are you looking for in a screening urine?
A
- protein
- specific gravity
- nitrites (infection)
- leukocyte esterase (infection)
for screening, the specimen that was voided 1st thing in the morning is the best for these things
BUT for glucose a post-prandial specimen is better
9
Q
what kind of urine sample do you want for a quantitative analysis?
A
a 24 hour urine specimen is needed
preservatives needed will depend on substances to be tested
10
Q
how is urine stored?
A
urine should be examined fresh or refrigerated
11
Q
what kind of urine sample do you want for cultures?
A
- straight cath
2. clean catch midstream
12
Q
what is a normal volume of urine?
A
1200-1500 mL/24 hrs
13
Q
what is oliguria?
A
<500 mL of urine daily
this signifies dehydration, renal disease, or obstruction
14
Q
what is polyuria?
A
2000+ mL/24 hrs
occurs in diabetes mellitus and diabetes insipidus and tubular renal diseases
15
Q
what are the 2 types of diabetes?
A
- diabetes mellitus
2. diabetes insipidus
16
Q
what is a normal specific gravity?
A
1.015-1.025
17
Q
what does low vs. high specific gravity signify?
A
low specific gravity:
1. diabetes inspidius
- tubular diseases
high specific gravity
1. diabetes mellitus
- dehydration
18
Q
what is the pH of urine? what precipitates at low vs high pH?
A
pH varies with diet
uric acid precipitates in acidic urine
phosphate crystals precipitate in alkaline urine
19
Q
what do you look for in a urine chemistry?
A
- nitrites*
- urobilinogen*
- blood*
- bilirubin*
- ketones
- glucose
- protein*
20
Q
how do you score how much protein is in the urine?
A
1+ = 250-500 mgm (24 hrs)
2+ = 500-1000 mgm (24 hrs)
3+ = 1000-2000 mgm (24 hrs)
4+ = >2000 mgm (24 hrs)
21
Q
if there’s glucose in the urine, which conditions could it signify?
A
- diabetes
- tubular defects
- decreased renal threshold
22
Q
if there’s ketones in the urine, which conditions could it signify?
A
- starvation
- diabetes
- gastroenteritis in children*
23
Q
if there’s blood in the urine, which conditions could it signify?
A
- hemoglobinuria
- UTI
- glomerular diseases
- interstitial nephritis
- tumors
24
Q
if there’s bilirubin in the urine, which conditions could it signify?
A
obstructive jaundice
green urine
25
if there's urobilinogen in the urine, which conditions could it signify?
1. hemolysis
2. hepatitis
brown urine
26
if there's nitrite in the urine, which conditions could it signify?
bacteruria = infection
leukocyte esterase also means infection
27
what shows up in the microscopic examination of urine?
1. cells
RBC, WBC, tubular cells, squamous malignant cells
2. crystals (not clinically significant)
3. casts
RBC, WBC, granular, hyaline, tubular
4. oval fat bodies
5. bacteria
6. yeast
28
what do RBCs in the microscopic examination of urine indicate?
hematuria
29
what do WBCs in the microscopic examination of urine indicate?
pyuria
30
what do tubular cells in the microscopic examination of urine indicate?
tubular necrosis
31
what do RBC casts in the microscopic examination of urine indicate?
acute nephritic syndrome
32
what do WBC casts in the microscopic examination of urine indicate?
acute pyelonephritis
33
what do granular casts in the microscopic examination of urine indicate?
acute nephritic syndrome
34
what do hyaline casts in the microscopic examination of urine indicate?
chronic renal disease
35
what do tubular casts in the microscopic examination of urine indicate?
acute tubular necrosis cells
they're muddy brown
36
what are oval fat bodies?
tubular cells loaded with lipid droplets
associated with nephrotic syndromes
37
are the kidneys, ureters and bladder normally sterile or non-sterile?
they are all normally sterile
38
how do people get UTIs?
the urethra is really close to the perineal area so organisms from that area can find their way to the urethra and once they're there they flourish since the urine has lots of nutrients in it!
there will be bacterial multiplication and infection
ex. placing a catheter
39
what can cause a UTI?
1. infection
| 2. obstruction
40
how can obstruction cause a UTI?
residual urine can lead to stagnation of the urine in the bladder and distention
the urine is a broth for the bacteria to flourish
also the dilated bladder means there's also compromise of blood supply which leads to ischemic changes that enhance the infection
ex. prostatic hypertrophy in older men
41
what are the 2 mechanisms that cause UTIs?
1. ascending via vesicoureteral reflux (common)
usually acquired due to repeated infection of the bladder and end of the ureter so the sphincter that controls one-direction urine flow is impaired and back flow of urine from bladder to kidney causes pyelonephritis
2. hematogenous (rare)
42
what are ether most common organisms that cause UTIs?
e coli is the most common!
other gram negative are common too
43
what are the normal protective mechanisms against UTIs?
1. urethra acts as a natural anatomic barrier
that's why UTI are more common in women because we have a short urethra
2. mucosal IgA
3. bactericidal substances in the prostatic secretions in males (also another reason we get more UTIs)
44
what part of the kidney are UTIs most common in? why?
medulla
1. low blood supply
2. hypertonicity of the medulla which interferes with and decreases phagocytosis
3. high concentration of ammonia which decreases bactericidal actions of the serum
45
24 year old lady present with dysuria, urgency, hematuria
UA: + ve esterase
+ nitrite
many leukocytes
diagnosis?
tests?
lower UTI infection that isn't involving the kidney
tests = microscopic exam of urine and cultures
46
24 year old lady present with dysuria, urgency, hematuria, turbid urine, flank pain and a temperature of 102.
