UMEM Educational Pearls

Category: Neurology

Title: Lower Leg Nerve Deficit from Knee Injury

Keywords: neuropathy, knee injury, sural nerve, peroneal nerve, tibial nerve (PubMed Search)

Posted: 7/23/2008 by Aisha Liferidge, MD (Updated: 12/7/2019)
Click here to contact Aisha Liferidge, MD

  • Don't forget to check for distal lower extremity neurologic deficit after knee injury, particularly when there is a direct blow to the popliteal fossa.
  • The common peroneal and tibial nerves exit from the lateral and middle sections of the popliteal fossa, respectively.
  • The common peroneal nerve wraps laterally around the fibula (where it's palpable), primarily supplying the lateral portions of the lower leg and foot.
  • The tibial nerve primarily supplies the muscles of the posterior compartment of the lower leg (i.e. gastrocnemius, soleus, popliteus).
  • Both the common peroneal and tibial nerve fibres branch into the sural nerve, which supplies the lateral foot.
  • Common peroneal also splits into deep and superficial branches which supply the muscles of the anterior lower leg compartment and lateral lower leg compartment, respectively.  The deep branch also provides cutaneous innervation of the cleft between the great and second toes.

--  IN SUMMARY:

  • Neurologic deficit of the posterior lower leg muscles likely = tibial nerve injury.
  • Neurologic deficit of the anterior and lateral lower leg muscles likely =  peroneal nerve injury.
  • Decreased sensation in the web space between the great and 2nd toes likely = (deep) peroneal nerve injury.
  • Decreased sensation over the lateral dorsum of the foot likely = sural nerve injury.

*** Speaking of such deficits by naming the affected nerve distribution is particularly helpful when consulting orthopedists, neurologists, etc.


Category: Critical Care

Title: Asthma and Mechanical Ventilation

Keywords: asthma, mechanical ventilation, hyperinflation (PubMed Search)

Posted: 7/22/2008 by Mike Winters, MD (Updated: 12/7/2019)
Click here to contact Mike Winters, MD

Mechanical Ventilation in Asthma

  • Approximately 25,000 asthmatics are intubated each year
  • Mismanaged mechanical ventilation in asthma carries significant morbidity and mortality
  • One of the primary goals of ventilating the asthmatic is to allow for lung deflation
  • The most effective way to allow for lung deflation, and reduce hyperinflation, is to reduce minute ventilation (TV x RR)
  • Initial tidal volume settings should be 6 ml/kg of predicted body weight; if plateau pressures are > 30 cm H2O tidal volume should be decreased to 4 - 5 ml/kg
  • Reduced respiratory rates will also allow longer exhalation times; initial recommended rates are 6 - 8 breaths per minute
  • If plateau pressures are still high despite lowering tidal volume and respiratory rate, you can then shorten the inspiratory time to allow for longer exhalation

Show References


Category: Vascular

Title: How Good Was That CT Pulmonary Angiogram You Ordered?

Keywords: CT, Pulmonary (PubMed Search)

Posted: 7/21/2008 by Rob Rogers, MD (Updated: 12/7/2019)
Click here to contact Rob Rogers, MD

How good was that CT Pulmonary Angiogram You Ordered?

CT is currently the gold standard imaging modality for pulmonary embolism. Since we order these quite a bit in the ED, we should know some of the important nuances regarding interpretation of the scan. All of us at some point have looked at a pulmonary CTA and thought that it looked a bit "fuzzy" or perhaps it didn't "look right"  This happens more often in obese patients. There is good literature to show that a suboptimal CTA misses clinically significant PE. So, it is important for emergency physicians to know a little about the CT scan ordered for our patients. 

How can you know if the CT scan YOU ordered to rule out PE is really "good enough" to rule out PE?

  • Well, you can rely on the radiologist. But remember they may not comment of the quality of the scan. Or, they may simply recommend another test.
  • Look at the Hounsfield Units (HU). For those who have PACS or some other computer radiology display,all you need to do is move the cursor to the main pulmonary artery and see what value (usually on the bottom of the screen) is displayed. 
  • A HU >280 indicates that the CT is "good" (i.e. good enough contrast bolus to detect clot). By the way, >350 looks white.

