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Patients presenting with acute rhabodmyolysis often require in the neighborhood of 10 liters of fluid per day. Why might the administration of large amount of normal saline be counterproductive?
NS can contribute to acidosis, due to the dilution of serum bicarbonate with a solution high in chloride ions, generating hyperchloremic metabolic acidosis. Acidosis exacerbates the renal injury associated with rhabdomyolysis (NEJM, Vol. 361, p. 62)
If venous ultrasonography of the lower limbs is performed first, lung scanning or multidetector CT can be avoided in about ??? of patients with suspected pulmonary embolism (1,17).
-10% of patients
Hemodynamically stable patients with suspected PE and ultrasonographically confirmed DVT can be given anticoagulant treatment without further testing (1).
In particular, venous ultrasonography should precede imaging tests in pregnant women with suspected PE (1,3).References:(1) Agnelli G, et al. Acute Pulmonary Embolism N Engl J Med 2010; 363:266-274.(2) Le Gal G, et al. A positive compression ultrasonography of the lower limb veins is highly predictive of pulmonary embolism on computed tomography in suspected patientsThromb Haemost 2006;95:963-966.(3) Marik PE, Plante LA. Venous thromboembolic disease and pregnancy N Engl J Med2008;359:2025-2033.
Why does the addition of octreotide offer a significant advantage over glucose or glucagon alone in the management of refractory hypoglycemia?
The addition of octreotide offers a significant advantage because it suppresses the secretion of endogenous insulin (JEM, Vol. 36, pg. 28).
A patient arrives to the Emergency Department with superior vena cava syndrome. No neurological symptoms are present. What is your ED treatment?
SVCS is not a true medical emergency unless neurological symptoms are present.
Stenting of the SVC is effective in relieving symptoms.
Chemotherapy and steroids can be used in tumors that are sensitive
(Mayo Clin Proc, Vol. 81, pg. 845).
80% of patients who present with pulmonary embolism have evidence of DVT in their legs; what is the explanation for not finding DVT in such patients?
If deep venous thrombosis is not detected in such patients, it is likely that the whole thrombus has already detached and embolized (NEJM, Vol. 358, pg. 1037).
Pulmonary Embolism and Blood Pressure: What happens after a fluid bolus?
Pulmonary Embolism and Blood Pressure: What happens after intubation?
Patients with massive PE will often develop worsening hypotension after a fluid bolus due to increased right ventricular distension and deviation of the interventricular septum towards the left side of the heart. This septal deviation decreases left heart cardiac output.
In addition, patients with massive PE will sometimes develop higher blood pressures after intubation as positive pressure ventilation reduces preload, decreases deviation of the septum, and increases left sided cardiac output.
How long until a warfarin-induced elevated INR returns to normal after administration of intravenous vitamin K?
It takes 6-24 hours for IV vitamin K to correct an elevated INR (Mayo Clin Proc, Vol. 82, pg. 84).
What is the current status of the use of heliox for the treatment of acute severe asthma?
A Cochrane analysis of 10 trials concluded that heliox might be beneficial in such patients who have not had a response to initial treatment; current guidelines reflect this conclusion (NEJM, 8/19/10, pg 755).
Pearls for Prescribing Steroids for Asthma
Current asthma guidelines encourage early systemic glucocorticoids for all patients who have a moderate or severe exacerbation, or in whom inhaled short-acting beta agonists do not fully correct the decrease in peak flow. In general, the onset of action of systemic glucocorticoids is not clinically apparent until as long as 6 hours after administration. Thus, the beneficial effect is not likely to be observed while the patient is in the ED.
The optimal dose is unknown; however, the equivalent of a prednisone dose of 40 - 60 mg per day in a single dose or two divided doses is typical for outpatient management. There is good evidence that a short course of oral steroids for 3 to 7 days after ED discharge prevents rebound asthma symptoms; no steroid taper is required for such a brief duration of therapy if inhaled glucocorticoids are prescribed for ongoing therapy. A few patients who frequently need systemic steroids and who are receiving high doses of inhaled steroids will do better with a longer course of steroids, including tapering the dose over time, but this is the exception rather than the rule.
