UMEM Educational Pearls

Does this Patient with Diabetes have Osteomyelitis?

• Diagnosis of lower extremity osteomyelitis in the diabetic patient remains challenging
• Bone biopsy with culture remains the gold standard for diagnosis but is not always obtainable
• What clinical features, therefore, raise the likelihood of osteomyelitis?
• In this review, an ulcer size > 2 cm² (LR 7.2), ability to probe to bone using a sterile stainless steel probe (LR 6.4), and an ESR > 70 mm/h were found to be useful in predicting the presence of osteomyelitis
• Clinical features NOT found to be useful included fever (sensitivity 19%), presence of erythema, swelling, or purulence (LR 1), elevated white blood cell count (sensitvity 14%-54%), and superficial swab culture
• A note about radiographic studies:
  • bony changes on plain films may take up to 2 weeks to develop
  • plain films alone are only marginally useful if positive (LR 2.3)
  • MRI is more accurate than bone scan or plain films
  • If you are going to order a radiographic study, your best bet is the MRI

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Does a normal d-dimer rule out aortic dissection?

A lot of research seems to be focused on using d-dimer as a rule-out strategy for acute aortic dissection. The idea is that a d-dimer <500 (which is what we use for ruling out PE in low-mod risk patients) rules out dissection as well.

A few pearls and pitfalls regarding this:

• Studies look very promising, but NO accepted cutoff point (d-dimer) has been defined
• This practice has NOT been widely accepted yet
• A d-dimer <100 ng/dL rules out aortic dissection with a sensitivity of 100%
• A d-dimer of <500 ng/dL rules out aortic dissection with a sensitivity of 98%
• Experts in this area seem to be advocating this as a potential rule out strategy
• Critics of this approach point out the fact that a subset of patients with dissection (those with intramural hematomas-i.e. no intimal tear) may not release d-dimer into the circulation. But almost all studies include patients with this variant and their d-dimers are almost always elevated.

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 Pregnancy and Acute Pulmonary Embolism

Women who are pregnant or in the postpartum period and women who take hormonal therapy are at an increased risk of pulmonary embolism.

Some facts:

• Risk of first episode of venous thromboembolism is 15 times as high in the postpartum period as during pregnancy
• Diagnostic workup and initial ED therapy is the same as it is for non-pregnant patients
• Although there are still some concerns about pulmonary CTA, both the American College of Obstetrics & Gynecology and the American College of Radiology agree that it is safe. It is unknown what happens to fetal nephrons after exposure to circulating contrast in the mother. Despite this, CTA can be used without fear if indicated. 
• Warfarin is a teratogen and should not be used for anticoagulation.

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Low QRS voltage on the ECG has various definitions; here's my simple definition for low voltage...either one of the following:
     If the added QRS amplitudes (whole R wave + S wave) in leads I + II + III total < 15 mm, OR
     If the added QRS amplitudes (whole R wave + S wave) in leads V1 + V2 + V3 total < 30 mm.

The potential causes of  low QRS voltage includes pericardial effusions, pleural effusions, obesity, COPD, infiltrative cardiac diseases (e.g. sarcoid, amyloid), end-stage cardiomyopathies, severe hypothyroidism.

If the patient has NEW low voltage compared to an old ECG, the only real possibilities are pericardial effusion, pleural effusion, and severe hypothyroidism (e.g. myxedema).

Calcaneus Fractures

Normally occur due to axial loading mechanism such as:

•     Fall from height
•     Motor Vehicle collisions
•     Repetitive impacts on a hard surface such as seen with running or jumping.

Miscellanous Facts:

1. 70% of calcaneal fractures are intra-articular
2. 10-15% are associated with spinal compression fractures
3. Estimated that 7-10% will have a fracture of the contralateral foot
4. Monitor for compartment syndrome of the foot.  Deep central compartment is most commonly affected with calcaneus fractures

Pearls:

1. Strongly consider getting Lumbar Spine Films and x-rays of the opposite foot in anybody that has a calcaneus fracture.
2. Perform frequent reassessments, and do not hesitate to check compartment pressures if you suspect they might be elevated.

Pertussis means "violent cough". 

Think of it with prolonged coughing, inspiratory whoop, absolute lymphocytosis, or chronic cough.

Don't Use cough suppressants.

