UMEM Educational Pearls

Case Presentation:

A Spanish speaking man in his late 20s is brought in by ambulance for severe dyspnea.  Given the language barrier and his clinical status you are unable to obtain any history. He is tachypnic, had a low pulse ox, and was placed on BiPAP.  On exam you hear bibasilar rales and a faint holosystolic murmur.

Clinical Question:

What should be included in the differential?

Answer:

Rheumatic heart disease is the result of valvular damage due to an abnormal immune response following a group A streptococcal infection.  It affects 15.6 to 19.6 million people worldwide.  Most patients present with dyspnea between the ages 20-50.  The most common valvular disease is mitral insufficiency, but it may present with mitral stenosis or aortic regurgitation.  The disease is most prevalent in sub-Saharan Africa and among the Indigenous population of Australia but it can be found in many developing countries.  People who live in rural areas without access to medical care are those at highest risk for developing rheumatic fever and subsequently rheumatic heart disease.

Bottom Line:

Rheumatic heart disease should be considered in patients who present from an endemic region.

 

University of Maryland Section of Global Emergency Health

Author: Jenny Reifel Saltzberg, MD, MPH

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Fluid boluses are often administered to patients in shock as a first-line intervention to increase cardiac output. Previous literature states, however, that only 50% of patients in shock will respond to a fluid bolus. 

Several validated techniques exist to distinguish which patients will respond to a fluid bolus and which will not; one method is the passive leg raise (PLR) maneuver  (more on PLR here). A drawback to PLR is that it requires direct measurement of cardiac output, either by invasive hemodynamic monitoring or using advanced bedside ultrasound techniques.

Another technique to quantify changes in cardiac output is through measurement of end-tidal CO2 (ETCO2). The benefits of measuring ETCO2 is that it can be continuously measured and can be performed non-invasively on mechanically ventilated patients.

A 5% or greater increase in end-tidal CO2 (ETCO2) following a PLR maneuver has been found to be a good predictor of fluid responsiveness with reliability similar to invasive measures.

 

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Question

38 year-old male with a past medical history of diabetes presents with back pain and hypotension. CT scan is shown below. What's the diagnosis?

 

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Title: Postural Tachycardia Syndrome

Category: Cardiology

Keywords: Postural Tachycardia Syndrome, POTS (PubMed Search)

Posted: 5/2/2013 by Semhar Tewelde, MD (Updated: 5/5/2013)
Click here to contact Semhar Tewelde, MD

  • Postural tachycardia syndrome (POTS) is defined as orthostatic intolerance w/ an increase in heart rate by 30 bpm (or HR>120 bpm) that occurs within 10 mins of standing or upright tilt
  • Orthostatic intolerance due to POTS will NOT cause orthostatic hypotension (defined as fall of >20/10 mm Hg on standing); instead patients may display no change, a small decline, or even a modest increase in blood pressure
  • Symptoms include: palpitations, fatigue, lightheadedness, exercise intolerance, nausea, diminished concentration, tremulousness, and syncope
  • POTS is a heterogeneous group of disorders with similar clinical manifestations  
  1. Primary POTS - partial dysautonomia form
  2. Secondary POTS - hyperadrenergic form
  • Tx varies according to the subtype/etiology of POTS and must be individualized
  • *Caveat inappropriate sinus tachycardia (IST) and POTS are two different diagnosis where significant overlap exists, however thebtachycardia in IST is NOT postural 

           

 

 

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Title: Hyperphosphatemia from Fosphenytoin?

Category: Pharmacology & Therapeutics

Keywords: phosphate, fosphenytoin, phenytoin, hyperphosphatemia (PubMed Search)

Posted: 4/29/2013 by Bryan Hayes, PharmD (Updated: 5/2/2013)
Click here to contact Bryan Hayes, PharmD

Introduction

Fosphenytoin is a prodrug and is metabolized quickly to phenytoin after administration. The conversion of fosphenytoin to phenytoin involves the release of phosphate. In fact, each mmol of fosphenytoin releases 1 mmol of phosphate.

Clinical Question

Are patients at risk for hyperphosphatemia after fosphenytoin loading?

