Renal Function

Question 1

Function of Kidney

Answer 1

Concentration of Urine
Reabsorption of Nutrients
Acid base and electrolyte balance
Excretion of waste
Blood pressure
Water reabsorption and concentration

Question 2

Hormonal Regulation of Body Water

Answer 2

Anti-Diuretic Hormone (Vasopressin)
Regulates water reabsorption

Question 3

Vasopressin Regulation

Answer 3

Increase ADH, increases water absorption
Decrease ADH, decreases water reabsorption

Question 4

Disease state with Increase ADH

Answer 4

Inappropriate ADH secretion

Question 5

Disease state with Decrease ADH

Answer 5

Diabetes insipidus

Question 6

Osmolality Defintion

Answer 6

Concentration of solutes dissolved in a body’s water
Expressed in milliosmoles (mOsm)/kilogram of water

Question 7

Osmolality Measure

Answer 7

Osmotic pressure across body membranes
Measure of the osmoles of solute or dissolved particles per kg

Question 8

Osmometry

Answer 8

Term used for the analysis osmolality

Question 9

Formula 1 for Osmolality

Answer 9

2.0(Na+) + (glucose/20) + (BUN/3)

Question 10

Formula 2 for Osmolality

Answer 10

1.86(Na+) + (glucose/18) + (BUN/2.8) + 9

Question 11

Osmolar Gap

Answer 11

Difference between the calculated and measures osmolalities

Question 12

Urine Osmolarity 24 hr Collection

Answer 12

300-900 mOsm/kg

Question 13

Urine Osmolarity Random

Answer 13

50-1200 mOsm/kg

Question 14

Urine to Serum Ratio

Answer 14

1.0-3.0

Question 15

Serum Osmolarity

Answer 15

275-295 mOsm/kg

Question 16

Osmolar Gap

Answer 16

5-10 mOsm/kg

Question 17

Principles of ABG Measurement

Answer 17

Freezing Point Decrease
Vapor Pressure Decrease
Boiling Point Increase
Osmotic Pressure Increase

Question 18

Freezing Point Osmometry

Answer 18

Determined super-cooling the sample below the freezing point
- Initiated by physical shock or very cold stir wire
- Water-ice mixture produced which remains at freezing point plateau long enough for temperature to be measured
- Uses a 2 point calibration against salt solutions

Question 19

Vapor Pressure Osmometry

Answer 19

Changes in concentration of solutes are accompanied by linear and proportional chances in properties
- Vapor pressure is a force exerted by the gaseous phase of a two phase system
- The pressure of the vapor that is formed above its liquid is called the vapor pressure

Question 20

Common Increases to Osmolar Gap

Answer 20

> 10 mOsm/kg
Mannitol
Glycine
Methanol
Ethylene glycol
Higher the gap, the worse the prognosis

Question 21

Basic Body Fluid Compartments

Answer 21

Two basic compartments
Intracellular Fluid Compartment (ICF)
Extracelluar Fluid Compartment (ECF)

Question 22

Water Osmolality

Answer 22

Moves passively across semi-permeable membranes
Lytes and other molecules do not
Osmotic Pressure

Question 23

Thirst Mechanism

Answer 23

Thirst Center in Hypothalamus
Osmoreceptors stimulated by increase in ionic concentration

Question 24

Renal Clearance

Answer 24

Determined by Glomerular Filtration Rate (GFR)
The mL/minute blood filtered by the kidney

Question 25

Creatinine Clearance Calculation

Answer 25

(U x V)/P x 1.73/A U = Urine Creatinine V = Volume/min P = Plasma Creatinine A = Area of patient - obtained via chart

Question 26

Non-Protein Nitrogen Compounds

Answer 26

NPN Nitrogen containing compounds that are not proteins BUN, Uric Acid, Creatinine/Creatine, Ammonia

Question 27

Renal Disease Marker

Answer 27

Creatinine

Question 28

Muscular Disorders Marker

Answer 28

Creatine

Question 29

Jaffe Reaction

Answer 29

Picric Acid reacts with NaOH Reaction creates Alkaline-Picrate Creatinine Complex Yellow-Orange Color inidicator

Question 30

BUN

Answer 30

Blood Urea Nitrogen

Question 31

Urea

Answer 31

Urine compound of Nitrogen Secretion of Ammonia to remove excess Nitrogen

Question 32

Azotemia

Answer 32

Increase levels of BUN in plasma

Question 33

Uremia

Answer 33

Increase BUN with renal failure

Question 34

BUN Increases Means

Answer 34

Low renal profusion Renal Disease High Protein Intake Dehydration

Question 35

BUN Decrease Means

Answer 35

Low Protein Intake Severe Liver Disease Severe Vomiting or Diarrhea

Question 36

Enzymatic detection of BUN

Answer 36

Conversion of urea to ammonia by enzyme urease BUN --- urease reaction to create ammonia + CO2

Question 37

Berthelot Reaction

Answer 37

Ammonium ion is reacted with phenol and hypochlorite in an alkaline medium to form indophenol Nitroprusside is used to catalyze the reaction - blue color

Question 38

Enzymatic Assay

Answer 38

Ammonia generated from urease Urease reacts with oxo-glutarate in presence of glutamate dehydrogenase and NAD(P)H

Question 39

Chemical Method

Answer 39

Urea is reacted directly with diacetyl to produce diazine - Not as commonly used as enzymatic methods

Question 40

BUN/Creatinine ratio in healthy individuals

Answer 40

10:1 to 20:1 ratio

Question 41

Pre-renal azotemia ratio

Answer 41

Increase ratio 20:1 to 30:1

Question 42

Post-renal azotemia ratio

Answer 42

Increase ratio of >>>20:1 with high creatinine level

Question 43

Low BUN coniditions

Answer 43

Decrease ratio <10:1 Associated with low urea production as in liver disease or malnutrition

Question 44

Uric Acid Product from

Answer 44

Purine Metabolism

Question 45

Increased Uric Acid

Answer 45

Gout - abnormal deposition or uric acid crystals Renal Insufficiency - not filtered UA can also elevate in malignancies (ie myelogenous leukemia)

Question 46

Decrease Uric Acid

Answer 46

Rare

Question 47

Uric Acid Methodology

Answer 47

Conversion of Uric Acid to Allantoin Uric Acid + Phosphotungstic acid = Tungsten Blue

Question 48

Formation of Allantoin

Answer 48

Breakdown of uric acid under action of enzyme uricase Use heparinize plasma, serum or urine Avoid lipemia and hemolysis Urine pH 8 to avoid precipitation

Question 49

Ammonia General Info

Answer 49

Produced from deamination of amino acids Bacterial metabolism in the gut Converted to BUN in liver Can be toxic especially to neural cells

Question 50

Ammonia Clinical Application

Answer 50

Increase hepatic failure Reyes Syndrome Pediatric disorder Post Viral Infection with Aspirin Administration Shows fatty infiltration of liver Inherited deficiencies of urea cycle

Question 51

Ammonia Methodology

Answer 51

Direct measurement Using Ion Selective Electrode - Ammonium ion converted to ammonia dependent on pH Enzymatic Method - Measuring conversion of NADPH to NADP - Glutamate dehydrogenase