So, a 34 yo obese patient who gets a CT scan to rule out PE, who has 170 HU in the main pulmonary artery, has not had an optimal CT. Thus, you really haven't ruled out PE even if the read is "negative." Often this is due to poor bolus timing. 

 

 

Show References


Category: Orthopedics

Title: Fracture Management

Keywords: Fracture, Management, Billing (PubMed Search)

Posted: 7/20/2008 by Michael Bond, MD (Updated: 12/7/2019)
Click here to contact Michael Bond, MD

Fracture Management:

 

In order to maximize billing when caring for patients with fractures two things should be done:

  1. The physician does not need to place the splint, but the physican must document that they checked the splint for proper placement and alignment for it to be billed appropriately..
  2. Emergency physicians also provide a lot of "definitive" care for fractures.  (i.e.: we provide the same care that the treating specialist would provide) and can bill for a higher level if this is documented properly. 
    1. For instance, if you are treating a impacted, stable distal radius fracture with a splint and pain medication this is the same definitive care the orthopedist would do as they are only going to exchange your splint for  a cast. 
    2. Another example is the treatment of rib fractures which may consist only of pain control, incentive spirometry and instructions to prevent pneumonia.
    3. In these patients, have the patients follow up more than 48 hours later.  If you document that the patient will followup in less than 48 hours, most auditors and billing companies will assume you are not providing definitive care and will not code for the higher earning RVU.

Finally,  you should obtain post-reduction x-rays on any fracture that you manipulate and document that the patient is neurovascularly intact prior to discharge.


Category: Cardiology

Title: reflux and ACS misdiagnosis

Keywords: reflux, esophagitis, misdiagnosis, myocardial infarction (PubMed Search)

Posted: 7/20/2008 by Amal Mattu, MD (Updated: 12/7/2019)
Click here to contact Amal Mattu, MD

 The most common misdiagnosis in cases of missed acute MI is reflux esophagitis. Various studies have demonstrated the following factors that lead to this misdiagnosis:
1. 20% of patients with acute MI describe their pain using the words "indigestion" or "burning."
2. Almost 50% of patients with acute MI report an increase in belching during their ischemic symptoms.
3. 15% of patients get some relief of their ischemic pain with antacids and 7% of patients get complete relief of their ischemic pain with antacids.
4. 8% of patients report that their ischemic pain began while eating.

Before you ever write "Reflux esophagitis" or "GERD" on the chart of a patient you are about to send home, think twice about the possibility of acute cardiac ischemia.
 


Category: Pediatrics

Title: Febrile Seizures

Keywords: pediatric fever, pediatric seizure (PubMed Search)

Posted: 7/18/2008 by Don Van Wie, DO (Updated: 12/7/2019)
Click here to contact Don Van Wie, DO

PEDIATRIC FEVER + SEIZURE = FEVER

When a child has a fever and a seizure, do the age appropriate workup for a fever and you won't go wrong!!!

  • Routine laboratory studies usually are not indicated unless they are performed as part of a search for the source of a    fever.
  • Electrolytes assessments are rarely helpful in the evaluation of febrile seizures.
  • Patients with febrile seizures have an incidence of bacteremia similar to patients with fever alone.

  • Category: Toxicology

    Title: Salicylate Serum Concentrations - Be Wary

    Keywords: Salicylate, aspirin, metabolic acidosisM (PubMed Search)

    Posted: 7/17/2008 by Fermin Barrueto, MD (Updated: 12/7/2019)
    Click here to contact Fermin Barrueto, MD

    •  Therapeutic concentration considered 10-20 mg/dL
    •  Some hospitals report in "mg/L" thus a level of 110 mg/L is therapeutic
    •  Symptoms of Toxicity usually > 40 mg/dL
    •  Consider Hemodialysis in any patient with a serum concentration >100 mg/dL

    First Line Therapy:  Urine Alkalinization (pH >7.5) by administrating NaHCO3

    Other Indications for Hemodialysis in Salicylate Poisoned Patient:

    1. Renal Failure
    2. CHF
    3. Acute Lung Injury
    4. Persistent CNS disturbances
    5. Refractory metabolic acidosis or electrolyte abnormality
    6. Hepatic insufficiency with coagulopathy

