UMEM Educational Pearls

Delirium has long been recognized as a common disorder of the geriatric ED population (seen in up to 20% of patients above the age of 65 years), but how good are we at detecting it?

Studies show that the diagnosis of delirium is made in the ED in only 11-46% of patients, which means that more than half go undiagnosed. The problem is, the risk of death at 3 months increases by 11% for every 48 hours of delirium the patient experiences, and so does their length of stay and functional decline. It is mostly missed in patients who have a baseline cognitive dysfunction, such as dementia.

So what can we do about that?

Treat delirium as a neurolgical emergency; be vigilant about diagnosing it and treating it. There are a lot of neurocognitive tests that can be used for diagnosis (such as the mini-mental status exam), but they are usually too cumbersome to use in an ED setting. The CAM (Confusion Assessment Method) has been extensively studied and has a sensitivity and specifity of about 95% to diagnose delirium. It includes the acuity of onset, fluctuant course, inattention (the hallmark), disorganized thinking and/or altered level of consciousness.

Bottom Line? Don't forget to screen your elderly patients for delirium and treat them accordingly!

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Does clinical decision support help reduce head CT utilization in mild traumatic brain injury related ED visits?

• Mild traumatic brain injury (mTBI) account for approximately 1.2 million outpatient visits per year
• Almost 1 million of these mTBI patients undergo head CT as part of their evaluation
• Less than 6% have significant intracranial injuries that require neurosurgical intervention

Are we utilizing clinical decision rules adequately to help us appropriately select patients for CT imaging?

Can clinical decision support (CDS) help us reduce head CT utilization in mTBI related ED visits?

• A recent study by Ip et al. reported on the use of a real-time computerized CDS in an EMR/CPOE system to provide feedback to an ordering provider on "low utility" CT's based on clinical decision rules (New Orleans Criteria, Canadian CT Head Rule, CT in Head Injury Patients Prediction Rule)
• Over a 2 year period, 1221 of 1988 (64%) of mTBI related ED visits were associated with a head CT being performed
• A 13.4% decrease in CT utilization was seen in the CDS intervention group (58.1% pre- vs. 50.3% post-, p=0.005)
• A control cohort using the National Hospital Ambulatory Medical Care Survey (NHAMCS) as a representative of emergency medical care delivered in the U.S. showed no significant change in CT utilization in the same time period (73.3% pre- vs. 76.9% post-, p=0.272)

Take Home Point:

Clinical decision support may be a useful tool to help reduce CT utilization in mild TBI related ED visits.

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There are a few available options for treatment of visual loss due to idiopathic intracranial hypertension (IIH). The Idiopathic Intracranial Hypertension Treatment Trial (IIHTT), the first randomized, prospective, placebo-controlled trial for the treatment of patients with visual loss from IIH, which results were published earlier this year, provided substantial evidence for the first 2 options.

1. Weight loss

2. Carbonic anhydrase inhibitors, such as Acetazolamide

3. Therapeutic lumbar puncture (reserved for pregnant patients or for occasional flare-ups)

4. Surgery:

a. Optic nerve sheath fenestration (ONSF): visual acuity and fields improve in most cases, but symptoms may recur. Benefit? No hardware!

b. Shunts: ventriculoperitoneal (VP) and lumboperitoneal (LP) shunts are the most frequently used. No clear benefit for one over the other. VP shunts may be programmable.

c. Cerebral venous stenting: endovascular stenting of the transverse sinus may improve the symptoms in some people.

BONUS PEARL: The headache does not correlate with the lumbar opening pressure, degree of papilledema or amount of visual loss. None of the above-mentioned management strategies is meant for the treatment of the headache alone. For that, medical management with standard symptomatic treatments, avoiding opiates and barbiturates, is recommended. Surgery is not recommended for headache alone.

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Anisocoria, or unequal pupil sizes, is a common condition.  Approximately 20% of the normal population have physiologic anisocoria.  However, pathologic anisocoria indicates disease of the iris, parasympathetic pathway or sympathetic pathway.  A systematic approach to the evaluation of anisocoria can help differentiate between etiologies that range from benign to life threatening.

The most important question in the evaluation of anisocoria is whether both pupils are normally reactive to light or is one (or both) poorly reactive.  If both pupils are reactive, the smaller pupil is abnormal and the lesion is likely in the sympathetic pathway because pupillary constriction (parasympathetic pathway) is intact.  If one pupil is poorly or non-reactive (and there is no relative afferent pupillary defect), the larger pupil is abnormal and the lesion is likely in the parasympathetic pathway.

