General Neurology: â€œMind Bendingâ€ Neurologic Neurology:...
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Metropolitan Underwriting Discussion Group
General Neurology: Mind Bending Neurologic Conundrums
Dave Rengachary, MDVice President and Medical AdvisorJanuary 26, 2015
Transient Ischemic Attacks (versus mimics)
We often receive attending physician statements where we have difficulty telling whether an individual had a TIA. We already know what TIAs are and how to apply ratings for these events. We need some guidance on situations where it is not entirely certain that a person had an actual TIA or whether it might be another condition like migraine
TIA: Previous definition
Sudden focal neurologic deficit lasting less than 24 hours, presumed to be of vascular origin, and confined to an area of the brain or eye perfused by a specific artery
TIA: New Definition (AHA/ASA)
a brief episode of neurologic dysfunction caused by focal brain or retinal ischemia, without evidence of acute infarction
Easton JD et al. Stroke. 2009; 40:228 1
Causes of TIA mimics
Amort M et al. Cerebrovascular Diseases. 2011;32:602
Diagnosis of Mimic PercentSeizure 44Migraine 23Psychogenic 7Hypertensive encephalopathy 4Transient Global Amnesia 4Sepsis 4Hypoglycemia 2Benign Paroxysmal Vertigo 2Cerebral venous thrombosis 2Brain Neoplasm 1Subarachnoid hemorrhage 1Peripheral nerve lesion 1*Syncope ??
Symptoms Predictive of TIA mimic
Headache - no mechanism whereby TIA should cause headache Memory Loss (*see below!) Blurred vision (as opposed to loss of vision or diplopia) Syncope Recurrent stereotyped episodes with negative workup Symptoms that do not conform well to a single artery - generalized
symptoms with a gradual or hazy onset rather than focal sudden onset symptoms ("weak" all over, "dizzy)
Lack of other vascular risk factors
Symptoms and TIAs
Sudden onsetWeakness face/arm/legSlurred speechAble to walkDizzinessSeizureLOCConfusion
0.1 1 10MIMIC OR TIA/STROKE
Stroke 2006; 37: 769-75 13
Lancet 2005; 4:727-34 14
Prognosis of TIA mimics
At 3 months, stroke, recurrent TIA and myocardial infarction were absent in patients with TIA mimics but occurred in 13 (5.2%), 20 (8.1%) and 3 (1.2%) TIA patients, respectively.
Amort M et al. Cerebrovascular Diseases. 2011;32:62 1
Transient global amnesia
One of the most interesting neurologic phenomenon happens in entirely normal people with little medical history
Pathogenesis unknown Key feature is sudden and profound inability to form new memories,
repetition of questions lasting on the order of hours without focal symptoms
Often follows exercise Workup typically normal (MRI, ECHO, carotids, EEG) Entirely different prognosis
Low rate of recurrence (6%) Lower rate of stroke, myocardial infarction or deathPantoni Let al. European Journal of Neurology. 2005; 12: 350
Funny Spots on the Brain
Notation is made of white matter hyperintensities these are nonspecific findings of unlikely clinical significance. However..
cannot exclude Lyme disease, vasculitis, multiple sclerosis and demyelinating variants, small vessel strokes, dementia, migrainous phenomenon, hypertensive disease, microbleeds..
.clinical correlation is advised(please dont sue me)
15Boddaert et al. 9 Creative Commons Attributions License
White matter hyperintensities Small vessel ischemic changes Leukoaraiosis Lacunar infarcts Microvascular Changes High Signal Intensity Areas (HSIA) Age related changes FLAIR hyperintensities Dilated Virchow-Robin Spaces UBOs (Unidentified Bright Objects)
Different names for the same game
Complicating matter further these and other incidental findings are quite common - NEJM article by Vernooij et al.6 found that about one in ten people in the general population had a incidentaloma on imaging.
Studies also vary significantly in terms of what is counted as a white matter change size? Number?
White Matter Hyperintensities
??? 25% risk of
MS with RIS8
Mortality Ratio of 2.3
Hazard Ratio of 2.9
Hazard Ratio of 3.1
Clinical Implication of White Matter Hyperintensities7
Vascular Risk Profile
Progression (or stability)
Factors to consider and Red Flags
Mild Carotid Stenosis
We receive carotid ultrasound reports that show lesions in the range of 10-49% obstruction. How worried should we be about this degree of obstruction?