    Category: Neurology

    Title: Sciatic Nerve Injury

    Keywords: sciatica, sciatic nerve, foot drop (PubMed Search)

    Posted: 7/16/2008 by Aisha Liferidge, MD (Updated: 12/7/2019)
    Click here to contact Aisha Liferidge, MD

    • The Sciatic Nerve is commonly injured during intramuscular buttocks injections as well as hip fracture dislocations and posterior dislocations.  In such instances, always confirm and document preserved sciatic nerve function.
    • Sciatic nerve injury often results in foot drop due to decreased function of the hamstring, calf, and anterolateral lower leg muscles.
    • Sciatic nerve injury may also cause loss cutaneous sensation over the calf , as well as the sole and lateral portions of the foot.

    Category: Critical Care

    Title: Noninvasive Ventilation Pearls

    Keywords: noninvasive ventilation (PubMed Search)

    Posted: 7/15/2008 by Mike Winters, MD (Updated: 12/7/2019)
    Click here to contact Mike Winters, MD

     Noninvasive Ventilation Pearls

    • Multiple studies support the use of noninvasive positive pressure ventilation (NPPV) in acute exacerbations of COPD, acute cardiogenic pulmonary edema, and immunocompromised patients (organ transplant) with hypoxic respiratory failure.
    • The timing of NPPV initiation is important.  NPPV should be started as soon as possible, as delays increase the likelihood of intubation
    • The best predictor of success is a favorable response to NPPV within the first 1 to 2 hours
      • reduction in respiratory rate
      • improvement in pH
      • improved oxygenation
      • reduction in PaCO2
    • Also crucial to NPPV success is a well fitting interface (mask)
    • Although patients report greater comfort with nasal masks, they also permit more air leakage through the mouth and have been associated with a higher rate of initial intolerance in the acute setting.
    • For acute applications of NPPV in the ED, a full face mask is preferred 

    Show References


    Category: Vascular

    Title: Ruling Out Pulmonary Embolism During Pregnancy

    Keywords: Pulmonary Embolism, Pregnancy (PubMed Search)

    Posted: 7/14/2008 by Rob Rogers, MD (Updated: 12/7/2019)
    Click here to contact Rob Rogers, MD

    Evaluating for Pulmonary Embolism During Pregnancy

    Highest risk of PE is within the first week postpartum

    Acceptable, safe, and medico-legally sound strategies to rule out PE in pregnancy:

    • Pulmonary CTA-this strategy is safe and accepted. Plenty of data to support you if you choose this strategy. Some evidence recently that shielding the baby may actually increase scatter radiation to the fetus. Check with your Radiologist. 
    • V/Q scan-also an acceptable strategy. Probably more radiation to the fetus. If you choose this test, remember that many experts recommend you insert a foley to drain the bladder (reduces radiation exposure to the fetus). 
    • Negative PERC (Pulmonary Embolism Rule Out Criteria) + Negative, trimester adjusted d-dimer level. Adjusted trimester cutoffs for d-dimer in pregnancy are: 1st 750 ng/dL, 2nd 1000 ng/dL, and 3rd 1250 ng/dL. So, figure out what trimester your patient is and if they are PERC - and the d-dimer falls below the cutoff,  you are done. Remember to adjust the pulse to 105 bpm if using the PERC rule for rule out as heart rate goes up in pregnancy.
    • Start with lower extremity US, if DVT +, you are done

    **For explanation of PERC rule, see earlier pearl.

    Show References


    Category: Cardiology

    Title: ECG changes in myopericarditis

    Keywords: myocarditis, pericarditis, myopericarditis (PubMed Search)

    Posted: 7/13/2008 by Amal Mattu, MD (Updated: 12/7/2019)
    Click here to contact Amal Mattu, MD

    The pericardium is electrically silent, and so true acute pericarditis should not be associated with ECG changes. STE actually implies concurrent involvement of the myocardium; i.e. myopericarditis. The greater the degree of myocardium involved, the more ECG changes will develop, including STE, AV blocks, and dysrhythmias. Additionally, myocardial involvement is implied by elevated troponin levels, the magnitude of which is related to the amount of myocardial involvement.

