UMEM Educational Pearls

Title: Arnold-Chiari (Chiari II) Malformation

Keywords: Arnold-Chiari (Chiari II) Malformation, Stridor, Sycope, Respiratory Distress, Weakness, Herniation (PubMed Search)

Posted: 9/7/2007 by Sean Fox, MD (Updated: 4/1/2023)
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Arnold-Chiari (Chiari II) Malformation Arnold-Chiari malformation = herniation of cerebellar tissue and the medulla downwards through the foramen magnum into the upper cervical spinal canal causing compression of the upper segments of the spinal cord. Two distinct ages are identified with Chiari II malformations: infants and adolescents ==> Infants often present with Respiratory Distress, Inspiratory Stridor, and/or apnea. -- These herald impeding brainstem compromise. ==> Older children more often present with syncopal episodes or muscle weakness. Chiari Malformation needs to be considered in all children with myelomeningocele, Down s Syndrome, Hydrocephalus, Sacral Dimple, or other neurologic abnormalities presenting with respiratory distress. ==> Myelomeningocele is associated with Chiari Malformation and hydrocephalus in 80-90% of cases. Recognition is critical, since movement of the head and neck can lead to further compression of the CNS structures. Rath GP, Bithal PK, Chaturvedi A: Atypical Presentations in Chiari II Malformation. Pediatric Neurosurgery 2006;42:379-382

Category: Toxicology

Title: Scombroid

Keywords: Fish, scombroid, seafood poisoning (PubMed Search)

Posted: 9/6/2007 by Fermin Barrueto, MD (Updated: 4/1/2023)
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Scombroid is one of the most common seafood poisonings. A classic EM board question. - Caused by ingestion of histamine in fish muscle - Naturally occurring histidine is converted to histamine by bacteria in unrefrigerated fish - Most common fish: tuna, mackerel, bonito, mahi mahi, blue fish and yellow tail - Symptoms: Within minutes to hours - flushing, urticaria, perioral burning, N/V/D - Treatment: Antihistamines, fluids, bronchodilators. Epinephrine and steroid for severe reactions.

Category: Neurology

Title: Transient Global Amnesia

Keywords: amnesia, TIA, memory (PubMed Search)

Posted: 9/5/2007 by Aisha Liferidge, MD (Updated: 4/1/2023)
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Transient Global Amnesia (TGA) is a rare (5 to 11 cases per 100,000 persons per year), but clinically well-defined disorder defined as an acute episode of short-term memory loss, in the absence of any neurologic signs or symptoms, which resolves within 24 hours. TGA is typically triggered by an event such as valsalva, exercise, emotional stress, sexual intercourse, immersion in cold water, painful stimuli, and severe exertion. While there are widely used diagnostic criteria, TGA is primarily a clinical diagnosis and one of exclusion. While TGA is benign, self-limiting, and there is no specific treatment other than reassurance, it is important to recognize and differentiate TGA from TIA, which has different prognostic implications. Agrawal, et al. "Transient Global Amnesia: An Uncommon Differential Diagnosis of Transient Ischemic Attack." Hospital Physician 43:8.

Category: Critical Care

Title: Life threatening hypophosphatemia

Keywords: hypophosphatemia, CHF, respiratory failure (PubMed Search)

Posted: 9/4/2007 by Mike Winters, MD (Updated: 4/1/2023)
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-Phosphate is predominantly an intracellular ion that is critical for an array of cellular processes -Hypophosphatemia is most commonly seen in alcoholics, DKA, and sepsis: frequency rates of 40%-80% -Severe hypophosphatemia ( < 1.0 mg/dL) in the critically ill can manifest as widespread organ dysfunction: respiratory failure (diaphragmatic weakness), CHF (decreased myocardial contractility), rhabdomyolysis, arrhythmias, seizures, hemolysis, impaired hepatic function, and depressed WBC function -Severe hypophosphatemia should be treated with intravenous replacement: 0.08 - 0.16 mmol/kg over 2-6 hours -Be aware of complications from too rapid intravenous replacement: hypocalcemia, tetany, hypotension, volume excess, and metabolic acidosis

