UMEM Educational Pearls - Neurology

• The brainstem is the lower extension of the brain that connects the brain to the spinal cord.

• Neurological functions located in the brainstem include those necessary for survival (breathing, digestion, heart rate, blood pressure) and for arousal (being awake and alert).

• Most of the cranial nerves come from the brainstem.  The brainstem is the pathway for all fiber tracts passing up and down from peripheral nerves and spinal cord to the highest parts of the brain.

• Remember that it is important to check a patient's peripheral vision when concerned about stroke, and when performing a neurological exam in general.
• Recognizing grossly abnormal peripheral vision often suggests the presence of various types of visual field cuts and helps localize a stroke lesion.
• When performing a general, very gross examination for peripheral vision abnormalities:

1. It is sometimes helpful to ask the patient to cover the eye that you are NOT checking for abnormality at the time.
2. Ask the patient to look straight ahead.
3. Ask the patient to tell you when they are able to see the long, narrow object (i.e. your finger, a pencil, etc.) that you slowly move forward into their view, starting from the point where the finger tips of the patient's laterally abducted arm would be (i.e. the object begins at a distance approximately equal to the patient's arm length).
4. Using this axis of reference, normal peripheral vision should occur at 45 degrees or less.

 

• Dihydroergotamine (DHE) is an older medication approved for the treatment of intractable migraine and cluster headaches.  Many of our Neurology colleagues still use this drug and its administration could start while the patient is 
  in the ED.
  
• Intranasal forms have become popular (i.e. Migranal).  Intramuscular and subcutaneous administration are also possible.
  
• The typical intravenous dose is 0.25 to 1 mg IV push over 2-3 minutes q 6 hours for 24 to 72 hours.
  
• DHE use is contraindicated in the following patients: 
  
  >    Patients concurrently on a protease inhibitor or macrolide antibiotic because of increased risk of life- threatening peripheral ischemia (**Black Box Warning**) 
  >    Patients with a hypersensitivity to ergot alkaloids 
  >    Patients with increased risk of developing vasospastic events 
  >    Patients who are concurrently taking vasoconstrictors 
  >    Patients who are pregnant or nursing 
  >    Patients with hemiplegic or basilar migraines
  
• Monitor for the following potential adverse reactions, which are typically related to vasoconstriction/spasm
  and warrant immediate abortion of the drug’s administration: 
  
  >    Myocardial infarction (check ECG's)
  >    Arrhythmia (place on cardiac monitor)
  >    Stroke (regular neuro. checks)
  >    Hypertension (check often) 
  >    Ischemia (monitor for clinical signs/symptoms) 
  
  
  
  
  -- Diener HC, Kaube H, Limmroth V. A practical guide to the management and prevention of migraine. Drugs. 1998;56(5):811-824.
  -- Fisher M, Gosy EJ, Heary B, Shaw D. Dihydroergotamine nasal spray for relief of refractory headache: A retrospective chart review. Curr Med Res Opin. 2007;23(4):751-755.
  -- http://www.aetna.com/cpb/medical/data/400_499/0462.html
  -- http://www.rxlist.com/cgi/generic/dihyergmes.htm
  
   

• Transient Neurological Attack (TNA) = attacks of sudden onset consisting of focal or non-focal neurological deficit, lasting no longer than 24 hours.
• Examples of TNA include TIA (when the deficit is focal), global amnesia, acute confusion, and syncope without a known cause.
• Patients who experience non-focal TNA are at higher risk for major vascular diseases and dementia than those without TNA.

 

Bos, et al.  "Incidence and Prognosis of Transient Neurologcial Attacks, " JAMA, pgs. 2877-85.  Dec. 26,  2007.

Johnston.  "Transient Neurological Attack:  A Useful Concept?," JAMA, pgs. 2912-13.  Dec. 26, 2007

 

• Neurologic manifestations are often the first, yet most insidious, signs of uremia (i.e. electrolyte abnormalities due to renal insufficiency).

