Hypertensive encephalopathy (HTE) is manifested by headache, confusion, seizures, and visual disturbance and may progress to coma and death.1 CT or MRI scans usually show transient, predominantly posterior white matter involvement that rapidly improves with control of hypertension.
The following three patients were unusual in having severe brainstem involvement without accompanying occipital lobe changes.
Case reports.
Patient 1. A 54-year-old woman with a history of poorly controlled hypertension presented with 3 days of walking difficulty, right leg weakness, and mild headache with nausea. She denied any visual problems. Examination showed blood pressure (BP) of 210/144 mm Hg. She was confused with mild right hemiparesis. Funduscopic examination showed scattered posterior pole exudates and hemorrhages without disc edema. The T2-weighted and fluid-attenuated inversion-recovery (FLAIR) images showed hyperintense signals in the brainstem, with scattered mild signal changes in the cerebellum and periventricular white matter (figure, A and B). Diffusion-weighted MRI showed only a small left subcortical infarct.
Figure. (A and B) Patient 1. MRI–fluid-attenuated inversion recovery (FLAIR). Predominant brainstem and scattered cerebellar high-intensity signal. (C and D) Patient 2. CT scan. Mild swelling and decreased signal in the pontine tegmentum is seen without supratentorial cortical involvement. (E and F) Patient 3. MRI-FLAIR. Severe brainstem and cerebellar signal changes on admission.
Lowering of BP resulted in rapid clearing of confusion, and she was discharged with residual right lower extremity weakness. Follow-up MRI 12 days later showed marked improvement of the brainstem and periventricular signal changes with resolution of edema.
Case 2.
A 22-year-old woman with known lupus erythematosus and chronic hypertension complained of headache and nausea of 2 days’ duration. She was brought to the emergency room, where a tonic-clonic seizure was observed. After stabilization, her BP was noted to be 213/133 mm Hg. She was drowsy but able to follow simple commands. A CT showed low-density signal changes and mild swelling in the brainstem; the occipital white matter was normal (figure, C and D). Rapid resolution of headache followed lowering of BP. Follow-up MRI 5 days later showed faint signal changes and resolution of swelling in the brainstem parenchyma.
Case 3.
A 49-year-old man with chronic hypertension had a 1-week history of headache, nausea and vomiting, and diffuse weakness but no visual symptoms. He was lethargic and confused with a BP of 211/156 mm Hg. T2-weighted and FLAIR sequences showed marked high-intensity signal changes of the brainstem and cerebellum with periventricular lesions (figure, E and F). Alertness and strength recovered within 2 days. Repeat MRI 13 days later showed marked improvement of previous brainstem signal changes.
Discussion.
Our patients presented with several days of headache, nausea, lethargy, and confusion associated with marked hypertension—the lowest readings being 210 mm Hg systolic and 133 mm Hg diastolic. Visual complaints were conspicuously absent, and clear-cut brainstem signs were not seen. Rapid improvement of headache and mentation followed lowering of BP. This characteristic clinical evolution, accompanied by rapid improvement of radiologic abnormalities, strongly suggests hypertension-induced encephalopathy.
Posterior cerebral localization is a hallmark HTE. Visual deficits are common, and the occipital lobes usually are the site of maximal CT and MRI changes. In our patients, the brainstem was severely involved, whereas the occipital lobes were largely spared.
Despite the emphasis on posterior supratentorial lesions with terms such as reversible posterior leukoencephalopathy syndrome,2 secondary cerebellar and brainstem involvement is not rare. In one radiologic study of 36 patients with HTE,3 15 had brainstem and 11 had cerebellar involvement. We were able to find only two case reports of HTE with predominant brainstem involvement.4,5 One of these required a shunt placement to relieve obstructive hydrocephalus from fourth ventricular compression.5 Thus, although minor brainstem or cerebellar involvement is not rare, predominantly posterior fossa lesions, as seen in our patients, is uncommon in HTE.
Clinical recognition of brainstem HTE may be difficult. Brainstem infarction can be ruled out by the lack of major brainstem signs, rapid clinical recovery, predominant white matter involvement in T2-weighted and FLAIR images, and absence of signal changes in diffusion-weighted MRI. Osmotic myelinolysis may produce a similar radiologic picture, but our patients had no consistent electrolyte abnormalities. Infectious brainstem encephalitis is unlikely in the presence of normal spinal fluid constituents and rapid recovery without specific treatment. The enlarged, edematous brainstem may suggest a tumor, but rapidity of clinical evolution should help differentiate. Postinfectious encephalomyelitis is perhaps the most difficult condition to exclude. “Clinical–radiologic dissociation” may be dramatic in both, but brainstem HTE usually is symmetric and unaccompanied by inflammatory CSF changes. Indeed, brainstem HTE is perhaps the most dramatic example of “the patient looking better than the MRI.”
Early diagnosis of brainstem HTE avoids unnecessary testing and facilitates prompt treatment.
Note added in proof. Since submission of this article, another case of hypertensive brainstem encephalopathy has been published.6
Footnotes
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Copyright © 1999 by the American Academy of Neurology
- Received January 5, 1999.
- Accepted March 24, 1999.
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