Happy New Year Ribbonites! We hope everyone weathered the bomb cyclone and are ready to fill your craniums with knowledge of varying utility. After a brief holiday hiatus the editorial staff at The Cortical Ribbon is happy to present the first 2018 edition. As always, we welcome cases, factoids, and neurology based Haikus from our readership. In case you aren’t already a regular subscriber, don’t forgot to add your email to the form on the bottom right section of the website.
Case of the Week:
“Though seeing, they do not see; though hearing, they do not hear or understand.”
An elderly male with multiple vascular risk factors and prior CVA with mild residual right sided weakness presented to the ED with acute onset confusion and visual changes. Per his wife, he was unable to read words from the magazine she presented to him but otherwise had normal speech without dysarthria. He reported word finding difficulties, more so when trying to read. He denies weakness or numbness. His exam was notable for a R superior quadrantanopia and L inferior quadrantanopia. In addition, his language was fluent with intact repetition, naming (high and low frequency objects), and comprehension, inability to read written words (unable to read the word physician and hospital) but able to read most individual letters, able to spell and write full sentences but unable to read the sentence he wrote. A CT Head with vascular imaging was obtained which showed no large vessel occlusions but there was a probable hypodensity in his L occipito-temporal region. MRI Stroke protocol was notable for diffusion restriction in the bilateral temporal lobes (shown below). During his hospital course, his language improved to the point where he could intermittently read short words or sentences, but notably he needed to spell the words out letter by letter before reporting their pronunciation and meaning.
For those that weren’t snoozing during the grand cognitive neurology lecture from Dr. Aguirre, this patient’s presentation is consistent with the prototypical disconnection syndromes known as Alexia without Agraphia. Classically these patients present with a left PCA stroke including the L occipital lobe as well as the forceps majors (the corpus callosum fibers connecting the bilateral occipital lobes). Additional findings can include a right homonymous hemianopia as well as color anomia. In our case, the patient’s visual field cuts were less than would be expected in this syndrome. In fact, the L sided ischemic disease may not have been extensive enough to contribute to this syndrome, and we hypothesize that the small but present R occipital ischemia may have infarcted the crossing fibers to complete the syndrome.
Pediatric Pearls: We all feel a bit Krabbe sometimes
Krabbe disease is an autosomal recessive disorder that is due to a deficiency of galactocerebrosidase (GALC) that affects the central and peripheral system white matter disorder. It is also known as Globoid Cell Leukodystrophy.
Galactacerebrosidase is a lysosomal enzyme that catabolizes galactocerebrosides. Therefore, due to a deficiency in galactocerebrosidase there is accumulation of galactosylceramide and psychosine which leads extensive demyelination (these byproducts are toxic to oligodendrocytes leading to loss of oligodendrocytes) and gliosis with globoid cells.
As an aside, cerebrosides are glycosphingolipids that are major components of nerve cell membranes and myelin sheath.
How common is it?
Estimated incidence is 1 in 100,000 with 85-90% of patients having the early infantile form. The other ten percent is made up of the juvenile onset form and the adult onset form. One case reports a patient as old as 84!
The infantile form has onset between 2-5 months of age. The classic presentation is irritability, stiffness, poor feeding, developmental arrest, poor head control, and episodes of increased temperature without fever. This initial presentation is followed by opisthotonic posturing, myoclonus, developmental regression, seizures, and vision loss. The final stage of the disease is characterized by lack of spontaneous movement and hypotonia. The most common cause of death is respiratory infection. Unfortunately these patients rarely make it past the age of 2 years. Juvenile onset form is characterized by genitive regression and vision loss. Most die around 2-7 years after diagnosis.
MRI reveals diffusely increased T2 signal in the periventricular, deep, or cerebellar white matter and generalized brain atrophy. Diagnosis is confirmed by measurement of GALC in leukocytes or skin fibroblasts. Can also confirm the diagnosis with targeted mutation or sequence analysis.
Treatment is supportive and symptomatic. Stem cell transplant attenuates the clinical course but it is not curative.
Moved by Movement Disorders: DYT5
It’s amazing how little we get to learn about movement disorders during JAR year as most of the patients do not present to our inpatient world. I find this quite unfortunate as there is a whole host of fascinating disorders with quite intriguing examinations if we just venture a few blocks over to Pennsylvania Hospital. Let’s start with a nice intro from the one and only Michael Jackson.
Briefly, a young female began having left foot in-turning at age 7 which resulted in her having a difficult time walking. She saw multiple doctors who were very unsure what this was. In high school her symptoms persisted and she was unable to run or play sports. At this same time she began developing hand tremors, trouble writing and brushing her teeth. Thankfully she saw a trusted pediatric neurologist who gave her Sinemet and her life completely changed. Wait, Sinemet? Isn’t that for patients with Parkinsons? Yes, but also for DYT-5.
DYT-5, otherwise known as Segawa syndrome, or more appropriately, Dopa-responsive dystonia is a genetic condition which can be divided into DYT5a (autosomal dominant mutation in GTP cyclohydrolase) and DYT5b (autosomal recessive mutation in tyrosine hydroxylase). Both mutations affect the ability of the body to produce dopamine. It presents normally in the first decade of life with an abnormal gait and isolated dystonias, often first with the feet, and hyperreflexia. Some patients develop postural tremors during adolescence. One unique aspects of this is that there is marked diurnal fluctuation and symptoms are noticeably worse in the evening. Think of this as the enzymes are able to “recharge” overnight but can’t keep up during the day as the body requires more dopamine. Patients remain on Sinemet throughout life and show a dramatic response, helping clinch the diagnosis. If you need help remembering this clinic pearl, just think of the PYT who got DYT. For more information, our very own Dr. Gonzalez-Alegre published a wonderful review article on Inherited Dystonias.
The Price is Rite Review
Somehow an ankle XR found its way to the neuro-bowl
You gotta admit, the neuro-bowl was super fun and for the most part the audience as a group could come up with most of the answers. But, let’s be honest, none of us could figure out what was going on with that ankle x-ray, so let’s review: Cerebrotendinous Xanthomatosis (CTX). CTX is an autosomal recessive mutation in CYP27A1 which results in a deficiency of sterol 27-hydroxylase leading to accumulation of cholesterol in neurons. Patients can develop a whole host of neurologic deficits including seizures, movement disorders, dysarthria, dementia and neuropathies. Notably, this condition also affects the eye causing cataracts and the arteries leading to coronary artery disease. Treatment is with chenodoxycholic acid with/without HMG-COA reductase inhibitors.
This is your Brain on Poetry – Weekly Neurology Haikus
Ode to TTM
Chilled sleeping beauties
Neuro folks no longer sure
How long their slumber