• Signs and symptoms of uremic encephalopathy range from normal to comatose.  Some specific examples include dysarthria, pruritus, restless legs, mental status abnormality, myoclonic jerks, tetany, seizure, confusion, asterixis.

• Elevated PTH and calcium levels have been shown to particularly correlate with uremic encephalopathy.

• Elevated BUN levels tend to correlate with the degree of decreased level of consciousness.

• Ammonia levels are not typically elevated with uremic encephalopathy unless there is simultaneous liver disease.

• The treatment is dialysis.

 

http://www.emedicine.com/neuro/topic388.htm

• Of the 700,000 annual strokes in the U.S., 200,000 are recurrent.

• Risk of recurrent stroke is reported to be:

              -->  11.5% at 1 week

              -->  6-15% at 1 month

              -->  18.5% at 3 months

• Risk of stroke following TIA is reported to be:

              -->  8% at 1 week

              -->  11.5% at 1 month

              -->  17.3% at 3 months

• Due to the significant risk of stroke recurrence and new stroke after TIA, many of which lead to permanent disability, death, and health care costs, it is imperative that due diligence be given to proactively and thoroughly working stroke/TIA patients up in a timely fashion after the initial event. 

• Secondary prevention, such as smoking cessation, weight management, alcohol consumption moderation, tight glucose control, and anti-platelet therapy, should also be encouraged.

 

 

Thom, et al.  AHA Statistics Committee and StrokeStatistics Subcommittee.  Heart Disease and Stroke Statistics-2006 Update.  Circulation 2006; 113:e85-151.

Sacco, et al.  Predictors of Mortality and Recurrence after Hospitalized Cerebral Infarction in an Urban Community:  the Northern Manhattan Stroke Study.  Neurology 1994;44:626-34.

Coull, et al.  Population Based Study of Early Risk of Stroke after Transient Ischaemic Attack or Minor Stroke:  Implications for Public Education and Organisation of Services.  BMJ 2004;328:326.

 

 

• Consider cervical artery dissection as the source of stroke in patients younger than age 40.
• About 20% of such strokes are due to carotid artery or vertebral artery dissections.
• Of these, internal carotid artery dissections are the most common.
• These patients often present with a triad of neck and head pain, Horner's syndrome, and pulsatile tinnitus.
• MRI/MRA is the best non-invasive diagnostic modality for arterial dissection.  Angiography may needed for confirmation.

 

Selim M, Caplan LR. Carotid Artery Dissection.  Current Treatment Options Cardiovascular Medicine.  2004; 6:  249-253.

Stapf C, Elkind MS, Mohr JP.  Carotid Artery Dissection.  Annual Review Medicine.  2000; 51:  329-47.

Schievink W. Spontatneous Dissection of the Carotid and Vertebral arteries.  NEJM.  2001; 344:  898-906.

• Less than 10% of sarcoidosis cases affect only the nervous system.
• In such cases, granulomas form within nervous tissue and usually only occurs when there is significant systemic involvement.
• Most sarcoid exacerbations affecting the nervous system are not recurrent. 
• Manifestations of neurosarcoidosis include:
  • 1)  Mononeuropathy - Cranial nerve dysfunction most common     (Heerfordt  syndrome = uveitis, fever, parotid gland inflammation, and facial nerve palsy).
  • 2)  Peripheral neuropathy - Sensation and/or motor dyusfunction
  • 3)  Central Nervous System -  Hypothalamus/pituitary gland, cerebral cortex, cerebellum, spinal cord (rare)

• Note that the use of steroids within 8 hours of injury for SCI is not routinely practiced worldwide and was initially based on a controversial study, the National Acute Spinal Cord Injury Study (NASCIS I & II).

• The approved methylprednisolone dose is 30 mg/kg IV bolus over 15 min, followed by 5.4 mg/kg/h over 23 h; begin IV infusion 45 min after conclusion of bolus.
  

