UMEM Educational Pearls

Cortical versus Subcortical Strokes

• Gray matter (neuronal cell bodies) of the brain forms a rim over the cerebral hemispheres, forming the cerebral cortex.
• White matter (neuronal axons coated in myelin) is located below the cortex and makes up the "subcortical" regions of the brain.
• Strokes affecting the cerebral cortex (i.e. cortical strokes) classically present with deficits such as neglect, aphasia, and hemianopia.
• Subcortical strokes affect the small vessels deep in the brain, and typically present with purely motor hemiparesis affecting the face, arm, and leg.
• Nearly 30% of all ischemic strokes are subcortical in nature, and includes lacunar infarcts which have the best prognosis.

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Aisha T. Liferidge, MD, FACEP
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Assistant Professor, Attending Physician
University of Maryland School of Medicine
Department of Emergency Medicine
Baltimore, MD 21201
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MPH Candidate, Columbia University 2011

AKI and the Critically Ill

• Acute kidney injury (AKI) is an abrupt reduction in kidney function causing disturbances in electrolytes, fluids, and acid-base balance.
• AKI occurs in up to 67% of critically ill patients and is associated with a substantial increase in morbidity and mortality.
• AKI in the critically ill is often multifactorial and most commonly due to sepsis, hypovolemia, medications, and hemodynamic instability.
• Medications account for up to 20% of AKI in the critically ill.
• Common medications that cause, or exacerbate AKI, in the critically ill include:
  • NSAIDS
  • Antibiotics (aminoglycosides, amphotericin, acyclovir)
  • ACE-inhibitors
  • Radiocontrast dye
• Take Home Point:  AKI is common in our critically ill ED patients and, whenever possible, avoid nephrotoxic medications that can result in additional injury.

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  Despite the traditional use of intravenous medications such as vasopressors and antiarrhythmics for victims of cardiac arrest, there is actually very little evidence to support these therapies. On the contrary, 2 recent multicenter center studies demonstrated that the use of intravenous medications that are advocated in standard advanced cardiac life support (ACLS) guidelines are ineffective at improving survival to hospital discharge of patients with primary cardiac arrest. In contrast, these medications have been shown to increase hospital admissions, bed and resource utilization, and costs. The only interventions that have been shown to improve meaningful outcomes are rapid defibrillation for shockable rhythms, good compressions, post-resuscitation therapeutic hypothermia, and there's increasing evidence for post-resuscitation cardiac catheterization as well.

In other words, the best thing you can do early for patients with primary cardiac arrrest is to focus on the basics.

 

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Pityriasis Rosea

• A common exantham that typically presents initially with a herald patch, followed by a generalized rash over the next 1-2 weeks and can last 4-6 weeks.
• Patients may initially have prodromal symptoms such as joint pain,headache, fever and malaise that precede the appearance of the rash.
• The primary plaque, herald patch, is seen on the skin in 50-90% of cases.
• The generalized rash typically develops in crops along the lines in the skin leading to a characteristic "Christmas tree" pattern.
• Pruritus is present in 75% of cases.
• Usually a self-limited, benign illness that does not require any treatment.  Though symptomatic treatment of the pruritus is reasonable.

Meningitis Prophylaxis in Children

While H1N1 and garden-variety influenza have been taking the spotlight lately, we can't forget about other disease processes.  Meningitis is still a severe, life-threatening/altering process which occurs in various social groups (e.g. military cadets, college students).

However, with more of our parents working out of the home, child care is more often the norm, and as such, you may find yourself dealing with cases of children who have been in proximity to another child or caregiver diagnosed with meningitis.  What do you do?

The causative agent will often dictate your choice of management.

Neisseria meningitidis - nursery/child care contacts should receive chemoprophylaxis and the Menactra vaccine (if they have not already received it) within 7 days of onset;  casual school or work contacts do NOT require prophylaxis

Streptococcus pneumoniae - no chemoprophylaxis or vaccination required (unless series was not continued)

Haemophilus influenzae - if only one case reported, no intervention;  if 2 or more cases within a 60-day period, Hib vaccination and chemoprophylaxis with rifampin for BOTH children and caregivers (especially if the center cares for young children who have not completed their Hib series)

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• Non-enhanced Brain CT (NECT) offers low yield in terms of its diagnostic utility for acute ischemic stroke (AIS), with sensitivities less than 67% at 3 hours out from symptom onset.

• A hyperdense middle cerebral artery (MCA) sign may represent acute thrombus and predicts impending large territorial infarct of poor prognosis (*see images of MCA Sign (left) and subsequent territorial edema representing infarct (right) below).

