UMEM Educational Pearls

When you draw a urine toxicology screen it can mislead more often than help you. Here is a quick list of the test followed by some medications that cause false positives - when in doubt, call your lab to find out specifics since results will vary lab to lab:

TCA - diphenhydramine, carbamazepine, cyclobenzaprine (side note: TCA screen should never be used to determine TCA toxicity, your ECG and physical exam should be enough to determine if the patient is toxic from TCA

Cocaine - the most accurate test on the screen, positive for up to 5 days

PCP - dextromethorphan and ketamine can turn it positive

Amphetamines - pseudoephedrine, ephedrine, phenylephrine and many other OTC cough decongestants can as well, the worst screening test with the largest number of false positives

• The majority of epilepsies (60%) are partial-onset or focal, such that a single, isolated part of the body is affected.
• Seizures arising from the temporal lobe of the brain are the most common type of partial-onset epilepsy and have been associated with childhood febrile seizures.
• Simple temporal lobe seizures, which do not result in a loss of consciousness, typically present as a sensation such as: 

              -- Deja' vu (feeling of familiarity)     -- Jamais vu (feeling of unfamiliarity)

              -- Specific or single set of memories     --  Amnesia

             -- Auditory        --  Gustatory       --  Visual       --  Disphoric     -- Euphoric 

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Warfarin and ICH

• Warfarin causes approximately 10-15% of all intracerebral hemorrhages (ICH)
• Many warfarin-related ICHs occur with INRs in the therapeutic range
• Patients with warfarin-related ICH have higher mortality and typically suffer worse neurologic outcome
• The primary pitfall in treating patients with warfarin-related ICH is the failure to rapidly normalize the INR
• Do not delay treatment while awaiting the results of coagulation labs
• Patients should receive IV vitamin K via slow infusion and FFP
• Prothrombin Complex Concentrate (PCC) is gaining popularity but much of the supporting literature uses agents not available in the US
• Similarly, there is no significant evidence that recombinant factor VIIa improves outcomes in patients with warfarin-related ICH

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A recent study of nearly 800 patients with chest pain evaluated symptoms and signs that are most predictive of ruling in for ACS. The following characteristics made acute MI more likely (likelihood ratios in parentheses): observed diaphoresis (5.18), central location of chest pain (3.29), associated vomiting (3.50), radiation of the pain to bilateral arms (2.69), and radiation of pain to the right arm (2.23).

As we've said before, if your patient sweats, it ought to make YOU sweat!

[BodyR, et al. Resuscitation 2010;81:281-286.]

Knee Dislocation:

• It is not uncommon for a patient to have dislocated their knee and it to spontanously reduce prior to presenting to the ED. 
• Consider the possibility of a spontaneously reduced knee dislocation in any patient with bicruciate (ACL and PCL) ligament instability.  
• Normal pulses and capillary refill does not exclude occult vascular injury to the popiteal artery.
• At a minimum the patient should have Ankle Brachial Indexs performed and if <0.9 serial exams and Doppler ultrasound studies should be obtained.
• Angiography is not absolutely required, and several studies have shown that a selective approach to angiography is acceptable.  As the studies below showed, most patients with findings requiring operative repair on angiography had abnormal physical exams.

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According to the Food Allergy and Anaphylaxis Network, the eight most common food allergies, which account for 90% of the food allergies in the U.S., are: dairy, soy, wheat, shellfish, fish, peanut, tree nut, and egg.

Several medications are formulated with these ingredients and should be avoided in patients with reported allergies.

• Propofol is a lipid emulsion that contains egg.  Avoid in patient with hypersensitivity to eggs, egg products, soybeans, or soy products.
• Ipratropium ± albuterol (Atrovent, Combvient®) inhalers may contain soy lecithin.  This can cause allergic reactions in patients with allergy to soy lecithin or related food products (e.g., soybean and peanut).  Nebulizer solutions (e.g., Duoneb®) seem to be free from this issue.
• Progesterone (Prometrium®) capsules contain peanut oil.

•  Focal seizures, such as those due to frontal lobe epilepsy (FLE), are not always easy to recognize and may be erroneously attributed to peripheral or psychiatric sources.
• FLE seizures may present as abnormal body posturing, sensorimotor tics, and/or other abnormal motor skills, and rarely may be associated with uncontrollable laughing and/or crying.
• Post-seizure confusion >may occur, but typically does not last as long as the post-ictal states associated with other types of epilepsy.

