UMEM Educational Pearls

Consider rhabdomyolyisis secondary to heat exposure as summertime approaches; have a low threshold to screen patients if they are at risk (e.g., people exercising in high-ambient temperatures).

Symptoms include muscle tenderness, cramping, and swelling with associated weakness. Patients with altered mental status (e.g., heat stroke) should be examined for limb induration, skin discoloration (i.e., ischemia), or compartment syndrome.

Complications:

• Electrolyte abnormalities (e.g., hyperkalemia and hypocalcemia) and malignant cardiac arrhythmias
• Metabolic acidosis
• Disseminated intravascular coagulation (release of tissue factor from muscle cells)
• Acute renal failure (myoglobin directly causes nephrotoxicity)

Treatment

• External cooling to cease the inciting process
• Aggressive fluid resuscitation with normal saline (avoid lactated ringers) for goal urine output of 200 to 300 ml/hour; foley catheters should be placed to monitor urine output.
• Start dialysis if potassium levels are elevated, acidosis, or oliguric renal failure. There is very limited evidence for the use of dialysis before the presence of these signs.
• There are no randomized controlled trials to support the use of mannitol (free radial scavenger and diuretic) or bicarbonate (to alkalinize the urine); their use is controversial.

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Naltrexone and methylnaltrexone are both mu-receptor antagonists that look similar and have similar names. But, they have very different uses.

• Naltrexone (ReVia, Vivitrol)
  • Used to treat opioid/alcohol dependence or to prevent relapse following opioid detoxifcation
  • Dose: 25 to 100 mg PO daily or 380 IM every 4 weeks
  • Crosses blood-brain-barrier and can precipitate withdrawal

• Methylnaltrexone (Relistor)
  • Used to treat opioid-induced constipation
  • Dose (weight-based): 8 to 12 mg (or 0.15 mg/kg) subcutaneously once daily
  • Peripherally acting, does not cross blood brain barrier

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Severe UGIB

• Differentiating between upper and lower GIB can be challenging. 
• A recent review evaluated the accuracy of historical features, symptoms, signs, and lab values in distinguishing between UGIB and LGIB. 
• Features with the highest likelihood for identifying UGIB included:
  • Melenic stool on exam (LR 25)
  • A prior history of UGIB (LR 6.2)
  • Serum urea:creatinine ratio > 30 (LR 7.5)
• Features that increased the likelihood of severe UGIB (defined as requiring blood transfusion, need for urgent endoscopy, surgery, or interventional radiology) included:
  • Heart rate > 100 bpm (LR 4.9)
  • Hemoglobin < 8 g/dL (LR 6.2)
  • History of cirrhosis or cancer (LR 3.7)
• For patients with an UGIB, the Blatchford Score can be used to determine the need for urgent intervention.  Those with a Blatchford Score of 0 have a low likelihood for severe UGIB and may not need emergent intervention.

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Ultrasound is useful during intubation; here is a video explaining how: http://ultrarounds.com/ultrarounds.com/Visual_Pearl_May_28,_2012.html

Today's Bonus Pearl:

EMRA has developed a great antibiotic guide for the iphone (http://itunes.apple.com/us/app/2011-emra-antibiotic-guide/id393020737?mt=8) or android (https://play.google.com/store/apps/developer?id=Emergency+Medicine+Residents'+Association). This app is a bit pricey ($15.99), but is easy to use and well organized. Enjoy!  

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[pearl provided by Dr. Semhar Tewelde]

Myocarditis is an under-diagnosed cardiac disease resulting from a broad range of infectious, immune, and toxic etiologies

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Hamate Fractures

Occur in two locations: the body of the hamate and the hook (hamular process) of the hamate

Fractures are present in 2 to 4% of carpal bone fractures

Body fractures are less common and are associated with dislocation of the fourth and fifth metacarpals

                Axial force transmitted down the metacarpal shaft (a fall or fist strike)

Hook fractures occur from a direct force from an object strikes the palm such as that from a bat, golf club or racket

Have increased suspicion in these athletes who present w/ ulnar sided wrist pain

Diagnosis is frequently missed;  chronic fractures are associated w/ flexor tendon rupture and ulnar neuropathy

PE:  Tenderness localized over the hamate (in the hypothenar eminence) and over the dorsal ulnar aspect of the wrist. Swelling may be present. Look for resisted flexion of the 5^th digit when the wrist is held in ulnar deviation. May note sensory changes in ulnar nerve distribution

Imaging: PA and lateral views of the wrist will show a body fracture but will frequently MISS a fracture of the hook of the hamate. In those with a clinical suspicion for this entity, order a “carpal tunnel view.”  In the proper clinical setting, CT imaging is excellent for those with high suspicion and normal plain films.

http://mulla.pri.ee/Kelley%27s%20Textbook%20of%20Rheumatology,%208th%20ed./HTML/f4-u1.0-B978-1-4160-3285-4..10044-0..gr2.jpg

Proper Feeding of the Newborn

The emergency physician must be comfortable with providing anticipatory guidance to parents of newborn, especially with regards to proper feeds of the neonate.

