Table 2.

Laboratory/imaging workup.

Differential diagnosis	Labs/imaging
Neurosarcoidosis	ACE
Cerebral sinus thrombosis	Catheter angiogram
Vasculitis	ANA, ANCA, SSA, SSB, ESR, CRP, Hepatitis panel
Reversible cerebral vasoconstriction syndrome	Catheter angiogram and high resolution vessel wall MRI
Autoimmune and paraneoplastic encephalitis	VGKC, NMDA, CASPR2, LGI1 paraneoplastic antibody panel, Cerebral FDG PET scan
CNS malignancy or metastasis	CSF cytology and flow cytometry, CT of the chest, abdomen, pelvis. PET of the brain
Infectious endocarditis with septic emboli	ESR, CRP, lactate
Encephalitis (Infectious etiologies)	TB, RPR, HIV, VZV, HSV, EBV, WNV, HTLV1/2, and others
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)	MRI
Drug-induced vasculopathy	Urine drug screen
Amyloid angiitis	Congo red and thioflavin on biopsy, MRI with Susceptibility-weighted imaging
Progressive multifocal leukoencephalopathy	HIV antibodies