Rapidly progressive glomerulonephritis (RPGN) is a clinical syndrome manifested by progressive loss of renal function in a short period. At renal biopsy, it is characterized by crescent formation. RPGN may be associated with the presence of circulating antibodies. We report a case of type IV RPGN [ANCA and Anti–glomerular basement membrane (anti-GBM) antibody disease], a severe disease causing a difficult to treat picture. Our case was complicated by severe thrombocytopenia due to the use of heparin and later on by thrombotic microangiopathy. These events occurred rapidly, making the clinical framing and management decisions very hard.