• While MCA Signs occur somewhat rarely, this finding is one of the earliest and most useful indicators of probable (clinical) stroke on NECT, and should be a recognizable hallmark for the emergency physician.

• Note that hyperdense MCA's can mimic a thrombus and actually represent atherosclerotic calcifications.

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How to stop dialysis fistula/graft bleeding

The number of patients being placed on hemodialysis seems to be increasing. And the ED is where they will go when there is a any complication from their fistula or graft.

Hemodialysis shunts require cannulation with large bore instruments. This combined with heparinization may lead to prolonged bleeding from puncture sites. 

What to do when a patient shows up in the ED with persistent bleeding from a fistula puncture site:

• Simple pressure may be all that is required in many cases. 
• If this doesn't work, place a single circular suture around the puncture site/incision. In some small studies this has been shown to be very useful in stopping persistent oozing

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Nikolsky's sign is positive when slight rubbing of the skin results in exfoliation of the skin's outermost layer.  The more technical term is acantholysis which is the loss of the normal adhesion of the epithelial skin cells which allows for this sloughing.

Seen in:

• Toxic Epidermal Necrolysis
• Pemphigus vulgaris
• Scalled Skin Syndrome
• Bullous impetigo
• Epidermolysis bullosa

Often helpful to differentiate pemphigus vulgaris from bullous pemphigoid. The sign is usually absent in bullous pemphigoid.  Just be careful with how much testing you are doing as this can be very painful to the patient.
 

After seeing all the electrical and extension cords supplying various seasonal holiday decorations, I thought this would be appropriate.

• most commonly occurs once children establish a grasp at 4months and 4 years when children finally learn not to touch cords, but most common from 1-2 years
• not surprisingly, more common in boys (60%)
• moist oral cavity creates a short circuit and electric arc which produces enough heat (up to 1371C/2500F) to cause a low-voltage electric burn
• 5% may suffer cardiac/respiratory arest
• electrical mouth burns result in significant soft tissue damage which forms an eschar
• beware sloughing of the nonviable eschar from the underlying viable tissue around week 2, that results in labial artery hemmorhage

A quick christmas one:

The Christmas Rose (Helleborus niger)

Actually containes cardioactive steroids - eating it will help your A fib with RVR as it will act like digoxin, as well as kill like it.

Attachments

0912242222_christmasrose.jpg (30 Kb)

• Elevated intracranial pressure (ICP) can sometimes be associated with focal symptoms related to mass lesions or herniation syndromes.

• Herniation is the result of pressure gradients between two regions of the cranial vault, such as that related to cerebral edema from an acute stroke.

• The following list describes areas most commonly affected by herniation syndromes: 

          --- subfalcine

          --- central transtentorial

          --- uncal transtentorial

          --- upward cerebellar

          --- cerebellar tonsillar/foramen magnum

          --- transcalvarial

Appropriate Antimicrobial Therapy for Sepsis

• In previous pearls, we have discussed the importance of early antimicrobial administration for patients with sepsis.
• In patients with septic shock, current guidelines recommend empiric antimicrobial therapy be initiated within 1 hour.
• Equally as important as early administration is the selection of appropriate antimicrobial therapy (i.e. choosing an antibiotic that is effective against the presumed or identified pathogen).
• In one of the most recent studies, investigators found a 5-fold reduction in survival (52% vs. 10.3%) between patients who received appropriate antibiotics compared to those who received antibiotics that were ineffective against the identified pathogen.
• In fact, choosing the right antibiotic is one of the strongest factors associated with patient outcome in sepsis.
• When selecting empiric antimicrobial therapy for patients with septic shock consider patient history, co-morbidities, the clinical site of infection, and local resistance data.

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 Wernicke's Encephalopathy

Wernicke's encephalopathy, considered a unique complication of alcoholism, is also seen in malnourished patients, bariatric surgery patients, and patients who have undergone bone marrow transplantation.

Some pearls about Wernicke's encephalopathy:

• The classic triad of confusion, ataxia, and opthalmoplegia is seen in only about 10-15% of cases
• The diagnosis is made before death in only about 10_15% of cases
• Most authorities on the disease have suggested that opthalmoplegia be replaced by ocular, since many ocular findings may be seen in these patients (nystagmus, retinal hemorhages, cranial nerve palsies)
• Essentially any alcoholic who presents with confusion (ever see these patients in your ED?) could have the disease, so give Thiamine liberally when the patient arrives. 
• It is a myth that administration of thiamine before glucose will precipitate Wernicke's. This dogma is based on a case series of 4 patients from the Irish Journal of Medical Sciences. 

