Diagnostic work up should include full septic screen with blood cultures and viral throat swab to assess for infectious cause.
Given the history a vasculitis screen should be carried out and includes ANA, dsDNA, RF, C3, C4, Immunoglobulins, Cryoglobulins, ANCA (anti-myeloperoxidase & anti-Protease-3) and also urinalysis to assess for haematuria and proteinuria with a suspected nephritis in pulmonary- renal syndrome.