You diagnose a patient in the ED with an acute pulmonary embolism and start IV unfractionated heparin. The patient then becomes hemodynamically unstable and a decision is made to administer thrombolytic therapy. What to do you do with the heparin?
It is recommended that the IV UFH is suspended during rtPA infusion.
Upon rtPA completion, the APTT should be checked. If it is < than 80 seconds, UFH should be reinitiated as a continuous infusion without a bolus (Mayo Clin Proc, 12/09, pg. 1120).
Homan sign, which is calf pain with dorsiflexion of the foot, was once a widely used test. What percentage of patients with a positive Homan sign have a DVT?
Only 15% of patients with a positive Homan sign have a DVT (Mayo Clin Proc, 9/10, pg. 859).
The main value of chest X-ray in the assessment of patients with symptoms suggestive of a pulmonary embolism is to help exclude other causes of the presentation. However, there are a few signs seen that are suggestive of PE. Name them (3).
Fleischner’s sign - a prominent central pulmonary artery due to its distension by a large embolism;
Westermark sign - area of oligemia distal to the embolism;
Hampton’s hump - a pleural-based wedge-shaped consolidation
(JEM, In Press, Online 7/26/10)
What is the primary concern in dialysis patients who receive a CT scan with iodinated contrast?
The primary concern about patients who are dialysis-dependent is the osmotic load of the contrast media, although direct chemotoxicity on the heart and blood-brain barrier is also of theoretical concern.
Unless there is significant underlying cardiac dysfunction, or very large volumes of contrast media are used, there is no need for urgent dialysis.
Patients with renal insufficiency who require only intermittent or occasional dialysis are at substantial risk for contrast media-induced nephrotoxicity with further permanent worsening of their renal function. Alternative imaging studies that do not require contrast media should be considered.
True or False: Hypertensive Encephalopathy (HE) is a clinical diagnosis and can look like many other disease entities.
Describe the symptoms of hypertensive encephalopathy:
- HE refers to a relatively rapidly evolving syndrome of severe hypertension in association with severe headache, nausea, and vomiting, visual disturbances, convulsions, altered mental status and, in advanced cases, stupor and coma
- The key is the presence of severe hypertension. Remember, though, that 160/105 mm Hg may be high for an individual patient. Most patients with the syndrome will have diastolic pressures well in excess of 120-130 mm Hg. The only way you will know if the diagnosis is correct is to treat the BP (carefully control), work up other etiologies, and see of symptoms improve with BP control
- Beware the patient with severe HTN and seizure. Seizure may be the first, and only, symptom of hypertensive encephalopathy.
When should you initiate antibiotic therapy for a patient with CAP?
Antibiotics should be chosen empirically based on information such as patient age, community resistance patterns, likely pathogens, and comorbid conditions.
Timely antibiotic administration is associated with improved outcomes.
Antibiotics should be administered when the diagnosis is made.
When are sputum cultures and gram stains most helpful?
Sputum culture and Gram stain are best performed in high-risk hospitalized patients such as those who are intubated and/or admitted to the intensive care unit.
True or false: Positive blood cultures reflect the etiologic agent more accurately than do sputum cultures.
TRUE: Positive blood cultures reflect the etiologic agent more accurately than do sputum cultures.
Blood cultures can be positive in up to 30% of severely ill patients with pneumonia.
However, overall, a positive blood culture infrequently changes treatment plans.
Management of an acute adrenal crisis consists of immediate intravenous administration of how much hydrocortisone?
Management of an acute adrenal crisis consists of immediate IV administration of 100 mg of hydrocortisone, followed by 100 - 200 mg every 24 hours and a continuous infusion of larger volumes of physiologic saline solution (NEJM, Vol. 360, pg. 2328).
Does the dialysis patient need emergency dialysis after administration of a gadolinium-based MR contrast agent (GBMCA)?
