Exam I Flashcards
What are the two dominant manifestations of acute glomerulonephritis?
proteinuria; hematuria with RBC casts
What are the causes of acute glomerulonephritis?
streptococcal infections, immune complex disease, hereditary disease, metabolic disorders
What are the clinical manifestations of acute tubular necrosis?
decreased urine flow, inability to concentrate urine, and loss of many tubular epithelial cells into urine
What is acute tubular necrosis often associated with?
reduced blood supply to renal tubules
What are the three manifestations of nephrotic syndrome?
proteinuria, hypoproteinemia, edema
What are the common causes of urinary obstruction?
congenital malformation, stricture from infection, tumors (neoplasia, such as cervical or prostatic tumors), stones (calculi)
Explain pyelonephritis.
an infection of the kidney(s) ad renal pelvis which initially affects renal interstitium but progresses into renal tubules; usually originates from colon or perineum, and most commonly follows a bladder infection in which bacteria follow the ureters up to the kidneys
What are the two main clinical findings in urine that may indicate diabetes mellitus?
glucosuria and ketonuria
What would you expect to see in regards to volume and specific gravity in diabetes mellitus?
both would be increased due to increased urine glucose and extra water required to excrete it
Explain unconjugated bilirubin (other names, characteristics, where and how it’s formed).
free or indirect bilirubin; found in the blood, where it is loosely linked to albumin; insoluble in water and therefore not found in urine; travels to the liver where it is separated from the albumin
Where is bilirubin formed?
in the spleen and other tissues of the reticuloendothelial (RE) system
Explain conjugated bilirubin (other names, characteristics, where and how it’s formed).
direct bilirubin or bilirubin diglucoronide; forms in the liver, where unconjugated bilirubin undergoes esterification with glucoronic acid; water soluble, therefore it can be found in urine
Explain urobilinogen (characteristics, where and how it’s formed).
formed when conjugated bilirubin travels through the bile duct to the small intestine, where intestinal flora reduce it to a colorless compound; some will be absorbed by intestinal mucosa and carried back to the liver to be re-excreted into the bile (enterohepatic/portal circulation) - a small amount of this reabsorbed portion escapes the liver and is excreted in the urine, though ~99% is excreted in the feces
What are the levels of bilirubin and urobilinogen in a healthy patient?
no bilirubin, normal or decreased urobilinogen
What are the levels of bilirubin and urobilinogen in hemolytic disease?
no bilirubin, normal or increased urobilinogen
What are the levels of bilirubin and urobilinogen in hepatic disease?
+ or = bilirubin, normal to increased urobilinogen
What are the levels of bilirubin and urobilinogen in biliary obstruction?
+ bilirubin, decreased or absent urobilinogen
Define PKU, including how it might be detected or diagnosed.
phenylketonuria; autosomal recessive disease in which the enzyme phenylalanine hydroxylase is deficient or defective, so the body cannot convert phenylalanine into tyrosine; marked by increased excretion of phenylpyruvic acid (its metabolite), urine will have a mousy odor; diagnosed using the Phentest - ferric ions, when combined with phenylpyruvic acid, produce a dark green to blue-green color
Define alkaptonuria, including how it might be detected or diagnosed.
rare, autosomal recessive disease in which the liver enzyme homogenistic acid (HGA) oxidase is deficient or absent, therefore it cannot oxidize HGA into maleylacetoacetic acid; large amounts of HGA will be present in the urine (urine will darken when alkali is added to it, or it is exposed to air and sunlight, and a fine black precipitate will form), Clinitest will be orange; diagnosed around middle age; other clinical symptoms include blue or black tissue pigment and degenerative arthritis
Define maple syrup disease, including how it might be detected or diagnosed.
deficiency of branched-chain alpha-keto acid dehydrogenase causes the accumulation of the amino acids leucine, isoleucine, and valine, and their corresponding keto and hydroxy acids in blood, CSF, and urine; urine will have a distinctive maple syrup or caramelized sugar odor, and Acetest will be purple; actual diagnosis is made following amino acid analysis of plasma, urine, or CSF using ion exchange chromatography; causes ketoacidosis, vomiting, seizures, and even death
Define Fanconi’s syndrome, including how it might be detected or diagnosed.
complication of inherited and acquired diseases characterized by generalized proximal convoluted dysfunction resulting in aminoaciduria, proteinuria, glucosuria, and phosphaturia; these deficiencies can cause death in childhood; common causes include heavy metal poisoning and the hereditary disease cystinosis
Define cystinosis, including how it might be detected or diagnosed.
inherited lysosomal storage disease resulting in the intracellular deposition of cystine in the lysosomes of cells, particularly in the kidneys, eyes, bone marrow, and spleen; cystine crystallizes and causes damage to the cells and their cellular function
Define cystinuria, including how it might be detected or diagnosed.