Category: Vascular

Title: Pulmonary Embolism-CT Accuracy vs. Outcome Studies

Keywords: Pulmonary Embolism, CT (PubMed Search)

Posted: 9/3/2007 by Rob Rogers, MD (Updated: 4/1/2023)
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There has been an explosion in recent years in the PE literature on CT scanning. Older literature, and even some current studies, emphasized the sensitivity of CT scanning for pulmonary embolism. In other words, how well does CT detect PE? The current trend in PE research is to report outcomes. So, a patient is evaluated for PE and the CT is negative. What is that patient's outcome (PE, DVT, death) at 30, 60, 90 days, etc? Dozens of studies in recent years have shown that patients generally have a superb outcome after negative CTs. Several recent studies have shown this, and in these studies the only imaging modality was CT (no ultrasound, etc). Pearl: Despite the difference in sensitivity for PE between single slice, multislice, and multidetector CT studies have shown that the outcome rates are relatively equal. Multidetector CT clearly picks up small, subsegmental clots better than single slice or 16, 32 slice CT. This might very well mean (according to some) that subsegmental (small, tiny) clots may not be that significant. We may very well be approaching an era where we don't treat small, peripheral clots. Pulmonary Embolism, second edition, Paul Stein 2007

Category: Cardiology

Title: fondaparinux in ACS

Keywords: fondaparinux, anticoagulation, acute coronary syndromes (PubMed Search)

Posted: 9/2/2007 by Amal Mattu, MD (Updated: 4/1/2023)
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Fondaparinux is a selective factor Xa inhibitor. Benefits of fodaparinux vs. heparin when anticoagulants are used in ACS: 1. It is not associated with heparin induced thrombocytopenia. 2. Significant reduction in 30-day and 6-month mortality vs. enoxaparin. 3. Significant reduction in bleeding complications. 4. Safer in patients with renal insufficiency vs. enoxaparin. Unfractionated heparin should be continued while the patient goes for PCI.

Category: Cardiology

Title: Acute Coronary Syndrome (our number one area of liability) [Part 2]

Keywords: ACS, Legal, documentation (PubMed Search)

Posted: 9/1/2007 by Michael Bond, MD (Updated: 4/1/2023)
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Acute Coronary Syndrome (our number one area of liability) [Part 2]

Describing the character of the pain is the most common element of the history (Braunwald and Lee & Goldman).
The history is the threshold issue and determines whether the patient enters risk stratification (Braunwald).
The most atypical features of chest pain are sharp, pleuritic and positional pain.
One-third of all patients with an MI have no chest pain.
One set of cardiac enzymes violates a strong national standard of practice.
Serial enzymes do not rule out unstable angina.
If discharging a patient, document why you felt the patient did not have ACS.
The plaintiff attorney literature advises litigators to focus on the history.

Thanks again to Larry Weiss, MD, JD Disclaimer: This information does not constitute legal advice, is general in nature, and because individual circumstances differ it should not be interpreted as legal advice. The speaker provides this information only for Continuing Medical Education purposes.

Category: Pediatrics

Title: Congenital Heart Disease

Keywords: Pediatric Congenital Heart Disease, Hyperoxia test, Prostaglandin E, Shock, CHF (PubMed Search)

Posted: 8/31/2007 by Sean Fox, MD (Updated: 4/1/2023)
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Congenital Heart Disease Clinical signs and symptoms of pediatric congenital heart disease are often subtle ==> Often misdiagnosed with respiratory illness or sepsis Can progress to CHF and shock ==> CHF in infants = tachypnea, tachycardia, and hepatomegaly (classic triad) -- JVD, Peripheral Edema, rales are UNCOMMON (unlike adults) Hyperoxia Test Is the etiology of the cyanosis cardiac or noncardiac? ==> If pulmonary disesase is the cause, 100% FiO2 will increase PaO2 to ~150mmHg and increase the Pulse Ox by ~10%. ==> If Heart Defect is the cause, there will be minimal improvement in condition and values. PGE1 administration ==> Used to reopen or maintain patency of ductus arteriosus until definitive intervention. ==> Consider it in a neonate presenting in shock (possibly undiagnosed ductal dependent lesion). ==> Side effects are hypotension, bradycardia, seizures, and APNEA. ==> Either intubate before or be prepared to intubate.

