Urine Analysis Interpretation PPT

Urine analysis interpretation Sara Hennawi,MD Lecturer of pediatrics Methods of collection 1- Spontaneous voiding: Simple and most commonly used method in clinical practice. Before collecting the sample, health personnel should be provided clear instructions to patients in order to minimize...

Urine analysis interpretation Sara Hennawi,MD Lecturer of pediatrics Methods of collection 1- Spontaneous voiding: Simple and most commonly used method in clinical practice. Before collecting the sample, health personnel should be provided clear instructions to patients in order to minimize the chance of contamination from penile/vaginal microbiota (“clean-catch” method). First void a small amount of urine into the toilet and afterward position the container mid- stream in the flow of urine. 2- Urethral catheterization French urinary catheter passed through the urethral meatus after the previous cleansing with proper equipment. In patients with a urinary catheter already placed, the specimen should never be taken from the catheter bag as it is considered contaminated. 3- Suprapubic needle aspiration of the bladder. Used in small children when samples may not be obtained or are persistently contaminated through previous methods. The main advantage is that, by bypassing the urethra, it minimizes the risk of obtaining a contaminated sample. Interfering Factors Light and Temperature: room temperature favors the growth of microorganisms, such as bacteria. Bacterial Growth: Contamination of the sample or pathogenic bacteria may produce a variety of inaccurate results. Alkaline pH: This concentration may show false-positive results regarding the presence of protein. Glucose: If present in the sample, it may be metabolized by microorganisms and cause a decrease in the sample's pH. Contrast Agents: May produce false-positive results of specific gravity. Exercise: May alter the specific gravity. Foods and Drugs: May alter the urine's color, odor, or pH value. Examples include, but are not limited to, red beets, blackberries, rhubarb, food coloring (e.g., aniline), ibuprofen, chloroquine, metronidazole, deferoxamine, nitrofurantoin, phenytoin, rifampicin, phenolphthalein, phenothiazines, and imipenem/cilastatin. Preservatives. Urine analysis components Physical examination describes the volume, color, clarity, odor, and specific gravity. Chemical examination identifies pH, red blood cells, white blood cells, proteins, glucose, urobilinogen, bilirubin, ketone bodies, leukocyte esterase, and nitrites. Microscopic examination encompasses the detection of casts, cells, crystals, and microorganisms. Physical examination Physical examination 1- Color: Normal: Yellow (light/pale to dark/deep amber) Brown/Black (Tea-colored): Bile pigments, homogentisic acid (alkaptonuria), metronidazole, myoglobin, nitrofurantoin, Dark Yellow: Concentrated specimen (dehydration, exercise) Green/Blue: biliverdin, clorets (breath mint), methylene blue, promethazine, propofol, pseudomonal UTI. Orange: Bile pigments, carrots, nitrofurantoin, phenothiazines, rifampin, vitamin C Pink/Red: Beets, blackberries, chlorpromazine, food dyes, hematuria, hemoglobinuria, menstrual contamination, myoglobinuria, uric acid crystals. Physical examination 2- Appearance: Normal: Clear or translucent 3- Volume: Normal: 0.5 to 1.5 cc/kg/hour or 600 to 2,000 mL daily in adults (typically 1,000– 1,600 mL/day) Anuria (less than 100 cc/day) and oliguria (less than 500 cc/day): Severe dehydration from vomiting, diarrhea, hemorrhage or excessive sweating; renal disease, renal obstruction, renal ischemia secondary to heart failure or hypotension  Polyuria (greater than 2,500 - 3,000 cc/day and in infants >4ml/kg/ day ) 1. Diabetes mellitus 2. Diabetes insipidus 3. Polycystic kidney 4. Chronic renal failure 5. Diuretics 6. Intravenous saline/glucose  Anuria (No or minimal urine output / less than 100 cc/day) Oliguria (Urine output< 1ml/kg/hr in infants and < 0.5 ml/kg/hr in less than 500 cc/day ): 1. Dehydration 2. -Vomiting, diarrhea, excessive sweating 3. Renal ischemia 4. Acute tubular necrosis 5. Obstruction to the urinary tract 6. Acute renal failure 4- Odor Normal: Aromatic "Urinoid" ○ Dehydration/Prolonged Room Temperature: Strong smell ○ Diabetic Ketoacidosis: Fruity/sweet ○ Gastrointestinal-bladder Fistula: Fecal smell ○ Maple-syrup Urine Disease: "Burnt sugar." ○ Prolonged Bladder Retention: Ammoniacal ○ Urinary Tract Infection: Pungent or fetid ○ Medications and Diet: Onions, garlic, asparagus 5- Specific gravity Normal: 1015-1025 `Depends on the concentration of various solutes in the urine High specific gravity 1- All causes of oliguria 2- Diabetes mellitus Low specific gravity 1- All causes of polyuria except glucosuria 2- Fixed specific gravity (isosthenuria)=1010 Seen in chronic renal disease when kidney has lost the ability to concentrate or dilute Chemical examination 1. Urine pH 2. Proteins 3. Sugars 4. Ketone bodies 5. Bilirubin 6. Bile salts 7. Urobilinogen 8. Blood  Chemical examination 1- Urine pH: Normal= 4.6-8 (usually 5.5- 6.6) Reaction reflects ability of kidney to maintain normal hydrogen ion concentration in plasma & ECF A urinary pH greater than 5.5 in the presence of systemic acidemia suggests renal dysfunction related to an inability to excrete hydrogen ions.  