Urinalysis Case Studies

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OBJECTIVES: At the end of this tutorial, and after studying the urinalysis handout, the student should be able to: Describe how to properly collect, store, and test a urine sample. List the types of urine collection procedures. Describe what urine specific gravity is and what affects it. Describe the significance and interpretation of urine dipstick reagent strip reactions for the following: pH, protein, glucose, ketones, bilirubin, blood, urobilinogen, nitrite, leukocyte esterase. Describe how red blood cells, white blood cells, squamous cells, transitional cells, and tubular epithelial cells get into urine and what their significance is. Describe how urinary casts are formed and list the types of casts. Describe the significance of yeast, bacteria, and crystals in urinary sediment. Correlate urinalysis findings with the clinical history. Determine what additional clinical procedures should be done upon finding an abnormal result. CASE 1 (Click here to go to the answers) History: A 14-year-old boy is brought to the pediatrician by his mother because he has had a fever with shaking chills for the past day. On physical examination, he has a temperature of 39.6 C and has mild right costovertebral angle tenderness. Macroscopic Urinalysis: Characteristic Result Color Yellow Appearance Turbid Leukocyte Esterase 3+ Nitrite Pos pH 6.5 Protein Neg Blood Neg Specific Gravity 1.015 Ketones 1+ Glucose Neg Bilirubin Neg Microscopic Urinalysis: Characteristic Result WBC/hpf >50/hpf RBC/hpf 5-10/hpf Casts Many WBC Other Occasional transitional cells Questions: How do you explain the appearance of the urine? How do you relate this to other findings? What is the significance of the finding on physical examination? Is there a relation between the color of the urine and the diagnosis? What findings on microscopic urinalysis are of help in this case? What is the suspected diagnosis? What else should you do? CASE 2 (Click here to go to the answers) History: A 23-year-old woman has noted an increase in her appetite and thirst over the past six months, although she has lost 2 kg (5 pounds). The patient also has had considerable frequency of urine output, without associated dysuria. On physical examination her vital signs include T 37 C, P 77/min, RR 16/min, and BP 120/70 mm Hg. A midstream clean catch urine sample is obtained. Macroscopic Urinalysis: Characteristic Result Color Yellow Appearance Clear Leukocyte Esterase Neg Nitrite Neg pH 5.5 Protein Neg Blood Neg Specific Gravity 1.025 Ketones 4+ Glucose 4+ Bilirubin Neg Microscopic Urinalysis: Characteristic Result WBC/hpf None RBC/hpf 1-2/hpf Casts None Other None Questions: What disease is suggested by these findings? Will all sugars be detected by the reagent test strip for glucose? Why? What is the significance of the positive test for ketones? What would you suspect if the ketones were positive and everything else was normal? What other laboratory tests should be done in this patient? What are some complications of her disease that can affect the urinary tract? CASE 3 (Click here to go to the answers) History: A 5-year-old boy usually drove his mother crazy by running around the house, but he has been lethargic for the past 2 weeks. On physical examination he is afebrile, but there is puffiness around his eyes. Macroscopic Urinalysis: Characteristic Result Color Yellow Appearance Hazy Leukocyte Esterase Neg Nitrite Neg pH 6.0 Protein 4+ Blood Neg Specific Gravity 1.020 Ketones Neg Glucose Neg Bilirubin Neg Microscopic Urinalysis: Characteristic Result WBC/hpf 1-2/hpf RBC/hpf None Casts None Other Occasional oval fat bodies Questions: What abnormal finding is present? Just what does the dipstick measure here, and what other test could be done on the urine? What is suggested by the child's physical findings? What other laboratory test(s) would be useful? What is the diagnosis? CASE 4 (Click here to go to the answers) History: A 45-year-old man comes to his physician after spending a second sleepless night with excruciating lower abdominal pain. The pain seemed to come in waves and was unrelieved by aspirin, tylenol, a six-pack of beer, or lying or standing in any position. He had not experienced any similar pain before. On physical examination there are no abnormal findings. Macroscopic Urinalysis: Characteristic Result Color Dark Yellow Appearance Cloudy Leukocyte Esterase Neg Nitrite Neg pH 6.0 Protein Neg Blood 3+ Specific Gravity 1.015 Ketones Neg Glucose Neg Bilirubin Neg Microscopic Urinalysis: Characteristic Result WBC/hpf 2-5/hpf RBC/hpf >100/hpf Casts None Other Occasional squamous epithelial cells Questions: What abnormal findings are present? What is the differential diagnosis? What diagnosis do you suspect? What other studies could be done? CASE 5 (Click here to go to the answers) History: A 22-year-old African-American woman is admitted to hospital because of swelling of the legs and a weight gain of 4 kg (10 lbs) over the past