28 Oct 2020

9/10/20: P-ANCA Vasculitis

PGY3 Alex Tonthat presented a case of a 36 year old female with history of anemia presents from hematology clinic for Hb 6.5.  Patient was previously in her usual state of health until 4 months ago when she started to develop swelling of the hands, wrists and legs.  She went to her PMD and was found to have a Hb of 8 and started on iron supplementation.  After 2 months, the patient’s anemia did not improve so was referred to hematology clinic who subsequently referred patient to the ED for Hb of 6.5.  Patient reports progressive SOB and fatigue over the last several months as well as occasional swelling of legs and hands that self resolve but otherwise feels well.  She also notes subjective fevers/chills a few times per week and 5lb unintentional weight loss over last 3 months.  Patient reports regular menstrual periods, once per month, requiring 5-7 pads per day for the first 1-3 days and lasting 7 days in duration.  Last period 1 week prior.  Denies any easy bruising or bleeding.  Denies any home medications, no significant family history and denies any tobacco/ethanol/drug use.  She was born in Thailand and immigrated to U.S. 23 years ago.

Vitals: T 39.3C, HR 94, RR 18, BP 95/49, O2 sat 100% RA

Physical Exam significant for normal cardiac and pulm exam, no swelling noted in extremities and palpable purpura on back, abdomen, bilateral anterior, posterior, and medial thighs.

CBC: WBC 3.8 > Hb 6.8/Hct 19.9 <Plt 274 (MCV 79.3, RDW 14.9%)

Diff: 80.3% PMN, 12.9% lymph, 6.3% monocytes and 0.5% basophils

CMP:

Na 136/K 4.7/Cl 103/HCO3 21/BUN 23/Cr 1.74 <Glucose 83 (Of note, Cr was 1.2 one month prior)

ALP 42>T.protein 7.8/Albumin 3.1/AST 24/ALT 17/Tbili 0.2/Dbili <0.2

Coags:PT 13.3, INR 1.02, PTT 40.8

Infectious workup:

  • BCx negative x2
  • UCx negative
  • Procal 0.18 ng/mL
  • HIV non-reactive
  • Hepatitis panel
    • HBc Ab reactive
    • HBs Ag nonreactive
    • HBs Ab 521.10 mIU/mL
    • Hepatitis DNA not detected
    • HCV Ab non-reactive
  • Anti-streptolysin O negative
  • Parvovirus IgM and IgG negative

Hematology workup:

  • Iron panel
    • Iron 13 mcg/dL (normal 37-145)
    • TIBC 142 mcg/dL (normal 250-430)
    • Iron sat 9% (normal 15-50)
    • Ferritin 202 ng/mL
  • Retic 0.9%
  • Abs Retic 2.3 x10^9 L
  • Peripheral smear shows some rouleaux effect, some hypochromasia
  • SPEP no aberrant protein band observed
  • UPEP no aberrant protein band observed
  • K/L ratio: 329.7/140.4 = 2.35

Rheum workup:

  • ESR 114 (normal 0-29)
  • CRP 47.3 (normal <4.9)
  • ANA 1:80
  • dsDNA negative
  • C3 81 (normal 90-180)
  • C4 27.2 (normal 10-40)
  • p-ANCA positive, 1:320
  • MPO Ab >800 AI
  • RF <10
  • SM Ab negative
  • SSA Ab 3.6, positive
  • SSB Ab <1, negative
  • Anti-GBM <1

Renal workup:

  • UA with 100 protein, large blood (>50 RBC), neg leuks/nitrites (4-10 WBC)
  • FeNa 1.1%
  • Uprotein/cr 1.40
  • Renal US: borderline enlargement of the L kidney (R 11.7cm, L 13.1cm).  Increase echogenicity of both kidneys compatible with medical renal disease.

CXR

Skin biopsy performed suggestive of early leukocytoclastic vasculitis.  Renal biopsy performed with findings consistent with pauci-immune crescentic GN with approximately 50% fibrocellular crescents without findings of lupus nephritis.

Treatment: Patient was initially started on solumerol 16mg Q8H given initial concern for SLE and transitioned to prednisone 50mg qday.  She was started on IV iron infusion due to anemia.  Once the MPO/p-ANCA labs returned positive, renal biopsy was performed along with checking for latent TB and hepatitis.  Patient was discharged and was followed up in Rheum clinic in which she was initiated on Rituximab.

Take home points:

  1. Differential for crescentic GN
  1. Management: IV steroids then rituximab or cyclophosphamide.  Can also consider plasma exchange.

Review Article:

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