A 79-year-old woman with familial hyperlipidemia was treated with low-density lipoprotein apheresis. She was hospitalized due to fatigue and edema, and massive proteinuria was discovered. Renal biopsy revealed no distinct abnormalities, thus suggesting a diagnosis of minimal change nephrotic syndrome. She developed acute kidney injury and hemodialysis was initiated. Two series of steroid pulse therapy were given, but the proteinuria did not decrease. Thereafter, she developed thrombocytopenia and fell into a stupor. Thrombotic microangiopathy (TMA) was the most likely diagnosis. Plasma exchange was initiated, resulting in improvements in platelet counts and in her level of consciousness. Clinicians should therefore be aware that TMA can occur as a result of steroid pulse therapy.