{"id":11357,"date":"2026-10-14T05:16:19","date_gmt":"2026-10-14T05:16:19","guid":{"rendered":"https:\/\/www.kauveryhospital.com\/ima-journal\/?p=11357"},"modified":"2026-10-14T09:26:15","modified_gmt":"2026-10-14T09:26:15","slug":"mpo-anca-associated-vasculitis-presenting-as-rapidly-progressive-glomerulonephritis","status":"publish","type":"post","link":"https:\/\/www.kauveryhospital.com\/ima-journal\/ima-journal-october-2026\/mpo-anca-associated-vasculitis-presenting-as-rapidly-progressive-glomerulonephritis\/","title":{"rendered":"MPO-ANCA\u2013Associated Vasculitis Presenting as Rapidly Progressive Glomerulonephritis"},"content":{"rendered":"

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A clinical case with pulmonary\u2013renal involvement and dramatic renal recovery after immunosuppression<\/h2>\n

Abstract:<\/h2>\n

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis can present with diverse pulmonary manifestations and may closely mimic severe respiratory infection. Interstitial lung disease (ILD), particularly a fibrotic pattern, is increasingly recognized in association with myeloperoxidase (MPO)-ANCA\u2013positive vasculitis. Early recognition of the pulmonary\u2013renal syndrome is crucial to prevent irreversible kidney injury.<\/p>\n

Case Report:<\/h2>\n

A 62-year-old female, Mrs. X, a known case of type 2 diabetes mellitus and hypertension, presented with fever and cough associated with mucoid expectoration for two days, with shortness of breath for one day. On admission, she was tachycardic with a pulse rate of 106\/min and tachypneic with a respiratory rate of 32\/min. Her blood pressure was 150\/90 mmHg, while oxygen saturation was only 60% on room air, indicating severe hypoxemic respiratory failure.<\/p>\n

Initial investigations showed hemoglobin of 7.8 g\/dL and leukocytosis with a total leukocyte count of 21,230\/\u00b5L with neutrophil predominance. Renal parameters showed urea 67.6 mg\/dL and serum creatinine 3.36 mg\/dL. Urine examination revealed 2+ proteinuria and microscopic hematuria. ECG showed sinus rhythm without significant abnormalities. Echocardiography showed normal cardiac chambers, no regional wall motion abnormality and preserved left ventricular systolic function with an ejection fraction of 60%.<\/p>\n

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CT chest showed subpleural coarse reticulation and honeycombing involving the bilateral lower lobes, predominantly the posterior basal and lateral basal segments. There were areas of cystic bronchiectatic change in the right middle lobe and tubular bronchiectatic changes in the basal segments of both lower lobes. These features were suggestive of fibrotic interstitial lung disease, with a differential of a usual interstitial pneumonia (UIP) pattern versus fibrotic nonspecific interstitial pneumonia (NSIP) pattern. In addition, there were bilateral extensive areas of ground-glass attenuation with a few small patchy areas of sparing, along with mottled irregular consolidative changes involving the right upper and lower lobes. These additional findings were considered suggestive of an infective etiology versus an acute exacerbation of the underlying interstitial lung disease. CT abdomen showed bilateral perinephric fat stranding with normal-sized kidneys and no hydronephrosis.<\/p>\n

However, during subsequent follow-up, an important discrepancy emerged. Despite improvement in the total leukocyte count and oxygenation following treatment of the presumed respiratory infection, renal function continued to deteriorate rapidly, with serum creatinine increasing from 3.36 to 5.7 mg\/dL within two days. The presence of proteinuria and hematuria, together with rapidly progressive renal dysfunction and pulmonary infiltrates, raised suspicion of a pulmonary\u2013renal syndrome and rapidly progressive glomerulonephritis.<\/p>\n

An RPGN work-up was therefore performed, including ANA, anti-GBM antibody and ANCA testing with anti-MPO and anti-PR3 antibodies. The patient was found to have a positive anti-MPO IgG ELISA, supporting MPO-ANCA\u2013associated vasculitis. In the clinical context of rapidly progressive kidney injury and pulmonary involvement, this was considered an ANCA-associated pulmonary\u2013renal syndrome.<\/p>\n

Following confirmation of the diagnosis, the patient received intravenous methylprednisolone 500 mg once daily for three days, followed by oral prednisolone at approximately 1 mg\/kg\/day, with subsequent tapering according to clinical and renal response. Following initiation of immunosuppressive therapy, renal function progressively improved. The patient became clinically better and prednisolone was gradually tapered. On the latest follow-up, serum creatinine had improved to 1.45 mg\/dL. She remains on regular follow-up with a tapering glucocorticoid regimen, while appropriate antihypertensive and antidiabetic therapy is continued.<\/p>\n

Conclusion<\/strong>: This case highlights the diagnostic challenge of distinguishing infection or acute exacerbation of ILD from ANCA-associated pulmonary involvement. The presence of fibrotic ILD, particularly a UIP-like pattern, may be an important clue to underlying MPO-ANCA\u2013associated vasculitis. Rapidly progressive AKI with hematuria and proteinuria in a patient with pulmonary disease should prompt early evaluation for a pulmonary\u2013renal syndrome. Recognition and timely initiation of immunosuppressive therapy can result in substantial renal recovery.<\/p>\n

Salient Features of the Case<\/h2>\n