DDx of anisocoria with normally reactive pupils:

• Physiologic anisocoria
• Horner syndrome

DDx of anisocoria with poorly or non-reactive pupil:

• Iris sphincter damage (traumatic mydriasis)
• Pharmacologic blockade
• Tonic pupil
• Cranial nerve III palsy

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The 2013 neurosurgery guidelines mention two of the more controversial therapies used in spinal cord injuries:

- “MAP Push” (maintaining the patient’s MAP 85-90mmHg, which theoretically increases the blood flow to the penumbra): evidence for the particular MAP goal is not great, but studies show that ICU level monitoring for the first 7-14 days improves outcome as patients may have delayed cardiovascular or pulmonary instability

- Steroids are not recommended anymore (they were an “option” in the previous guidelines)

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Use of acetazolamide to decrease CSF production is not effective in long-term treatment of hydrocephalus.  About 75% of patients with hydrocephalus require CSF shunt placement.

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Attachments

• 1410082208_20141008_Figure_1.JPG (51 Kb)
• 1410082208_20141008_Figure_2.JPG (45 Kb)

Jolt accentuation, the exacerbation of a headache with horizontal rotation of the neck, or shaking of the stretcher in the less cooperative patient, has been promoted for the past few years as the "go-to" test to assess for meningeal irritation in patients with headache. Previous studies have quoted sensitivities as high as 97.1%. (1)

A new prospective study in AJEM challenges this belief by looking at a total of 230 patients with headaches and subsequent LPs. 197 of them had the jolt accentuation test done, which had a sensitivity of only 21% for pleocytosis (defined as greater than or equal to 5 cells/high power field in the 4th CSF tube). Kernig's and Brudzinski's signs both did even more poorly, with a sensitivity of 2% each. (2)

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Why is everyone obsessed about blood pressure management in stroke?

Greater than 60% of patients with stroke have elevated blood pressure, and 15% have a systolic blood pressure (SBP) greater than184 mmHg. That is more common in hemorrhagic stroke than ischemic stroke. 

Whether it's an acute hypertensive response or a premorbid uncontrolled hypertension, it is likely to negatively affect the clinical course and neurological outcome. 

Below is a suumary of the current guidelines for blood pressure management of stroke subtypes; for a more detailed summary of the guidelines, refer to the original article (below)

Ischemic stroke:

Lytic patients have a target SBP of <185mmHg, whereas nonlytic patients have a higher SBP target of <220mmHg

Hemorrhagic Stroke:

Non-aneurysmal hemorrhage patients with a SBP >180mmHg have a target SBP of <160 mmHg, whereas if their SBP was 150-220 mmHg then lowering it to 140 mmHg is safe. Patients with aneurysmal hemorrhage have a target SBP of <160mmHg

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Elevated intracranial pressure (ICP), defined as >20mmHg, is frequently encountered in patients with severe traumatic brain injury (TBI). A step-wise approach would include:

1.     Analgesia and sedation: frequently forgotten.

2.     Hyperosmolar agents: both hypertonic saline and mannitol can be used. Neither is superior.

3.     Induced arterial blood hypocarbia using hyperventilation (must monitor for cerebral ischemia)

4.     Barbiturates (last resort due to side effects)

5.     Surgical:

a.     CSF drain

b.     Decompressive craniectomy: benefits challenged by the DECRA study

Stocchetti N, Maas AIR. Traumatic Intracranial Hypertension. N Engl J Med 2014; 370:2121-30. 

Maybe not! A new prospective study looked at 600 adult trauma patients presenting with mild traumatic intracranial hemorrhage (with a GCS 13-15), and derived a clinical instrument that predicted the need for a “critical care intervention” (and therefore needing an ICU level of care). These interventions included intubation, neurosurgical intervention and need for invasive monitoring, among other things.

The derived instrument consisted of 4 variables:

1.     GCS less than 15

2.     Non-isolated head injury

3.     Age 65 years or older

4.     Evidence of swelling or shift on the initial head CT

The presence of at least one of these variables predicted the need for critical intervention, identifying 114 of the 116 patients who actually did require it, making it 98.3% sensitive.

This clinical decision rule is yet to be externally validated. 

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In patients presenting to the ER with a TIA (transient ischemic attack), the classic teaching has been to calculate their ABCD2 score (age, blood pressure, clinical features, duration of episode and diabetes) to determine their risk of developing a stroke.

The problem is, a moderate-to-high ABCD2 score is sensitive (86%) but not specific (35%) for a stroke in 7 days. 

The solution: Combining imaging data with the scoring system!
 

The presence of an acute infarct on a diffusion-weighted MRI (DWI) in a patient with an ABCD2 score of 4 or more carries the highest risk of stroke, at 14.9% at 7 days. On the other hand, a negative DWI predicts a 0-2% stroke risk at 7 days irrelevant of the ABCD2 score.

