Woman referred for blurred vision, retro-orbital headache
Bilateral moderate disc edema and hyperemia with mild retinal exudates and Paton's lines were seen on posterior segment examination.
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A 45-year-old white woman was referred by the Tufts Medical Center neurology service to the Tufts-New England Eye Center neuro-ophthalmology service for 3 weeks of blurred vision in the left eye and retro-orbital headache.
Her medical history included hypertension, obesity, rosacea and anemia. Her medications included hydrochlorothiazide and topical metronidazole.
Examination
Best corrected visual acuities were 20/20 in the right eye and 20/40 in the left eye. Confrontation visual fields were full, and automated perimetry (HVF 30-2 SITA Fast) showed enlarged blind spots bilaterally (Figure 1). Color vision using the Hardy Rand and Rittler standard pseudoisochromatic color plates was normal in both eyes. The pupillary examination revealed pupils equal in size and response, with no evidence of a relative afferent pupillary defect. Extraocular motility was full. The anterior segment examination was unremarkable. The posterior segment examination was pertinent for bilateral moderate disc edema and hyperemia with mild retinal exudates and Paton’s lines (Figure 2).
Source: Allison Coombs, DO, MS, and Laurel N. Vuong, MD
What is your diagnosis?
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Bilateral disc edema
The differential for bilateral disc edema includes elevated intracranial pressure from space-occupying lesions, cerebrospinal fluid (CSF)-producing tumors, obstruction of arachnoid villi, intracranial venous thrombosis, venous stenosis and idiopathic intracranial hypertension. Bilateral disc edema without elevated intracranial pressure can result from compressive optic neuropathies, diabetic papillopathy, hypertensive emergency, or infectious etiologies causing neuroretinitis, including cat scratch disease (Bartonella henselae), tuberculosis, Lyme disease and syphilis. Noninfectious optic neuritis may be related to multiple sclerosis, neuromyelitis optica spectrum disorder and anti-myelin oligodendrocyte glycoprotein syndrome.
Case continued
Upon further questioning, the patient endorsed occasional pulsatile tinnitus and recently gained 10 pounds. She denied experiencing diplopia or transient visual obscurations. She was not currently taking vitamin A supplements or derivatives, tetracycline/minocycline, steroids or oral contraceptive pills.
Physical examination revealed no localized neurologic findings, and her blood pressure was normal. Initial blood work including HbA1c and infectious serologies including Bartonella henselae and Lyme disease were within normal limits. CBC results were consistent with her known microcytic anemia. MRI of the brain and orbits, with and without contrast, did not show any compressive lesions, inflammation of the optic nerves or white matter changes. MRV of the head showed bilateral dural venous sinus thrombosis of the transverse sinuses, partial occlusion and dilation of the right transverse sinus, and complete occlusion of the left transverse venous sinus (Figures 3 and 4). A lumbar puncture showed an opening pressure of 36 cm H2O with a normal CSF profile. The patient was diagnosed with bilateral dural venous sinus thrombosis resulting in elevated intracranial pressure associated with bilateral papilledema, headaches and pulsatile tinnitus.
The patient was admitted to the hospital to initiate IV anticoagulation. She was started on a heparin drip and transitioned to apixaban before her discharge. She was also started on oral acetazolamide to treat the elevated intracranial pressure (ICP) until the clots resolved and the ICP normalized. Blood was drawn for a hypercoagulable workup during the admission, and the results ultimately showed elevated PTT, factor VIII and anti-cardiolipin IgM.
She had a hematology consultation as an outpatient to determine any underlying etiology and for guidance regarding the duration of her anticoagulation. The results of the hypercoagulable workup were not thought to be consistent with a prothrombotic condition. It was thought to be possibly secondary to the ongoing clot burden and/or suggestive of an underlying autoimmune condition. On further questioning, it was revealed that she was already undergoing an autoimmune workup for a new onset malar rash.
