Chemical Pathology/ Abnormal Urinalysis Results

Question 1

What component of a urinalysis helps assess a patient’s hydration status as well as the concentrating ability of the kidneys?

Answer 1

Urine specific gravity

Question 2

When patients develop the following conditions, does their urine specific gravity increase or decrease from baseline?

—> Dehydration

—> Diabetes insipidus

—> Syndrome of inappropriate antidiuretic hormone

Answer 2

• Dehydration —> Increases
• Diabetes insipidus —> Decreases
• Syndrome of inappropriate antidiuretic hormone —> Increases

Question 3

Urinary pH generally reflects the serum pH except in patients with what renal disease?

Answer 3

Renal tubular acidosis

Question 4

What is hematuria?

Answer 4

The presence of red blood cells in the urine (according to the American Urological Association this equals three or more red blood cells per high-powered field in two out of three, clean catch, midstream urine samples)

Question 5

When a dipstick test for hematuria is positive, why is it important to subsequently confirm hematuria microscopically?

Answer 5

Some conditions (myoglobinuria, hemoglobinuria) produce a false positive test for blood on dipstick. In true hematuria, microscopic analysis reveals intact erythrocytes in the urinary sediment.

Question 6

Exercise-induced hematuria is a self-limited and benign condition that should resolve within how many hours?

Answer 6

48 to 72 hrs

Question 7

In general, hematuria accompanied by proteinuria usually indicates that the blood loss is originating from the renal glomeruli. True or false?

Answer 7

True (glomerular hematuria often also presents with erythrocyte casts and dysmorphic RBCs).

Question 8

What is the most common cause of glomerular hematuria?

Answer 8

IgA nephropathy (Berger disease)

Question 9

In general, hematuria in the absence of proteinuria and RBC casts usually indicates a urologic or nonglomerular renal source of bleeding. True or false?

Answer 9

True

Question 10

Give some examples of renal causes of bleeding that present this way(with hematuria in the absence of proteinuria and RBC casts).

Answer 10

• tumors
• cysts
• arteriovenous malformations
• infarctions of the kidney

Question 11

When blood clots are present in urine, is the blood most likely glomerular or urologic in origin?

Answer 11

Urologic

Question 12

What is the next step in management following a positive urine cytology test?

Answer 12

Referral for cystoscopy to rule out malignancy

Question 13

Visualization of the upper urinary tract in a patient being evaluated for urologic bleeding is accomplished through what tests?

Answer 13

CT without contrast or intravenous (IV) pyelogram

Question 14

What environmental exposures are associated with urologic malignancy?

Answer 14

• Smoking
• recreational
• work-related chemical exposure (eg, benzene)

Question 15

A patient with hematuria and the following characteristics would make you suspect what disease?

–> Family history of renal failure and cerebral aneurysms

Answer 15

Polycystic kidney disease

Question 16

A patient with hematuria and the following characteristics would make you suspect what disease?

Family history of male renal failure and hearing loss

Answer 16

Alport syndrome

Question 17

A patient with hematuria and the following characteristics would make you suspect what disease?

–> Fever, weight loss, rash, arthritis

Answer 17

Connective tissue disease (eg, lupus)

Question 18

A patient with hematuria and the following characteristics would make you suspect what disease?—-> Severe flank pain radiating to the groin

Answer 18

Urethral distention most likely from stones

Question 19

A patient with hematuria and the following characteristics would make you suspect what disease?

—-> Palpable purpura of the skin, nausea, vomiting, diarrhea, blood in stool

Answer 19

Henoch-Schonlein purpura

Question 20

What is the definition of proteinuria?

Answer 20

Abnormal urinary protein excretion (borderline proteinuria equals 150-300 mg/day, clinical proteinuria is >300 mg/day)

Question 21

What is the difference between proteinuria and albuminuria and why is it important to make this distinction?

Answer 21

Proteinuria and albuminuria are abnormally high protein and albumin excretion in the urine, respectively. Albumin is a small protein and often the first to leak when there is kidney damage. However, not all patients with proteinuria have albuminuria (such as with light chain proteinuria [Bence-Jones]).

Question 22

Urine dipsticks, which are often used in a clinical setting, offer a method to screen for proteinuria but may give false negative results under what conditions?

Answer 22

Dipstick analysis measures protein concentration so it can miss proteinuria if the urine is dilute. Also, the reagent on the test strips is highly specific for albumin and may miss nonalbumin proteins.

Question 23

What are some causes of transient proteinuria?

Answer 23

• Dehydration
• exercise
• emotional stress
• fever
• seizures
• orthostatic proteinuria

Question 24

What is the workup of asymptomatic transient proteinuria?

Answer 24

None, since it is rarely indicative of significant disease

Question 25

What are the first follow-up tests in the workup of persistent proteinuria?

Answer 25

Spot urine protein to creatinine ratio (often preferred over 24-hour urinary protein excretion), microscopic examination of the urinary sediment, urinary protein electrophoresis (UPEP helps identify nonalbumin proteins), creatinine, and electrolytes

Question 26

Nephrotic syndrome is indicative of glomerular disease. True or false?

Answer 26

True

Question 27

What are the clinical signs that characterize nephrotic syndrome?

Answer 27

* Proteinuria exceeding 3.5 g/day * hypoalbuminemia * edema * hypercholesterolemia

Question 28

Light chain proteinuria (often nephrotic range) with or without renal failure presenting with malignant plasma cells, renal failure, hypercalcemia, anemia, lytic bone lesions, and pathologic fractures suggest the presence of what disease?

Answer 28

Multiple myeloma

Question 29

Light chain proteinuria (often nephrotic range) with or without renal failure presenting with restrictive cardiomyopathy, peripheral neuropathy, hepatomegaly, swelling of extremities suggest the presence of what disease?

Answer 29

Amyloidosis

Question 30

What is the most common cause of nephrotic syndrome in children?

Answer 30

Minimal change disease

Question 31

What is the treatment for minimal change disease?

Answer 31

Steroids

Question 32

Glucosuria occurs when the amount of glucose filtered by the glomerulus exceeds the ability of the proximal tubule to reabsorb it. Usually, this indicates that serum glucose is at least how high?

Answer 32

200 mg/dL (very often an indication of uncontrolled diabetes mellitus)

Question 33

What kind of cells in a urine specimen suggest contamination?

Answer 33

Epithelial cells

Question 34

What is the most common cause of pyuria (\>10 leukocytes/mL)?

Answer 34

Infection

Question 35

What are some causes of pyuria not associated with infection?

Answer 35

* Tumors * nephrolithiasis * trauma * glomerulonephritis * drugs (corticosteroids, cyclophosphamide) * balanitis of noninfectious origin * urethritis of noninfectious origin