A case of Takayasu arteritis complicated with acute pericarditis at initial presentation.

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; 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 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.