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The Prehospital Acute Neurological Treatment and Optimization of Medical Care in Stroke Study (PHANTOM-S) was a randomized prehospital  clinical trial. On certain days, a dedicated Stroke Emergency Mobile (STEMO) responded to possible ischemic stroke incidents. Outcomes measured included time to thrombolysis and adverse events such as intracerebral hemorrhage. As opposed to usual prehospital care, a STEMO ambulance was equipped with a CT scanner, point of care laboratory, and a neurologist. According to the study, STEMO use resulted in reduced time to treatment (tPA) without adverse events. 

Though this trial did not specifically measure clinical endpoints, it addresses issues central to the delivery of specialized prehospital care:

1) Are there certain conditions which might warrant a tailored, super-specialized EMS response?
2) Are EMS systems capable of delivering definitive care to the patient as opposed to delivering the patient to definitive care? 

Stateside study has already started.  The Houston Fire Department, in partnership with UTHeath, has already loosed a "Mobile Stroke Unit" on the streets. Like the STEMO, the specialized ambulance will be University hospital based, carry a neurologist, and have the capability to administer tPA. 

STEMO pictures courtesy of the "NeuroEMS Blog"
http://www.neuroems.com/2014/05/14/tpa-in-the-truck-results-of-the-phantom-s-trial/

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• While the NIH Stroke Scale (NIHSS) may be relatively cumbersome and quite comprehensive, it is an extremely important tool that must not be ignored; it serves as a "common language" between emergency physicians and neurologists and often significantly shapes the management of acute ischemic stroke patients.
• Its prognostic usefulness (i.e. in cases wherein treatment is not initiated) has been validated and should be applied in emergent settings to determine optimal patient candidates for tPA treatment.
• For example, NIHSS > 20 in patients over 75 years old = 45% mortality; NIHSS >17 in patients with atrial fibrillation = positive predictive value for poor outcome of 96%; NIHSS of 6 or less = good spontaneous recovery.
• An abbreviated version of the NIHSS has been validated and assesses those components which are the best indicators of prognosis.  Therefore, when unable to perform a full NIHSS, one should strongly consider using this tool rather than not performing a stroke scale assessment at all.
• This abbreviated version consists of only 5 categories which assess ability to see (1. best gaze; 2. best visual), walk (3. motor function of left leg; 4. motor function of right leg), and talk (5. best language).  Can patient "see, walk, and talk?"  This scale is scored from 0 to 16, with 16 representing the worst prognosis. (see attached abbreviated NIHSS).

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Attachments

• 1112281605_Abbreviated_NIH_Stroke_Scale.docx (98 Kb)

• When performing a lumbar puncture, an opening intracranial pressure (ICP) greater than 20 to 25 mm of H2O is elevated.  

• If it is thought that a patient's headache is due to elevated pressure, cerebrospinal fluid (CSF) can be therapeutically removed.  It is typically recommended that the pressure not be lowered by more than 50% of the amount above which it is normal.

• The source of elevated ICP should be determined and addressed.  Common causes of increased intracranial pressure include:

             --- Venous drainage obstruction (i.e. cerebral venous sinus thrombosis).

             --- Endocrine (i.e. obesity, hypothyroidism, Cushing's disease, Addison's disease).

             --- Medications (i.e. vitamin A, cyclosporine, lithium, lupron, oral contraceptives,

                  amiodorone, and antiobiotics such as tetracyclines and sulfonamides).

             --- Other conditions (i.e. pregnancy, steroid withdrawal, acromegaly, polycystic ovary

                  syndrome, systemic lupus erythematosus, sleep apnea, HIV).

• While botulism is a rare condition (about 145 reported cases annually), it should still be considered in cases of descending neuromuscular weakness, as it can cause rapid loss of respiratory function and death (mortality < 8%).  Check patient's vital capacity.
• Botulism results from ingesting (onset of symptoms 6 to 48 hours) or having contamination of a wound (onset 4-14 days; associated with intravenous drug use) with Clostridium botulinum, an anaerobic, spore-forming bacteria; it has been used as a bio-terrorist agent as well.
• Patients typically present with anticholinergic symptoms and the four "D's" - (1) dry moth, (2) dysarthria, (3) diplopia, and (4) dysphagia.
• The definitive diagnosis is made by isolating the toxin in serum and/or stool.
• Treatment is supportive and might include use of equine trivalent anti-toxin and human botulism immunoglobulin.  Antibiotic and anti-cholinergic therapy has not been shown to be particularly effective.