Although we tend to "shotgun" when ordering labs in elderly patients with syncope, the literature actually indicates that we can be very selective in testing with this group, letting the history and PE determine whether any tests are indicated. The most recent literature supporting this concept demonstrated that even cardiac enzyme testing and head CTs in elderly syncope patients were helpful in only 0.5% of cases. The only test that should routinely be obtained is the ECG...a good history and PE should be sufficient to determine when any other tests are indicated.

[Mendu, et al. Yield of diagnostic tests in evaluating syncopal episodes in older patients. Arch Intern Med 2009]

Hypothermia Pearls:

• Lidocaine is generally ineffective in preventing ventricular arrhythmias, as is cardiac pacing or atropine to increase the heart rate.
• Should the patient fully arrest be prepared to perform CPR for a long time.  If your ED does not have a automatic CPR device consider calling your local fire department or ambulance service as they might have one that can be loaned to your department.
• Warm fluids, heated blankets and heat lamps will typically increase a patients temperature about 1' C an hour.
• Gastric lavage, peritoneal lavage and heated IV fluids can warm as much as 3' an hour.
• To rewarm quickly as high as 18'C an hour requires cardiac bypass or thoracic lavage.

Finally, remember to monitor the patient closely when you first start rewarming as this can induce cardiac arrest.  This is thought to occur as colder peripherial blood returns to the central circulation as peripherial veins and arteries dilated from the warm fluid.

• 4-5% of Prepubertal Vaginal Complaints are the result of foreign body.
• Vaginal bleeding is the most sensitive (93%), and specific (82%)
• Discharge usually foul-smelling is only seen in 18% of patients
• Undiagnosed symptoms may be chronic, (case reports lasting years).
• Complications of delayed removal include infection, toxic shock syndrome, fistulas, adhesions and even infertility
• Exam in knee chest position, and removal with irrigation or tissue forceps.
• Failure to remove FB may require exam under anesthesia.

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Here is a table adapted from Goldfrank's Textbook of Toxicologic Emergencies 8th Edition - Drugs that May Induce Parkinsonism. MPTP is the story that everyone hears about and actually has links to Maryland. In 1976, Barry Kidston, a 23-year-old chemistry Maryland graduate student, synthesized MPPP (Meperidine or Demerol) incorrectly and injected the result. It was contaminated with MPTP, and within three days he began exhibiting symptoms of Parkinson's disease. Ooops - permanent.

Reversible

• Chemotherapeutics (several)
• Cyclosporine
• Calcium Channel Blockers
• Dopaminergic withdrawal
• Kava Kava (with manganese)
• Progesterone
• Sertraline
• Valproic Acid
• Trazodone

Irreversible

• Carbon Monoxide
• Cyanide
• Heroin
• Manganese
• MPTP

• Frank hypointensity (i.e. dark hue) on CT of the brain, particularly if involving greater than one-third of the middle cerebral artery (MCA) territory, is a contraindication to treating acute ischemic stroke with tPA.

• Early signs of infarct on brain CT, regardless of extent, are NOT contraindications to treatment.

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Red blood cell transfusion in the critically ill patient has been and continues to be surrounded by controversy and lack of hard data.  Up to 90 percent of transfusions in the ICU are given for anemia, an indication which is least supported by the data.  The joint taskforce of EAST, ACCM and SCCM has published a clinical practice guideline which outlines recommendations and rationale.  These recommendations are summarized as follows:

• RBC transfusion is indicated for patients with evidence of hemorrhagic shock.
   
• RBC transfusion may be indicated for patients with acute hemorrhage and hemodynamic instability or inadequate DO2.
   
• Transfusion triggers for Hb<7 are as effective as those for Hb<10 in hemodynamically stable critically ill patients, except for those with AMI or USA.
   
• Hb used as a sole trigger is not advised; transfusion decisions should be based on intravascular volume status, evidence of shock, duration and extent of anemia, and cardiopulmonary physiologic parameters.
   
• Consider RBC transfusion if Hb<7 in resuscitated critically ill patients, patients who are being mechanically ventilated or critically ill patients with stable cardiac disease.
   
• RBC transfusion should not be considered as an absolute method to improve tissue oxygen consumption in critically ill patients.
   
• RBC transfusion may be beneficial in patients with acute coronary syndromes with Hb<8 on hospital admission.

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