caused by cystinosis; characterized by urinary excretion of large amounts of cystine and the dibasic amino acids (arginine, lysine, ornithine), due to the nephrons (proximal tubule cells) being unable to reabsorb these amino acids, as well as defective intestinal reabsorption of them; cystine has a pKa of 8.3 (pH of a solution in which half the acid molecules are ionized), so cystine crystals will appear in urine with a pH of = 8; the amino acids are soluble regardless of pH and require additional testing; in vivo cystine precipitation and renal calculi formation can occur; hematuria and sudden severe abdominal or lower back pain are also clinical manifestations
Define galactosemia, including how it might be detected or diagnosed.
associated most often with three rare disorders that cause an enzyme in the galactose metabolic pathway to be defective or deficient. This causes galactose and galactose 1-phosphate to accumulate in the blood, where they are metabolized by alternate pathways to galactitol or galactonate
What are the types of galactosemia disorders and what are their clinical manifestations?
Type I (GALT deficient) - infants present with failure to thrive, vomiting, jaundice, and diarrhea; hepatomegaly is common, with possible progress to cirrhosis; sepsis and shock can occur, as well as cataracts. Type II (GALK deficient) - cataracts are the predominant symptom, usually present shortly after birth. Type III (GALE deficient) - extremely rare; mild to severe cataracts, failure to thrive, liver and kidney disease
What laboratory testing can be done to diagnose galactosemia?
testing the urine for galactose (galactosuria) is a means of screening, with a = on the dipstick for glucose and a + Clinitest; confirmation requires enzymatic assays, chromatography, and molecular methods on blood and cultured fibroblasts
Define hematuria, including some conditions that may cause it.
urine with an abnormal quantity of red cells; urine appears smoky/cloudy, and color can range from normal yellow to pink, red, or brown; can be caused by kidney and urinary tract disease (glomerulonephritis, pyelonephritis), cystitis (bladder infection), renal calculi (stones), benign or cancerous tumors, trauma, hypertension, normal or strenuous exercise, smoking, medications (cyclophosphamide, anticoagulants), and chemical toxicity
What type of urine container and/or specimen is required for a urine culture?
sterile container; midstream clean catch, catheterized (urethral), suprapubic aspiration
What type of urine container and/or specimen is required for overall patient health?
any urine container; random specimen, routine void, midstream clean catch, pediatric collection bag, first morning specimen
What type of urine container and/or specimen is required for Addis count?
large urine container; 12 hour specimen
What type of urine container and/or specimen is required for postprandial urine?
any urine container; fractional collection, 2-3 hours after eating
What type of urine container and/or specimen is required for protein?
any urine container, first morning or 24 hour specimen
What type of urine container and/or specimen is required for glomerular filtration rate (GFR)?
large urine container; 24 hour specimen
What type of urine container and/or specimen is required for quantitative glucose?
large urine container; 24 hour specimen
What are the physical changes that can occur as a urine specimen remains at room temperature?
color will darken or change due to oxidation/reduction of solutes; clarity decreases from crystal precipitation and bacterial proliferation; odor becomes ammoniacal/foul (bacterial conversion of urea to ammonia, loss of CO2)
What are the chemical and cellular changes that can occur as a urine specimen remains at room temperature?
pH increases; glucose decreases (consumed by cells and/or bacteria); ketones decrease (volatilization and bacterial conversion); bilirubin decreases (photo-oxidation to biliverdin); decreased urobilinogen (oxidization to urobilin); increased nitrite (bacterial conversion to dietary nitrates); decreased blood cells (lysis and/or disintegration); decreased casts (disintegration); increased bacteria (exponential proliferation); decreased trichomonads (loss of characteristic motility and death)
Define catheterization, including when and on what patients it is used.
sterile catheter inserted into the bladder through the urethra; urine flows directly through the catheter and accumulates in a plastic resevoir bag - urine can be collected from this bag at any time; used for elderly, immobile, unconscious, or pediatric patients
Define suprapubic aspiration, including when and on what patients it is used.
urine collected directly from the bladder by puncturing the abdominal wall and distended bladder using a needle and syringe, primarily for anaerobic bacterial cultures; usually performed on infants, patients being tested for anaerobes, and especially on patients not able to pass urine due to obesity and/or severe illness
What three characteristics of urine are routinely recorded as part of the physical examination of urine?
color, clarity, and odor
Which urine preservative gives a false positive for albumin in a protein precipitate (turbidity) test?
thymol
What is the best method of urine preservation for bacterial cultures?
refrigeration
Which preservatives are used to preserve the cellular elements in urine?
formalin (preferred), Saccomanno’s fixative
For which Multistix reactions is timing not critical?
pH and protein
What is the total time needed to read all Multistix reactions?
