Question of the Week # 11

A 7-year-old boy is brought to the emergency department by his mother because of “tea-colored urine” for the last several days. He has also had some nausea and vomiting, and his eyes appear swollen when he wakes up in the morning. The eye swelling tends to resolve over the course of the day. He is generally very healthy and there is no family history of any chronic diseases. His temperature is 36.7 C (98.0 F), blood pressure is 130/90 mm Hg, pulse is 96/min, and respiratory rate is 16/min. Physical examination is unremarkable. A urinalysis shows red cell casts. At this time the most appropriate study to confirm your diagnosis is

A. antinuclear antibody
B. antistreptolysin O antibody
C. renal biopsy
D. renal ultrasound
E. urine culture

Copy Rights: Archer USMLE Reviews

35 Responses

  1. D.

  2. answer B ( post streptrococal glomeruonephritis)

  3. B. antistreptolysin O antibody,
    to rule out post step. nephritis

  4. Answer B

  5. b

  6. its bbbbbbbb

  7. b

  8. C. Renal biopsy
    the only confirmatory test in the list.
    indicated inGN with hematuria

  9. C. Renal biopsy
    the only confirmatory test in the list.
    indicated in GN with hematuria

  10. I’d like to go with B.

  11. c


  13. I’ll go with c, the renal biopsy. ASO is useful but not 100% sensi and only provides possible clue of association, not the diagnosis-the pathology

  14. C is the answer

  15. It seems a like presentation for PSGN so I would expect the RBCS ,hypertension,facial swelling and +anti-strep antibody but i expect a HX of URI -GI infection
    I also do agree with NOOK seeing is believing !

  16. biopsy

  17. C. renal biopsy

  18. B. antistreptolysin O antibody

    Consider renal biopsy only in presence of acute renal failure, nephrotic syndrome, negative streptococcal test or normal complement or if present for more than 2 months after onset.

  19. Renal biopsy
    – minimal change disease.

    Why ASO? No history of soar throt, exudate or adenopathy..

  20. In a differential of nephritic (includes PSGN, IgA, SLE, Goodpastures) versus Nephrotic (minimal change disease, membranous) the nephritic has proteinuria, hematuria and the nephrotic has severe proteinuria (>3.5gm/dL) edema, hypoalbuminemia (this could cause eye swelling) and hyperlipidemia (incidentally there too). Only renal biopsy can distinguish causes of nephrotic syndrome, so this is really a great question. most likely is minimal change disease..note that PSGN (ASO titer positive and low compliment) usually occurs 7-10 days after hematuria, while IgA appears in 2 days but these are both nephritic.. Good thoughtful clinically relevant.

    • Mr medicine man.. This is a case of Nephritic on Nephrotic syndrome! You do not differentiate nephritic vs nephrotic. Although, biopsy is correct for an adult for a confirmation. In children, when there’s proteinuria you must start with a course of steroids and in this case the only positive finding is RBC casts, so it is best to do ASO titre if there’s no clear history as to wether the child had an infection or not. Your right this may be IGA nephropathy which appears in 2 days but it’s always best to rule out PSGN with an ASO titre before doing a Renal biopsy in a child.

      • You are absolutely right. Also, here is a nephritic syndrome, with hematuria, not nephrotic, so, it points to glomerulonephritis, which is not the case with minimal change disease or nephrotic syndrome. So checking ASO titre is definitely the most reasonable next step.

  21. Although Renal Biopsy is the answer for confirmation of diagnosis because ASO titre is not that specific, you never do a renal biopsy in a child. You always start with a course of steroids. On the contrary, if this were an adult then biopsy is the correct answer.

  22. Dr Red please explain this

  23. renal biopsy,,,,even if it be PSGN for confirm the diagnosis biopsy should be done and ASO could not confirm the diagnosis

  24. guys, what is the dfinitive or the correct answer?