Pertussis can be a life threatening Infection!!  Especially in infants and young children.

Pertussis is a reportable infectious disease in the United States.

•  Dapsone has been used to treat leprosy but more commonly to in brown recluse spider bites and to prevent PCP pneumonia and toxoplasmosis in our HIV population
• It can cause methemoglobinemia: a reduced form of iron (ferrous to ferric) in the Hb molecule that decreases your oxygen carrying capacity. 
• Due to its color, cyanosis is a predominant symptom out of proportion to symptoms.
• Treatment: Methylene Blue 1-2 mg/kg IV
• Pitfall: Dapsone's long half-life may cause reoccurrence of MetHb and require retreatment

• Poor differentiation of the type and cause of confusion in the elderly is associated with poor outcomes (i.e. increased mortality/morbidity, prolonged hospital stays, and functional decline).

• Confusion in the elderly can be categorized into three types with the following typical features:

1. Delirium - caused by organic illness, acute onset, agitated or drowsy, variable short-term memory, disorganized thoughts, hallucinations.
2. Dementia - chronic confusion due to long-term neurologic illness like Alzheimer's disease, progressive, irreversible, short-term memory loss, simple task performance and language impairment, aggression, personality changes.
3. Acute or Chronic Confusion - treatable illness (i.e. infection) triggers delirium in patient with baseline dementia.

Patients with cancer that present with pleuritic chest pain often have pulmonary emboli, but don't forget about pericarditis. Lung and breast cancer, especially, are known to metastasize to the pericardium and produce pericarditis or pericardial effusions. Anticoagulation for presumed PE in patients with pericardial mets. can produce hemorrhagic tamponade, a disastrous iatrogenic complication, so think twice before starting empiric anticoagulation on patients...make sure your patient doesn't have pericarditis or an pericardial effusion.

The ECG in patients with cancer-related pericarditis or pericardial effusion does not always demonstrate the classic ST elevation wtih PR depression (which is most commonly seen in viral pericarditis). Patients with pericardial effusions often demonstrate low voltage and tachycardia. Electrical alternans, though "classic," only appears in 1/3 of patients with pericardial effusions.

Hip Fractures:

Typically divided into four types:

1. Intracapsular,
   1. femoral head and neck fractures
2. Extracapsular
   1.  trochanteric,
   2. Intertrochanteric
   3. subtrochanteric fractures. 

• Non-displaced fractures, especially in osteoporotic elderly patients, may be missed on plain films. This is estimated to occur in 2-9% of cases. 
• It can take up to 72 hours for a fracture to be seen on bone scan. And it is estimated that only 80% of fractures will be seen at 24 hours.
• MRI is now the preferred imaging modality (100% sensitivity and specificity) to confirm a hip fracture when plain films are negative and equivocal. A MRI will have positive findings in as little as 4 hours after a fracture.
• Consider CT scan of the hip if MRI is not available at your center.

Here is a link to a picture with a good representation of the different types of fractures.

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Here is a short list of medications that will actually prevent a patient from being anticoagulated by coumadin. These medications will make it difficult for the patient to reach therapeutic levels and need to be warned about this drug-drug interaction with coumadin:

• Antacids
• Antihistamines
• Barbituates
• Carbamazepine
• Cholestyramine
• Corticosteroids
• Griseofulvin
• OCPs
• Phenytoin
• Rifampin
• Vitamin K

Reference: Goldfrank's Textbook of Toxicologic Emergencies, 6th Edition

• The ABCD and ABCD² scores are validated scales based on both prospective and retrospective data to assess patients' risk of stroke at 7 and 2 days after a TIA, respectively.  The biggest difference between the two is that the ABCD² Scale includes diabetes as a factor.

• ABCD Scale
• Age:  at least 60 = 1 point
• BP:  SBP > 140 and/or DBP > 90 = 1 point
• Clinical features:  unilateral weakness = 2 points; speech disturbance w/o weakness = 1 point;  any other neurologic  finding = 0 points.
• Duration:  at least 60 min. = 2 points; 10-59 min. = 1 point; < 10 min. = 0 points. 
• Score:  4 points = 1.1% risk;  5 points = 12.1% risk;  6 points = 31.4% risk.