Nephrogenic systemic fibrosis (NSF)
is a potentially debilitating or even fatal fibrosing condition that most often affects the skin, but can involve multiple organs. NSF is associated with the administration of a GBMCA in patients with renal insufficiency.
- It is recommended that hemodialysis be performed immediately after GBMCA administration in patients already undergoing hemodialysis - preferably initiated within 2 hours - and again 24 hours laterThis recommendation is based on the principle of clearing as much of the agent as possible from the patient's circulation to minimize risk.
- Use of GBMCAs should especially be avoided in patients undergoing peritoneal dialysis, in whom plasma clearance of such agents is relatively ineffective.
- References:(1) Juluru k. Quality Initiatives MR Imaging in Patients at Risk for Developing Nephrogenic Systemic Fibrosis: Protocols, Practices, and Imaging Techniques to Maximize Patient Safety RadioGraphics 2009;29: 9-22.(2) Kanal E. ACR Guidance Document for Safe MR Practices AJR 2007;188. (3) Prince MR, et al. Nephrogenic systemic fibrosis and its impact on abdominal imagingRadiographics 2009;29:1565-74.
Correction factor for ESR in the elderly:
The top normal ESR in the elderly is (age + 10)/2.
For example, an 80 yo patients would have a top normal ESR of (80+10)/2 = 45.
Most laboratories do not, however, report this correction factor, but simply list < 20 (or thereabouts) as normal. Be certain to take this correction factor into account when using ESRs for workups for temporal arteritis or other similar conditions.
A patient presents to the ED for evaluation of an acutely red eye. You make the diagnosis of iritis and find, on review of symptoms, that the patient has been experiencing pulmonary complaints such as dyspnea and cough. What diagnosis is of concern?
Iritis is associated with antigen HLA-B-27 linked diseases. Patients with pulmonary complaints should undergo chest imaging to assess for possible sarcoidosis (EMCNA, Vol. 26, pg. 50).
The American Diabetes Association recommends an IV bolus of regular followed by a continuous infusion for DKA. The utility of the insulin bolus has recently been called into question. What is the rationale behind the use of the bolus?
The use of bolus insulin is thought to be useful to overcome a certain amount of insulin resistance that has been found to exist in the DKA state, when compared to well-controlled type 1 diabetes
(JEM, 5/10, pg. 422).
According to the AHA, when managing hypertension in the ED for a patient presenting with an acute intracerebral hemorrhage, what is the target blood pressure?
- The AHA recommends that if systolic BP > 180 mm Hg, parenteral medication shouild be used to target a BP of 160/90
- (JEM, November, 2009, pg. 436).
If an apparent allergic reaction occurs on primary exposure to a drug, does this rule out that an immune mechanism is the cause of hypersensitivity?
No, previous contact with the causative drug is not obligatory. An immune mechanism should be considered as the cause of hypersensitivity, even in reactions that occur on primary exposure (Mayo Clin Proc, 3/09, pg. 268).
Why is a patient who had an adverse event after contrast injection unlikely to experience a similar or more severe reaction if given contrast again?
Reactions to contrast agents are anaphylactoid reactions, which are not IgE mediated.
Non-immune-mediated means no immune system memory
(JEM, In Press, Online 1/4/10).
What portion of neurologically normal patients presenting with abrupt-onset, severe, unusual headache will have subarachnoid hemorrhage?
Approximately 10% (JEM, Vol. 34, pg. 237).
Subungual Hematoma Pearls:
1) Subungual hematomas are collections of blood that form under the nail with injuries to the distal phalanx.
2) Those that are < 25% of the nailbed can be drained via trephination and heal well.
3) Up to 94% of subungual hematomas that are are associated with a distal phalanx fracture have a nailed laceration. It is commonly taught this hematomas should have the nail removed and the nailbed repaired. However studies from the 1990's have shown that as long as the nail is attached to the nailbed or paronychia and is not displaced; trephination alone can be done to achieve similar outcomes.