Newborns will lose some weight in the first 5-7 days of life. A 5% weight loss is considered normal for a formula fed newborn. A 7%-10% loss is considered normal for the breastfed baby. Most babies regain their birth weight by days10-14 of life. During the first 3 months, infants gain about an ounce a day (30 g) or 2 pounds a month (900 g).  By age 3-4 months, healthy term infants have doubled their birth weight.

Breast-fed Neonates:
- Should be fed every 2-3 hours while awake
- 5-20 minutes of sucking per breast
- May gain weight slower than formula-fed counterparts

Formula-fed Neonates:
- 0.5-1 ounces per feeding every 3-4 hours for the 1st week
- Then 1-3 ounces per feeding every 3-4 hours
- Typical formula contains 20 cal/ounce

In general, overfeeding during the neonatal period has been associated with adult obesity. The American Academy of Pediatrics recommends exclusive breastfeeding for at least the 1st 6 months of life. Earlier switches to formula has been associated with atopy, diabetes and obesity


References:
- Fleischer DM. “Introducing formula and solid foods to infants at risk for allergenic disease.” UptoDate;2012.
- Hammer LD, et al. “Development of feeding practices during the first 5 years of life.”  Nutrition;1999;189-194.
- Philips SM and Jensen C. “Dietary history and recommended dietary intake in children.” UptoDate;2011.
- Prior LJ and Armitage JA. “Neonatal overfeeding leads to developmental programming of adult obesity.” J Physiol;2009:2419.

Nitrous Oxide(N2O) is a common gas utilized to assist with procedural sedation especially in the pediatric population and dental offices. It has a long track history of safety but also has been abused.

N2O is 35x more solube in blood than N2. This means any air-filled space can have pressure increase thus complications like pneumothorax, TM rupture and bowel distention can occur.

When abused chronically can cause bone marrow suppression, B12 deficiency and resulting in polyneruopathy.

On the street, "whip its" are N2O from whipped cream containers. Balloons filled with N2O are inhaled which combine nitrous oxide and hypoxia effects.

Carcinoid tumors are neuroendocrine malignancies typically located in the GI tract; most commonly in the terminal ilium and appendix.

Carcinoid tumors produce serotonin, histamine, bradykinin, and/or prostaglandin that result in diarrhea, facial flushing, or bronchospasm. These vasoactive substances may also lead to hypotension and vasodilatory shock.

The tumor may also affect the tricuspid and pulmonary valves leading to right-heart failure secondary to valvular regurgitation, stenosis or both.

Treatment is directed at controlling the malignancy (e.g., octotrotide and tumor resection) as well as managing the right-sided heart failure when it occurs (e.g., inotropes, diuretics, vasopressors, etc.).

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There has been no link found between Sudden Infant Death Syndrome (SIDS) and an Acute Life Threatening Event (ALTE)

There are several factors that dispute previous claims of each being manifestations of the same disease state:

1)      Timing: approx 75-80% of  SIDS deaths occur between midnight and 6 AM; 80-85% of  ALTE occur between 8 AM and 8 PM 

2)      Prevention: Interventions to prevent SIDS (ex, “back to sleep”) have not resulted in a decreased incidence of ALTE

3)      Risk factors:

a.       SIDS: prone sleeping, bottle feeding, maternal smoking

b.      ALTE: repeated apnea, pallor, history of cyanosis, feeding difficulties

BONUS PEARL: A thorough history and physical will lead to the diagnosis for the source of the ALTE in 21%

Pertinent historical items: detailed bystander history of event (parents, EMS), activity and behavior prior to event and any past medical issues or medications (focus on GERD and pulmonary)

Pertinent physical exam: detailed neurological and cardiopulmonary system eval with focus on signs of non-accidental trauma (retinal hemorrhaging, bulging fontanel, bruising) as up to 10% of ALTEs involve some form of abuse

More and more people are going to holistic medicine and "naturopaths". These have been an interesting source of toxicology case reports due to therapeutic misadventures. Vitamins have been an ever increasing adjunct to these health philosophies. The following are the vitamins and their related toxicity in overdose:

Vitamin A: Pseudotumor cerebri, increase ICH, hair thinning, hepatotoxicity

Vitamin D: Hypercalcemia

Vitamin E: can antagonize vitamin K particularly in vitamin K deficient people, could result in coagulopathy

Vitamin K: problem if supplement contains this and patient on coumadin, ask patient

Vitamin C: Association with increased kidney stones though controversial

Balloon Tamponade for Variceal Bleeding

• Despite advances in pharmacology and endoscopy, placement of a balloon tamponade device is occasionally required to stabilize a patient with acute variceal bleeding.
• Currently, there are 3 devices available: the Linton-Nachlas (gastric balloon only), the Blakemore (gastric and esophageal balloons), and the Minnesota (gastric and esophageal balloons) tubes.
• The tube should initially be passed at least to the 50-cm mark and preferably to the maximum depth allowed by the length of the tube.
• Once the gastric balloon is inflated and correct position confirmed, traction must be applied to keep the gastric balloon engaged in the cardia and fundus of the stomach.
• An overhead pulley system is the preferred method to deliver traction.  If you don't have weights for the pulley system, a 1-liter bag of crystalloid provides the desired 1.0 kg of traction.

This week's visual pearl is an interesting ultrasound of a psoas abscess submitted by Dr. Sa'ad Lahri. He is an Attending physician in the Emergency Department of the Khayelitsha Hospital in Cape Town, South Africa. The video quality is grainy, but it automatically replays so you can watch it a few times.

http://ultrarounds.com/ultrarounds.com/Visual_Pearl_May_14,_2012.html

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[pearl provided by Dr. Semhar Tewelde]

Peripartum cardiomyopathy (PPCM) is a relatively rare idiopathic form of heart failure that occurs during the last months of pregnancy or the first months after delivery

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Panner's disease refers to osteochondrosis of the capitellum.

Affects the dominant elbow of boys between the ages of 5 and 10

Associated with the repetitive trauma of throwing

Must be differentiated from osteochondrosis dissicans (occurs in the older child >13yo)

Hx: Intermittent pain and stiffness of the elbow. Better w rest, worse w activity.

PE: tenderness over capitellum w/ slight effusion. Loss of 20 degrees full extension

The articular surface of the capitellum appears irregular with areas of radiolucency.

Tx: Symptomatic treatment with rest. In severe cases a long arm splint/cast may be applied for 2-3 weeks.

http://www.ultrasoundcases.info/files/Jpg/org_34277-Afbeelding1.jpg

• Ethylene glycol can result in elevated lactate concentrations secondary to hypotension and organ failure in severely poisoned patients. However, lactate production by these mechanisms tends to result in serum concentrations less than 5 mmol/L.

• Unfortunately, higher lactate levels don't necessarily rule out ethylene glycol. The glycolate metabolite causes a false-positive lactate elevation when measured by some analyzers, particularly with whole blood arterial blood gas analyzers. Specific models implicated include: ABL 625, Radiometer ABL 700, Beckman LX 20, Chiron 865, Bayer (formerly Chiron) 860, Rapidlab (Bayer) 865, Integra and to a lesser extent, Hitachi 911 analyzers, but not the Vitros 950 or Vitros 250.

• The degree of lactate elevation directly correlates with the concentration of glycolate present, and the artifact probably results from the lack of specificity of the lactate oxidase enzyme used in these machines.

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Severe acute pancreatitis (SAP) is a life-threatening form of pancreatitis, with up to 30% mortality.

SAP may lead to hypovolemic shock (secondary to vasodilation and capillary leak), hypoxemia (from acute respiratory distress syndrome), and multi-organ failure.

Suspect SAP with signs and symptoms of pancreatitis plus any of the following:

• Hypotension
• Hypoxemia
• Elevated hematocrit (secondary to hemoconcentration)
• Metabolic acidosis
• Decreased ionized calcium

Treatment of SAP should focus on:

• Hemodynamic support including intravascular volume repletion
• Respiratory support to correct hypoxemia
• Screening for abdominal compartment syndrome (risk increased with SAP)
• Prophylactic antibiotics are not recommended

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Increasing literature over recent years has demonstrated that young women (1) DO have MIs, (2) present more atypically than men, and (3) are more often misdiagnosed than men. Two recent trials have now also confirmed that young women have a higher in-hospital mortality compared to men, even when properly diagnosed. They may be due to lack of aggressive workups or treatment, or perhaps other as-yet unidentified factors.

The takeaway points are simple: be very wary when women (incuding young women) present with any cardiopulmonary complaints or anginal equivalent-type symptoms; and treat them aggressively.

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