Data

There are only two cases of reported hyperphosphatemia.

  • A 17-year old African-American male with end-stage renal disease developed acute hyperphosphatemia to 3.9 mmol/L (12.1 mg/dL) following the IV administration of 1000 mg of fosphenytoin for an idiopathic complex partial seizure
  • An infant in status epilepticus had marked hyperphosphatemia 8.4 mmol/L (25.9 mg/dL) after a 5-10 fold dosing error.

Bottom Line

Despite the phosphate load from fosphenytoin administration, hyperphosphatemia is very rare and probably associated with renal insufficiency and dosing errors.

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Title: Varicella-related stroke

Category: Pediatrics

Keywords: stroke, children, infection (PubMed Search)

Posted: 5/3/2013 by Jenny Guyther, MD (Updated: 11/24/2024)
Click here to contact Jenny Guyther, MD

Acute ischemic stroke occurs in 3.3/100,000 children per year.  Up to 30% of these are caused by varicella.  This can be diagnosed if the patient has had varicella infection within the past 12 months, has a unilateral stenosis of a great vessel, and has a positive PCR or IgG from the CSF.

Treatment includes anticoagulation, acyclovir for at least 7 days and steroids for 3-5 days.

Outcome is normally good and spontaneous improvement can be seen.

Inflammation of other arteries, including other areas of the brain, can also be seen.  Treatment options for this can include high dose glucocorticoids and possibly immunosuppresive agents.

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Title: Prothrombin Complex Concentrate Approved by FDA

Category: Pharmacology & Therapeutics

Keywords: Prothrombin Complex Concentrate, warfarin, coumadin, vitamin K antagonist, anticoagulant, PCC (PubMed Search)

Posted: 5/2/2013 by Ellen Lemkin, MD, PharmD
Click here to contact Ellen Lemkin, MD, PharmD

 

  • Prothrombin Complex Concentrate (PCC) Kcentra™ has been approved for urgent reversal of major bleeding in patients taking vitamin K antagonists (e.g. warfarin).
  • It contains factors 2,7,9 and 10, and antithrombotic Proteins C and S.
  • Both fatal and non-fatal arterial and venous thromboembolic complications have occurred with Kcentra™. Thrombotic events occurred more frequently in the PCC group compared to plasma, although the differences were not statistically significant.
  • Volume overload occurred less frequently in the PCC group, as there is a smaller volume  administered with PCC compared to that of plasma.
  • Percentage of INR ≤ 1.3 at 30 minutes was 62% in the PCC group and 9.6% in the plasma group.

Approval of Kcentra™ may open the door for studying treatment of the bleeding patient on newer oral anticoagulants.



Title: Concentration-Dependent Antibiotics

Category: International EM

Keywords: antibiotics, concentration-dependent, infectious disease, international, levofloxacin, gentamicin (PubMed Search)

Posted: 5/1/2013 by Andrea Tenner, MD
Click here to contact Andrea Tenner, MD

General Information:  Antibiotics are generally classified as time- and concentration-dependent.

Concentration-dependent antibiotics

  • Rate of kill is highly dependent on peak concentrations and is tissue-specific (generally 10x MIC needed for optimal bactericidal effect)
  • As concentrations of the drug decrease, the bactericidal effect decreases
  • Need less frequent dosing but higher doses
  • Examples:

                    -Fluoroquinolones (i.e. Levofloxacin)

                    -Aminoglycosides (i.e. Gentamicin)

                    -Azithromycin

Relevance to the EM Physician:

Concentration-dependent antibiotics should be given at the highest appropriate dose for the target tissues (i.e. Levofloxacin 750mg for pneumonia is preferable to 500mg).  This is also the rationale for high dose, extended-interval dosing for Gentamicin (>5mg/kg initial dose).