2 minutes
What are the ten tests performed in a routine chemical analysis of urine?
glucose, bilirubin, ketones, specific gravity, blood, pH, protein, urobilinogen, nitrites, and leukocytes
What can a pale yellow color indicate about a urine sample?
it is diluted, possibly due to polyuria
What can a dark yellow to amber color indicate about a urine sample?
excessive urobilin or bilirubin
What can a dark yellow-green color indicate about a urine sample?
biliverdin
What can an orange color indicate about a urine sample?
due to food and/or certain medications
What can a yellow-brown color indicate about a urine sample?
medication such as Nitrofurantoin
What can a pink color indicate about a urine sample?
the presence of blood (hemoglobin and/or red cells), or an inherited disease (porphobilin)
What can a red color indicate about a urine sample?
blood (hemoglobin and/or red cells), beet ingestion, medication (Senna)
What can a red-purple color indicate about a urine sample?
inherited disease (porphyrins)
What can a brown color indicate about a urine sample?
presence of myoglobin, blood, bilirubin, or medications
What can a dark brown to black color indicate about a urine sample?
presence of melanin or HGA (homogentisic acid, inherited)
What can a blue or green color indicate about a urine sample?
Pseudomonas aeruginosa infection, indican, radiographic dyes, or medication
What constituents of urine can cause turbidity?
crystals, amorphous, lipids, microbes, increased numbers of white cells or squamous epithelial cells, radiographic contrast media, contaminants (lotion, powder, feces, etc.)
What is the presence of lipids in urine associated with?
nephrotic syndrome
What may cause large amounts of white or yellow foam in urine when a sample is shaken?
white - protein, yellow - bilirubin
What kind of urine smells faintly aromatic?
normal
What kind of urine smells ammoniacal?
an aged sample
What causes urine to smell pungent or fetid?
urinary tract infection
What causes urine to smell sweet or fruity?
ketones
What causes urine to smell mousy or barny?
phenylketonuria (PKU)
What causes urine to smell like maple syrup?
Maple Syrup Disease
What causes urine to smell rancid?
tyrosinemia
What causes urine to smell like old or rotting fish?
trimethylaminuria
What causes urine to smell like cabbage or hops?
methionine malabsorption
What causes urine to smell like sweaty feet?
isovaleric and glutaric acidemias
What causes urine to smell distinctive?
specific types of food or drink ingested, such as asparagus
What causes urine to smell like menthol?
phenol-containing medication
What causes urine to smell like bleach?
contaminated specimens
What causes urine to smell phenolic?
disinfectants, probably due to an inappropriate container or a contaminated specimen
What is the specific gravity range or normal urine?
1.002 - 1.030
What three substances might be present in urine that can cause high specific gravity readings?
protein, glucose, and radiographic dye
Define refractive index.
ratio of light refraction in two differing medias, such as the velocity of light in air vs. the velocity of light in a solution
Define osmolality.
an expression of concentration in terms of the total number of solute particles present per kilogram of solvent, denoted as osmoles per kilogram of water
Define specific gravity.
a measure of the concentration of a solution based on its density; solution density is compared with that of an equal volume of water, and denoted as mass of solutes per volume of solution
What is the main difference between osmolality and specific gravity?
osmolality is not affected by the weight of the particles present, whereas specific gravity is
What two normal constituents of urine contribute the most to its specific gravity?
urea and NaCl
What effect would diabetes insipidus have on specific gravity?
abnormally low
What effect would diabetes mellitus have on specific gravity?
abnormally high
Define oliguria, including causes and characteristics.
significant decrease in the volume of urine excreted in a day (
Define anuria, including causes and characteristics.
absence or cessation of urine excretion, which can be fatal if not treated; caused by major hemolytic transfusion reaction, kidney injury from antigen-antibody complexes, urinary obstruction, renal tubular dysfunction, or any other condition that destroys functioning renal tissue
Define hyposthenuria, including causes and characteristics.
urine with a specific gravity
Define polyuria, including causes and characteristics.
excretion of large amounts of urine (>3L/day); also called diuresis; caused by diabetes mellitus
Define nocturia, including causes and characteristics.
increased or excessive excretion of urine at night (>500mL); often associated with kidney disease
Define isosthenuria, including causes and characteristics.
urine that has the same specific gravity and osmolality of plasma (fixed specific gravity of 1.010); indicates significantly impaired renal tubular function, such as chronic renal disorder
Define hypersthenuria, including causes and characteristics.
urine with a high specific gravity; caused by diabetes mellitus with glucosuria, nephrotic syndrome with proteinuria, dehydration (due to fever, vomiting, or diarrhea), and radiographic dyes
What would cause a refrigerated urine specimen to become cloudy?
amorphous crystal formation (urate and phosphate)
What two properties can be utilized in the determination of urine osmolality?
freezing point depression (most common) and vapor pressure
What are the normal and average volumes of urine excreted by an adult in a 24-hour period?
normal: 600-1800mL/day (