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• Micturation syncope is a relatively rare phenomenon (2.4 to 8.4% of fainting episodes) which most commonly affects males, and can often be diagnosed by simply taking a thorough history.
• Straining to urinate triggers the vagus nerve which results in hypotension and bradycardia; in turn, cardiac output and brain perfusion is decreased, often resulting in diaphoresis, pallor, and weakness, followed by syncope or fainting. 
• This process is transient and vital signs as well as consciousness typically return to normal rapidly.
• When evaluating a patient for syncope, pay close attention for the presence of the following factors in order to make the diagnosis:

             -- occurs during or immediately following urination, often when bladder is full.

             -- occurs at night or after standing from the recumbent position of a deep sleep to urinate.

             -- risk factors: enlarged prostate, alpha blocker therapy, dehydration, alcohol, fatigue.

• Sometimes defecation, coughing, or severe vomiting can also result in syncope.

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• Seizures occur commonly and it is estimated that 1 of 26 people will develop epilepsy at some point in their life.
• A first seizure provoked by an acute brain insult is less likely to recur (3-10%) than a first-time unprovoked seizure (30-50% over the next 2 years).
• As an emergency provider managing an adult who presents with their first-ever seizure, there are four primary questions that require answering:

1. Was it in fact a true seizure? (often associated with tongue biting, urinary/bowel incontinence, preceding aura, post-ictal phase; examples of seizure mimics include syncope (i.e. cardiogenic, neurogenic, vasovagal), vertigo, myoclonic jerking, psychogenic convulsions, movement disorders.)
2. Does the patient have epilepsy? (defined a having at least 2 unprovoked epileptic seizures by any immediately identifiable cause.)
3. What type of epilepsy? (cryptogenic (i.e. of unknown etiology) or symptomatic (i.e. caused by prior central nervous system insult such as brain injury.)
4. What is the cause? (metabolic panels to assess for uremia, electrolyte and glucose abnormalities, and drug intoxications should be performed, as well brain imaging to determine the presence of focal intracranial lesions.)

• Many patients do not require anticonvulsant medication following a single, first time seizure; A general consensus is that such therapy should be strongly considered for initiation after a second episode of seizure activity. 

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• Studies have shown that the natural history of Bell's Palsy without treatment is such that 85% show signs of recovery within 3 weeks of symptom onset, and 71% experience complete recovery.
• Of the remaining individuals who do not completely recover, 13% experience persistent mild sequelae and 16% have residual weakness, synkinesis, and/or contracture.
• Those with incomplete lesions (i.e. incomplete paralysis) are more likely to return to normal function (94%), while only 60% of those with clinically complete lesions return to normal function.
• Herpes zoster is associated with more severe paresis and a worse prognosis.  When little to no recovery is seen within the first 21 days following symptom onset, the prognosis is less favorable.

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• Myasthenia Graves (MG) is an autoimmune disorder wherein antibodies attack acetylcholine nicotinic postsynaptic receptors at the myoneural junction, resulting in muscle fatigue (commonly bulbar) that worsens with use and improves with rest.  MG flares are most commonly due to infection or inadequate treatment with cholinesterase inhibitors.

• The Tensilon (edrophonium) challenge test can be used to help distinguish an MG crisis from a cholingergic crisis.  Once the airway and ventilation are secure, escalating doses of edrophonium (i.e. 1 mg, then 3 mg, then 5 mg, up to a maximum of 10 mg total) can be administered with the goal of relieving the muscle weakness.  If a true MG crisis is present, patients usually respond with dramatic improvement within 1 minute.  Patients having a cholinergic crisis, on the other hand, typically respond with increased salivation, bronchopulmonary secretions, diaphoresis, and gastric motility.  

• Monitor closely as edrophonium can cause significant bradycardia, heart block, and asystole (only 0.16% risk by reports, but have atropine nearby). 

• Once the edrophonium wears off, patients having an MG crisis may develop increased secretions and respiratory distress as their muscle weakness returns, so manage expectantly and with caution.  

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• Remember that lithium overdoses should not be treated with oral activated charcoal, as these charged particles are not adequately absorbed by this method.
• Instead, whole bowel irrigation using 500 mL to 2 liters of polyethylene glycol should be administered within the first 2-3 hours of presumed large ingestions (ie. at least 10 to 15 pills), with a goal of having the patient pass stool to the point of clear rectal effluent.
• Hemodialysis (HD) should be reserved to treat severe lithium toxicity, which is somewhat loosely defined as a serum level greater than 3.5 to 4 meq/L (mmol/L). 
• For levels > 4 meq/L, most experts agree that HD should be performed regardless of whether associated symptoms are present.  For levels > 2.5 meq/L with associated clinical signs/symptoms (i.e. tremulousness, dizziness, lethargy, seizure), conditions that would limit lithium excretion (i.e. renal insufficiency), or conditions that would limit ability to aggressively hydrate (i.e. CHF), HD should be performed.   

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