    [Imazio M, Trinchero R. Myopericarditis: etiology, management, and prognosis. Int J Cardiol 2008;127:17-26.]


    Category: Orthopedics

    Title: Scaphoid Fracture

    Keywords: scaphoid, fracture (PubMed Search)

    Posted: 7/13/2008 by Michael Bond, MD (Updated: 12/7/2019)
    Click here to contact Michael Bond, MD

    SCAPHOID FRACTURE:

    • One of the most frequently missed fractures in the ED
    • Most common carpal fracture.
    • 10-20% fractures are “occult”
    • Significant long-term complications:
      • Non-union
      • Avascular necrosis
    • Complications more common due to the fact the blood supply comes form from the distal end of the bone.
    • The more distal the fracture, the greater risk of complications
    • MR remains the best test for occult fx.

    Category: Pediatrics

    Title: Intussusception

    Keywords: Intussusception (PubMed Search)

    Posted: 7/12/2008 by Don Van Wie, DO (Updated: 12/7/2019)
    Click here to contact Don Van Wie, DO

     

          Intussusception
    •  Intussusception is the telescoping or prolapse of one portion of the bowel into an immediately adjacent segment.
    • 90 % occur at the terminal ileum (ie, ileocolic).
    • Male-to-female ratio is approximately 3:1.
    • Usually seen between 5-9 months of age and 66% of all cases are in the first year of life.
    • The classic triad of colicky abdominal pain, vomiting, and red currant jelly stools occurs in only 21% of cases
    • Currant jelly stools are observed in only 50% of cases.
    • Most patients (75%) without obviously bloody stools have stools that test positive for occult blood.
    • If intussusception is strongly suspected, perform a contrast or air  enema without delay.
    • Mortality with treatment is 1-3%.
    • If untreated, this condition is uniformly fatal in 2-5 days.

    Category: Toxicology

    Title: Metformin Toxicity - An Emergency Department Diagnosis

    Keywords: lactic acidosis, metformin, renal failure (PubMed Search)

    Posted: 7/10/2008 by Fermin Barrueto, MD (Updated: 12/7/2019)
    Click here to contact Fermin Barrueto, MD

     

     

    • Metformin is the most commonly prescribed oral diabetic mediction in US
    • Relative contraindication is in renally impaired patients, they are susceptible to the lactic acidosis
    • Lethal adverse effect is the increase production of lactate
    • ED patient with an anion gap metabolic acidosis, check for metformin and check the lactate
    • The lactic acidosis is often severe (>10 mmol/L) and carries a high mortality rate that has been estimated at >40%
    • Correction of pH and emergent hemodialysis are essential

    Show References


    Category: Neurology

    Title: Reasons to Call your Neurointerventionalist

    Keywords: neurointerventionalist, vascular dissection, ischemic stroke, subarachnoid hemorrhage (PubMed Search)

    Posted: 7/9/2008 by Aisha Liferidge, MD (Updated: 12/7/2019)
    Click here to contact Aisha Liferidge, MD

    Top Reasons to call your Neurointerventionalist:

    1. Vascular "blowouts" (i.e carotid tumor or trauma). 
    2. Symptomatic dissections within 6 hours of onset (i.e. carotid or vertebral).
    3. Ischemc Stroke with visible clot on CT angiogram outside of 3-hour IV tPA window.
    4. Ischemic Stroke with visible clot on CT angiogram outside of 3-hour IV tPA window or with contraindication for tPA (i.e may be MERCI Device candidate).
    5. Subarachnoid hemorrhage of aneurysmal origin.

    Category: Critical Care

    Title: Redefining Hypotension

    Keywords: hypotension, trauma, elderly (PubMed Search)

    Posted: 7/7/2008 by Mike Winters, MD (Emailed: 7/8/2008) (Updated: 12/7/2019)
    Click here to contact Mike Winters, MD

    Hypotension begins at 110 mmHg?

    • Many of us use the historical SBP cut-off point of 90 mmHg or less to identify hypotension and shock
    • Importantly, there is no data to support this arbitrary value
    • Particularly in older patients, hypotension, hypoperfusion, and increased mortality may begin sooner than previously realized
    • In this study of over 80,000 patients from the National Trauma Data Bank, a SBP < 110 mmHg was found to be more clinically relevant for identifying hypotension and hypoperfusion
    • Take Home Point: strongly consider raising your threshold for identifying hypotension and initiating resuscitation, especially in the older trauma patient.

