UMEM Educational Pearls

Meralgia Paresthetica - caused by entrapment of the lateral femoral cutaneous nerve (LFCN)

The LFCN is responsible for sensation of the anteriorlateral thigh.

http://www.chiropractic-help.com/images/Meralgia-Paresthetica.jpg

NOTE*  It has no motor component!

Associated with pregnancy, wearing tight pants, belts, girdles, and in diabetic and obese patients.

Symptoms include numbness, paresthesias and pain (not weakness). Worse w walking, standing. Better w sitting.

Diagnosis is clinical but may be confirmed with nerve conduction studies

Treatment includes, NSAIDs, injection and surgery for refractory cases.

"Ear to sternal notch" positioning has gained wide acceptance in the emergency medicine and anesthesia literature.  Most often, this teaching is brought up with respect to obese adult patients whose large body habitus requires the raising of the neck and head to achieve airway alignment.

However, the correct anatomic positioning principle applies to all ages.  Specifically, with regard to neonates, a shoulder roll is often placed indiscriminately to put the patient into the now out-dated "sniffing position," usually worsening the view of the airway.  

Though this positioning is frequently misused, it can be easily adapted to apply ear to sternal notch positioning to neonates, whose misaligned airway is the result of a large occiput rather than a large torso.  In all ages, if you follow these positioning principles, you will improve your view of the airway:

1. Align the ear to the sternal notch

2. Keep the face parallel to the ceiling (do NOT hyperextend the neck, as in the sniffing position)

3. In adults, the head usually needs to be raised (Image 1), while in infants, the torso usually needs to be raised (image 3).

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Several patients have recently presented with a medication history including tapentadol (Nucynta), the newest opioid formulation.  It is approved for treatment of acute moderate-severe pain.  Here are some key points:

• Mechanism similar to tramadol: mu-receptor agonist, also inhibits norepinephrine reuptake
• Potency stronger than tramadol, but less then morphine
• Usual dose is same as tramadol 50-100 mg every 4-6 hours prn pain
• Schedule II controlled substance, similar to morphine/oxycodone (tramadol is not a controlled substance)
• Overdose should present like other opioids, but potentially also including tachycardia, serotonergic effects, and seizures (similar to tramadol)

Causes of Pulsatile Tinniitus 

• Pulsatile tinnitus, also known as objective tinnitus, results from altered blood flow or increased blood turbulence near the ear.  People other than the person experiencing the tinnitus are often able to hear this rhythmic, pulse-patterned noise.  
• While there are several benign causes of pulsatile tiniitus such as strenuous exercise, atherosclerosis, and ruptured tympanic membranes, there are only a few serious etiologies.
• It is important that the astute emergency provider be aware of and know the appropriate treatment for the following life-threatening and/or high morbidity-associated causes of pulsatile tinnitus:

1. Idiopathic intracranial hypertension (previously known as pseudotumor cerebri)
2. Carotid artery aneurysm
3. Carotid artery dissection
4. Vasculitis such as giant cell arteritis  

Although oral metronidazole is indicated for mild to moderate Clostridium difficile associated diarrhea, oral vancomycin should be considered first-line therapy in critically-ill patients with moderate to severe disease. Vancomycin dosing should begin at 125mg PO q6 and increased to 250mg q6 if poor enteral absorption exists. Consider adding metronidazole IV if either reduced enteral absorption or severe disease exists. 

Recently, fidaxomicin has been shown to be non-inferior to oral vancomycin in the treatment of mild to moderate C. difficile. While promising, the study population was not critically-ill and extrapolation should be avoided.

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Question

70 yo female from nursing home with fever. RUQ ultrasound is shown below. Diagnosis?

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Beck's triad is well known to many physicians, but here's some simple things you may not have known.

Beck actually described two triads, one for acute and one for chronic tamponade.
The triad for chronic tamponade consists of increased CVP (JVD), ascites, and a small quiet heart (muffled heart sounds).
The triad for acute tamponade consists of JVD hypotension, and muffled heart sounds.

Almost 90% of patients have at least 1 of the signs, but only one-third have all 3. Furthermore, it appears that the simultaneous occurrence of all 3 signs is a very late manifestation of tamponade, usually preceding cardiac arrest.
 

