Kidney Week

Abstract: TH-PO727

Cognitive Bias in the Diagnosis of Acute Nephritis: A Case of Complementary Details

Session Information

• Glomerular Diseases: Case Reports - 1
  October 24, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Rokaw, Sarah, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States

Sarah Rokaw, MD

• Wagner, Benjamin A., Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States

Benjamin A. Wagner, MD

• Mistry, Kavita, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States

Kavita Mistry, MD, PhD

• Rosen, Seymour, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States

Seymour Rosen, MD

• Zandi-Nejad, Kambiz, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States

Kambiz Zandi-Nejad, MD, FASN

• Rosas, Sylvia E., Joslin Diabetes Center, Boston, Massachusetts, United States

Sylvia E. Rosas, MD, MS, FASN

• Lecker, Stewart H., Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States

Stewart H. Lecker, MD, PhD, FASN

Introduction

The etiologies of acute nephritis are characterized by complement levels and systemic versus renal-limited diseases. Both pauci-immune glomerulonephritis (GN) and anti-GBM disease have normal complements and systemic involvement, while lupus nephritis is classically associated with low complements. Nonetheless, studies demonstrating diagnostic sensitivity of complement levels are small and variable.

Case Description

A 33-year-old woman with asthma and prior tobacco use presented with subacute hemoptysis and was found to have acute hypoxic respiratory failure and anemia. Prior to admission, her respiratory symptoms had initially improved with steroids and antibiotics. On presentation, vital signs were remarkable for hypertension and new hypoxia requiring high flow nasal cannula. Physical exam revealed bibasilar rales and 2+ lower extremity edema. Creatinine was at baseline of 0.8 mg/dL with albumin of 3.4 g/dL. Hemolysis labs were positive. Urinalysis revealed 3+ blood and 4+ protein quantified at 3.3 g/g, and sediment demonstrated innumerous RBC casts, WBC casts, and acanthocytes. Bronchoscopy revealed diffuse alveolar hemorrhage. ANA was positive at 1:320 in nuclear homogenous pattern with negative dsDNA and anti-Sm. C3 was slightly low at 83 mg/dL, and C4 was normal. Pulse-dose steroids were initiated, and she received three sessions of plasmapheresis for presumed pauci-immune GN or anti-GBM disease. Additional workup then returned as follows: positive p-ANCA 1:320 with negative MPO and PR3, positive SS-A, negative HIV and hepatitis B/C, negative lupus anticoagulant, and negative antibodies for GBM, anti-PLA2R IgG, cardiolipin, beta-2-glycoprotein, RNP and SS-B. Renal biopsy was delayed for one week due to antecedent NSAID use, though ultimately revealed endocapillary proliferative GN with limited crescent formation and very focal necrosis and immunofluorescence consistent with lupus nephritis.

Discussion

The mildly low C3 was an important diagnostic clue - overlooked due to data mismatch with diagnostic schema. However, the patient met criteria for SLE, which includes a score for low C3 or C4. This case illustrates that a simplified framework of classifying GN must be contextualized both with the sensitivity of available tests and the clinical picture to avoid cognitive bias and diagnostic inaccuracy.