Acidic urine 1. Ketosis: diabetes, starvation, fever 2. Systemic acidosis 3. UTI- E.coli 4. Acidification therapy Alkaline urine 1. Systemic alkalosis 2. UTI- Proteus 3. Alkalization therapy Chemical examination 2- Proteins: are normally present in urine in trace amounts. Proteinuria: Protein excretion>150 mg/24 h Degree Mild :150-500 mg/24 h Moderate :500-1000 mg /24 h Massive : >1 gm/24 h  Types of proteinuria Selective: the protein in urine is of low molecular weight. Nonselective: high molecular weight protein 1-  Causes of proteinuria 1- Transient -Heavy exercise, fever, stress, dehydration. 2- Persistent - Postural - Tubular: interstitial nephritis, acute tubular necrosis - Glomerular: glomerulonephritis 3- Glucose The renal threshold for glucose (RTg) corresponds to a blood glucose level of ~180 mg/dL; Causes: Glycosuria with hyperglycemia: diabetes, acromegaly, cushing disease, hyperthyroidism, drugs like corticosteroids. Glycosuria without hyperglycemia: renal tubular dysfunction 4- Ketones: Normal : No ketonuria Causes of ketonuria 1- Diabetes: with diabetic ketoacidosis 2- Non-diabetic causes 5- Bilirubin Causes of bilirubinuria : -Liver diseases: injury, hepatitis -Obstruction to biliary tract Urobilinogen Causes: hemolytic anemias Bile salts Cause: Obstruction to bile flow (obstructive jaundice) Nitrite testing is sensitive, but not specific, in detecting UTIs. Normally no nitrites are detected in the urine. Urinary nitrates are converted to nitrites by bacteria in the urine. A positive nitrite result signifies that bacteria capable of this conversion (eg, Escherichia coli, Klebsiella, Proteus, Enterobacter, Citrobacter, Pseudomonas) are present in the urinary tract. WBCs contain an enzyme known as leukocyte esterase, which is released when WBCs undergo lysis. Normally, too few WBCs are present in the urine for the test to be positive. However, when the number of WBCs in the urine increases, the result becomes positive. A positive leukocyte esterase test result indicates pyuria. Pyuria typically implies a UTI. Sterile pyuria is seen in analgesic nephropathy and UTIs due to organisms that do not grow by standard culture techniques (eg, Chlamydia, Mycobacterium tuberculosis, Ureaplasma urealyticum). Microscopic examination Contents of normal urine Contains few epithelial cells, few crystals RBCS 0-5/HPF Pus cells 0-5/HPF 1- RBCs (Hematuria) The presence of 5 or more (RBCs) per high-powered field (HPF) Renal :brown colored, edema, hypertension, RBCs cast, proteinuria Urologic: red urine, may contain blood clot  Causes I. Glomerular Isolated Renal disease: -Post infectious GN -Focal Segmental Glomerulosclerosis -IgA Nephropathy (Berger disease) -Alport syndrome (hereditary nephritis) -Anti-glomerular basement membrane disease. -Membranoproliferative GN Multisystem disease: -Systemic Lupus Erythromatosus -Goodpasture Syndrome -Hemolytic uremic syndrome -Sickle cell glomerulopathy -Vasculitis syndromes (Wegener granulomatosis. Polyarteritis nodosa) II. Extra-Glomerular a.Upper urinary tract Polycystic kidney , trauma, hydronephrosis , tumor , vascular , hemoglobinopathy and crystalluria b. Lower urinary tract: Inflammation , stone, trauma, coagulopathy 2- WBCs The number of WBCs considered normal is typically 2-5 WBCs/hpf or less. A high number of WBCs indicates infection, inflammation, or contamination.Typically, most of the WBCs found are neutrophils. 3- Crystals Crystals in acidic urine 1. Uric acid 2. Calcium oxalate 3. Cystine 4. Leucine Crystals in alkaline urine 1. Ammonium, magnesium, phosphates 2. Calcium carbonate 4-Urinary casts: are cylindrical aggregations of particles that form in the distal nephron, dislodge, and pass into the urine. In urinalysis they indicate kidney disease. Hyaline casts may be seen in healthy individuals. Other types of casts are not normally found and are suggestive of renal disease. In particular, the finding of cells within a cast is diagnostic of an intrarenal origin  Types of casts Acellular casts Cellular casts Hyaline casts Red cell casts Granular casts White cell casts Waxy casts Epithelial cell cast Fatty casts Pigment casts  Hayline casts The most common type of cast. Seen in fever, exercise, damage to the glomerular capillary Granular casts indicative of chronic renal disease Waxy casts suggest severe, longstanding kidney disease such as renal failure (end stage renal disease). Fatty cast found in nephrotic syndrome and diabetic or lupus nephropathy  Pigment casts such as hemoglobin hemolytic anemia , myoglobin in rhabdomyolysis, and bilirubin in liver disease. RBCs cast RBCs within the cast is always pathologic, and is strongly indicative of are glomerular damage usually associated with nephritic syndromes. WBCs cast Indicative of inflammation or infection , pyelonephritis ,nephrotic syndrome, or post-streptococcal acute glomerulonephritis. Epithelial cast in acute tubular necrosis and toxic ingestion, such as from mercury, or salicylate.