Patient is a 43-year-old female with underlying Sjogren’s syndrome and Postural Orthostatic Tachycardia Syndrome (POTS).  As part of her routine follow up by primary care physician and rheumatologist, she was found to have increasing proteinuria. This was considered to be quite unusual as her POTS and Sjogren’s syndrome have both been stable and are typically not associated with glomerular pathology.

Over the subsequent several months her proteinuria increased to over 2 g/g creatinine and microscopic hematuria developed. ANCA titer was checked and was positive (pANCA 1:320, quantitation >800).  Given her subtle disease (biopsy below) and normal kidney function, it was quite an unusual presentation for ANCA-associated vasculitis.  She had been on allopurinol for gout, which was changed to febuxostat.

Medical history:
Cataract
Allergic rhinitis
Gout

Medications:
Loratadine PRN
Febuxostat

Physical Exam:
Well appearing woman, without edema, rash, or other focal findings

Laboratory and other data:
Baseline creatinine 0.8 – 0.9
pANCA 1:320 (anti-MPO)
ANA 1:160
dsDNA neg, complements normal
Urinary protein to creatinine ratio 2.4 gram

Short term follow up:
Patient was given 4 doses of rituximab and CD20 repopulated 5 months later.
Kidney function has remained normal (creatinine 1.16 mg/dl, same as at rituximab initiation, but slightly higher than the previous baseline of 0.8-0.9 a year ago).
Proteinuria persists (peak 2.4g/g 6 months ago, 1.9g/g now), microhematuria unchanged, ANCA hasn’t disappeared but has improved (1:160).