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• Response to a letter by Dr. G. Banerjee
  Filipa Ladeira, Raquel Barbosa, Luisa Alves and Miguel Viana-Baptista
  Published on: 11 August 2018

• Published on: 11 August 2018

  Response to a letter by Dr. G. Banerjee

  • Filipa Ladeira, Neurology Resident Neurology Department, Hospital de Egas Moniz, Centro Hospitalar de Lisboa Ocidental
  • Other Contributors:
    • Raquel Barbosa, Neurology Resident
    • Luisa Alves, Neurology Consultant
    • Miguel Viana-Baptista, Neurology Consultant

  We read with great interest the recent report of Banerjee and colleagues of three cases of minimally symptomatic cerebral amyloid angiopathy-related inflammation (CAA-ri) cases, drawing attention to the possibility of a wider spectrum of clinical manifestations in patients with CAA-ri than previously described1.
  Cerebral amyloid angiopathy-related inflammation (CAA-ri) is a rare form of meningoencephalitis, presenting acutely with cognitive decline, seizures, headache and /or encephalopathy in most patients. The prognosis is poor even in patients under immunosuppressive treatment, with a mortality rate of 30% and only a minority of patients making a full recovery2-3. However, in the three cases reported by Banerjee and colleagues, patients presented with mild symptoms despite the magnitude of the MRI findings and made a full clinical and radiologic recovery in 2 of the cases with immunosuppressant treatment and in the remaining without any treatment.
  We have recently evaluated a similar patient, that presented with mild transient symptoms in whom the diagnosis was made following the finding of characteristic CAA-ri changes in brain MRI.
  He was a 62 year-old-man with a past history of hypertension, who was referred to the Emergency Department (ER) due to moderate frontal headache followed by left hemisensory numbness with Jacksonian march lasting a few minutes. He was asymptomatic on arrival at the ER and his neurological examination was normal. He perfor...

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  We read with great interest the recent report of Banerjee and colleagues of three cases of minimally symptomatic cerebral amyloid angiopathy-related inflammation (CAA-ri) cases, drawing attention to the possibility of a wider spectrum of clinical manifestations in patients with CAA-ri than previously described1.
  Cerebral amyloid angiopathy-related inflammation (CAA-ri) is a rare form of meningoencephalitis, presenting acutely with cognitive decline, seizures, headache and /or encephalopathy in most patients. The prognosis is poor even in patients under immunosuppressive treatment, with a mortality rate of 30% and only a minority of patients making a full recovery2-3. However, in the three cases reported by Banerjee and colleagues, patients presented with mild symptoms despite the magnitude of the MRI findings and made a full clinical and radiologic recovery in 2 of the cases with immunosuppressant treatment and in the remaining without any treatment.
  We have recently evaluated a similar patient, that presented with mild transient symptoms in whom the diagnosis was made following the finding of characteristic CAA-ri changes in brain MRI.
  He was a 62 year-old-man with a past history of hypertension, who was referred to the Emergency Department (ER) due to moderate frontal headache followed by left hemisensory numbness with Jacksonian march lasting a few minutes. He was asymptomatic on arrival at the ER and his neurological examination was normal. He performed a cranial CT scan that revealed a right subcortical temporoparietal hypodensity which led to the request of a brain MRI that showed a right pseudotumoral temporoparietal white matter lesion, hyperintense on T2-weighted sequences without gadolinium enhancement, and multiple corticosubcortical microbleeds in T2* co-localized with the T2-lesion. CSF evaluation disclosed a mild elevation of proteins (53mg/dl) with a normal white cell count and no oligoclonal bands. Alzheimer disease (AD) biomarkers in CSF were consistent with a DA-related pathophysiology Aβ1-42: 494 pg/mL (normal range (NR) >542), total-tau: 252 pg/mL (NR <212), phospho-tau: 126 pg/mL (NR < 32). We further evaluated the presence of antibodies against Aβ which were positive (48.17 ng/mL). Neuropsychological evaluation and EEG were normal. At this point, a diagnosis of probable CAA-ri was made, according to the clinicoradiological criteria of CAA-ri4. The Apo-E genotype was ɛ4/ɛ4 further supporting the CAA-ri diagnosis. Given the benign course of the disease, a conservative approach was adopted, and steroid therapy and biopsy were deferred. The patient has been followed for 2 years and remains asymptomatic. A 3-month and 1-year follow up MRI showed complete reversion of the temporoparietal T2-hyperintense lesion and stabilization of the number of microbleeds.
  Given the findings reported by Banerjee and colleagues and our own, we agree that CAA-ri might be underdiagnosed, its clinical spectrum might be wider than previously thought, and the entity might be underdiagnosed in patients with mild clinical symptoms. We also believe that the increasing availability of brain MRI will probably keep expanding the clinical spectrum of manifestations associated with CAA-ri.
  Dr. Banerjee and colleagues suggested that milder phenotypes of CAA-ri might relate to a genotype of ApoE other than ɛ4/ɛ4, which is known to associate with a higher risk of developing the classic form of CAA-ri. However, in our patient, the genotype of Apo E was ɛ4/ɛ4, and previous reports could not find a relation between the ApoE genotype and the clinical course of CAA-ri5. Still, information regarding the relationship between ApoE genotype and the CAA-ri clinical course is scarce, and further studies will be needed to evaluate this hypothesis.
  Finally, in our patient, we identify antibodies against Aβ in the CSF. Although their precise role remains to be established we can speculate a possible implication in the overlap described by Banerjee and colleagues, between the entity of minimal symptomatic amyloid angiopathy and amyloid-related imaging abnormalities (ARIA) found in patients with AD under anti-amyloid immunotherapy
  To conclude our case reinforces the existence of a variant of minimal symptomatic CAA-ri described by Dr. Banerjee and colleagues. A high index of suspicion is key to identifying these patients. In the cases described so far, patients’ demographic characteristics and radiologic findings resembled those with a classic form of CAA-ri (the majority were men, with a mean age of 63 years). Further studies are needed to characterize this different phenotype, including CSF findings, ApoE genotype as well as the role of antibodies against Aβ in the CSF.

  Acknowledgments
  The authors thank Dr. Fabrizio Piazza for the evaluation of antibodies against Aβ in the CSF.

  References
  1. Banerjee G, Alvares D, Bowen J, et al. J Neurol Neurosurg Psychiatry. Epub ahead of print: [March 13, 2018]. doi:10.1136/jnnp-2017-317347
  2. Corovic A, Kelly S, Markus HS. Int J Stroke. 2018: 13(3): 257-267. doi.org/10.1177/1747493017741569
  3. M, Caetano A, Pinto M, et al. Stroke-Like Episodes Heralding a Reversible Encephalopathy: Microbleeds as the Key to the Diagnosis of Cerebral Amyloid Angiopathy–Related Inflammation—A Case Report and Literature Review J Stroke Cerebrovasc Dis. 2015 24(9), e245-e250. 10.1016/j.jstrokecerebrovasdis.2015.04.042
  4. Auriel E, Charidimou A, Gurol E, et al. Validation of Clinicoradiological Criteria for the Diagnosis of Cerebral Amyloid Angiopathy-Related Inflammation. JAMA Neurol. 2016; 73 (2):197-292. doi: 10.1001/jamaneurol.2015.4078
  5. Kinnecom MS, Lev MH, Wendell L, et al. Neurology. 2007:68 (17): 1411-6. doi: 10.1212/01.wnl.0000260066.98681.2e

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  Conflict of Interest:
  None declared.

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