University of Maryland Section of Global Emergency Health

Author:  Andi Tenner, MD, MPH

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Neuromuscular Blocking Agents in the Critically Ill

  • NMBAs are used in critically ill patients for RSI, patient-ventilator asynchrony, reducing intra-abdominal pressure, reducing intracranial pressure, and preventing shivering during therapeutic hypothermia.
  • There are a number of alterations in critical illness that affect the action of NMBAs
    • Electrolyte abnormalities
      • Hypercalcemia: decreases duration of blockade
      • Hypermagnesemia: prolongs duration of blockade
    • Acidosis: can enhance effect of nondepolarizing agents
    • Hepatic dysfunction: prolongs effects of vecuronium and rocuronium
  • In addition, there are a number of medications that may interact with NMBAs
    • Increased resistance: phenytoin and carbamazepine
    • Prolongs effect: clindamycin and vancomycin
  • Key complications of NMBAs in the critically ill include:
    • ICU-aquired weakness (controversial)
    • DVT: NMBAs are one of the strongest predictors for ICU-related DVT
    • Corneal abrasions: prevalence up to 60%

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Question

57 year old male presents with a cough. The CXR is shown below. What's the diagnosis?

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  • B-type natriuretic peptide (BNP) is a useful prognostic biomarker in patients with reduced LVEF, but data in heart failure (HF) with preserved ejection fraction (HFPEF) is minimal
  • A recent study sought to determine the prognostic value of BNP in patients with HFPEF in comparison to data in HF patients with reduced left ventricular EF <40%
  • 615 patients with mild to moderate HF were followed for 18 months and BNP was measured at baseline and related to the primary outcomes (mortality and HF hospitalization)
  • BNP levels were significantly higher in patients with reduced LVEF than in those with HFPEF (p < 0.001), however the risk of adverse outcomes and prognosis in patients with HFPEF is as poor as in those with reduced LVEF  

 

 

 

 

 

 

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Title: What should I MRI

Category: Orthopedics

Keywords: MRI, spinal cord compression (PubMed Search)

Posted: 4/27/2013 by Brian Corwell, MD
Click here to contact Brian Corwell, MD

You have a patient with a spinal cord syndrome and you order the MRI. Have you ever had that conversation with radiology where you have to "choose" what part of the spine you want imaged?

The entire spine needs to be imaged!

The reason: False localizing sensory levels.

For example: The patient has a thoracic sensory level that is caused by a cervical lesion.

 

A study of 324 episodes of malignant spinal cord compression (MSCC) found that clinical signs were very unreliable indicators of the level of compression. Only 53 patients (16%) had a sensory level that was within 3 vertebral levels of the level of compression demonstrated on MRI.

Further, pain (both midline back pain and radicular pain) was also a poor predictor of the level of compression.

Finally, of the 187 patients who had plain radiographs at the level of compression at referral, 60 showed vertebral collapse suggesting cord compression, but only 39 of these predicted the correct level of compression (i.e. only 20% of all radiographs correctly identified the level of compression).

The authors note that frequently only the lumbar spine was XR at the time of clinical presentation (usually at the referring hospital), presumably due to false localizing signs and a low awareness on the part of clinicians that most MSCC occurs in the thoracic spine (68% in this series).

 

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An overweight 5 year old male presents with acute onset abdominal pain that localizes to the right lower quadrant. What are some causes of a limited or nondiagnostic ultrasound study in children?

Acute appendicitis is a time sensitive diagnosis. Ultrasound is frequently used as the initial diagnostic imaging in children. There are several reasons why the appendix may not be visualized, including retro-cecal location, normal appendix, perforation, and inflammation around the distal tip. An additional clinical predictor associated with poor or inconclusive ultrasound results in appendicitis is increased BMI (body mass index).

A study examining 263 pediatric patients found when BMI > 85th percentile and clinical probability of appendicitis was <50%, 58% of ultrasounds were nondiagnostic. Children with a BMI <85th percentile and clinical probability of appendicitis was <50%, had nondiagonstic scans 42% of the time. These trends were also mimicked in the patients with a higher clinical probability of appendicitis. In the child with a nondiagnostic ultrasound, options include observation and repeat ultrasound scan or CT scan, both of which have associated risks.

 

Reference:
Schuh S, et al. Predictors of non-diagnostic ultrasound scanning in children with suspected appendicitis. J Pediatr. 2011 Jan;158(1):112-8.


