What Is Your Diagnosis?
NeuroQuiz Section Editor: Lawrence S. Honig, MD, PhD, Columbia University, New York, New York.
An 84-year-old, right-handed, independent, community-dwelling woman with a history of hypertension, hyperlipidemia, angina, and asthma was in her usual good health until noted one afternoon by a neighbor to have slowness of conversation without other evident problems. That evening, the patient's family was unable to reach her by telephone. Emergency response was activated and the patient was found unconscious on the floor, with markedly abnormal slurred speech and right-sided weakness. She was taken to the emergency department, where brain computed tomography showed left temporoparietal lucency compatible with a stroke. Clinical history was consistent with the patient having had an unwitnessed seizure, but continuous electroencephalographic monitoring showed lateralized epileptiform activity without seizures. Cerebrospinal fluid analysis showed a white blood cell count of 77/μL (to convert to x106 per liter, multiply by 1.0), a red blood cell count of 222/μL (to convert to x106 per liter, multiply by 1.0), a protein level of 163 mg/dL (to convert to grams per liter, multiply by 0.01), and a glucose level of 46 mg/dL (to convert to millimoles per liter, multiply by 0.0555). Treatment with acyclovir and antibacterial antibiotics was initiated. Body weakness resolved substantially, but the patient remained very obtunded, confused, and less responsive. Cytological, microbiological, polymerase chain reaction, and serological study findings were negative, including tests for viruses, bacteria, and fungi. Magnetic resonance imaging (Figure) demonstrated an extensive region of swelling in the left hemisphere, involving temporo-parieto-occipital regions, of T2 signal hyperintensity consistent with tumor or encephalitis. Gradient-echo imaging showed 2 foci of apparent microhemorrhage. Diffusion-weighted imaging showed cortical ribbon hyperintensity. Contrast administration showed minimal contrast enhancement.
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Correct Answer: Amyloid angiopathy-associated inflammation.
QUIZ RESULTS
What is your diagnosis?
Magnetic resonance imaging shows an extensive area of swollen brain in the left temporal, parietal, and occipital regions. While this was originally interpreted as a stroke owing to apparent acuity and radiographic appearance, the involved vascular territory includes both middle cerebral artery and posterior cerebral artery regions. The isolated cortical signal abnormality on diffusion-weighted imaging is also less consistent with a stroke. While the swollen nature might be consistent with a tumor, the lack of significant contrast enhancement and the markedly cellular fluid make brain neoplasm much less likely. Herpes encephalitis was a reasonable consideration given acuity, location, and cerebrospinal fluid pleiocytosis, but the distribution of the signal abnormality (sparing the ipsilateral medial temporal lobe, not involving the contralateral hemisphere whatsoever, and involving the ipsilateral parietal and occipital neocortex), the lack of hemorrhage, and the negative microbiological, serological, and polymerase chain reaction test results make this diagnosis very unlikely. The large swollen tissue area in an elderly patient, with the concomitant presence of 2 microhemorrhages in the affected area, were deemed most consistent with amyloid angiopathy–associated inflammation. The cellular response in the cerebrospinal fluid can be seen in this condition. A cerebral cortical biopsy confirmed extensive amyloid angiopathy with extensive birefringent material that stained for β-amyloid in the vasculature. There were also destructive vessel changes with extensive granulomatous angiitis, with infiltration of vessel walls with CD68-positive macrophages and inflammatory cells. No parenchymal deposits of β-amyloid were observed, no neurofibrillary tangles were noted, and cortical neuronal density and white matter myelination were preserved. There was no evidence of Alzheimer disease.