A Case of Sarcoidosis Diagnosed Based on Progressive Renal Dysfunction and Lymphadenopathy

Several series have suggested that kidney involvement (as defined by either histological changes in the kidney or a decline in kidney function in the absence of a biopsy) occurs in approximately 10 to 50 percent of patients with sarcoidosis. A large study examining more than 1200 hospitalized patients with sarcoidosis reported that kidney manifestations were present in approximately 6% of cases. The case is that of an 89-year-old woman. She experienced paroxysmal nocturnal dyspnea starting four days before her visit. Three days before coming to our hospital, she consulted a nearby clinic, leading to a suspicion of heart failure, and she was referred for further evaluation. Physical examination revealed left axillary lymphadenopathy, coarse crackles in both lung fields, and slow pitting edema over both tibial tuberosities. Blood tests showed Cr: 2.10 mg/dL and B-type natriuretic peptide (BNP): 1144.4 pg/mL. The sIL-2R obtained for the purpose of differentiating malignant lymphoma was 3290 U/mL and elevated. A plain chest CT scan showed cardiomegaly, pulmonary edema, pleural effusion, and left axillary lymphadenopathy. Based on subjective symptoms, physical findings, and laboratory test results, the patient was diagnosed with an acute exacerbation of chronic heart failure. Treatment with atrial natriuretic peptide and loop diuretics was started on the same day for heart failure. Her dyspnea gradually improved, and her weight also decreased. Radiographic findings also showed an improvement in pulmonary congestion. However, by the 14th day of hospitalization, her creatinine level had worsened to 5.85 mg/dL, indicating renal dysfunction. Due to persistent lymphadenopathy and rapidly progressing renal dysfunction, renal sarcoidosis was suspected, and the patient was transferred to another hospital for further investigation. A lymph node biopsy from the left inguinal region revealed non-caseating epithelioid cell granulomas. The serum lysozyme level, which has been shown to be elevated in cardiac and renal sarcoidosis, was 30.6 μg/mL. The diagnosis was sarcoidosis, with heart failure and renal failure attributed to cardiac sarcoidosis and granulomatous interstitial nephritis. Maintenance dialysis was decided upon for renal dysfunction. Sarcoidosis is a systemic disease characterized by the appearance of non-caseating epithelioid cell granulomas. Organs such as the heart, kidneys, eyes, lungs, and nervous system, which impact quality of life and prognosis, require careful monitoring over time. Lymphadenopathy, which does not align with the usual course of heart failure, and progressive renal dysfunction despite achieving diuretic effects, should raise suspicion for this condition.