  25. A healthy child suddenly develops tea colored urine and urinalysis shows red cell casts. – suggests an acute glomerular injury/ leakage of red cells (hematuria)
    He develops swollen eyes when he wakes up in the morning – suggestive of hypoproteinemia or renal impairment.
    He has had nausea and vomiting as well – suggesting an acute renal disease in this setting
    He has blood pressure of 130/90 mmHg – elevated blood pressure suggests a glomerular vasculitis, an acute inflammatory type as opposed to Nephrotic syndrome which will cause normotension if not hypotension.
    Question is, as a good physician, ‘at this time, the most appropriate study is…’ ‘…to confirm your diagnosis’
    ANSWER: The least discomforting, least invasive, least expensive, the least risky, PLUS the most yielding study. (Can’t by-pass the first four qualities of the most appropriate study)
    DIFFERENTIALS – PSGN, a post -infectious immune mediated acute glomerular disease (my clinical diagnosis) – presenting as an acute nephritic syndrome. If this child had a background chronic illness, I would have considered chronic nephritis presenting as Acute Nephritis not Nephrosis.
    Not IgA nephropathy – rarer (< 5%) cause of symptomatic nephritic syndrome more so in this age group. And the natural history is slow and progressive. Abrupt onset of symptoms, denovo in a healthy child is very usual.
    Not HSP – no purpura, no joint pains, no abdominal pain
    Not Alport Syndrome (Hereditary Nephritis) – No family history of ‘chronic disease’
    Not Thin GBM disease (familial benign hematuria) – diagnosis of exclusion.
    Not MCGN – therapeutic diagnosis (use of high dose steroids) is more ideal in children. MCGN causes abrupt & more profound onset of nephrotic syndrome more than nephritic syndrome. But for benefit of doubt, I consider it safer (best practice) to rule out strep residual infection using initial diagnostic/confirmatory tests with ASO titre since therapeutic diagnosis (use of high dose steroids) is not in the list of options.
    Option A – This is not SLE, or Mixed connective tissue disorder, both are chronic processes. Use of Antinuclear antibodies is unlikely to be helpful.
    Option B – BEST.
    Option C – Renal biopsy should not be in a child unless there is unexplainable loss of renal function, renal malignancy, or renal transplant. To confirm the diagnosis, less invasive tests and high dose steroids are usually sufficient for successful treatment.
    Option D – Renal Ultrasound may be potentially diagnostic in PSGN (De Pietro et al 1997) but larger systematic reviews will be needed to substantiate this claim. Di Pietro A, Proverbio MR, Pescatore L, Tammaro V, Riccio E, Sarnelli C, Cicale F. ‘Potential diagnostic role of renal sonography in acute post-streptococcal glomerulonephritis (APSGN) "with minimal urinary signs’ Pediatr Med Chir. 1997 Jul-Aug;19(4):265-6.
    Option E – Urine culture – Bacteria are not physically present in the glomeruli in PSGN. If this was an ascending infection, the child will have a history of rigors, chills, pyelonephritis, ill health, etc. In PSGN, the ASO titre remains elevated for 2 to 4 months after ‘a trivial’ sore throat or skin infection. A negative test does not rule out PSGN.
    PSGN is a more serious disease than MCGN even though majority of children may actually have MCGN and it deserves attention. PSGN can progress acutely to RPGN and ESRD if misdiagnosed or poorly treated. IgA nephropathy should be excluded with urine or blood test. Renal biopsy cannot be ‘at this time’, the most appropriate confirmatory test. We should consider it if medical management and therapeutic diagnostic tests are unyielding. (last resort in children, because acute renal diseases in healthy children usually resolve satisfactorily without renal biopsy and so the risk of procedure outweigh the benefits.) Even though use of renal biopsy is a common acceptable practice among pediatricians (42%) Feld et al 1993, it is not the best practice ‘at this time’ given that less traumatic tests and medical management can provide satisfactory and speedy recovery. In my opinion, I will reserve renal biopsy for children with renal malignancy, unexplained renal impairment, or renal transplant surveillance and I will consider all less traumatic diagnostic/therapeutic options first. (including ASO, renal function test, high dose steroid and Urine IgA test and penicillin)
    References: Glomerular diseases & tutorial on Glomerular disease pathology -PSGN – Thin Basement Membrane Disease – MCGN -Hereditary Nephritis IgA nephropathy – Acute nephritic syndrome – Nephrotic Syndrome – Role of renal ultrasound in PSGN
    Feld LG, Stapleton FB, Duffy L. ‘Renal biopsy in children with asymptomatic hematuria or proteinuria: survey of pediatric nephrologists’ Pediatr Nephrol. 1993 Aug;7(4):441-3. pubmed 8398657

  26. Summary – Even though renal biopsy is the most accurate confirmatory test, it is not the most appropriate study to confirm diagnosis at this time. Option B – ASO, Or, Urine IgA, High dose steroids, are more appropriate studies to confirm diagnosis. Please note that the most appropriate confirmatory diagnostic study may not be the most accurate confirmatory study and the most accurate confirmatory test may not be the most appropriate confirmatory test. ‘Most accurate’ -renal biopsy but ‘Most appropriate’ – ASO. Keep the distinction between these two phrases please colleagues. Positive ASO is the most appropriate not most accurate test to confirm PSGN. There is no test to confirm PSGN. Even renal biopsy does not confirm PSGN.
    What is the test here? Will you inflict pain on your child or patient if non traumatic treatment will provide satisfactory recovery? What is more appropriate?

    Answer is B

  27. Just Answer the Question –to confirm the Dx: Renal Biopsy –with or without therapy nephritic or nephrotic Sx “cures by it self” or in the worst case it evolves to Renal failure (rare) —Tx: is Corticoid in whatever nephrotic or nephritic and Blood pressure control “symptomatic control does NOT Cure it just Tx–

  28. B

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