Neurolist February 2009 Discussion Summary


 

1. Selective Dysgeusia: 50 y/o patient with history of ocular myasthenia currently on Predisone treatment developed diminished ability to distinguish sweet taste. The possible involvement of autoimmune mechanism in this symptom and the possibility of zinc supplement as a potential treatment were discussed. In a followed up discussion, the possibility of zinc interfering with copper absorption was also discussed as a potential side effect to the treatment. The possibility raised the need to monitor serum zinc and copper levels in patients taking zinc.

 

2. Management of carotid artery dissection. The treatment options of carotid artery dissection were discussed. While usage of anticoagulation therapy in these patients are common practice, the practice is not backed by evidences from randomized controlled trials proving its effectiveness. While no randomized controlled trial existed to support the usage of anticoagulation therapy vs. antiplatelet therapy in patients with carotid artery dissection, the anticoagulation therapy is indicated in certain cases based on physiological consideration. Further discussion of anticoagulation vs antiplatelet therapy in these patients can be found in this article:  Antiplatelets Versus Anticoagulation in Cervical Artery Dissection. Stroke 2007;38;2605-2611.

 

3. Brand vs Generic medications: The varied bioavailability rate between the brand name and various generic medication may result in break through seizures in epilepsy patients. The discussion raised the issue of how difficult it can be to manage seizures in epilepsy patients, especially those whose symptoms are already hard to control. To prevent/minimize the occurence of breakthrough seizures in patients with epilepsy, having patients taking the same medication from the same manufacturer/pharmaceutical company may be very important.

 

4. The (understandable) frustration of trying to minimize pain for patients during EMG and nerve conduction studies was discussed. Several ways to help providing comfort for the patient were suggested. These includes distracting patients by providing other stimuli, constant chatting and reassuring patients, discussion of topics of interest to both the patient and the practioner can also help. The different responses of different ethnic groups to pain was also discussed under this topic.

 

5. Treatment options for migraineurs with aura and new neurological symptoms are discussed. Antiplatelet therapy, thorough work up including imaging, vascular, and anticoagulation work ups might be warranted in order to rule out rare diseases causing the symptoms. Antiplatelets, valproic acid, and prophylactic therapies might also be helpful depending on the patient's symptoms, frequencies of occurences, and exam findings.

 

6. The question of whether or not patient's position during lumbar puncture can affect the opening pressure was raised. The discussion agreed that having patient in the lateral decubitus position is the most accurate way to obtain opening pressure during lumbar puncture. Meanwhile, the opening pressure obtained while patient was lying in prone position might be falsely elevated due to the increased pressure on the abdomen, causing effects similar to that of valsalva manuver.

 

7. Anticoagulation in stroke patients with atrial fibrillation. While the standard of care calls for anticoagulation treatment in these patients to prevent further strokes, heparin use as a bridging therapy for coumadin is discouraged in this situation. The reasons are: a) heparin was not found to decrease the chances of recurrent stroke; b) anticoagulation therapy during the time of acute stroke can increase the likelihood of bleeding/hemorrhagic conversion. Thus, heparin should not be used as bridging therapy in this situation.

 

8. Diagnosis for CJD can be challenging as some labs no longer perform the 14-3-3 protein analysis. The question was raised as to the usage of MRI studies as a diagnostic study for the disease. Per UpToDate article on the topic, the MRI study of the patients with CJD does demonstrate certain changes in the CNS area, with the T2 and FLAIR signal in the putamen and head of caudate being the most common finding on MRI studies. The DWI abnormalities in the cortical area, however, are the most specific finding during the early phase of the disease. Moreover, MRI findings changes in accordance with the disease progression, thus can be used to track the degree of disease progression. Other study that might assist in the diagnosis include EEG study, which can demonstrate characteristic periodic synchronous bi- or triphasic sharp wave complex (PSWC). The WHO criteria for probable CJD includes the following:

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Progressive dementia

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At least two of the following symptoms: myoclonus, visual or cerebellar disturbances, pyramidal/extrapyramidal dysfunction, and akinetic mutism

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A typical EEG during disease of any duration and/or positive 14-3-3 CSF assay with a clinical duration to death of less than two years

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Routine investigation failed to suggest an alternative diagnosis.

 

9. Treatment for neurosarcoidosis. According to UpToDate article on neurological sarcoidosis, 50% of patients with neurosarcoidosis will develop peripheral cranial nerve palsy. Hypothalamic inflammation resulting in neuroendocrine dysfunction is also a frequent finding in patients with neurosarcoidosis. Meningeal involvement and peripheral neuropathy can also be found in some patients. Contrast enhanced MRI is the study of choice in patients with suspected neurosarcoidosis. Lumbar puncture can also assist in the diagnosis. Typical CSF findings includes:

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Increased total protein up to 250mg/dL in 2/3 of patients

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Normal or low glucose level

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Prodominantly mononuclear cell pleocytosis

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Elevated IgG index

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Presence of oligoclonal band

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Elevated ACE concentration on occasion

For patients diagnosed with neurosarcoidosis, steroids remained the first line of thereapy. Dosing of the steroid therapy depends on the symptoms and extent of neurological involvement. A slow prednisone taper can be considered for severely compromised or with patients needing chronic course of steroid treatment. The steroid is usually tapered at the rate of 5mg every 2 weeks as tolerated until a dose of 10mg/day is approaching. Then the dose is tapered at the rate of 1mg every 1 to 2 weeks with the goal of Prednisone dose at 10mg/day. During the taper, if patient experienced relapse at Prednisone dose >10mg/day, then the dose should be doubled. If patient starts to experience relapse of symptoms at rate of <10mg/day, then the dose should be increased to 10 to 20mg/day.

Alternative therapies such as Azathioprine, methotrexate, mycophenolate, cyclophospohamide, cyclosporine, etc. should not be initiated unless patient's symptoms continue to deteriorate despite aggressive steroid therapy, steroid intolerance, or if steroid usage is contraindicated in the particular patient.

 

10. Appearance of blood on MRI varies depending on the age of the blood. Furthermore, the appearances of blood also differs between T1 and T2 sequences. The following table are taken from the book Neuroanatomy through Clinical Cases by Dr. Blumenfeld.

Time since hemorrhage T1 Sequence T2 Sequence
Acute, first 6-24 hours (intracellular oxyhemoglobin) Gray Light gray
Early subacute, 1-5 days (intracellular deoxyhemoglobin) Gray Dark gray
Middle subacute, 3-7 dyas (intracellular methemoglobin) White Dark gray
Late subacute, 3-30 days (extracellular methemoglobin) White White
Chronic >14days (hemosiderin, mainly on the outer rim) LIght gray with outer rim appears dark gray Light gray with outer rim appears black

 

11. In discussion labeled "Speech entering from left or right", the author brought up some interesting questions and phenomenon for the readers. Those who are interested, please refer to the original post on 2/08/09.

 

 

Revised March 4, 2009

(C) 2009 Medical College of Georgia