Dose of Odansetron for Pediatric Patients:
Don't skimp on dosing. The dose is 0.1 - 0.15mg/kg, and you don't reach a max until 8mg. To put this in perspective, a scrawny 115lb (about 53kg) middle school tennis player would get 8mg, an initial dose often reserved for chemo patients in the adult ED.
Although it not known for certain why only some individuals develop angioedema with the ingestion of ACE inhibitors, what is the current most accepted hypothesis?
It is believed that ACEI's cause the accumulation of bradykinin
, which increases in vascular permeability
- It has been hypothesized that some may possess a deficiency of an enzyme critical to the metabolism of bradykinin
- (JEM, Vol. 36, pg. 24).
Anaphylaxis occurs as a result of the immune system becoming sensitized to an allergen and creating IgE specific to that allergen. How does an anaphylactoid reaction differ from an anaphylactic reaction?
Anaphylactoid reactions are not caused by IgE and thus require no pre-exposure.
In anaphylactoid reactions, mast cells and basophils degranulate as a result of direct stimulation, not immune system triggering by IgE
(JEM, In Press, Online 1/4/10).
Radiology departments often ask about shellfish allergies to determine if a patient might be allergic to iodine before administering contrast. Iodine is not and cannot be an allergen. What, then, is the source of an allergic reaction to shellfish?
- Both fish and shellfish contain iodine, but it is not the source of people's allergies. The major allergens in shellfish are tropomyosins -proteins important in muscle contraction which have no relation to iodine
- (JEM, In Press, Online 1/4/10).
Although the exact definition of DKA is quite variable, what are the lab abnormalities most experts agree must be present to make the diagnosis?
Most experts agree that a blood glucose level >250 mg/dL, a bicarbonate level of <15 mEq/L, and an arterial pH of <7.3 with moderate ketonemia constitute the diagnosis.
(JEM, 10/10, pg. 449).
When performing an LP, not reinserting the stylet before removing the spinal needle is associated with a higher risk of subsequent headache. What mechanism is thought to be responsible for this increased risk?
An arachnoid strand enters the needle along with outflowing CSF and is threaded back through the dura during needle removal, producing prolonged leakage of CSF. Reinsertion pushes the arachnoid out of the needle (JAMA, Vol. 296:2012).
Name four factors that portend a poor prognosis for complete recovery from Bell's palsy.
Patients with hypertension, impaired taste, pain other than in the ear, and complete facial weakness all carry a poor prognosis
(ACP Journal Club, Vol. 148, pg. 29).
What is the recommended compression-ventilation ratio for neonatal resuscitation?
The recommended compression-ventilation ratio is 3:1. If the arrest is known to be of cardiac etiology, a higher ratio (15:2) should be considered.
How does the presence of anemia affect the ability of CT scan to detect acute subarachnoid hemorrhage?
Intracranial blood in anemic patients (Hct < 30%) may appear isodense with brain and therefore more difficult to see and can result in falsely-negative CT for SAH
(JEM, Vol. 34, pg. 237).
Why must a patient with a history of hypokalemic periodic paralysis avoid meals heavy in carbohydrates?
Consumption of large amounts of carbohydrate increases serum insulin which drives potassium into the muscle cells. In patients with periodic paralysis, a genetic mutation allows excessive amounts of potassium enter the muscle cell (JEM,2009;36:236).
What is the most important initial step in treating patients with symptomatic hypercalcemia?
Fluid resuscitation is the most important initial step. Hypercalcemia causes increased filtration across the glomerular membrane, interferes with urine concentration, and results in diuresis and hypovolemia
(Mayo Clin Proc, 12/09, e9).
Does the lack of detectable myoglobin in the urine exclude the presence of clinically significant rhabdomyolysis?
- Even in the presence of clinically signficant rhabdomylolysis, myoglobin may be undetectable in urine until after 6 hours
- (Am J EM, 9/09, pg. 876).
Although endotracheal administration of epinephrine during resuscitation is possible, why is it considered detrimental?
