Urinalysis and Body Fluids 6th Edition by Majorie DiLorenzo, Susan Strasinger

Exercise 4

B.J. is a seriously ill 40-year-old man with a history of several episodes of macroscopic hematuria in the past

20 years. The episodes were associated with exercise or stress. Until recently the macroscopic hematuria had spontaneously reverted to asymptomatic microscopic hematuria. Significant laboratory results include a BUN of 80 mg/dL (normal 8 to 23 mg/dL), serum creatinine of 4.5 mg/dL (normal 0.6 to 1.2 mg/dL), creatinine clearance of 20 mL/min (normal 107 to 139 mL/min), serum calcium of 8.0 mg/dL (normal 9.2 to 11.0 mg/dL), serum phosphorus of 6.0 mg/dL (normal 2.3 to 4.7 mg/dL), and an elevated level of serum IgA. Results of a routine urinalysis are as follows:

a. What specific disease do the patient’s laboratory results and history suggest?

b. Which laboratory result is most helpful in diagnosing this disease?

c. What additional diagnosis does his current condition suggest?

d. What is the significance of the positive result for urine glucose?

e. Is the specific gravity significant? Why or why not?

f. What is the significance of the waxy casts?

Step 1 of 6

a.

The history and results suggest IgA nephropathy.

• IgA nephropathy is also called Berger disease. It shows high serum levels

• Immune complex IgA deposits on glomerular membrane, which causes glomerulonephritis

• Serum has high levels of IgA due to mucosal infection

• Patients generally present with macroscopic hematuria followed by strenuous exercise

• Macroscopic hematuria recovery is spontaneous but increased IgA levels in serum and asymptomatic microhematuria persists