Category: Toxicology

Title: Methemoglobinemia

Keywords: pyridium, methemoglobinemia, methylene blue (PubMed Search)

Posted: 8/30/2007 by Fermin Barrueto, MD (Updated: 4/1/2023)
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- Classic Clinical Finding: Cyanosis out of proportion to clinical symptoms (look real blue but not SOB) - Causative Agents: Benzocaine (and other local anesthetics), dapsone, nitrites, phenazopyridine (Pyridium) - When do you treat: significant tissue hypoxia (MI, CVA, Dysrhythmias), and if MetHb >20% asymptomatic - Treatment: Methylene Blue 1-2 mg/kg (0.1 -0.2 mL/kg of 1% methylene blue) over minutes

Category: Neurology

Title: Cheyne Stokes Respirations

Keywords: Cheyne Stokes, stroke, increased intracranial pressure (PubMed Search)

Posted: 8/29/2007 by Aisha Liferidge, MD (Updated: 4/1/2023)
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Cheyne-Stokes (CS) respirations, also known as "periodic breathing," results from the inability of the respiratory center of the brain, the brain stem (i.e. pons and medulla oblongata), to rapidly compensate for changing serum partial pressure of oxygen and carbon dioxide. CS is characterized by respirations of gradually increasing and decreasing tidal volumes, with interspersed periods of apnea. Conditions associated with CS: - Increased ICP (i.e. space occupying brain lesions such as hemorrhage and tumors) - Congestive heart failure - Altitude sickness - Toxic-metabolic encephalopathy - Carbon monoxide poisoning - High-dose morphine administration CS was first described by physicians John Cheyne and William Stokes. Wikipedia Encyclopedia. The Diagnosis of Stupor and Coma by Plum and Posner.

Category: Critical Care

Title: A quick vasopressor review

Keywords: norepinephrine, dopamine, vasopressin, phenylephrine (PubMed Search)

Posted: 8/28/2007 by Mike Winters, MD (Updated: 4/1/2023)
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-Norepinephrine: has both alpha-1 and beta-1 activity; stronger alpha than beta receptor agonist; increases MAP primarily through increase in SVR; dose 2-20mcg/minute -Phenylephrine: all alpha-1 activity; increases MAP through increase in SVR; initial dose 100-180 mcg/minute and titrate 40-60 mcg/min; primarily a 3rd line vasopressor -Vasopressin: a non-adrenergic vasoconstricting agent; activates vasopressin receptors; dose 0.01-0.04 Units/min; currently used as a second-line agent in the setting of sepsis; should not be used as the sole vasopressor medication due to gut and cardiac ischemia -Dopamine: activates dopaminergic receptors; at doses of 10-20 mcg/kg/min it has both alpha-1 and beta-1 activity; increases MAP primarily through increases in CO; stronger chronotropic agent than norepinephrine - will worsen existing tachycardia -Epinephrine: has potent beta-1 activity with moderate alpha-1 and beta-2 activity; at lower doses increases MAP through increase in CO; at higher doses increases MAP by increase in SVR; primarily used in anaphylactic shock; dose 1-20 mcg/min

Category: Vascular

Title: Weird Causes of Thoracic Aortic Aneurysm

Keywords: Thoracic, Aortic Aneurysm (PubMed Search)

Posted: 8/27/2007 by Rob Rogers, MD (Updated: 4/1/2023)
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Well, I know you have been having trouble sleeping lately since you have been asking yourself, "What are some really weird causes of thoracic aortic aneurysms?" So, here is a short list: 1. Syphilis 2. Takayasu's arteritis 3. Behcet's disease 4. Psoriatic arthritis 5. Relapsing polychondritis Great pearl for an upcoming Visual Diagnosis Jeopardy....oh yeah, baby, it's coming to a wednesday conference near you!