- ETTT administration results in lower blood concentrations than when given IV. The lower epinephrine concentrations may produce ?-adrenergic effects, which can cause hypotension, lower CPP and reduced potential for ROSC
- (Circulation, 2010;122:S729.)
Under current ACLS guidelines, what is the immediate next step after defibrillating a patient for ventricular fibrillation/pulseless ventricular tachycardia?
Guidelines now emphasize minimizing interruption in chest compressions. Compressions resume immediately after shock (without rhythm or pulse check). After 2 minutes, the CPR sequence is repeated, starting with a rhythm check
Name the only two ACLS interventions during cardiac proven to increase survival to hospital discharge.
- High-quality CPR and defibrillation of VF/pulseless VT
- (Circulation. 2010;122:S729-S767).
When given orally for the treatment of hyperkalemia, when is the onset of action of sodium polystyrene (Kayexalate)? When does the maximum effect occur?
The onset of action is at least 2 hours and the maximum effect may not be seen for 6 hours or more
(Crit Care Med, Vol. 36, pg. 3249).
Clinicians frequently try to palpate arterial pulses during chest compressions to assess the effectiveness of compressions. Why must caution be exercised when relying on palpation of the femoral artery during CPR?
Because there are no valves in the IVC, retrograde blood flow into the venous system may produce femoral vein pulsations. Thus, palpation of a pulse in the femoral triangle may indicate venous rather than arterial blood flow (Circulation,2010:S729).
Which antiarrhythmic drug has been shown to increase survival to hospital discharge when given routinely during human cardiac arrest?
There is no evidence that any antiarrhythmic increases survival to discharge. Amiodarone, however, has been shown to increase short-term survival to hospital admission as compared to placebo or lidocaine
Purpura can be categorized into 2 major groups, nonpalpable and palpable. Acute ITP is characterized by the sudden onset of severe thrombocytopenia often after recovery from a viral URI. Is the purpura palpable or nonpalpable?
Acute ITP is a common disease in children but is rare in adults. The thrombocytopenia leads to nonpalpable purpura in dependent portions of the body (Mayo Clin Proc, Vol. 82, pg. 745).
If a healthy adult is preoxygenated with 100% oxygen and ventilating effectively and then becomes apneic, how long will it take before oxygen saturation decreases to less than 90%?
(Annals of EM, Vol 52, pg. 3).
A patient presents to the ED with myxedema coma. What two medications should be administered intravenously in the ED?
Myxedema coma, a potentially lethal complication of hypothyroidism, is treated with levothyroxine IV. An IV glucocorticoid is also recommended until adrenal insufficiency has been excluded
(Journal of Emergency Medicine, Vol. 28, pg. 203).
You reduce an anterior shoulder dislocation in the ED. Shoulder immobilization is recommended for what duration?
Younger patients should be immobilized for about 3 weeks. Those > age 60 should have early follow-up (5-7 days) to allow for early mobilization to avoid joint stiffness
(Roberts: Clinical Procedures in Emergency Medicine, ed. 4, pg. 957).
Each year in the US, 236,000 to 325,000 patients experience out-of-hospital cardiac arrest. What is the median survival to discharge?
The prognosis is generally grim with a median survival to discharge rate of only 8.4%
A patient arrives to the ED shortly after experiencing a concussion and cannot recall his name or birth date. What is the significance of this memory loss?
Concussion does not cause a loss of autobiographical information, such as one's name and birth date; this type of memory loss is a symptom of hysteria or malingering
(NEJM, Vol. 356, pg. 166).
Name 3 actions that likely decrease the risk of post-LP headache.
Using a small-gauge needle, reinsertion of the stylet prior to removing the spinal needle, and mobilization of patients after completing the LP are recommended
(JAMA, Vol. 296:2012).
When inserting a Coude catheter into the bladder, how is the curved tip oriented?
When inserting a Coude, the curved tip is pointing up, cephalad, and advanced with continuous pressure past any resistance point (typically in the region of an enlarged prostate)
(JEM, Vol. 35, pg. 193).
