A Case of IgA Nephropathy Complicated with Pulmonary Infection by Mycobacterium Abscess

In August 2023, our hospital confirmed a case of IgA nephropathy complicated with pulmonary infection by Mycobacterium abscess. The patient sought medical attention at our hospital due to "gross hematuria for 10 years, recurrence for 10 days, coughing and sputum production". The patient had pulmonary tuberculosis 15 years ago and had been cured. He had bronchiectasis for 10 years.

Chest CT, fiberoptic bronchoscopy examination, urine routine (urine analysis + sediment quantification), urine trace protein measurement//urine creatinine (random urine), urine protein quantification (24-hour urine), antinuclear antibody measurement (ANA), sputum culture, alveolar lavage fluid bacterial culture, alveolar lavage fluid acid fast staining, and alveolar lavage fluid mNGS.

Chest CT: Cystic dilation of bronchi in both lungs, mainly in the lower lungs, with visible phlegm clots inside. Fibrobronchoscopy: A large amount of white foam like secretions can be seen in the lumens of the middle lobe of the right lung and the lower lobes of both lungs. Urinary routine (urine analysis + sediment quantification): protein+↑, occult blood+++. Urine Microprotein Determination//Urine Creatinine (Random Urine): Microalbumin 156.00 mg/L, Urine mALB/Urine Creatinine 132.73 mg/g; Quantitative determination of urine protein (24-hour urine): total protein 0.93 g/24-hour urine; Antinuclear antibody assay (ANA): weakly positive; Sputum bacterial culture: negative; Bacterial culture of bronchoalveolar lavage fluid: Mycobacterium abscess++, NGS in bronchoalveolar lavage fluid: Mycobacterium abscess. Clinical treatment plan: 0.25 g of azithromycin qd po+ 0.4 g of amikacin sulfate qd ivgtt+ 1 g cefmetazole sodium q12hours ivgtt. After 10 days of treatment, the patient improved and was discharged.

This article reports a case of IgA nephropathy complicated with pulmonary abscess mycobacterial infection. Mycobacterium abscess was quickly and accurately identified by mNGS. Reasonable treatment measures were adopted clinically. The patient improved and was discharged. This study has important reference significance for the clinical diagnosis and treatment of Mycobacterium abscess infection. In addition, mNGS, as a novel detection method, has considerable prospects for rapid diagnosis of pathogens.