Question of the Week # 43

A 55 y/o woman with history of well controlled DM Type II presents for her regular follow-up visit. She has no new complaints. She has been well controlled on Metformin alone with a hemoglobin A1c of 6.5. The patient is afebrile with a B.P 96/72, HR 88, RR 16. Physical examination is benign except for decreased sensation in her bilateral lower extremities consistent with diabetic neuropathy and bilater lower extremity edema. Her last urinary microalbumin about one year ago was negative. A repeat dipstick test now is positive for protein and blood but negative for leucoesterase and nitrite. Subsequent urine microscopy reveals 4 dysmorphic RBCs/HPF and red cell casts. Labs reveal elevated serum creatinine at 1.4 as opposed to her baseline creatinine of 0.8 6 months ago. The next important step in approaching this patient’s Renal Insufficiency is:

A) Obtain CPK level
B) 24 hour urine for microalbumin
C) Start ACE inhibitor
D) Repeat urinalysis in 3 months
E) Referral to Nephrologist and Renal biopsy
F) Start emperic antibiotic therapy for UTI

10 Responses

  1. c

  2. c

  3. E
    Presence of dysmorphic RBCs suggest a glomerular problem

  4. C

  5. Ans. E.

    The presence of red cell casts indicate glomerular origin of this patient’s hematuria. Etiologies include various glomerulonephritis and hence, a renal biopsy is warranted. A nephrotic syndrome that is expected with Diabetic nephropathy should not have dysmorphic red cells or red cell casts in urine. Presence of these indicates Nephritis but not nephrotic syndrome.

    A. is not the answer because here a positive dipstick is also followed by a positive urinalysis indicating true hematuria. A myoglobinuria will have positive dipstick but no RBCs on urine microscopy.

    B. is not the answer because it does not add anything to elucidate the cause of this patient’s hematuria. In view of concomitant presence of RBC casts, this patient’s acute onset protein in the urine may be secondary to glomerulonephritis rather than DM nephropathy.

    C. Presence of RBC casts indicate glomerual cause of hematuria. So, the patient should be referred to a nephrologist rather than a urologist

    D. Repeating urinalysis in 3 months is appropriate for a new microscopic hematuria with out any features suggesting kidney involvement. Here hematuria is clearly glomerular in origin and requires further work up as soon as possible.

    F. Is incorrect because this patient has no evidence of UTI. The patient’s clinical features as well as urinalysis findings do not suggest a UTI. The patient has no fever or dysuria. Dipstick is negative for leucoesterase or nitrite. Urinalysis has no WBCs or WBC casts. Absence of all these make UTI an unlikely etiology of her hematuria.

  6. Great ! This questions allows us to clearly differentiate between the expected renal changes micro-albuminuria (nephrotic) & those that aren’t namely hematuria, red cell cast or dymorphic red cells(nephritic)

  7. good question

  8. Very good
    The Pt has damage to the kidney based on the protein and blood in the urine
    It is important to know the extent of the damage so nephrology should be involved with a renal biopsy.

  9. thx, good explanation!

  10. good question; great explanation. Thank you Dr. Red.

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