A patient presents to the ED with flu-like symptoms and you suspect acute HIV infection; the patient had unprotected sexual intercourse 2 weeks earlier with a stranger. Why would testing for serum HIV antibodies not be appropriate?
- During sexual transmission, HIV invades the body and is present in the blood within 4–11 days. During this initial phase, antibodies have not yet been formed.
- In 2–3 months, seroconversion will occur
(JEM, In Press, Online 10/15/10).
When performing a lumbar puncture, reinsertion of the stylet before removal of the needle has been shown to reduce the incidence of post-LP headache. What is the explanation for this?
It is thought that a strand of arachnoid enters the needle along with the outflowing CSF; if the stylet is not replaced, the strand is threaded back through the dura during needle removal, producing prolonged CSF leakage
(JAMA, Vol. 296, pg. 2016).
Malignant otitis externa is a skull-based osteomyelitis seen primarily in diabetics and caused primarily by P. aeruginosa. What is the characteristic clinical finding?
The characteristic clinical finding is granulation tissue at the junction of the bony and cartilaginous external auditory canal
(NEJM, 11/25/10, pg. 2151).
Why shouldn't heliox be used for a severe asthmatic that is quite hypoxic?
Because the heliox mixture requires at least 70% helium for effect, it cannot be used if the patient requires >30% oxygen
Which one of the following is the most accurate predictor of outcome in patients who have an intracerebral hemorrhage: (a) Hematoma volume (b) Rate of hematoma growth (c) Initial neurologic exam (d) Time from onset to presentation (3) INR on arrival.
- Among patients presenting to the ED with an acute ICH, larger hematoma volumes are associated with higher morbidity and mortality; hematoma volume is the most accurate predictor of outcome
- (Mayo Clin Proc, Vol. 82, pg. 987).
Aortic dissection involves weakening of any of the 3 layers of the aortic wall: intima, media, and adventitia which leads to a tear in the intima that permits entry of blood between the intima and
adventitia. Where do most intimal tears occur?
Most intimal tears occur in the ascending aorta (Mayo Clin Proc, Vol. 84, pg. 912).
What laboratory tests define acute hepatitis B?
- IgM antibody to hepatitis B core antigen (anti-HBc) positive
- hepatitis B surface antigen (HBsAg) positive
(MMWR, Surveillance Summaries, May 22, 2009).
Is the presence of hypotension necessary to make the diagnosis of cardiac tamponade?
No; some patients, especially those with preexisting hypertension, may actually be hypertensive with tamponade physiology
(JAMA, Vol. 297, pg. 1810).
When do alcohol-related seizures typically occur after the last drink? Multiple seizures occur in 60% of patients without treatment; what is the usual interval between the first and the last
Alcohol-related seizures occur 6 - 48 hrs after the last drink. When multiple seizures occur, the interval between the first and the last seizure is usually less than 6 hrs.
(Journal of Emergency Medicine, Vol. 31, pg. 158).
What hematologic disease state can lead to higher endogenous CO-Hgb levels?
In hemolytic anemia, CO-Hgb may increase to 3% to 4%
(Emerg Med Clin NA; Vol. 22:985)
You diagnose a patient in the ED with an acute pulmonary embolism. You happen to note that the patient exhibits peripheral edema, has a low serum albumin and proteinuria. What is the diagnosis?
The nephrotic syndrome is a prothrombotic condition that is a risk factor for acute PE
(NEJM, Vol. 358, No. 25).
What is the most likely etiologic agent of any viral conjunctivitis?
Adenovirus is the most likely cause of viral conjunctivitis. Common modes of transmission are fingers, medical instruments, and swimming pool water
(EMCNA, Vol. 26, pg. 35).
What is pituitary apoplexy?
Pituitary apoplexy is hemorrhage or infarction of the pituitary gland. It occurs most commonly in patients with pituitary macroadenomas but can occur in pregnancy, general anesthesia, and bromocriptine therapy
(Mayo Clin Proc, 7/10, e44).
