To preserve patient privacy and for didactic purposes, case descriptions and pathology reports have been anonymized and partially fictionalized. The pathology images are representative images from a mixture of similar cases.

Invited Speakers

Ali Poyan Mehr
Ali Poyan MehrCase Presenter | Beth Israel Deaconess Medical Center, Boston, MA, USA | Conflict of interest reported: Mallinckrodt - Glomerular Disease Consultant and Research Grant
Isaac Stillman
Isaac StillmanNephropathology Discussant | Beth Israel Deaconess Medical Center, Boston, MA, USA | No conflict of interest reported
Timothy Yau
Timothy YauNephrology Discussant | Washington University, St. Louis, MO, USA | No conflict of interest reported

Case

Patient is a 70-year-old female, referred to renal clinic for AKI, and new proteinuria. She had seen her family physician for an annual visit, and had complained of dark urine, mild malaise, and a “head cold”. Over the past several months, she has had some on-and-off symptoms of cold, some nausea, and poor appetite. She had seen GI specialist for that, but the workup was negative. Relates possibly to “breast cancer meds”. She denies any cough, hemoptysis. No fevers, chills, no myalgias, no rashes, no dysuria.

Medical history:
Breast CA: stage I ER+. sp lumpectomy on letrozole
Thyroid nodules
Pre-diabetes
Hypertension

Medications:
Amlodipine, atorvastatin, carvedilol, hydralazine (started 9 months prior to current presentation), letrozole (had developed arthralgia on anastrozole), losartan, aspirin, vitamin D, iron supplement.

Physical Exam:
BP: 179/70. Heart Rate: 57. O2 Saturation%: 100. Weight: 181 pounds. BMI: 27.5.
General: Somewhat fatigued appearing otherwise well and NAD. No rash, no edema.

Laboratory and other data:
Baseline serum creatinine 0.8 mg/dl. Now within few days at current presentation: -> 1.4 -> 1.8 -> 2.3
Hb 9.8 mg/dl,
WBC normal, with normal differential, platelets borderline low
Serologies: MPO pANCA>8 (normal<0.4 units), Anti-Histone Ab 1.2 U (normal<1.0 U), ANA 1:640, C3 70 mg/dl (90-180), C4 4 mg/dl (10-40),  RF negative, Cryo negative, SPEP/UPEP neg
>Urinary protein to creatinine ratio: 0.6 g/g (urine dip in the past: negative)
Sediment in clinic: Numerous red blood cells, some rare to occasional acanthocytes, no casts.
Renal ultrasound notable for increased cortical echogenicity bilateral, normal-sized kidneys.

Kidney Pathology

Pathology images pending

Less than 10% of glomeruli are globally sclerotic, the others show irregular mesangial proliferation with a small focus of possible fibrinoid change. A single glomerular tuft shows a fibroepithelial crescent.

Mesangial staining is seen with IgG (minimal), IgA (1+), IgM (2+), C3 (minimal), kappa light chain (1+), lambda light chain (1+). C1q, fibrin and albumin are negative.

On EM: Fine structural studies reveal focal foot process effacement. Mesangial matrix is increased. There is focal mesangial interposition. No subepithelial or subendothelial deposits are noted.

Questions posed & summary of key discussion points

1. How “straightforward” is this case and is there anything else in the differential?
2. Would you have not biopsied, or is serum titer sufficient to guide diagnosis and treatment?
3. What initial therapy would you choose for her?
4. How long would you provide maintenance, and is there any utility in following any particular labs as a marker of treatment response/relapse prediction?

Author(s) of case summary:

Case summary pending

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