Category: Cardiology

Title: GPIIB/IIIA inhibitors in NSTE-ACS

Keywords: GPIIB/IIIA inhibitors, acute coronary syndrome, antiplatelet medications (PubMed Search)

Posted: 8/26/2007 by Amal Mattu, MD (Updated: 4/1/2023)
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The 2007 ACC/AHA Guidelines for management of patients with unstable angina and non-STEMI were just released. They once again suggest the use of abciximab (Reopro) as the preferred glycoprotein receptor antagonist in patients that are going for PCI. If there is an anticipated delay to PCI, then eptifibatide (Integrilin) or tirofiban (Aggrastat) are preferred. The best evidence for these medications is in patients being managed invasively rather than just medically.

Category: Med-Legal

Title: Acute Coronary Syndrome Legal Pearls (Part 1)

Keywords: Legal, Acute Coronary Syndrome, (PubMed Search)

Posted: 8/26/2007 by Michael Bond, MD (Updated: 4/1/2023)
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Acute Coronary Syndrome (our number one area of liability) ===>Undiagnosed MI is the number one area of liability in emergency medicine, internal medicine, and family practice. ===>In emergency medicine, undiagnosed MI accounts for approximately 30% of all dollars lost in litigation. ===>MI patients mistakenly discharged have a 25% mortality rate, twice the rate of admitted patients. ===>Emergency physicians miss 2% of MIs. Office practitioners miss about 10% of MIs. ===>Failure-to-diagnose is the most common allegation in litigation following missed MIs. Misinterpretation of EKGs is the second most common allegation. ===>Poor documentation is the most common mistake in failure-to-diagnose cases (ie: failure to document why the physician decided the patient did not have ACS). Thanks to Larry Weiss, MD, JD Disclaimer: This information does not constitute legal advice, is general in nature, and because individual circumstances differ it should not be interpreted as legal advice. The speaker provides this information only for Continuing Medical Education purposes.

Category: Pediatrics

Title: Lead Poisoning

Keywords: Lead Poisoning, Toxicology, Plumbism, CaEDTA, BAL, DMSA, Lead Lines, Basophilic Stippling (PubMed Search)

Posted: 8/24/2007 by Sean Fox, MD (Updated: 4/1/2023)
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Lead Poisoning In Baltimore, 4.6% of kids screened had high lead levels in 2006 Plumbism presents often with vague and nonspecific symptoms; however, have high index of suspicion if: ==> Listlessness, clumsiness, or loss of developmental skills, ==> Recurrent or intermittent abdominal pain, vomiting, and constipation ==> Afebrile Convulsions ==> Resides in a house built before 1950 ==> Family history of elevated lead ==> History of Pica ==> Iron Deficiency Anemia ==> Evidence of neglect/abuse Lead Level will not come back in a timely fashion to help direct care, therefore, presumptive Chelation may be warranted. Evidence to Support Lead Posioning: ==> Micorcytic Anemia ==> Elevated Erythrocyte Protoporphyrin ==> Basophilic stippling of erythrocytes ==> Glycosuria, aminoaciduria (from development of Fanconi s Syndrome) ==> Radiopaque flecks on AXR ==> Lead Lines (dense metaphyseal bands on knee and wrist x-rays) Chelation with CaEDTA, BAL, or DMSA depending on level and symptoms.

Category: Toxicology

Title: Colchicine Toxicity - The Point of No Return

Keywords: Colchicine, toxicity, poisoning (PubMed Search)

Posted: 8/23/2007 by Fermin Barrueto, MD (Updated: 4/1/2023)
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- Few medications are uniformly lethal after a certain amount is ingested. - Colchicine is one of those medications, >0.8 mg/kg ingested=100%mortality regardless of treatment. - Many people prescribe it without knowing the adverse effect profile. - In fact, the prescribing instructions tell you to take the patient to toxicity (nausea and vomiting). - After an acute overdose this would be the sequence of events assuming surivival: Phase Signs & Symptoms i Nausea, vomiting, diarrhea, dehydration, leukocytosis (0-24hrs) II Sudden cardiac death (24-36hrs), pancytopenia, renal failure sepsis, ARDS, rhabdo (1-7d) III Alopecia, myopathy, neuropathy, myoneuropathy (>7d) - Colchicine prevents/destroys microtubule spindle formation and thus acts like a chemotherapeutic agent killing the cells that replicate most. - Think twice when prescribing this medication to someone, especially a patient at risk for suicide or medication noncompliance (where they think a little is good so more is better).

