SUN-575 Can Nodular Glomerulosclerosis be Considered Idiopathic in Prediabetes?

Abstract

Idiopathic nodular glomerulosclerosis is a rare condition that occurs in the absence of diabetes and is associated with smoking and HTN. We present a case of nodular sclerosis and nephrotic-range proteinuria in a patient with prediabetes. A man in the 7th decade of life was admitted for elective carotid artery stent placement. Past medical history included essential hypertension, coronary artery disease, HFrEF, prediabetes (HbA1c 6.4%), and tobacco smoking. He denied excessive NSAID use or family history of renal disease. On presentation his temperature was 36.9 °C, blood pressure 156/88 mmHg, heart rate 63 bpm, respiratory rate 16, oxygen saturation 93% on room air, and body weight 96.70 kg. Physical exam revealed bilateral 1+ pitting edema in his lower extremities and mild wheezes in bilateral lungs. Initial serum laboratory testing showed Na 136 mmol/L, K 4.3 mmol/L, Cl 111 mmol/L, bicarbonate 20 mmol/L, BUN 34 mg/dL, creatinine (Cr) 3 mg/dL (baseline 1.2), eGFR 22 mL/min and albumin 2.5 gm/dL. Urinalysis detected hematuria and proteinuria in the nephrotic-range with urine albumin:creatinine ratio of 4983 mg/g. Serology was normal-range for HIV, hepatitis B and C, rheumatoid factor, complements C3 and C4, anti-GBM, ANCA, anti-ds DNA, and anti-PLA2R. SPEP and UPEP with immunofixation and serum free light chains did not detect monoclonal proteins. A renal biopsy specimen showed nodular glomerulosclerosis in the absence of heavy and light chain immunoglobulin deposition.Nodular glomerulosclerosis is qualified as “idiopathic” (ING) when monoclonal gammopathy and diabetes mellitus are excluded. ING is linked to hypertension, gout, tobacco smoking, and obesity. Diagnostic criteria for ING in prediabetics are less reliable. Clinicians must be aware of the timeline of progression to diabetic kidney disease, which may require a decade before nephrotic-range proteinuria is detected. By this time, irreversible chronic glomerulosclerosis may be underway. Thus, qualifying nodular glomerulosclerosis as idiopathic requires careful consideration in patients with pre- or new onset diabetes mellitus who present with nephrotic-range proteinuria and contributing factors of tobacco smoking and hypertension, as with our patient.