• ABCD² Scale
• Age:  same as ABCD Scale
• BP:  same as ABCD Scale
• Clinical features:  same as ABCD Scale except "any other neurologic finding = 0 points" component is omitted.
• Duration:  same as ABCD Scale except  "< 10 min. = 0 points" component is omitted.
• Diabetes:  1 point
• Score:  4-5 points = 4% risk;  6-7 points = 8% risk;  0-3 points = 1% risk.

• Question = When considering sending a patient home prior to a thorough and appropriate TIA/stroke work-up, how low of a percent risk is acceptable?

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Passive Leg Raising (PLR)

• We have discussed that static measures of volume (CVP, PA wedge pressures) are not reliable markers of fluid responsiveness
• PLR has recently gained interest as a simple and transient way to assess fluid responsiveness in the critically ill
• Patients are placed in the horizontal position (not Trendelenburg) and the legs are raised to 45 degrees
• A hemodynamic response should be seen in 30 - 90 seconds
• Patients who have improvement in hemodynamics with PLR are said to be fluid responsive (i.e on the ascending portion of their Starling Curve) and require additional volume resuscitation

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 Thrombolytic Therapy for PE

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Just a reminder...an initially normal or non-specific ECG can certainly occur in patients that are actively having chest pain from acute MI. A 2001 study published in JAMA nicely pointed this out:

7.9% of patients having an acute MI had an initial normal ECG.
35.1% of patients having an acute MI had non-specific abnormalities on ECG.
57% of patients having an acute MI had diagnostic changes on ECG.

The greater the abnormality on the ECG, the worse the prognosis, but note that even when the ECG was normal, the in-hospital mortality in acute MI patients was 5.7%.

Although serial ECGs won't detect 100% of acute MIs, the diagnostic yield does certainly increase, and so whenever a patient has a concerning presentation, especially in the presence of on-going pain, make sure to get repeat ECGs!

[ref: Welch RD, et al, JAMA 2001]

Now that we have entered the session of cookouts, picnics, and family get togethers I thought I would review some of the more common causes of food poisoning and the typical foods that they are found in.

Remember to save childrens lives be aggressive with septic shock treatment early!

Do NOT allow long delays at IV attempts before moving to central lines or IOs.

        Goal in the first 0 to 15 minutes from presentation:

• Recognize decreased perfusion and mental status, maintain airway, and obtain access.
• Push 20 ml/kg of Isotonic bolus (up to and over 60 ml/kg) and reassess shock after each.*
• Correct Hypoglycemia and hypocalcemia if present. 

When community ED physicians successfully achieved shock reversal (defined by return of normal systolic blood pressure and capillary refill time) in the first 75 min from arrival there was an associated 96% survival and a > 9-fold increased odds of survival.  Each additional hour of persistent shock was associated with >2-fold increased odds of mortality.

*To push this amount of fluid in an infant or young child it may be easier to use 60 ml syringes for boluses rather than pumps

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Trandermal Delivery Systems

• Uses a gradient (high concentration drug in patch) and a matrix to facilitate transdermal absorption
• Patch often contains up to 100x the amount of drug that is on the label (ex: fentanyl 100mcg/hr actually = 10 MILLIGRAMS of fentanyl in patch)
• When prescribing the following will increase absorption: sweating, heat, swallowing the patch, trying to eat the gel in the patch
• Fentanyl and clonidine are the two most lethal patches on the market in regards to toxicity.
• Rarely needed in the ED, shouldn't be prescribed except in rare instances

• One large study showed that cerebrovascular diseases represented the most common etiology of secondary epilepsy.
• Animal studies have shown most antiepileptic drugs to be neuroprotectants.
• Animal studies have also shown, however, that phenytoin, benzodiazepines, and phenobarbital may impair post-stroke motor recovery.
• Carbamazepine (Tegretol) has not been found to demonstrate any significant hinderance of  post-stroke recovery.
• From an anicdotal clinical perspective, levetiracetam (Keppra) is often used to treat post-stroke seizure.

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Submitted on behalf of Dr. Winters:

Sepsis, Fluids, and ESRD
-ESRD patients are at increased risk of sepsis and bacteremia secondary to
indwelling devices
-Many of are hesitant to aggresively fluid resuscitate patients with ESRD
-Several studies have concluded that volume resuscitation should proceed the
same as patients without ESRD, even if that means more patients are eventually
intubated.

Reference:
Otero RM, et al. Chest 2006;130:1579-95.