week. She has felt extremely tired for the past month. On physical examination she is afebrile. Her blood pressure is 145/95 mm Hg. A chest radiograph shows marked pleural effusions. Macroscopic Urinalysis: Characteristic Result Color Yellow Appearance Cloudy Leukocyte Esterase Neg Nitrite Neg pH 6.0 Protein 3+ Blood 2+ Specific Gravity 1.020 Ketones Neg Glucose Neg Bilirubin Neg Microscopic Urinalysis: Characteristic Result WBC/hpf <5/hpf RBC/hpf 5-10/hpf Casts Many hyaline, WBC, RBC, granular casts Other Mucus, renal tubular cells Questions: What is suggested by these findings? What are possible underlying disease processes? What additional laboratory tests would be helpful? CASE 6 (Click here to go to the answers) History: Two construction workers manage to dislodge a large boulder from the path of a new water pipe installation. As the boulder begins rolling, they suddenly become aware of a pickup truck parked below them at the bottom of the hill. The boulder smashes through the side window and lands on the driver's lap. The injured 44-year-old man has multiple contusions from the blunt trauma to his thighs and lower abdomen. Radiographs reveal no bony fractures. A paracentesis yields no blood. That evening in hospital, the injured man's urine output begins to drop. Macroscopic Urinalysis: Characteristic Result Color Yellow-Brown Appearance Slightly Cloudy Leukocyte Esterase Neg Nitrite Neg pH 7.0 Protein Trace Blood 3+ Specific Gravity 1.010 Ketones Neg Glucose Neg Bilirubin Neg Microscopic Urinalysis: Characteristic Result WBC/hpf <2/hpf RBC/hpf 0-1/hpf Casts Occasional hyaline, granular casts Other Squamous and renal tubular epithelial cells Questions: How do you explain the macroscopic findings in view of the microscopic findings? How does the history fit with this? What further laboratory studies would be of help? Explain the appearance of the casts and epithelial cells. What are some other causes for this condition? CASE 7 (Click here to go to the answers) History: A 48-year-old man has noted increased thirst and urine output, even getting him up at night, along with mild back pain. On physical examination he is afebrile, but his blood pressure is 160/100 mm Hg. There is right costovertebral angle tenderness. Family history reveals that his father died in his early 50's of "kidney" disease. An intravenous pyelogram (IVP) shows no hydronephrosis or filling defects, but both his kidneys are markedly enlarged. Macroscopic Urinalysis: Characteristic Result Color Yellow Appearance Slightly Cloudy Leukocyte Esterase Neg Nitrite Neg pH 6.5 Protein 1+ Blood 1+ Specific Gravity 1.010 Ketones Neg Glucose Neg Bilirubin Neg Microscopic Urinalysis: Characteristic Result WBC/hpf <2/hpf RBC/hpf 5-10/hpf Casts None Other Many oxalate crystals Questions: What do the historical findings suggest? What laboratory tests would be useful? If you were to give the patient anti-diuretic hormone (ADH) or if he didn't drink any water for 12 hours, and then the urinalysis was repeated and the specific gravity was still 1.010, what would this suggest? Why do you think the kidneys are enlarged? CASE 8 (Click here to go to the answers) History: A 57-year-old man has a routine urinalysis as part of his company's yearly required physical examination. He has a chronic cough (50 pack/year smoking history). His only complaints referable to the urinary tract are some mild dysuria and hesitancy, but he otherwise feels fine. On physical examination there are no abnormal findings. Macroscopic Urinalysis: Characteristic Result Color Amber Appearance Hazy Leukocyte Esterase Neg Nitrite Neg pH 5.0 Protein Trace Blood 2+ Specific Gravity 1.020 Ketones Trace Glucose Neg Bilirubin Neg Microscopic Urinalysis: Characteristic Result WBC/hpf <2/hpf RBC/hpf 10-30/hpf Casts Occasional hyaline casts Other Atypical urothelial cells present Questions: What do these findings suggest? What further studies are indicated? What social or environmental history would be important? CASE 9 (Click here to go to the answers) History: A 39-year-old woman comes to you complaining of lower abdominal pain which she has had for the past day. She left her job as a nurse's aide (her second day on the job) because the pain was so bad. She says the pain began after she had fallen off a stepstool while getting a bedpan off a top shelf. No one saw her fall, but she convinced her supervisor that she had an industrial accident and needed medical attention because of blood in her urine. To prove it, she brings in a urine specimen. Macroscopic Urinalysis: Characteristic Result Color Red Appearance Clear Leukocyte Esterase Neg Nitrite Neg pH 7.0 Protein Neg Blood Neg Specific Gravity 1.015 Ketones Neg Glucose Neg Bilirubin Neg Microscopic Urinalysis: Characteristic Result WBC/hpf <2/hpf RBC/hpf None Casts Occasional hyaline casts Other Few squamous epithelial cells Questions: How do you correlate the macroscopic and microscopic findings? What do you think is happening?

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