Supplementary Material for: Acute interstitial nephritis associated to Pertussis infection: a case report and review of the literature

Background: Whooping cough (pertussis) is an acute respiratory infection primarily caused by Bordetella pertussis, which predominantly affects children. While the disease commonly presents with upper respiratory symptoms, it can lead to severe complications such as pneumonia, encephalopathy, and even death. The association between respiratory infections and renal injury, specifically acute interstitial nephritis (AIN), remains poorly understood. This report describes a rare case of AIN in a patient with whooping cough.
Case Presentation: A 73-year-old male with a history of systemic arterial hypertension, dyslipidemia, and previous left nephrectomy presented with a five-day history of fatigue, fever, cough, and nasal obstruction. Initial laboratory findings revealed mild leukocytosis and significantly elevated serum creatinine (5.17 mg/dL), with urinalysis showing leukocyturia and proteinuria. A respiratory infection panel confirmed Bordetella pertussis, and the patient was treated with azithromycin. Despite improvement in respiratory symptoms, renal function remained impaired. Renal biopsy revealed moderate tubulointerstitial nephritis, and the patient was treated with prednisone, leading to gradual recovery of renal function, with serum creatinine decreasing to 2.3 mg/dL at discharge and 1.85 mg/dL three weeks later.
Conclusion: This case highlights the potential renal complications of whooping cough, specifically acute interstitial nephritis, a rarely reported association. Although respiratory infections such as pertussis are well-known for pulmonary involvement, clinicians should be aware of the possibility of concurrent renal injury. Prompt recognition and appropriate treatment, including corticosteroids in the case of AIN, can lead to significant improvement in renal function. Further research is needed to better understand the mechanisms by which B. pertussis may cause renal damage.