Takayasu arteritis (TAK) is a rare, large-vessel vasculitis, frequently presenting at approximately 20 years of age. Patients with TAK without characteristic clinical findings are sometimes left undiagnosed and are followed by a fever of unknown origin; and, delayed diagnosis may lead to irreversible ischaemia and organ damage. Here, we report a case of an 18-year-old woman with TAK complicated by acute pericarditis at initial presentation. She was diagnosed with idiopathic acute pericarditis and treated with non-steroidal anti-inflammatory drugs (NSAIDs). However, the patient’s fever and pain in the chest and upper back persisted. On admission to our hospital, magnetic resonance angiography and ultrasonography revealed wall thickening in the common carotid artery, subclavian artery, and aorta, along with vascular narrowing in the celiac, superior mesenteric, and bilateral renal arteries. The patient was diagnosed with TAK, and treated with glucocorticoids, including methylprednisolone pulse therapy, and azathioprine. The treatment improved the patient’s signs and symptoms, and the pericardial effusion decreased. Acute pericarditis is a rare manifestation of TAK, but it is important to differentiate diseases, including TAK in patients with acute pericarditis who fail to respond to 2–3 weeks of conventional therapy with NSAIDs.

An 18-year-old Japanese woman with systemic lupus erythematosus (SLE) experienced dyspnoea, headache, tinnitus, and purpura for two weeks and was admitted to our hospital. The patient had been diagnosed with SLE and secondary immune thrombocytopenia eight years before and treated with high-dose prednisolone (PSL) and mycophenolate mofetil. Since the blood test on admission showed haemolytic anaemia with a positive direct Coombs test and anti-glycoprotein IIb/IIIa antibodies, the patient was initially diagnosed with Evans syndrome (ES). The patient was treated with pulse intravenous methylprednisolone followed by 45 mg/day prednisolone; however, the patient’s platelet count did not normalise. Based on a low level of a disintegrin-like metalloproteinase with thrombospondin type 1 motif 13 (ADAMTS-13) activity and a high level of ADAMTS-13 inhibitors, a diagnosis of acquired thrombotic thrombocytopenic purpura (TTP) was confirmed. After undergoing therapeutic plasma exchange for six consecutive days, the patient’s platelet count recovered rapidly. Although concurrent acquired TTP and ES have not been reported previously, the findings from this case highlight the importance of measuring ADAMTS-13 activity and inhibitors to rule out acquired TTP, especially when ES is refractory to glucocorticoids.

Idiopathic pleuroparenchymal fibroelastosis (iPPFE) is a rare type of idiopathic interstitial pneumonia, which is characterised by pleural fibrosis and subjacent parenchymal fibroelastosis of the upper lobes. Herein, we present a case of microscopic polyangiitis (MPA) following PPFE. The patient had abnormal shadows on chest radiographs 15 years before the onset of MPA, and the patient was diagnosed with PPFE. Four years after the PPFE diagnosis, the patient was diagnosed with MPA based on persistent fever, purpura, mononeuritis multiplex, myeloperoxidase-antineutrophil cytoplasmic antibody positivity, and pathological findings of peritubular capillaritis on kidney biopsy. The patient was treated with glucocorticoids, including methylprednisolone pulse therapy and rituximab, followed by maintenance therapy with rituximab. One year after treatment, the PPFE had not worsened. PPFE occasionally occurs secondary to connective tissue disease, including MPA; however, to the best of our knowledge, this is the first report of PPFE preceding MPA. Our case suggests that PPFE, as other interstitial lung diseases, may be associated with MPA and precede the onset of MPA. Accumulation of more cases are needed to clarify the characteristics of MPA-associated PPFE.