Bracken MB, Shepard MJ, Collins WF, et al: A randomized, controlled trial of
methylprednisolone or naloxone in the treatment of acute spinal-cord injury.
Results of the Second National Acute Spinal Cord Injury Study. N Engl J Med
1990 May 17; 322(20): 1405-11. 

• IA lytics for stroke emerged to increase the 3-hour window for treatment.

• IA tPA may also be indicated for:

              --  candidates with severe neurological deficits (NIHSS score > 10)

              --  candidates with a recent history of major surgical procedures

              --  candidates with occlusion of major cervical or intracranial vessels

• Early IA lytic trials utilized urokinase and tPA, usually within a 6-hour window, though some reports extended the window to 12 hours for posterior circulation ischemic strokes.

• Studies have shown that THERE IS NO SIGNIFICANT DIFFERENCE IN RECANALIZATION RATE, SYMPTOMATIC HEMORRHAGE, AND NIHSS FOR IV PLUS IA LYSIS VERSUS IA LYSIS ALONE.

 

Zaidat OO, Saurez JL, Santillan C, et al.  "Response to intra-arterial and combined intravenous and intra-arterial thrombolytic therapy in patients with distal internal carotid artery occlusion."  Stroke 2002, 33:  1821-1826.

Bellolio MF, et al.  "Stroke Update 2007:  Better Early Stroke Treatment (BEST)," Emergency Medicine Practice, Augst 2007, Volume 9, Number 8.

• 325 mg of aspirin should be given within 48 hours of symptom onset in ischemic stroke; while its good form to give it when appropriate while the patient is still in the ED, per recent guidelines, it is not imperative.

• Aspirin should not be given to stroke patients who will receive tPA.

• Prior administration of aspirin is not a contraindication to giving tPA, however.

• If dysphagia and/or aspiration risk is suspected, give 300 mg of aspirin per rectum.

 

2007 AHA and ASA Guidelines for the Early Management of Adults with Ischemic Stroke and Guidelines for the Management of Spontaneous Intracerebral Hemorrhage in Adults.

Today's joint conference with the UMMS' Neurology Department was quite beneficial and applicable to our daily practice in the Emergency Department (ED).

The topics discussed included:

• Third Nerve Palsy (aneurysmal versus vasculopathic)
• Painful Post-ganglionic Horner's Syndrome
• Cluster Headache
• Carotid Dissection
• Pituitary Apolplexy

While the information provided for each of these clinical topics was comprehensive, be sure to review these disorders in the near future, in order to commit them to memory and increase your comfort level with diagnosing and treating them in the ED.  If you'd like a copy of the handouts, just let me know.

Today's pearl will highlight pituitary apoplexy.

Take Home Points about Pituitary Apoplexy:

• Defined as hemorrhage or infarction of a pituitary tumor.
• Neurologic emergency that can be fatal, usually due to hemorrhage.
• Typically presents with acute onset of headache +/- meningeal irritation, altered mental status,  photophobia, and  ophthalmoplegia (usually 3rd cranial nerve palsy, followed by 6th and 4th cranial nerve dyfunction).
• CT head (dry) may appear normal.  MRI typically makes the diagnosis.
• Ophthalmoplegia (of 3rd CN) + CSF with significant red cells may prompt an angiogram in search of a PCOM (posterior communicating artery) aneurysm, when an MRI is acutally all that's needed.
• Treatment:  high dose steroids (hydrocortisone 100 mg IV q 6-8 h) +/- decompressive surgery via Neurosurgery.

 

• Fever in the setting of acute ischemic stroke is associated with increased mortality and morbidity.

• These effects are possibly due to increased metabolic demands, neurotransmitter release, and free radical production.

• Use of antipyretics to achieve normothermia may improve outcome.

• Studies have shown that hypothermia is neuroprotective.

• Look for a potential source of fever, which may have caused or prompted the stroke (i.e. infective endocarditis, complications of pneumonia).

 

Adams, et al.  Guidelines for the Early Management of Adults with Ischemic Stroke.  AHA/ASA Guidelines.  2007.