Central venous cannulation increases the risk of central venous thrombosis; thrombosis may occur as early as the 1st day after cannulation. Which is the site with the lowest risk for thrombotic complications?
The site with the lowest risk for thrombotic complications is the subclavian vein
(NEJM, Vol. 356:e21).
Acute human immunodeficiency virus (HIV) infection is a highly infectious phase of disease that is characterized by nonspecific clinical symptoms. How long does it typically last?
Acute HIV infection lasts approximately 2 months
(MMWR Weekly, Vol. 58 / No. 46 , 2009).
Transient global amnesia is characterized by the sudden onset of dense anterograde amnesia, without alteration consciousness or focal neurologic deficits or seizure activity. What are the proposed theories regarding the pathophysiology of TGA?
Theories to explain TGA include migraine, seizure, arterial ischemia, and venous congestion of the brain leading to ischemia (resulting from a Valsalva response), but the precise mechanisms remain unclear
(JEM, epub, Online 10/2/08).
What are the characteristic AST, ALT, and Bilirubin levels seen with alcoholic hepatitis?
The combination of an AST level that is elevated (but <300 IU/ml) and a ratio AST:ALT > 2, and a total serum bilirubin > 5 mg/dl is indicative of alcoholic hepatitis
(NEJM, Vol. 360, pg. 2759).
Hyperglycemia is associated with worse clinical outcome in patients with acute ischemic stroke, but there is no direct evidence that glucose control improves outcome. Current AHA/ASA recommendations call for what when the serum glucose is above what level?
Current AHA/ASA recommendations call for the use of insulin when the serum glucose level is greater than 185 mg/dL in patients with acute stroke
How long can pruritis last after treatment of scabies?
Pruritis can persist for up to 4 weeks after the end of correctly administered scabicide therapy. After that time, the cause of itching should be reinvestigated
(NEJM, Vol. 354:1718).
Hypoglycemia is a recognized cause of focal neurologic deficits and is in the differential diagnosis of a patient presenting to the ED with an apparent stroke. What is the postulated mechanism by which hypoglycemia results in a focal deficit?
Hypoglycemic-mediated vasospasm, structural narrowing of selective cerebral vessels resulting in more pronounced localized effects of hypoglycemia, and vulnerability of selective neurons to hypoglycemia have been postulated
(Am J EM, Vol 23, pg.823).
The typical non-rebreather mask used in the ED provides what fiO2 to the patient?
(JEM, ePub, Online 09 April 2010).
What effect do corticosteroids have on postherpetic neuralgia? When should steroids be prescribed in the setting of shingles?
- Steroids have no effect on PHN; when used with antivirals, they modestly reduce severity & duration of acute symptoms.
- They should be used only for severe symptoms at presentation or when no steroid contraindications exist
(Mayo Clin Proc V 84 p 274)
Typically, hospitalization is unnecessary for acute pericarditis unless poor prognostic indicators are identified. Name those indicators that mandate hospitalization.
Myocarditis, cancer, conditions that confer a predisposition to tamponade (pericardial effusion > 2 cm, trauma, anticoagulation), and indicators of possible purulent pericarditis (fever, immunosuppression)
(NEJM, vol. 356, pg. 1153).
How long does the rash of zoster (shingles) usually last? How long does it take for complete healing to typically occur?
The rash usually lasts 7-10 days, with complete healing within 2-4 weeks
(MMWR, Vol. 57, No. 22).
Administration of glucagon may be helpful for severe cardiovascular instability associated with Beta-blocker toxicity that is refractory to standard measures, including vasopressors. What is the recommended dose?
The recommended dose of glucagon is a bolus of 3 to 10 mg, administered slowly over 3 to 5 minutes, followed by an infusion of 3 to 5 mg/h (0.05 to 0.15 mg/kg followed by an infusion of 0.05 to 0.10 mg/kg/hr).
What is the clinical significance of the hyperdense middle cerebral artery sign?
The hyperdense MCA sign is one of the early markers on CT scan of acute ischemic stroke. A clot in the middle cerebral artery carries a high risk of bleeding if anticoagulated or thrombolyzed due to the extent of tissue death
(JEM, Vol. 33, pg. 417).