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Tendon Lacerations:

• Flexor tendon lacerations have historically not been repaired by emergency providers due to the extensive pulley systems involved and possibility of loss of mobility from scarring.
  • However, if both ends of the tendon can be visualized in the ED it is not unreasonable to place 1 or 2 horizontal mattress sutures between the two ends to prevent retraction of the proximal portion which can make a formal repair more difficult.
• Extensor tendon lacerations can be repaired by emergency providers.
  • One technique is to use a running horizontal mattress suture with non-absorbable nylon sutures. 
  • The ultimate strength of the repair is dependent on the number and size of the sutures placed.
  • Careful placement of the sutures can prevent gap formation between the ends when the tendon is stressed.

A reasonable approach to all tendon lacerations is to close the wound and splint in the hand in the position of function until the patient can be seen by a hand surgeon in the next 1-3 days.  These injuries do not require immediate surgical repair.

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Continuing the theme of endotracheal tube size pearls...  You get a box call for a pre-term baby delivered precipitously by mom at home and baby is blue.  EMS is bagging but unable to secure a definitive airway.  What size ETT do you reach for?  If you try to apply the formula "uncuffed ETT = (age/4) + 4", how much smaller than size 4 can you go?

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IV acetaminophen has been approved for use since November 2010

It is indicated for the:

• Treatment of mild to moderate pain
• Combination therapy with opioids for treatment of moderate to severe pain
• Fever reduction

The results of studies demonstrating opoid sparing effects have been mixed; some studies have not demonstrated either a reduction in opioid dose or opioid side effects.

The dose is the same for acetaminophen administered by other routes.

It must be administered over 15 minutes, and onset of activity is 15 minutes. Peak effect occurs at one hour.

The MAJOR drawback is the cost, which is $13 dollars per vial. This is compared to oral acetaminophen and ibuprofen, which are pennies.

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Lithium Toxicity

• Lithium toxicity is common and occurs in 75 to 90% of patients receiving long-term lithium therapy at some point during their management.  It most often results from inadequate renal excretion.
• Toxic patients typically present with mild side effects such as hand tremor, but other symptoms like weakness, delirium, rigidity, hyperreflexia, altered gait, seizure, and EEG changes may also result.
• While severe lithium toxicity typically correlates with elevated serum levels, not all patients with high lithium levels present with advanced symptoms, at least in the early stages; this is due to delayed distribution within tissues.  Similarly, patients with lower serum levels of lithium may present with advanced symptoms, if the drug has accumulated in the cerebrospinal fluid to a greater extent than it has the serum. 

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Gastrointestinal Changes of Obesity that Complicate Critical Illness

• Obesity predisposes patients to several gastrointestinal abnormalities that can cause, or complicate, critical illness.
• Important abnormalities to keep in mind when managing a critically ill obese patient include:
  • Increased intra-abdominal pressure which predisposes to abdominal compartment syndrome
  • Increased incidence of nonalcoholic fatty liver disease which may lead to prolonged drug metabolism
  • Increased incidence of cholelithiasis which may result in pancreatitis or cholangitis

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I found this neat little pearl on Michelle Lin's blog, Academic Life in Emergency Medicine, and thought it was worth sharing with everyone:

"In my theme of detoxifying malodorous smells in the ED (see Toxic Sock Syndrome and abscess drainage), I recently learned of a new way of masking odors. Imagine the stress on your olfactory nerves from the combined effects of urinary and fecal incontinence from a nursing home patient.

An ingenious nurse proposed nebulizing actual coffee within the room. Unfortunately, our ED was out of coffee at the moment.

Trick of the Trade:
Nebulized orange juice

I only learned of this trick after walking into the patient's very subtly foggy room. About 4 cc of orange juice had been nebulizing for a few minutes. The room smelled a little like a Jamba Juice (a smoothies/ juice shop). Quite pleasant actually. I was shocked to find that it masked the odors quite well."

Thanks for the tip, Michelle. Freshly-squeezed anyone??

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Cocaine-associated MI occurs fairly early after acute cocaine use. 50% of MIs occur in patients prior to their arrival in the ED, and 24% of the total will occur within the first hour of cocaine use. If a patient has not ruled in by 12 hours post-arrival in the ED, it is extremely unlikely that the patient will rule in or suffer ACS-related complications from the cocaine....thus the concept behind using rapid rule out protocols in these patients.