 

• Apraxia = Inability to carry out physical acts despite intact motor function.

• Agnosia = Inability to recognize and identify objects and/or sounds despite intact sensory function.

 

What should I do about this finding on the MRI I ordered

Now tha ta lot of EDs are getting MRIs on a more urgent basis, we will need to know what to do with the resutls.  However, the natural history of findings on MRI has not been well studied, so what should we do with that small meningioma you find.  Well some researchers in the Netherlands have attempted to address your question. In a population-based study [Rotterdam Study] , 2000 adults aged 45 or older underwent a brain MRI.

Some of the common findngs were:

• Asymptomatic brain infarcts were observed in 7%.
• Aneurysms and benign tumors (mostly meningiomas) were each found in nearly 2%.
• The two most urgent findings were a chronic subdural hematoma and a 12-mm aneurysm. Both required surgey.
• Only two out of the 2000 (0.001%) people had symptoms related to their MRI findings (hearing loss in both).
• The prevalence of asymptomatic brain infarcts and meningiomas increased with age, as did the volume of white-matter lesions, whereas aneurysms showed no age-related increase in prevalence.

Most of the study patients were white and middle class so these results may not be generalized to the general public.  I am sure more studies are in the works, but for now don't be two suprised if you find an asympomatic infarct or meningioma.

Vernooji MW, Ikram MA, Tanghe HL. Incidental Findings on Brain MRI in the General Population. NEJM. 2007;357(18):1821-1828.

• Xanthochromia is the result of metabolized hemoglobin in cerebrospinal fluid (CSF), which suggests intracranial bleed.
• It helps differentiate traumatic lumbar puncture results from true intracranial bleeding.
• It causes the CSF to have a yellowish color which can be detected with the naked eye or analyzed with a machine (done visually at UMMS).
• It typically takes at least 6 hours for xanthochromia to manifest itself. 

 

Don't forget to do  thorough assessment of deep tendon reflexes on physical examination when appropriate.  DTR assessment can help localize a lesion and determine a diagnosis (i.e. thyroid disease, Guillain Barre, spinal cord and peripheral nerve lesions).

DTR Assessment Scale:

• 4+ - very brisk, hyperactive with clonus<
• 3+ - brisker than normal
• 2+ - average, normal
• 1+ - somewhat diminished, low normal
• 0 - no response

Major DTR Assessment Locations:

• Triceps (C6, C7)
• Supinator or Brachioradialis (C5, C6)
• Knee (L2, L3, L4)
• Ankle (mainly S1)
• Plantar (L5, S1)

• The most common (80%) cause of non-traumatic subarachnoid hemorrhage (SAH) = ruptured saccular (berry) aneurysm.
• Saccular aneuryms are thought to be present in up to 5% of the population.
• There is a strong familial association with cerebral aneurysms, and prevalence is increased in people with Marfan Syndrome and Polycystic Kidney Disease.
• Other causes of non-traumatic SAH include:  AV malformation, cavernous angioma, mycotic aneurysm, and blood dyscrasia. 

Horner's Syndrome Deficit in descending sympathetic pathways Miosis + Ptosis + Anhidrosis Associated with lateral medullary infarctions, which are caused by disrupted flow to the posterior inferior cerebral artery (PCA) (i.e. Wallenberg Syndrome)

Common causes of stroke in young patients: --> Arterial dissection (most commonly involving the carotids, often trauma related) --> Cardioembolic events (most commonly via a patent foramen ovale (PFO) associated with an atrial septal aneurysm; also atrial septal anuerysms and myxomatous mitral valve prolapse; most common amongst our patient population is likely endocarditis) --> Large vessel disease (typically in 5th decade of life) --> Small vessel disease (typically in 5th decade of life) --> Coagulopathies (i.e. Sickle cell anemia) --> Vasculopathies/Vasculitis Cerrato, et al. "Stroke in young patients: Etiopathogenesis and risk factors in different age classes." Cerebrovascular Diseases 2004;18:154-159.