66-year-old Hispanic female presented to the LA County ED with:
Worsening of “blurry vision” over several weeks
One-year history of intermittent binocular diplopia, pulsating left ear pain and tinnitus
PMH: HTN, DM Type 2, Dyslipidemia, Hyperthyroidism
ROS negative for headaches, nausea, or sudden loss of vision
Exam Findings
BCVA 20/20 OD, 20/30 OS, IOP WNL, no RAPD, Ishihara color plates normal OU
Anterior segment exam on slit lamp only notable for 2+ NSC of the lens OU
Dilated fundus exam: normal appearing optic nerves with CDR 0.4 without evidence of swelling or atrophy
Figure 1: CT head without contrast was obtained in the ED. The scan revealed a prominent empty sella (white arrow) and crowded ventricles (red arrows)
Differential Diagnosis of Bilaterally Swollen Optic Nerves with Near Normal Optic Nerve Function
Elevated Intracranial Pressure (ICP):
The enlargement of the (“empty”) sella as seen in our case, can be suggestive of chronically increased ICP. Elevated ICP can be etiologically subdivided as follows:
Recent LP prior to current presentation demonstrated elevated opening pressure with normal CSF composition, but no documented eye exam at the time
MRI brain with and without contrast was obtained to better characterize the etiology of the elevated ICP
Figure 2: Axial (left) and sagittal (middle) cuts of the MRI brain demonstrate an absence of flattening of the back of the globe or tortuosity of the optic nerve – both features that can be seen with elevated ICP. The right photo demonstrates a markedly empty sella (arrow)
Figure 3: MRI brain post-contrast, sequential axial T1 images revealed an avidly enhancing mass (blue arrow) measuring 23 x 15 x 24 mm (TV x AP x CC) within and expanding the left jugular foramen, and enveloping the left internal jugular vein (white arrow). The image on the right shows the feeding left sigmoid sinus (red arrow)
Diagnosis
Paraganglioma causing compression of the left internal jugular vein
Jugular venous obstruction resulted in impaired CSF absorption, leading to elevated ICP
Sufficiently compartmentalized CSF pressure may allow some cases of elevated ICP to present without papilledema
Pathophysiology
Paragangliomas are rare neuroendocrine tumors that are usually sporadic
Jugular paragangliomas can present with symptoms and signs of raised intracranial pressure when they cause occlusion or obstruction of the internal jugular veins and thus impair cerebral venous outflow
Elevated pressure within the cerebral venous system can impair the ability of the arachnoid granulations to absorb CSF, in turn leading to elevated ICP
This is the mechanism by which venous sinus thrombosis leads to increased ICP
Over 90% of pseudotumor cerebri patients demonstrate venous sinus stenosis – specifically at the intersection of the sigmoid sinus and transverse sinus
Treatment
Since malignant behavior is only seen in 4% of jugulotympanic paragangliomas, there are a variety of treatment options that include observation, surgical resection with preoperative embolization, radiotherapy and radiosurgery
Our patient was seen eight weeks after initial visit and given the stable nature of the patient’s symptoms, we chose to monitor her with dilated fundus exams and Humphrey visual fields at subsequent visits
She is also being followed by Neurology and ENT services as an outpatient for possible surgical intervention if symptoms worsen
Prognosis and Future Directions
Several neuroimaging features can be seen in patients with elevated ICP. Recognition of these findings is particularly important in cases where ICP elevation is suspected, but papilledema is absent. In fact, the modified Dandy criteria for the diagnosis of pseudotumor cerebri now include certain cross-sectional features that are correlated with elevated ICP, and can help support the diagnosis in the absence of papilledema:
Flattening of the posterior aspect of the globe (top left in figure below)
Empty sella (top right)
Distention of the perioptic subarachnoid space with or without a tortuous optic nerve (bottom left)
Transverse venous sinus stenosis (bottom right – see arrow)
This case illustrates the importance of the cerebral venous system in the regulation of CSF pressure and neuroimaging features that can support a suspicion of elevated ICP
References
Bussiere M, Falero R, Nicolle D, Proulx A, Patel V, Pelz D. Unilateral transverse sinus stenosis stenting of patients with idiopathic intracranial hypertension. American Journal of Neuroradiology 2010; 31(4): 645-650.
Friedman DI, Liu GT, Digre KB. Revised diagnostic criteria for the pseudotumor cerebri syndrome in adults and children. Neurology 2013; 81 (13): 1159-1165.
Lertakyamanee P, Srinivasan A, De Lott LB, Trobe JD. Papilledema and vision loss caused by jugular paragangliomas. Journal of Neuroophthalmology 2015; 35(4): 364-370.
Maralani PJ, Hassanlou M, Torres C, Chakraborty S, Kingstone M, Patel V, Zackon D, Bussiere M. Accuracy of brain imaging in the diagnosis of idiopatic intracranial hypertension. Clinical Radiology 2012; 67(7): 656-663.
Thurtell MJ, Kirby PA, Wall M. Bilateral jugular paragangliomas: A rare cause of raised intracranial pressure. Neurology 2014; 82(8): 732-733.