    Show References


    Category: Critical Care Literature Update

    Title: Etomidate and adrenal suppression

    Keywords: etomidate, adrenal insufficiency (PubMed Search)

    Posted: 7/7/2008 by Mike Winters, MD (Updated: 12/7/2019)
    Click here to contact Mike Winters, MD

    Recent Articles from the Critical Care Literature

    Duration of adrenal insufficiency following a single dose of etomidate in critically ill patients

    Vinclair M, Broux C, Faure P, Brun J, Genty C, et al. Intensive Care Med 2008;34:714-9.
                Etomidate has become a favored first-line induction agent for intubation in the emergency department.  Given its excellent hemodynamic tolerance, etomidate is especially useful in hemodynamically unstable patients. A known side effect of etomidate is adrenal suppression, due to inhibition of 11β-hydroxylase, the enzyme that converts 11β-deoxycortisol into cortisol. As a result, recent literature has raised concerns that etomidate may worsen patient outcomes in those with relative adrenal insufficiency, namely those with septic shock.
                The current study is a prospective, observational study conducted in France from October 2005 to January 2006. The purpose of the study was to assess the duration of adrenal suppression following a single dose of etomidate, given either in the field or in the emergency department for RSI. Importantly, patients with septic shock, or those with preexisting adrenal insufficiency, were excluded from this study. To diagnose adrenal insufficiency, the investigators measured total cortisol and 11β-deoxycortisol following a high-dose cosyntropin stimulation test (250 mcg). Values were obtained at 12, 24, 48, and 72 hours following etomidate administration. An accumulation of 11β-deoxycortisol with a lack of cortisol rise was used to establish etomidate-related adrenal insufficiency.
                A total of 40 patients were included in this study. The majority of patients required intubation as a result of either trauma or subarachnoid hemorrhage. At hour 12, 80% of patients fulfilled the investigators definition of etomidate-related adrenal insufficiency, whereas by hour 48, only 9% met criteria. In addition, at hour 24, patients with etomidate-related adrenal suppression required larger doses of norepinephrine that those without adrenal inhibition. From their data, the authors conclude that a significant proportion of patients without septic shock have adrenal suppression for at least 12 hours following a single dose of etomidate. This effect, however, appeared reversible in that most patients recovered adrenal function by hour 48. Finally, the authors recommend that systemic steroid supplementation be considered during the first 48 hours in hemodynamically unstable patients who have received etomidate for intubation.
                There are a number of limitations with this study. The most important limitation is, perhaps, the authors’ definition of etomidate-related adrenal insufficiency. Diagnosing adrenal insufficiency in critically ill patients remains controversial. The cosyntropin test (high- or low-dose) has many recognized limitations. In addition, measurement of 11β-deoxycortisol is difficult because reference values for critically ill patients are rare. The authors also chose to measure total serum cortisol, rather than the more biologically active free serum cortisol. Lastly, data for all 40 patients at 72 hours was not complete.
                Take Home Points: This small, observational study found a high incidence of adrenal suppression for at least the first 12 hours in unstable patients receiving etomidate for intubation. Importantly, this study excluded patients with sepsis or septic shock. Given the limited number of patients and the difficulty in defining adrenal insufficiency in the critically ill, this study provides some interesting results and is hypothesis-generating at best. Their recommendation for systemic steroid supplementation during the first 48 hours following etomidate administration in unstable patients cannot be supported by this study.

    Category: Vascular

    Title: Ruling Out Pulmonary Embolism in Cancer Patients

    Keywords: Pulmonary Embolism, Cancer (PubMed Search)

    Posted: 7/7/2008 by Rob Rogers, MD (Updated: 12/7/2019)
    Click here to contact Rob Rogers, MD

    Ruling Out PE in Cancer Patients: Use D-Dimer??

    Most of us are aware of the data that suports using a highly-sensitive d-dimer combined with low-moderate risk score to r/o PE. Sounds simple enough. What about using d-dimer in a cancer patient to rule it out? Well, this is being studied more and more.