Title: Acetaminophen Toxicity - When Should I Consider Liver Transplant?

Category: Toxicology

Keywords: Kings College, apap, acetaminophen (PubMed Search)

Posted: 4/25/2013 by Fermin Barrueto (Updated: 11/24/2024)
Click here to contact Fermin Barrueto

If you are working in a community hospital and have an acetaminophen overdose, one of the criteria to transfer the patient to a tertiary care center is presence of the King's College Criteria.

The below is taken from mdcalc.com -  http://www.mdcalc.com/kings-college-criteria-for-acetaminophen-toxicity/

Each one is assigned points and can be prognostic for severe toxicity and need for transplant. The lactate and phosphorus are new ones and have modified the criteria. Phosphorus is utilized to create glycogen. If the liver is injured and trying to heal, your phosphorus will be low (good). If the liver is injured and unable to repair itself the phosphorus will be high (bad). This single test has an excellent prognostic ability.

 

Lactate > 3.5 mg/dL (0.39 mmol/L) 4 hrs after early fluid resuscitation?
pH < 7.30 or lactate > 3 mg/dL (0.33 mmol/L) after full fluid resuscitation at 12 hours
INR > 6.5 (PTT > 100s)
Creatinine > 3.4 mg/dL (300 µmol/L)
Grade 3 or 4 Hepatic Encephalopathy?
Phosphorus > 3.75 mg/dL (1.2 mmol/L) at 48 hours

 



Title: Wait--the creatinine is what?!?!?

Category: International EM

Keywords: international, laboratory, lab values, SI, conventional (PubMed Search)

Posted: 4/24/2013 by Andrea Tenner, MD
Click here to contact Andrea Tenner, MD

General Information:

The two main units used by medical laboratories are "conventional (used in the US) and SI (used by most other countries).

Pearls to know:

  • For monovalent ions (i.e. Na+, Cl-) -- mEq/L=mmol/L (135 mEq = 135 mmol/L)
  • For divalent ions (i.e. ionized Ca2+, Mg2+) -- mEq/2=mmol (Mg2+ of 2 mEq/L = 1 mmol/L)
  • Creatinine -- Multiply conventional untis by 88 (1 mg/dL = 88 mmol/L)
  • Glucose -- Multiply SI units by 18 (4 mmol/L = 72 mg/dL)
  • Hemoglobin--Multiply conventional units by 10 (14 g/dL = 140 g/L)

Relevance to the EM Physician:

These tips will help you convert labs to familiar values when reading medical literature, when working in another country, or when working with international colleagues.

University of Maryland Section of Global Emergency Health

Author: Andi Tenner, MD, MPH

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Necrotizing fasciitis (NF) is a rapidly progressive bacterial infection of the fascia with secondary necrosis of the subcutaneous tissue. In severe cases, the underlying muscle (i.e., myositis) may be affected.

Risk factors for NF include immunosuppression (e.g., transplant patients), HIV/AIDS, diabetes, etc.

There are three categories of NF:

  • Type I (poly-microbial infections)
  • Type II (Group A streptococcus; sometimes referred to as the “flesh-eating bacteria)
  • Type III (Clostridial myonecrosis; known as gas gangrene)

In the early stage of disease, diagnosis may be difficult; the physical exam sometimes does not reflect the severity of disease. Labs may be non-specific, but CT or MRI is important to diagnose and define the extent of the disease when planning surgical debridement.

Treatment should be aggressive and started as soon as the disease is suspected; this includes:

  • Aggressive fluid and/or vasopressor therapy
  • Broad spectrum antibiotics covering for gram-positive, gram-negative, and anaerobic bacteria; clindamycin should be added initially as it suppresses certain bacterial toxin formation
  • Emergent surgical consult for debridement
  • Once the patient is stable, other treatments may include intravenous immunoglobulin and hyperbaric oxygen therapy

 

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Title: Otitis Media (submitted by Ari Kestler, MD)

Category: Pediatrics

Keywords: antibiotics, wait and see (PubMed Search)

Posted: 4/19/2013 by Mimi Lu, MD
Click here to contact Mimi Lu, MD

2013 AAP AOM Guidelines UPDATE

 
-AAP released a new clinical practice guideline for diagnosis and management of acute otitis media (AOM).
 