UA: + ve esterase
+ nitrite
many leukocytes
WBC casts
diagnosis?
tests?
acute pyelonephritis
turbid urine = lots of neutrophils and bacteria
flank pain = kidney infected
47
what is the clinical presentation of acute pyelonephritis?
it's an infection of the renal pelvis and parenchyma that is usually associated with an ascending bacterial infection of the bladder
systemic = fever, chills, vomiting
local = urgency, frequency, dysuria, back pain
48
what is in the urine analysis of acute pyelonephritis?
1. bacteria
2. WBC casts = renal involvement**
3. RBCs
49
what test do you need to do for acute pyelonephritis?
urine culture with a calibrated loop
if you see more than 10ˆ6 microorganisms/mL of one type of bacteria, it indicates an infection
if you have multiple bacteria it's probably contaminated
50
what is the course of acute pyelonephritis?
1. acute pyelonephritis that heals with small scars if no obstruction
2. high recurrence due to vesicoureteral reflux
3. chronic pyelonephritis if there's multiple scars due to recurrence
4. papillary necrosis (flank pain going to the groin and WBCs in the urine with necrotic tissue because the kidney tries to expel them which causes a lot of pain)
51
what are the complications of pyelonephritis?
1. papillary necrosis
patient present with severe flank pain radiating to the groin and necrotic tissue and WBCs in the urine due to coaulative necrosis of the papillae = necrosis caused by tissue ischemia, which denatures proteolytic enzymes --> if the papillary necrosis is due to pyelonephritis you'll also see WBCs but if it's being caused by any other etiology like NSAIDs or sickle cell it'll be sterile pyuria
this is a special hazard in patients with DM because they already have ischemic kidneys so if you add an infection or NSAID use it gets worse because you increase the blood flow compromise
2. death
3. stone formation
52
what are the causes of papillary necrosis?
1. acute pyelonephritis
2. analgesic abuse (NSAIDs)
3. sickle cell disease = sickle cells lodge in vessels and obstruct them which leads to ischemic damage of papilla
4. DM
53
how are stones associated with UTIs?
stones can lead to infection and infection can lead to stones = chicken and the egg
stones lead to infection because they cause obstructions which is a predisposing factor for UTIs because of stagnation of the urine
repeated infections can lead to stone formation especially when the infection is due to urea splitting organisms --> they split urea into ammonia which raises pH of the urine and in alkaline urine magnesium ammonium phosphate and calcium phosphate crystals can attain large sizes which impacts the calyces and eventually in the pelvis which eventually leads to a staghorn stone** (super large stones that fill the entire renal pelvis and calyces)
54
what is a staghorn stone?
a very large stone obstructing the pelvis and calices of the kidney
common in alkaline conditions like UTIs caused by urea-splitting organisms
proximal to the stone the kidney will enlarge = hydronephrosis --> dilated calyces means urine stagnates and infection sets in which leads to pyonephrosis = large kidney filled with pus
55
what are the gross changes seen with chronic pyelonephritis?
1. multiple wedge shaped scars on the surface of the kidneys
| 2. U-shaped or geographic scars
56
what are the microscopic changes seen with chronic pyelonephritis?
1. heavy interstitial lymphocytic infiltrates
2. interstitial fibrosis
3. arteriolar sclerosis
4. hyaline casts in tubules
5. thyroid-like arrangement of tubules = tubules become atrophic and are filled with proteinaceous casts and look like mini thyroid particles
6. periglomerular fibrosis
7. hyalinized glomeruli
57
RBCs casts
nephritic syndromes
58
muddy brown casts
acute tubular necrosis
59
WBC casts
acute pyelonephritis
60
hyaline casts
chronic kidney problems
occasionally you might just be spilling a few hyaline casts and they don't mean anything
61
eosinophils in the urine
acute interstitial nephritis
62
sterile pyuria
sterile pyuria = WBCs and necrotic tissue without bacteria
papillary necrosis = coagulative necrosis of the renal medullary pyramids and papillae = type of necrosis caused by tissue ischemia, which denatures proteolytic enzymes
63
tubulorrhexis
ischemic tubular injury
64
tubular cell casts
acute tubular necrosis
65
analgesics
chronic interstitial nephritis
66
tubular damage and oxalate crystals
ethylene glycol toxic tubular necrosis
67
staghorn stones
1. hydronephrosis
| 2. pylonephrosis
68
A 58 year old lady with rheumatoid arthritis for 25 years presents with renal colic and turbid urine
UA reveals many neutrophils but no organisms
what is your DX?
what would you like to ask the patient?
sterile pyuria = chronic interstitial nephritis with papillary necrosis (flank pain)
ask about NSAID use
69
```
70 year old male with constipation for 4 weeks presents to the ER with back pain and renal failure
diagnosis?
Tests
Renal changes
```
multiple myeloma
run serum protein electrophoresis and bone marrow biopsy
changes = obstructive uropathy, amyloidosis, calcinosis, interstitial plasma cells, light chain glomerulonephritis, tubular damage from light chains
70
cholesterol crystals in urine?
hyperlipidemia
nephrotic syndrome became you're spilling lipid into the urine
71
muddy brown cast
tubular necrosis
72
oval fat body
nephrotic syndrome
73
2+ protein
500-1000
74
luekocyte estase
UTI
75
acidic pH precipitate
uric acid
76
alkaline pH precipitate
phosphate crystals
77
black urine
1. melanoma
| 2. alkaptonuria
