In hypertensive encephalopathy, brain magnetic resonance imaging characteristically shows a posterior leukoencephalopathy that predominantly affects the white matter of the parieto-occipital regions.1 Brainstem hypertensive encephalopathy predominantly affects the brainstem and cerebellum while sparing the parieto-occipital region and has not been documented in the ophthalmologic literature.
A 46-year-old white woman described intermittent nausea, daily headaches, and a central scotoma in the right eye for approximately 1 week following blunt trauma to the face. Visual acuity was 20/200 OD and 20/40 OS. Pupils were brisk without an afferent pupillary defect. The anterior segments and intraocular pressures were normal. Funduscopy of the right eye revealed marked optic disc edema and diffuse intraretinal exudate involving the fovea (Figure 1). The retinal vessels were tortuous with marked arteriolar constriction. Numerous areas of linear pigment epithelial hypertrophy with surrounding hypopigmentation were seen throughout the periphery of both fundi. The left optic disc was swollen to a lesser degree. Goldman perimetry revealed a large cecocentral scotoma in the right eye and an enlarged blind spot in the left eye. Blood pressure was 250/145 mm Hg. She was referred to the emergency department.
Fundus photography and fluorescein angiogram on initial examination. A, Fundus photography of the right eye showed marked optic disc edema, splinter hemorrhages, and haziness of the retinal vessels at the disc margins. Surrounding the nerve head, there were subretinal fluid, diffuse intraretinal exudate involving the fovea, a single nerve fiber layer infarct, and intraretinal hemorrhages. B, Fundus photography of the left eye showed marked optic disc edema with radial exudates surrounding, but not involving, the fovea. C, Peripheral fundus photography of the right eye shows an area of linear retinal pigment epithelium hypertrophy with surrounding choroidal hypopigmentation consistent with a Siegrist streak, a characteristic finding in hypertensive choroidopathy. D, Fluorescein angiography of the right eye confirmed focal arteriolar narrowing and revealed areas of macular capillary nonperfusion, microaneurysms, and occasional arteriolar obstruction.
The patient was admitted to the neurological intensive care unit where her blood pressure was controlled using intravenous nicardipine along with metoprolol, amlodipine, and hydrochlorothiazide. Neurologic examination findings remained unchanged, and testing for causes of secondary hypertension was unrevealing. Magnetic resonance imaging revealed abnormal signal and symmetric enlargement of the pons and, to a lesser degree, the medulla and midbrain, extending into the middle cerebellar peduncles and the adjacent deep cerebellum (Figure 2A). The cerebellar tonsils were displaced downward through the foramen magnum. Early hydrocephalus was suggested by dilation of the lateral and third ventricles.
Magnetic resonance imaging findings of hypertensive brainstem encephalopathy. A, Axial T2-weighted image on initial examination shows abnormal signal and enlargement of the pons consistent with edema. B, Axial T2-weighted image 8 days later, after blood pressure was controlled, shows improvement of abnormal signal and decreased enlargement of the pons.
Repeat brain magnetic resonance imaging 8 days later showed marked improvement in the appearance of the entire brainstem with much less crowding of the foramen magnum (Figure 2B). On the day of hospital discharge, she was receiving oral valsartan, metoprolol, amlodipine, hydrochlorothiazide, and potassium and had a blood pressure of 133/69 mm Hg. Fourteen days after her initial examination, funduscopy revealed markedly improved disc edema with persistent macular exudates and stable vision in both eyes.
Despite the presence of extensive brainstem lesions on neuroimaging of brainstem hypertensive encephalopathy, there are often few symptoms other than headache, and this has been coined “clinical radiologic dissociation.”2,3 The differential diagnosis of the neuroimaging of hypertensive brainstem encephalopathy includes neoplasm of the brainstem and infectious encephalitis. The lack of cranial nerve findings and other focal deficits on neurological examination along with the rapid clinical evolution and resolution of symptoms with correction of hypertension helps establish the diagnosis of hypertensive encephalopathy. Neuroimaging typically reveals complete resolution of brainstem findings following blood pressure control. Abnormal vision on initial examination occurred in one third of published cases.2 Severe hypertensive retinopathy, disc edema, optic nerve pallor, ptosis, and ophthalmoplegia have been documented in these patients. Our patient illustrates that the ophthalmologist might be the first to diagnose hypertensive brainstem encephalopathy because of decreased vision from retinopathy and choroidopathy.
Correspondence: Dr Foroozan, Baylor College of Medicine, Department of Ophthalmology, 6565 Fannin, NC-205, Houston, TX 77030 (firstname.lastname@example.org).
Financial Disclosure: None reported.
Funding/Support: This work was supported by unrestricted grant from Research to Prevent Blindness, Inc.
Albini TA, Lakhanpal RR, Foroozan R, Lopez GA, McPherson AR. Retinopathy and Choroidopathy as the Initial Signs of Hypertensive Brainstem Encephalopathy. Arch Ophthalmol. 2006;124(12):1784-1786. doi:10.1001/archopht.124.12.1784