Category: Neurology

Title: Cushings Reflex and Triad

Keywords: increased intracranial pressure, cushings triad, cushings reflex, intracranial hemorrhage (PubMed Search)

Posted: 8/22/2007 by Aisha Liferidge, MD (Updated: 4/1/2023)
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Cushings reflex = a hypothalamic response to brain ischemia wherein the sympathetic nervous system is activated which causes increased peripheral vascular resistance with a subsequent increase in BP. The increased BP then activates the parasympathetic nervous system via carotid artery baroreceptors, resulting in vagal-induced bradycardia. The brain ischemia that leads to cushings reflex is usually due to the poor perfusion that results from increased ICP due to head bleeds or mass lesions. Cushings reflex leads to the clinical manifestation of Cushings triad. Cushings triad = hypertension, bradycardia, and irregular respirations (Cheyne-Stokes breathing). Some sources describe widened pulse pressure (increasing difference between systolic and diastolic BP) as the 3rd component of the triad, rather than irregular respirations. Cushings triad signals impending danger of brain herniation, and thus, the need for decompression. Consider administering mannitol, hyperventilation, and elevation of the head of bed as temporizing measures. Cushings triad was first described in 1902 by Harvey Williams Cushing, an American neurosurgeon. -Physiology, 2nd Edition, Saunders, 2002, page 150. -Ayling, J (2002). "Managing head injuries". Emergency Medical Services31 (8): 42.

Category: Critical Care

Title: Anaphylaxis - Epinephrine use

Keywords: anaphylaxis, epinephrine (PubMed Search)

Posted: 8/21/2007 by Mike Winters, MD (Updated: 4/1/2023)
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-Epinephrine is the drug of choice for anaphylaxis -Several studies indicate that epi is underutilized in ED patients with anaphylaxis -Indications for epinephrine include bronchospasm, laryngeal edema (hoarseness, stridor, difficulty swallowing), hypotension, rapidly progressive reaction, and severe gastrointestinal symptoms (due to bowel edema) -The dose of epinephrine is 0.3 to 0.5 mL of 1:1000 IM -Pearl: IM injection into the lateral thigh (vastus lateralis) has been shown to produce considerably faster time to maximum drug concentration than subq injection or IM injection into the deltoid

Category: Vascular

Title: Neurologic Manifestations of Aortic Dissection

Keywords: Aortic Dissection, Neurologic (PubMed Search)

Posted: 8/20/2007 by Rob Rogers, MD (Updated: 4/1/2023)
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A retrospective study by Gaul et al. of 102 patients with aortic dissection showed that 29% of patients presented with neurologic symptoms. Interestingly, almost 1/3 of these patients reported NO chest or back pain...i.e. painless aortic dissection with neurologic manifestations. Neurologic presentations discussed in the study include: stroke-like symptoms, syncope, ischemic neuropathy, somnolence, seizures, coma, and spinal ischemia. Pearl: Consider the possibility of aortic dissection in patients with neurologic symptoms especially if symptoms are unusual or combined with other findings. Gaul C, et al. Stroke 2007 From Emergency Medical Abstracts (July 2007)

Category: Cardiology

Title: ACS and cardiac risk factors

Keywords: acute coronary syndromes, cardiac risk factors (PubMed Search)

Posted: 8/19/2007 by Amal Mattu, MD (Updated: 4/1/2023)
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The presence of "classic" cardiac risk factors (i.e. risk factors identified in the Framingham studies) is most useful for predicting the long-term risk of developing CAD, but they have limited utility at ruling out acute coronary syndrome. A recent study (ref below) from the CRUSADE registry (multicenter registry including tens of thousands of patients with ACS), for example, demonstrated that 10.5% of patients with proven non-STE MI had NONE of the traditional cardiac risk factors. NEVER rule out ACS just because a patient has few or no cardiac risk factors. The decision to admit and risk stratify patients should always be based on your HPI (OLDCAAR). [Roe MT, Halabi AR, Mehta RH, et al. Documented traditional cardiovascular risk factors and mortality in non-ST-segment elevation myocardial infarction. Am Heart J 2007;153:507-514.]