Three months after diagnosis while maintained on acetazolamide and apixaban, her headache and pulsatile tinnitus resolved. The papilledema was resolved in both eyes, and automated perimetry testing no longer showed enlarged blind spots. The duration of her treatment is pending the results of her repeat MRV and repeat hematologic blood work.
Discussion
Cerebral venous sinus thrombosis (CVST), also known as dural venous sinus thrombosis, is an occlusion of venous outflow from the cerebral circulation. The incidence of CVST is rare, estimated to be between 0.22 to 1.5 per 100,000 patients, with a predilection for females, and is typically seen in patients younger than 40 years old. The consequence of dural thrombosis results in localized vasogenic edema, disruption of the blood-brain barrier and an increased hydrostatic gradient. Ultimately, CSF accumulates, leading to increased intracranial pressure. In some cases, localized hemorrhage and parenchymal damage may occur.
Transient risk factors for CVST include infection of the head and neck, pregnancy or puerperium due to hormonal changes, dehydration, mechanical precipitant such as trauma or surgery to the head and neck, or medications such as hormone replacement, hormonal contraception and glucocorticoids. Permanent risk factors for CVST include inflammatory diseases such as lupus, sarcoidosis, ANCA vasculitis, malignancies of the central nervous system, intracranial mass or prothrombotic hematologic states.
Patients with CVST may present with variable symptoms secondary to the elevated ICP. The most common symptom at presentation is headache, which is characterized as severe and worse with recumbency or Valsalva maneuver. Patients with acute CVST may also present with encephalopathy and may have focal or non-focal neurologic deficits. Rarely, CVST may present as a cavernous sinus syndrome or subarachnoid hemorrhage or have multiple cranial nerve palsies. Presentation and manifestation of symptoms are influenced by the patient demographic, location and size of thrombosis, the number of occlusions, and if there are secondary parenchymal or hemorrhagic changes.
The ophthalmic examination in CVST may be nonspecific and may include varying degrees of optic neuropathy, which may manifest as pupillary abnormalities, decreased color vision or visual field changes. Rarely, patients with CVST may have cranial neuropathies, most commonly seen as CN VI palsy. There may be varying degrees of unilateral or bilateral optic disc edema with venous tortuosity or engorgement as well associated subretinal fluid and/or retinal exudate.
Patients presenting with CVST may present similarly to idiopathic intracranial hypertension (IIH); however, IIH is a diagnosis of exclusion that requires full workup in order to exclude other etiologies contributing to elevated ICP.
Workup for bilateral disc edema includes intracranial imaging consisting of MRI of the brain and orbits with and without contrast and MRV of the head to assess for thrombosis. Laboratory studies should be performed to assess for underlying infectious etiologies or underlying hypercoagulable conditions if there are clinical and/or radiographic concerns for such processes. Patients with bilateral disc edema may also warrant lumbar puncture to assess opening pressure.
Patients with elevated ICP from CVST are managed with systemic therapy to acutely lower the pressure. The underlying etiology of the thrombosis should be evaluated by hematology for further workup and management. Selection and duration of anticoagulation therapy depends on the mechanism and underlying etiology of CVST. Patients should be monitored closely for improvement or worsening of signs and symptoms to adjust management appropriately.
- References:
- Aaron S, et al. Ann Indian Acad Neurol. 2017;doi:10.4103/aian.AIAN_11_17.
- Ferro JM, et al. Stroke. 2004;doi:10.1161/01.STR.0000117571.76197.26.
- Ryan K, et al. Throm Res. 2012;doi:10.1016/ j.thromres.2011.10.002.
- Zhao T, et al. BMC Neurol. 2018;doi:10.1186/s12883-018-1156-7.
- For more information:
- Allison Coombs, DO, MS, and Laurel N. Vuong, MD, can be reached at New England Eye Center, Tufts University School of Medicine. 800 Washington Street, Box 450, Boston, MA 02111; website: www.neec.com.
- Edited by Alison J. Lauter, MD, and Sarah E. Thornton, MD. They can be reached at the New England Eye Center, Tufts University School of Medicine, 800 Washington St., Box 450, Boston, MA 02111; website: www.neec.com.