Key Action Statements:
 
Diagnosis if presence of middle ear effusion and
(1) moderate to severe bulging of tympanic membrane (TM) or new otorrhea or
(2) mild bulging of TM and recent ear pain or intense erythema of TM
 
Treatment options:
  • Severe unilateral or bilateral AOM (>6mo): give antibiotics.  Severe AOM is defined as fever >102.2 (39 C), moderate/severe otalgia, or symptoms >48h.
  • Nonsevere unilateral AOM (6-23 months): Advise the parents to consider a period of close observation and follow up (24-72h).  If the childs clinical status deteriorates give antibiotics.
  • Nonsevere bilateral AOM (6-23 months): give antibiotics.
  • Nonsevere unilateral or bilateral AOM (>24 months): Advise the parents to consider a period of close observation and follow up (24-72h).  If the childs clinical status deteriorates, give antibiotics.
 
 
Reference: Pediatrics Vol. 131 No. 3 March 1, 2013


Title: Ricin - of course

Category: Toxicology

Keywords: Ricin (PubMed Search)

Posted: 4/18/2013 by Fermin Barrueto (Updated: 11/24/2024)
Click here to contact Fermin Barrueto

With recent events, a few notes about ricin seems appropriate:

  1. Easy to make from castor bean though heat labile
  2. No antidote, though Fab like digibind is in development
  3. Granule size of the grain of sand can kill
  4. Inhalation, IM, IV all effective
  5. After immediate exposure likely no symptoms
  6. Vomiting and diarrhea initially, acute lung injury and death in 3-5 days

CDC website: http://www.bt.cdc.gov/agent/ricin/



 

General Information:

A parasitic infection caused by the tissue-dwelling filarial nematode worm Wuchereria bancrofti; a wide range of mosquitoes transmit the infection. When the worm is mature, it inhabits lymph nodes and produces sheathed microfilarial larvae that circulate in the peripheral blood.

Clinical Presentation:

- Infection with the adult worms produces painless subcutaneous nodules that are usually less than 2 cm in diameter, typically over bony prominences.

- Symptoms depend on where the microfilariae migrate to, and vary accordingly. They include: pruritus, papular dermatitis, dermal atrophy and depigmentation or hyperreactive skin disease (Sowda), keratitis, iritis, chorioretinitis, optic atrophy and eventually blindness, orchitis, hydrocele, chyluria, elephantiasis, pulmonary eosinophilia, cough, wheezing, and splenomegaly.

Diagnosis:

- Peripheral blood smear taken between 11pm and 1am or after provocation using diethylcarbamazine (DEC).

- Filarial antigen test.

- Eosinophilia, and specific antiflarial IgG and IgE antibodies.

Treatment:

- DEC which must be obtained directly from the CDC.

- Alternatively Doxycycline. Both drugs are effective against both macro and micro-filaria.

Bottom Line:

One billion people globally are at risk for infection with filaria. 120 million already have the infection. Suspect the infection in patients that have been to Africa, Asia, especially India, Western pacific, Haiti, the Dominican Republic, Guyana and Brazil.

 

University of Maryland Section of Global Emergency Health

Author: Walid Hammad, MD

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Massive Transfusion Pearls

  • As discussed in previous pearls, massive transfusion (MT) is defined as the transfusion of at least 10 U of packed red blood cells (PRBCs) within 24 hours.
  • While the optimal ratio of PRBCs, FFP, and platelets is not known, most use a 1:1:1 ratio.
  • Though scoring systems have been published to identify patients who may benefit from MT (ABC, TASH, McLaughlin), they have not been shown to be superior to clinical judgment.
  • A few pearls when implementing massive transfusion for the patient with traumatic shock:
    • Monitor temperature and aggressively treat hypothermia.
    • Monitor fibrinogen levels and replace with cryoprecipitate if needed.
    • Monitor calcium and potassium.  MT can induce hypocalcemia and hyperkalemia.

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