Non-stenotic carotid disease
0 10 20 30 40 50 60 70 80 90 100
Diameter Stenosis %
Velocity versus Degree of Stenosis
Adapted from Zwibel et al.10
ulceration complex heterogeneous soft intraluminal thrombus plaque hemorrhage Echo Lucent (high lipid content)
Bottom line: red flags for non-stenotic carotid lesions
Impact of heterogeneous plaque on mortalityPetersen C et al. Cardiovascular Ultrasound 11 Creative Commons Attributions License
Carotid Intima Media Thickness (CIMT)
Abhashi, et al.12 Creative Commons Attributions License
It is fairly common for us to see applicants with either sensory or motor neuropathies as determined by either clinical history or EMG reports. Which ones should we worry about, and which ones are less concerning?
23% of patients aged 70-7915
40% of patients over 8015
Bottom line : isolated absence of sural nerve likely little consequence in terms of morbidity and mortality, especially in the elderly
Normal loss of sural nerve with aging
Time course Demyelinating Any neuropathy that affects the arms or cranial nerves suggests a more advanced
process Same as indicators for nerve biopsy:
o Demyelination by NCTso Asymmetry (also indicate an immune process)o Significant functional disability (e.g. foot drop/AFO)o Hereditary history (e.g. Friedreichs ataxia, familial amyloid, certain spino-
cerebellar ataxias)o Systemic disease (vasculitis, Sjogren's, amyloid)
Peripheral neuropathy: malignant indicators
Red flag indicators in NCT/EMG reports
"Demyelinating" or "significant slowed conduction velocities"
"Conduction Block AsymmetricNCT "Acute" "Fibrillations" "Positive Sharp
Waves" these latter two are indicators of an active recent process very much analogous to contrast enhancement on MRI
Diabetic peripheral neuropathy
57% of patients who died related to complications of diabetes (68% cardiovascular) had neuropathy compared to 23% of those survivors at the end of a 9 year follow up period16.
Diabetic autonomic neuropathy
The 5-year mortality rate in patients with diabetic autonomic neuropathy is three times higher than in diabetic patients without autonomic involvement17
Silent cardiac ischemia a particular concern
Vinik et al.18 Creative Commons Attributions License
Please define a syrinx and help understand the associated mortality.
Cross sectional Spinal Cord Anatomy
http://upload.wikimedia.org/wikipedia/commons/e/ee/Anatomy_and_physiology_of_animals_The_spinal_cord.jpg uploaded by Ruth Lawson, Oligo Polytechnic Creative Commons Attribution 3.0 Unported License
Cape like pattern of
Bowel and Bladder loss
and sensory loss
http://commons.wikimedia.org/wiki/File:Syringomyelia.jpg uploaded by Cyborg Ninja license CC Attribution ShareAlike 3.0
Very often can be an incidental or equivocal finding (a slightly enlarged central canal is a normal variant)
Overall rare condition (8.4 out of 100,000, mean age of onset is 30) with a wide variety of underlying structural conditions:
Birth Defects (Chiari Malformations) Tethered Spinal cord
Acquired Spinal cord tumors Trauma Hemorrhage Meningitis Arachnoiditis Idiopathic
Surgical indications and outcomes are unclear (are you treating the cause or temporizing a solution? - shunts can become clogged)
Good prognostic indicators Idiopathic, asymptomatic, incidental Localized syrinx (< 3 vertebra)
predicted stability without surgical intervention
Bad prognosticators: Any progression (clinically or
radiographically) over time Higher = worse - more to lose
Syrinx prognostic indicators
91% of 48 children with idiopathic (but not necessarily incidental) syrinxes remained asymptomatic over 2.5 years19
In a retrospective study of small incidental syrinxes (2 mm and < 3 vertebral levels) , none of the 32 syrinxes enlarged at 32 months20
Arnold Chiari Malformations
Please review the various types of Arnold Chiari Malformations and mortality concerns with each.
Arnold Chiari Malformations
43http://upload.wikimedia.org/wikipedia/commons/e/e8/Brain_chrischan.jpg uploaded by Christian Linder Creative Commons Attribution Share Alike L