Spontaneous rupture of kidneys triggered by microscopic polyangiitis

Rationale: Microscopic polyangiitis (MPA) is defined by the 2012 revised Chapel Hill Consensus Conference Nomenclature of Vasculitides as necrotizing vasculitis, with few or no immune deposits, predominantly affecting small vessels (i.e. capillaries, venules, or arterioles) and granulomatous inflammation is absent. MPA is clinically characterized by small-vessel vasculitis primarily affecting the kidneys and lungs but other organs may be involved as well. Spontaneous rupture of kidneys is a rare but extremely dangerous event in clinical practice. Here is reported a successfully treated case of spontaneous renal rupture triggered by MPA. Patient concerns: A 57-year-old female complaining of fever for 2 weeks and edema for 1 week presented with newly developed severe lumbago, delirium, acute renal failure, and hemorrhagic shock. Radiological imaging revealed large bilateral peri-renal hematoma and compression of renal parenchyma. Diagnoses: Acute renal failure and hemorrhagic shock caused by spontaneous rupture of kidneys which was triggered in turn due to MPA. Interventions: Measures of absolute bed rest, blood transfusion, hemostasis, and rehydration were immediately taken as first aid measure to stabilize vital signs. Methylprednisolone pulse therapy was the core of MPA treatment. Oral administration was given after discharge. During the follow-up period, the dosage of glucocorticoid reduced step by step and lasted for 15 months. Outcome: Renal function was recovered and binaural listening was improved markedly. Hypoalbuminemia, proteinuria, and hematuria was cured, CT examination demonstrated remarkable absorption in peri-renal hematoma and less compression of renal parenchyma. Conclusion: MPA could trigger spontaneous rupture of kidneys without warning and should be included in the differential diagnosis of spontaneous renal rupture; conservative treatment based on glucocorticoid is safe and effective for the renal rupture caused by MPA.