IMAGE IN NEUROLOGY
|Year : 2016 | Volume
| Issue : 2 | Page : 272-274
An unusual case of cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy with occipital lobe involvement
Bhavesh Trikamji1, Mariam Thomas2, Gasser Hathout3, Shrikant Mishra4
1 Department of Neurology, Olive View-UCLA Medical Center, Sylmar; Department of Radiology, VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
2 Department of Neurology, Olive View-UCLA Medical Center, Sylmar, Los Angeles, California, USA
3 Department of Neurology, Olive View-UCLA Medical Center, Sylmar; Department of Radiology, VA Greater Los Angeles Healthcare System; University of California, Los Angeles (UCLA), California, USA
4 Department of Neurology, Olive View-UCLA Medical Center, Sylmar; Department of Radiology, VA Greater Los Angeles Healthcare System; University of California, Los Angeles (UCLA); Keck School of Medicine, University of Southern California (USC), Los Angeles, California, USA
|Date of Submission||24-Aug-2015|
|Date of Decision||06-Oct-2015|
|Date of Acceptance||15-Oct-2015|
|Date of Web Publication||12-May-2016|
|Date of Print Publicaton||12-May-2016|
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Source of Support: None, Conflict of Interest: None
| Abstract|| |
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an autosomal dominant angiopathy caused by a mutation in the notch 3 gene on chromosome 19. Clinically, patients may be asymptomatic or can present with recurrent ischemic episodes and strokes leading to dementia, depression, pseudobulbar palsy, and hemi- or quadraplegia. Additional manifestations that have been described include migraine (mostly with aura), psychiatric disturbances, and epileptic seizures. Neuroimaging is essential to the diagnosis of CADASIL. On imaging CADASIL is characterized by symmetric involvement by confluent lesions located subcortically in the frontal and temporal lobes as well as in the insula, periventricularly, in the centrum semiovale, in the internal and external capsule, basal ganglia, and brain stem; with relative sparing of the fronto-orbital and the occipital subcortical regions. We describe a 49 year old male with CADASIL with absence of temporal lobe findings on MRI but predominant lesions within the periventricular white matter, occipital lobes with extension into the subcortical frontal lobes, corpus callosum and cerebellar white matter. Although CADASIL characteristically presents with anterior temporal lobe involvement, these findings may be absent and our case addresses the atypical imaging findings in CADASIL.
Keywords: Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), dementia, migraine, magnetic resonance imaging (MRI), occipital lobe, seizures
|How to cite this article:|
Trikamji B, Thomas M, Hathout G, Mishra S. An unusual case of cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy with occipital lobe involvement. Ann Indian Acad Neurol 2016;19:272-4
|How to cite this URL:|
Trikamji B, Thomas M, Hathout G, Mishra S. An unusual case of cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy with occipital lobe involvement. Ann Indian Acad Neurol [serial online] 2016 [cited 2019 Jun 19];19:272-4. Available from: http://www.annalsofian.org/text.asp?2016/19/2/272/173403
| Case|| |
A 49-year-old previously healthy male presented with a 2-year history of gradually progressive speech abnormalities, unstable mood, gait imbalance, vision changes, and overall cognitive decline. On examination, he was alert and oriented but very anxious. Cranial nerve examination revealed visual acuity of 20/200 in both eyes and mild dysarthria. He had difficulty in identifying objects and was unable to repeat certain phrases. He was hyperreflexic throughout with bilateral upgoing toes and had positive cortical release signs such as glabellar reflex, palmomental reflex, and jaw jerk. His cerebellar function was slow but intact. Additionally, he had a wide-based gait. Initial laboratory findings were unremarkable but magnetic resonance imaging (MRI) of the brain revealed hyperintensity on T2 and fluid-attenuated inversion recovery (FLAIR) images within the periventricular white matter and significant involvement of the subcortical white matter in the occipital lobes. Additionally, there was diffuse atrophy with asymmetric right white matter volume loss greater than left white matter volume loss, particularly within the occipital lobes and hyperintensity in the splenium of the corpus callosum. There was no significant signal change in the anterior temporal lobes. A wide array of tests was performed including adrenoleukodystrophy but neurogenetic testing finally revealed a heterozygous c.3691C > T variant in the NOTCH3 gene, confirming the diagnosis of cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).