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Primary Intracranial hemorrhage is associated with the following risk factors:

• hypertension, smoking, alcohol, hypocholesterolemia, genetic factors, warfarin, phenylpropylamine, cocaine and methamphetamine. 

Common causes of secondary ICH are as follows:

• vascular malformations, arteriovenous malformations, cavernous angiomas, small arterial telangiectasia, and primary and secondary brain tumors.

The question of how to address elevated blood pressure in spontaneous intracranial hemorrhage has been debated.  High blood pressure may cause hematoma expansion, but this has not been proven.  Lowering blood pressure may help reduce neurologic deterioration, but this has also not been proven in the literature. 

The AHA recommended guidelines for blood pressure management in spontaneous ICH are as follows:

If SBP>200 or MAP>150, consider aggressive reduction of BP with continuous IV infusion, monitoring BP every 5 minutes

If SBP>180 or MAP>130, with evidence or suspicion of elevated ICP, consider monitoring ICP and reducing BP using intermittent or continuous IV medications to keep CPP>60 to 80

If SBP>180 or MAP>130 without evidence or suspicion of elevated ICP, then consider a modest reduction of BP (MAP of 110 or targeted SBP 160/90) using intermittent or continuous IV medications, monitoring BP every 15 minutes

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Splenic Artery Aneurysm (SAA)

Ever scanned someone and the report says "incidental note of a splenic artery aneurysm"? Well, if it hasn't happened yet, it will sooner or later. This type of aneurysm isn't that rare and with the number of abdominal CTs we order we are bound to see this in clinical practice.

Some important points to remember about SAA:

• 3rd most common location of intra-abdominal aneurysm, 1st-aortic aneurysm, 2nd-iliac artery aneurysm
• Most common complication is sudden rupture and occurs in as many as 3-10% of cases
• 80% pf patients with SAA are asymptomatic
• Symptomatic aneurysms may present with left upper quadrant pain, nausea, and vomiting
• Splenic infarct is a rare complication
• Most important is followup: patients will need close followup for asymptomatic splenic artery aneurysms. Consultation with a surgeon will need to be arranged if it is thought that the patient has symptoms due to the aneurysm

Major and minor clinical prognostic predictors for pericarditis have been described as follows:

Major: fever > 38 degrees C, subacute onset, large effusion, tamponade, lack of response to aspirin or NSAIDs after at least 1 week of therapy

Minor: myopericarditis, immunodepression, trauma, oral anticoagulant therapy

Patients with any of these criteria [major or minor] should strongly be considered for admission. In the absence of these factors, studies show that patients managed as outpatients do well.

[Imazio M, Spodick DH, Brucato A, et al. Controversial issues in the management of pericardial diseases. Circulation 2010;121:916-928.]


 

Pelligrini-Stieda Lesion:

A Pelligrini-Stieda lesion is shown in the radiograph below.  This lesion was originally described in 1905, and is associated with a tear of the Medial Collateral Ligament.  Heterotrophic calcification forms causing chronic pain, which typically needs to be surgically excised.

So for the students out there, it is possible to diagnosis an MCL tear on plain radiographs.  Just not very often.

• Frontal Lobe Epilepsy (FLE) is characterized by recurrent, brief, focal seizures arising from the frontal lobe of the brain, often occuring during sleep.
• FLE is the second most common form of epilepsy, behind Temporal Lobe Epilepsy (TLE).
• FLE presents in 2 forms:  (1) simple partial (focal) seizures (no affect on awareness or memory), or (2) complex partial (focal) seizures (affects awareness and memory before, during, and/or after the seizure).
• FLE seizures are often misdiagnosed as psychiatric disorders, non-epileptic convulsions, or sleep disorders, due to the unusual symptoms that they often produce.

Ventilating the Patient with Traumatic Brain Injury

• Many patients with acute TBI will require intubation and mechanical ventilation for a variety of reasons.
• Ventilating the patient with TBI becomes a balancing act between maintaining adequate cerebral perfusion and minimizing lung injury.
• Some pearls to consider:
  • Avoid hypoxia: although guidelines recommend a P_aO₂ > 60 mm Hg, most suggest a higher P_aO₂ (> 80 mm Hg) be initially targeted.
  • Avoid hypercapnia:  many patients will develop hypercapnia when ventilated using the low tidal volume strategy (6 ml/kg) of the ARDSnet trial; titrate TVs to maintain a P_aCO₂ between 32-35 mm Hg.
  • PEEP: the application of PEEP remains controversial in patients with TBI given the theoretical risk of increasing ICP through reductions in venous return; if PEEP is applied pay close attention to the cerebral perfusion pressure to ensure it remains > 60 mm Hg.

