Laboratory Studies
Blood tests usually do not contribute to the diagnosis of papilledema. If the diagnosis is in doubt, CBC count, blood sugar, angiotensin-converting enzyme, erythrocyte sedimentation rate, and syphilis serology may be helpful to look for signs of infectious, metabolic, or inflammatory diseases. [1] Patients with cerebral venous sinus thrombosis can be tested for hypercoagulation. [4]
Imaging Studies
Urgent neuroimaging (eg, CT scan, MRI) of the brain with contrast should be performed in an attempt to identify a CNS mass lesion. [1, 4]
Consider magnetic resonance (MR) venography to detect venous sinus thrombosis. [4]
Optical coherence tomography can be used to document the elevation of the nerve fiber layer and can be used in a serial fashion. [9]
B-scan ultrasonography may be useful to rule out buried disc drusen.
Fluorescein angiography is sometimes helpful in establishing the diagnosis. Acute papilledema exhibits increased dilation of the peripapillary capillaries with late leakage of the dye. Autofluorescence may reveal disc drusen. [4]
Other Tests
Perimetry
Visual fields should be tested. They commonly show enlargement of the blind spot. With extreme disc edema, a pseudo–bitemporal hemianopsia may be seen.
With chronic papilledema, constriction of the visual field, especially inferiorly, gradually can occur, which eventually may progress to a loss of central acuity and total blindness. [4]
Stereo color photography
Stereo color photographs of the optic discs are useful to document changes. [4]
Procedures
If no mass lesion is detected on MRI, a lumbar puncture can be performed to assess the opening pressure of the CSF and to obtain CSF for analysis to rule out neoplastic and infectious etiologies. The lumbar puncture may provide transient headache relief, as the CSF pressure is reduced temporarily. [4]