CADASIL is an autosomal dominant hereditary arteriopathy caused by a mutation in the NOTCH3 gene on chromosome 19p13. The gene encodes a receptor for vascular smooth muscle cells and the mutation leads to loss of vascular smooth muscle cells, which leads to fibrosis of the small penetrating vessels leading to chronic white matter ischemia.
The clinical symptoms usually start in the fourth decade and the mean age of presentation is 47 years (±10 years). The first clinical manifestation in CADASIL is often associated with attacks of migraine with aura. This is seen in 20-30% of the patients and presents between the age of 20 years and 40 years. The most frequent clinical manifestation of CADASIL is ischemic manifestation, which is seen in 60-80% of the patients in their fourth and fifth decades. Cognitive deficits are reported in most individuals after the age of 50 years and dementia is usually seen after the age of 60 years. Psychiatric symptoms that are mainly due to episodes of mood disturbances are seen in 10-20% of the patients during the course of the disease. Seizures have also been reported.
MRI is the imaging method of choice for CADASIL. The lesions on MRI include:
- White matter hyperintensities on T2-weighted images and FLAIR sequences, which are symmetric, bilateral, and usually seen in the periventricular region and deep white matter. This is predominant in the frontal, parietal, and anterior temporal lobes followed by the external capsule. The occipital lobe is less severely affected.
- Lacunar infarcts present as low signals on T1-weighted images and are often seen in the semiovale, thalamus, basal ganglia, and pons. The lacunar infarcts tend to occur later in life.
- Cerebral microbleeds present as low signals on T2 gradient echo images. They may occur anywhere in the brain but preferential sites are the cortical/subcortical areas, white matter, thalamus, and brainstem. The cerebral microbleeds are found in 25-69% of the patients with CADASIL.,
An involvement of the anterior temporal lobe is said to be diagnostic of CADASIL with a specificity of 100% and sensitivity of 90%. However, it may be absent, particularly in the Asian population. An involvement of the external capsule has a specificity of 45% and sensitivity of 93%.,
Our case exemplifies the atypical imaging features in CADASIL. It is a rare case of occipital lobe predominant CADASIL lacking the typical anterior temporal lobe involvement. The absence of temporal involvement in patients with CADASIL has been reported in the Asian population but our patient was not Asian. Our case had predominant involvement of the occipital lobe [Figure 1] and [Figure 2], which is not as frequently involved in CADASIL. Our case also lacked involvement of the external capsule and the characteristic lacunar infarcts and cerebral microbleeds that is often seen in patients with CADASIL [Figure 3] and [Figure 4]. Our patient did have an involvement of the corpus callosum, which can occasionally be seen with CADASIL. Previously, involvement of the corpus callosum was often confused with multiple sclerosis.
|Figure 1: Axial FLAIR with increased signal in the periventricular white matter and subcortical white matter of the occipital lobe. There is increased signal in the splenium of the corpus callosum|
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|Figure 2: Axial T2 image with normal signal intensity in the anterior temporal lobes|
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|Figure 3: Axial FLAIR image with increased signal in the periventricular white matter and external capsule and small foci of increased signal in the basal ganglia. The increased signal on the FLAIR image in the external capsule suggests CADASIL|
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MRI in general is helpful in the diagnosis of CADASIL and for follow-up of disease progression. However, in our case, the MRI findings were not characteristic of CADASIL. Although MRI is an invaluable tool for the diagnosis of CADASIL, it is important to identify that occasionally atypical findings on MRI may be seen and not all patients will have the characteristic anterior temporal lobe or external capsule involvement.
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There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]