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• a collection of blood UNDER the periosteum of the outer surface of the skull
• occurs in 2.5% of live births
• most commonly occurs ove the parietal bones
• because the blood is below the periosteum, it will NOT cross suture lines
• usually enlarge during the first few days of life, then slowly resolve over weeks or months
• significant bleeding is a risk
• when the blood resorbs, it can aggravate neonatal jaundice
• aspiration and xrays are not routinely indicated

The Segond Fracture:

An benign appearing avulsion fracture of the lateral tibeal plateau that is marker for more significant injuries such as:

1. Anterior Cruciate Ligament (ACL) tear associated with this fracture 75-100% of the time
2. Injury to the Medial Meniscus occurs with a Segond fracture 66-75% of the time.

If this avulsion fracture is seen consider immobilzing the patients knee until they can follow up with Orthopedics and/or get an MRI to determine if additional injuries are present.

Precedex (Dexmedetomidine) - Great for pediatric imaging procedures

Alpha-2 agonist with sedative properties

No analgesic effect alone, but shown to decrease the amount of opioids required for a painful procedure

Benefits pts go to sleep and awake in a more natural state.  Caregivers tend to prefer this as opposed to other sedatives.  Short recovery time- about 30 minutes

Adverse effects include bradycardia and hypotension.  Not recommended in any child with cardiac abnormalities.  Paradoxical hypertension with loading dose has also been observed

Effective for MRI or CT scans at loading doses of 2mcg/kg over ten minutes, then maintenance of 1mcg/kg/hr

Residents can gain experience with Precedex with Peds sedation on M,W,F mornings with sedation team, contact me to arrange a time for you to participate.

• The 7-day risk of completed ischemic stroke after TIA is 5%.
• The use of reliable stroke prediction tools are potentially invaluable in guiding the degree of urgency that one applies to the management of TIA patients.
• Accuracy of the ABCD² Score, considered to be the most-refined tool of its kind, was recently again evaluated.
• This 7-point scale assigns risk based on 5 factors: Age > 60 (1 pt.), BP > = 140/90 (1 pt), Clinical features - weakness (2 pts), speech impairment w/o weakness (1 pt); Duration  >=60 min (2 pts), 59 to 10 min (1 pt); Diabetes (1 pt).
• The study found that the discriminatory power of the ABCD² Score may best be applied when used in patients at low risk for an early, disabling ischemic stroke.     

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The question of hyperglycemia in the critically ill and how to address it has been the topic of considerable study over the years.

There have been several attempts to try to quantify the best target glucose levels in critically ill patients.  This is still a moving target, but a recent study sheds some light on the effect of different levels of hyperglycemia and the types of patients who are particularly vulnerable.

This is a retrospective cohort study whic reviewed 259,000 ICU admissions over a three year period at 173 separate sites.  Their findings were as follows:

Compared with normoglycemic patients, the adjusted odds for mean glucose 111-145, 146-199, 200-300, and >300 was 1.31, 1.82, 2.13 and 2.85 respectively.

There is a clear association between the adjusted odds of mortality related to hyperglycemia in patients with AMI, arrhythmia, unstable angina, pulmonary embolism, pneumonia and gastrointestinal bleed.

Hyperglycemia associated with increased mortality was independent of type of ICU, length of stay and/or pre-existing diabetes.

So, even though we have not come to solid conclusions about how far down to keep the glucose levels down, it makes sense to pay particular attention and be more vigilant of the blood glucose levels, especially in the higher-risk patients  listed above. 

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Suspect your patient has an aortic dissection? Don't wait to lower the blood pressure.

A few considerations for the patient with suspected aortic dissection:

• If the patient is hypertensive AND you really think they could have the disease, start the drip then. Don't wait until the CT is done. Every second that goes by with extremely elevated BP may increase the dissection length.
• If you are really worried about a patient having a proximal aortic dissection, don't wait for the creatinine to come back...scan them without it. If you are really suspicious this is justified in many cases.
• There is very little (to no) role in performing a dry CT (because the patient's creatinine comes back elevated). Dry CT is very insensitive. Instead get a transesophageal echo or an MRI.