The most important thing we as physicians can do for these patients is to strongly emphasize discontinuation of cocaine use and refer to rehab whenever possible. If the patient discontinues using cocaine, the prognosis for absence of subsequent cardiac events is excellent.

[thanks to Dr. Ellen Lemkin for her contribution to this pearl}

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Tendon Lacerations:

Hand lacerations need to be carefully explored in order to determine whether there is an associated tendon laceration.  These can be be difficult to find unless a systematic approach is followed:

• The laceration should be explored to its base in a bloodless field while the fingers and wrist are moved through their full range of motion (ROM).  A tendon laceration can easily be missed if the hand is only visualized with the fingers extended. The area of the tendon that was lacerated can retract into the hand, or not be visible if the area was injured when the fingers were flexed. By extending the finger, the location of the injury may not line up with the wound making it impossible to see unless the fingers are moved through their full ROM.
• The fingers and wrist ROM should be tested actively and against resistance as the patient may only experience an increase in pain and have a completely normal ROM if there is only a partial tendon laceration.
• If there is a suspicion of a tendon laceration (decreased ROM, or increased pain with resistance when ROM is tested) the laceration may need to be extended in order to completely visualize the tendon if it can not be done through the wound that was created with the original injury.

Future pearls will cover techniques on how to repair tendon lacerations.  Stay tuned.

You decided to intubate a child and wisely remembered that you should also follow with an NG/ OG after intubation to decompress the stomach.  In order to avoid the blank stare when asked "what size"?  Here's a nice mneumonic about Pediatric "tube" sizes... easy as 1-2-3-4!!!  Please note ETT = endotracheal tube size.

• 1 x ETT = (age/4) + 4 (formula for uncuffed tubes)
• 2 x ETT = NG/ OG/ foley size
• 3 x ETT = depth of ETT insertion
• 4 x ETT = chest tube size (max, e.g. hemothorax)

So for example, a 4-year-old child would get intubated with a 5-0 ETT inserted to depth of 15 cm (3x ETT), a 10Fr NG/OG/foley (2x ETT), and a 20Fr chest tube (4x ETT).

Also, remember that you can use cuffed tubes in any child except neonates but the formula needs to be adjusted as follows: cuffed endotracheal tube ID (mm) = (age/4) + 3.5

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Treating a patient with clinical hypoglycemia (neuroglycopenia if you want to sound cool) is with "1 amp of D50". Then some are starting D5 drips and D10 drips. Here is the actual breakdown of what you are giving:

1 amp of D50 = 50% dextrose = 50g/100mL = 25g x 4Kcal/g carbs = 100 calories bolus

1 L D5W at 100mL/hr = 5% Dextrose = 5g/100mL x 1L = 50g x (4Kcal/g) = 200 cal infusion of 20 cal/hr!

1 L D10W at 100mL/hr = 10%D= 10g/100mLx1L= 100g x (4Kcal/g)= 400 cal at infusion of 40 cal/hr!

Snickers Bar = 271 calories in one serving - most people will eat in 5 minutes =  54.2cal/min

Take home message is feed your patient once they are awake and alert. Much more effective.

Contraindications to performing lumbar puncture (LP):

- INR > 1.4 or other coagulopathy

- Platelets < 50

- Infection at desired puncture site

- Obstructive / non-communicating hydrocephalus

- Intracranial mass

- High intracranial pressure (ICP) / papilledema (relative contraindication depending on etiology; especially a concern with intracranial mass lesion secondary to the increased risk of transtentorial or cerebellar herniation)

- Focal neurological symptoms/signs, decreased level of consciousness

- Partial / complete spinal block

- Acute spinal trauma

A mortality benefit from combination antimicrobial therapy has not been clearly demonstrated in sepsis. However, when only the most severely-ill patients (i.e., septic shock) are considered in subgroup analysis, there appears to be a mortality benefit to using two antimicrobials against a suspected organism.

Combination antimicrobial therapy may reduce mortality through three mechanisms.

1. Increased probability that the causative organism will respond to at least one drug. 
2. Preventing emergence of antimicrobial resistance.
3. Two antimicrobials may act synergistically.

Always obtain appropriate cultures before initiating therapy. Although identification and susceptibility of the organism may take some time, eventually narrowing antimicrobial therapy to monotherapy in the ICU is still recommended. 

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Question

Patient presents with the following X ray after yawning. Diagnosis?

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