    Most of us would be a little uneasy about using a d-dimer as a stand-alone test to r/o PE in a cancer patient. After all, they have cancer, aren't they high risk?

    The following study showed that the there was a VERY high negative predictive value and a VERY high sensitivity of a negative d-dimer in this group of cancer patients.


    Abstract
    PURPOSE: To prospectively evaluate (a) the diagnostic performance of D-dimer assay for pulmonary embolism (PE) in an oncologic population by using computed tomographic (CT) pulmonary angiography as the reference standard, (b) the association between PE location and assay sensitivity, and (c) the association between assay results and clinical factors that raise suspicion of PE. MATERIALS AND METHODS: This HIPAA-compliant study had institutional review board approval; informed consent was obtained. Five hundred thirty-one consecutive patients were clinically suspected of having PE; 201 were enrolled (72 men, 129 women; median age, 61 years) and underwent CT pulmonary angiography and D-dimer assay. Relevant clinical history, symptoms, and signs were recorded. CT images were interpreted, and the location of emboli was recorded. The negative predictive value (NPV), positive predictive value (PPV), sensitivity, specificity, and diagnostic likelihood ratios of the D-dimer assay results were calculated. RESULTS: Forty-three patients (21%) had pulmonary emboli at CT. D-Dimer results were positive in 171 patents (85%). The NPV and sensitivity were 97% and 98%, respectively. The specificity and PPV were 18% and 25%, respectively. No association was shown between clinical history, symptoms, or signs and NPV, PPV, sensitivity, or specificity or between location of PE and sensitivity.
    CONCLUSION: D-Dimer results have high NPV and sensitivity for PE in oncologic patients and, if negative, can be used to exclude PE in this population. Combining the assay with clinical symptoms and signs did not substantially change NPV, PPV, sensitivity, or specificity.

    Whether this is ready from prime time or not remains to be determined, but it is interesting that we might be able to do this in the future to r/o PE in cancer patients.
     

    Show References


    Category: Cardiology

    Title: Myopericarditis

    Keywords: myocarditis, pericarditis, myopericarditis (PubMed Search)

    Posted: 7/7/2008 by Amal Mattu, MD (Updated: 12/7/2019)
    Click here to contact Amal Mattu, MD

    Both acute pericarditis and myopericarditis are intensely inflammatory. As a result, CRP testing is extremely sensitive for these conditions and is excellent for evaluating their presence or absence.

    Show References


    Category: Orthopedics

    Title: Joint Fluid Analysis

    Keywords: Arthrocentesis, Joint, Fluid, Septic (PubMed Search)

    Posted: 7/6/2008 by Michael Bond, MD (Updated: 12/7/2019)
    Click here to contact Michael Bond, MD

    Joint Fluid Analysis:

    This is hte session in Baltimore for crab eating and beer drinking so we begin to see an increase in Gout pain.  For those that are presenting with their first episode and you are concerned that they might have a septic joint, I am including this pearl to help analysis the fluid you will obtain from arthrocentesis.

     

    Synovial Fluid Interpretation
    Diagnosis Appearance WBC PMNs Glucose % of
    Blood Level
    Crystals
     Normal  Clear  <200  <25  95 - 100  None
     Degenerative
    Joint Disease
     Clear  <4000  <25  95 - 100  None
     Traumatic
    Arthritis
     Straw colored  <4000  <25  95 - 100  None
     Acute Gout  Turbid  2000 - 50,000  >75  80 - 100  Negative birefringence
     PseudoGout  Turbid 2000 - 50,000  >75  80 - 100  Positive birefringence  
     Septic Arthritis  Purulent / turbid  5000 - > 50,000  >75  < 50  None
     Rheumatoid
    Arthritis
     Turbid  2000 - 50,000  50-75  ~75  None

     To view a gout crystal click this link.

    To view a pseudogout crystal. Click this link

    Pearls: 

    • A WBC Count >50,000 is septic arthritis until cultures are negative. 
    • Due to the wide range of WBC for septic arthritis have a high index of suspicion and do not discount the diagnosis because the WBC count is only 10,000.

    Show References