Because focal neurologic signs may occur with hypertensive encephalopathy (HE), its distinction from acute ischmeic stroke may be difficult. How can they be differentiated?
HE is subacutely progressive, and associated with generalized signs and symptoms of brain dysfunction (eg, headache, lethargy, or seizures). HE will routinely be associated with papilledema and uremia
(Am J EM, Vole. 25, pg. 949).
Optic neuritis is a condition where the diagnosis is made by history and physical examination. What are the typical clinical findings?
- Optic neuritis is a clinical diagnosis that often includes eye pain, a relatively abrupt vision and color differentiation loss, and an afferent papillary defect
- (Am J of EM, Vol. 25:834).
Codeine is a prodrug that exerts its analgesic effects after metabolism to what drug?
Codeine is a prodrug that exerts its analgesic effects after metabolism to morphine
(Mayo Clin Proc, 7/09, pg. 613).
Is the pupillary response to light preserved following rapid sequence intubation with succinylcholine or rocuronium?
Pharmacologic neuromuscular blockade with succinylcholine or rocuronium during ED RSI does not appear to inhibit pupillary response
(Annals of EM, In Press, Online 1/10/11).
What is the CDC-recommended regimen for prophylaxis against chlamydia, gonorrhea, and trichomonas following sexual assault?
Ceftriaxone 250 mg IM in a single dose
OR Cefixime 400 mg orally in a single dose
- Metronidazole 2 g orally in a single dose
- Azithromycin 1 g orally in a single dose OR Doxycycline 100 mg orally twice a day for 7 days
- (MMWR 59(RR12);1-110).
How long until a warfarin-induced elevated INR returns to normal after administration of intravenous vitamin K?
It takes 6-24 hours for IV vitamin K to correct an elevated INR
(Mayo Clin Proc, Vol. 82, pg. 84).
How significant is the Brugada Syndrome as a cause of sudden death?
The Brugada syndrome is estimated to be responsible for 4% of all sudden deaths and up to 20% of deaths in patients with structurally normal hearts
(Annals of Int Med, Vol. 148, pg. 82).
What are the suspected causes for vancomycin- induced ototoxicity and nephrotoxicity?
The cited reference indicates that vancomycin-induced ototoxicity and nephrotoxicity manifested by tinnitus/high-tone hearing loss and elevated serum creatinine levels have been correlated with persistently high vancomycin peak or trough serum levels. Today, ototoxicity is extremely unusual if serum concentrations are maintained below 30 mg/L. Renal toxicity, while uncommon, is more likely to occur when vancomycin is combined with aminoglycosides, especially in adults receiving therapy longer than 21 days and if trough vancomycin levels exceed 10 microgr/mL.
(Levine DP. Vancomycin: Understanding Its Past and Preserving Its Future. 2008 Southern Medical Journal, 101(3): 284-291)
What commonly prescribed antibiotics causes reversible elevation of serum potassium and creatinine levels?
The trimethoprim component of trimethoprim-sulfamethoxazole
- (Mayo Clin Proc, 1/11, pg. 70).
Is the recurrence of herpes zoster in a person who is apparently immunocompetent unusual enough to mandate an evaluation for an underlying immune disorder?
No. Data indicate that rates of HZ recurrence are comparable to rates of first HZ occurrence in immunocompetent individuals
When does physiologic jaundice in healthy newborns typically occur and when does it typically resolve spontaneously?
Jaundice appearing during the second to third day of life is most likely physiologic and will dissipate by the fifth or sixth day
(EM Clin NA;25:1117)
What is the onset of action of a single bolus of IV insulin for the treatment of hyperkalemia? When is the effect maximal?
An IV dose of 10 units of regular insulin to anephric adult patients lowers the serum potassium by about 0.6 mmol/L. The onset is within 15 minutes and the effect is maximal at 30-60 minutes
(Crit Care Med, Vol. 36, pg 3248).