Rationale: Acute kidney injury (AKI) accounts for 8% to 16% of hospital admissions and can quadruple hospital mortality, placing a serious burden on the health economy. Acute kidney injury (AKI) is mainly caused by dehydration, shock, infection, sepsis, heart disease, or as a side-effect of nephrotoxic drugs. About 10% to 60% of patients with rhabdomyolysis develop AKI, and 10% of AKI is attributable to rhabdomyolysis. However, rhabdomyolysis-induced AKI secondary to undifferentiated connective tissue disease (UCTD) has rarely been reported before.
Patient concerns: We report the case of a 50-year-old male of UCTD presented with dark brown urine, swelling and edema of the upper limbs, and decreased urine output.
Diagnosis: The patient was diagnosed with rhabdomyolysis-induced AKI secondary to UCTD.
Interventions: The patient was successfully treated with intravenous methylprednisolone with other supportive treatment.
Outcomes: After 3 days of initiating treatment of medicinal charcoal tablets, sodium bicarbonate and intravenous fluids upon admission, the patient's serum creatinine changed mildly from 145.0 μmol/L to 156.0 μmol/L, but the urinary output increased from 1000 mL/24 h to 2400 mL/24 h, with his creatine kinase (CK) and myoglobin rose from 474 IU/L to 962 IU/L and from 641.5ng/mL to 1599 ng/mL, respectively. We then tried to empirically initiate UCTD therapy by giving corticosteroids. After the administration of the 40 mg of methylprednisolone daily, the serum creatinine level dropped to 97 μmol/L the second day, CK decreased to 85 IU/L within 1 week and myoglobin decreased to 65.05 ng/mL within 10 days. When maintenance dose of 4 mg daily was given, the patient showed no abnormalities in creatinine or CK levels.
Lessons: There have been few reports on the association between rhabdomyolysis-induced AKI and UCTD and its mechanism remains unclear. Clinicians should be aware of UCTD as a possible cause to rhabdomyolysis-induced AKI.