UA Clinical Final Rotation Exam

Anuria

Lack of urine production

Oliguria

Less than 400ml/day of urine production

Polyuria

More than 2500ml of urine production per day

Nocturia

Increase in nocturnal excretion of urine

How long can urine sit out?

Must be analyzed within 2 hrs of collection

If more, must be refrigerated, then brought to room temp to avoid amorphous crystals

Medulla

Inner portion of kidney, made of…

• Pyramids (Striated tubular structures)

• Papulla (pointed ends of pyramids)

• Calyces (cuplike projects, collect urine)

• Pelvis (Central region, collects urine)

Where does blood enter the glomerulus

Afferent arteriole

Where does blood leave the nephron

Efferent arteriole

Bowman’s capsule

main purpose: filtration

surrounds glomerular capillaries and acts like a bowl to catch the ultrafiltration

Basement membrane

Main purpose: Shield of negativity

influences which molecules can bass form capillaries to Bowman’s space

Mesangium

Main purpose: Structural support

Provides support for glomerulus, variable contraction to help control perfusion

Juxtaglomerular apparatus (JGA)

Main purpose: Vasoconstriction, Renin secretion, and structural support

Made of…

• Macula Densa cells (Chemoreceptors in DCT which sense Na/Cl and triggers vasoconstriction)

• Juxtaglomerular cells (sense cell shrinkage and secrete renin)

• Extraglomerular mesangial cells (Provide support/contraction)

What makes up the glomerulus?

Bowman’s capsule

Basement membrane

Mesangium

JGA

Vasa recta

Vasa recta

Main purpose: Reabsorbs/secretes

specialized capillary network derived from efferent arteriole that are intertwined throughout the nephron

Proximal Convoluted Tubule (PCT)

• Has cuboidal/columnar cells (brush border) to help with reabsorption

• Performs Active transport (Reabsorbs 2/3 Amino acids, Na, Cl, K, HCO3) and Passive transport (Reabsorbs urea/water)

Loop of Henle

• Concentrates urine using countercurrent multiplication

• Descending loop: Only permeable to H2O (Reabsorption)

• Ascending loop: Only permeable to Na/Cl (Reabsorption)

Distal Convoluted Tubule (DCT)

Located next to the JGA cells

Last step for reabsorption

Connects nephron to Collecting Ducts

Collection Ducts

Collects urine from several nephrons

Tubular secretion

Eliminates waste products not filtered out, regulates acid-base balance in the body via secretion of H+

• H+ can combine with phosphate/ammonia to be excreted

• H+ can combine with HCO3 to be reabsorbed

Erythropoietin

• Glycoprotein Hormone

• Released in response to low O2 levels

  • Stimulates erythropoiesis in bone marrow

Renin Angiotensin Aldosterone System (RAAS)

1. Angiotensinogen is released by the liver, cleaved by renin= Angiotensin 1

2. Angiotensin 1 travels to the lungs to be cleaved by ACE (Angiotensin Converting Enzyme)= Angiotensin 2

3. Angiotensin 2 travels the body, results in vasoconstriction, stimulates release of aldosterone, and stimulates the pituitary to release ADH (Anti-diuretic hormone)

What stimulates the RAAS

1. Decrease in Blood Pressure

2. Sympathetic nerve stimulation (Fight or Flight)

3. Decreased sodium concentration in DCT

What happens to unpreserved urine?

Physical: Darker color/clarity, increased odor

Chemical:

• Increased: pH, Nitrite, Bacteria

• Decreased: Glucose, Ketones, Bilirubin, Urobilinogen, RBCs, WBCs

Refractometry

Comparison of the velocity of light in the air with the velocity of light in the solution

Confirmation test for specific gravity >1.030

Specific Gravity terms/RI

RI: 1.003-1.035

Hyposthenuric <1.010

Hypersthenuric >1.010

Leukocytes

Reaction: Indoxycarbonic acid ester

False positive: Bleach

False negative: Ascorbic acid (Vit. C)

Nitrite

Greiss reaction (Diazonium salt)

False positive: Highly pigmented urine

False negative: Antibiotics/Ascorbic acid

Urobilinogen

Ehrlich reaction (P-dimethylaminobenzaldehyde)

False positive: Highly pigmented urines

False negative: High concentrations of nitrite

Increased in: Hemolytic anemia, liver disease, biliary disease

Decreased in: Biliary obstruction, liver dysfunction

Protein

Tetrabromophenol blue, protein error of indicators

False positive: Highly alkaline urines

False negative: Proteins other than Albumin

Microalbuminuria

Persistent elevation of albumin

Proteinuria

Pre-renal: Not detected by protein pad, made of Hemoglobin, myoglobin, Bence-Jones

Renal: Due to damage glomerulus= Increased albumin/WBCs/RBCs

Tubular renal: Due to Toxins, Heavy metals, Fanconi’s

Post-Renal: Due to normal tubular reabsorption failure can see bacteria, menstruation blood, or sperm

pH

Double- indicator system (Methyl Red and Bromothymol Blue)

No interferences (except runover from other pads)

