What is your typical workup for a patient with a spontaneous renal infarct?

Broadly speaking, in the setting of a renal infarct, consider a thromboembolic event (venous thrombosis with paradoxical embolism or an arterial source) or a local vascular event such as dissection. The latter can be easily missed because the appropriate imaging is generally not performed. Once a vascular dissection is excluded, a search for an arterial source (most commonly cardiac in the setting of atrial fibrillation) should be undertaken e.g. transesophageal ECHO with bubble study, holter monitor, and if non revealing a loop recorder device, etc. Investigation of the arterial vascular tree with appropriate CT angiograms may be needed and should be done especially to exclude vascular dissection. Anecdotally, a number of referrals I have seen over the years end up being vascular dissection as opposed to systemic embolism. With regard to hypercoagulable testing, all patients should have testing for antiphospholipid antibodies (lupus anticoagulant, anticardiolipin, and antibeta2 GPI). If a PFO is found, one has to determine if it should be closed. The role for routine hereditary thrombophilia testing is indeterminate and the reality is that it is the first panel of tests that is ordered.