If pH is >8.5 its probably bad collection

alkaline tide= alkaline urine pH after food ingestion

Blood

Pseudoperoxidase activity of hemoglobin

False positive: Menstrual contamination, Bleach

False negative: Ascorbic acid

Hematuria

Hematuria- typically due to renal/urinary tract disease (Calculi, glomerulonephritis, pyelonephritis, cystitis)

Hemoglobinuria- Due to intravascular hemolysis, hemolytic anemia, burns, infections

Myoglobinuria- Due to crush trauma, muscle destruction

Hemosinderinuria- Reabsorption by tubular cells of filtered Hgb

Specific Gravity Pad

pKa change of polyelectrodes

The higher the concentration of urine, the more H+ ions are released, causing the pH to be lower

Ketone

Sodium nitroprusside reaction

Reacts with Acetoacetate/acetone

False positive: Highly pigmented urine, levodopa

False negative: Breakdown of ketones

Bilirubin

Diazo reaction (bilirubin + Diazo salt= azo dye)

Only detects conjugated bilirubin

False positive: Highly pigmented urine

False negative: Exposure to light

Glucose

Double sequential enzyme reaction with glucose oxidase and peroxidase

False positive: Peroxides/Bleach

False negative: Ascorbic acid

Confirmatory Tests

• Benedicts reaction- Confirmation for reducing sugars, not specific to glucose

• Clinitest- Modified benedicts reaction, screens for galactose/other reducing sugars

• Ictotest- confirmatory for bilirubin

• Acetest- confirmatory for ketones

• SSA/ Sulfasalycilic acid precipitation- confirmatory for albumin

• Cyanide nitroprusside- confirmatory for cystine

Squamous Epithelial Cells

Large, Irregular borders, Distinct nucleus

Causes: Normal Cellular Sloughing

Transitional Epithelial cells

Comes from Renal Pelvis/calyces/ureters/bladder

Increased post invasive procedure (Trauma/catheter)

Larger than WBCs, Central nucleus

Renal Epithelial Cells

Slightly larger than WBC, eccentric nucleus, 1:1 N:C

Seen with tubular injury (Slight increase is normal in neonates)

Oval Fat Body

Renal Epithelial cells that have absorbed lipids

Must be ID with Fat stains or polarizing microscopy

Seen with Diabetes mellitus, Tubular necrosis, Lipiduria (with nephrotic syndrome)

White Blood Cells

Multi-lobed nuclei

“Glitter cells”

Seen with tubular damage, Infection, or Inflammation

Red Blood Cells

Smaller than WBCs

Dimorphic RBCs= Problems with filtration membrane

Ghost cells- RBCs in alkaline urine (Alkaline urine causes cells to lyse)

Acetic acid- used to distinguish RBCs and Yeast, RBCs will lyse

Casts

Made of Tamm-Horsfall protein matrix (Uromodulin)

Formed in the lumens of DCT/CD

Hyaline Cast

Most frequently seen

Almost see-through, rounded edges

Normal, only pathological in large numbers

RBC Cast

Seen with glomerular damage

MUST have free floating RBCs to call

Group of RBCs with matrix around them

WBC Cast

Group of WBCs with cell matrix

Seen with Upper UTI’s, acute interstitial nephritis and glomerulonephritis

RTE Cast

Seen with tubular destruction

RTE’s in a clear matrix

Granular Cast

Disintegration of Cellular casts

Waxy Cast

Seen with chronic renal failure

Slightly opaque, blunt edges

Fatty Cast

Seen with oval fat bodies/free fat droplets in lipiduria

Seen with nephrotic syndrome, Diabetes, and crush injuries

Amorphous urates

Normal Crystals

Acidic urine

Calcium oxalate

Normal and Abnormal Crystals

Acidic to Normal Urine

Dihydrate-Envelopes

Monohydrate- Dumbells

Monosodium urate

Slender needles, typically antibiotic related

Normal, Seen in acidic urine

Uric acid Crystals

Colorless/yellow-brown, Rosette or Rhomboid form

Normal, Seen in acidic urine

Ammonium biruate crystal

Yellow/brown, throny apples

Normal, Seen in alkaline urine

Calcium phosphate

Colorless, flat rectangles/rosettes

Normal, seen in alkaline urine

Triple Phosphate

Prism/Coffin-lid

Normal Crystals, seen in alkaline urine

Ampicillin Crystals

Long thin clusters of needles

Due to high levels of antibiotics

Sulfanimide crystals

Yellow/brown, Fan-shaped bow-ties

Abnormal, Drug-associated

Bilirubin crystals

Yellow/brown, fine amorphous needles

Abnormal, due to liver disease

Cholesterol Crystals

Flat plates with corner notches

Abnormal crystals, seen with lipiduria/proteinuria

Cystine crystals

6-sided plates, refractile

Abnormal, seen with cystinosis/cystinuria

Hemosiderin

Brown, granules in clumps

Abnormal, seen post-hemolytic event

Leucine

Dark yellow/brown, spheres with concentric circles

Abnormal, seen with liver disease

Tyrosine

Colorless-brown fine needles (Pine needles)
Abnormal, Seen with liver disease

Trichomonas

Looks similar to WBC, must be moving to call

Parasitic eggs/worms

can be schistoma or enterobius

Spermatozoa

Must see heads and tails to call

Starch Crystals

Pseudo maltese cross

From gloves