UMEM Educational Pearls

Patients with aortic dissection (Type A or B) who develop intestinal/renal, etc. ischemia should be considered for aortic fenestration-a procedure in which holes are literally created in the aortic lumen to connect the true and false lumen-this allows perfusion of the involved vessel to occur from true lumen into the false lumen into the involved vessel.

Patients with large vessel malperfusion have a VERY HIGH mortality rate, AND most CT surgeons will not operate even on a Type A unless the involved vessels have been opened up.

This procedure is useful when major vessels (SMA as an example) branch from the aortic false lumen.

So, when to consider this procedure:

• Aortic Dissection (A or B) with severe abdominal pain, elevated lactate, OR imaging study showing malperfusion to a vessel (SMA, renal, etc)
• Most of the time in the ED we will see this on CT in a sick patient.

Who do you call?

• Vascular Surgery and IR-normally perormed percutaneously via a femoral approach

A few pearls regarding pacing a patient with an unstable bradycardia:

If the patient has an implanted pacemaker (which isn't working properly), the transcutaneous pacing pads should be placed at least 10 cm away from the implanted PM pulse generator.

Placement of a transvenous pacemaker is absolutely contraindicated if the patient has a prosthetic tricuspid valve.

Neither transcutaneous or transvenos pacing is likely to work in the setting of severe acidosis or severe hypothermia. Severely hypothermic patients, in fact, have very irritible myocardial tissue and therefore attempts at pacing may produce ventricular dysrhythmias.

Volvulus Quick Facts

• Volvulus causes 10-15% of large bowel obstructions and occurs most commonly in the elderly.
• The most common type of volvulus is sigmoid volvulus.
• Midgut volvulus is most common in the neonatal period.
• Cecal volvulus:
  • Occurs in all ages, but most commonly in the 25- to 35-year-old age group
  • Associated with:
    • previous abdominal surgeries
    • young, healthy marathon runners.
• Sigmoid volvulus most commonly occurs in two groups of individuals:
  • Inactive elderly persons with a history of severe chronic constipation
  • Patients with severe psychiatric or neurologic disease.

Atrial Myxomas:

• Rare primary heart tumor
• Most involve the left side of the heart

• Symptoms may include fatigue, fever, rash, chest pain, syncope, and/or focal neuro deficits
  • Symptomatic emboli occur in 20-45% of pts with atrial myxomas
  • >50% of emboli go to the brain
  • Hemiplegia, aphasia, retinal artery occlusion, embolic “rash” in a child should all raise concern for cardiac source in pediatric pt.
    
    • Embolus from the heart is the most common cause of retinal artery occlusion in pts <40yrs.

• Emboli are most often myxoma tissue and not blood clot (so thrombolytics aren’t of much value)

Majeed Al-Mateen, et al. Cerebral Embolism From Atrial Myxoma in Pediatric Patients. Pediatrics, Aug 2003; 112: e162 - e167.

• Fever in the setting of acute ischemic stroke is associated with increased mortality and morbidity.

• These effects are possibly due to increased metabolic demands, neurotransmitter release, and free radical production.

• Use of antipyretics to achieve normothermia may improve outcome.

• Studies have shown that hypothermia is neuroprotective.

• Look for a potential source of fever, which may have caused or prompted the stroke (i.e. infective endocarditis, complications of pneumonia).

Adams, et al.  Guidelines for the Early Management of Adults with Ischemic Stroke.  AHA/ASA Guidelines.  2007.

Remember that PE can clinically look exactly like pneumonia:

Both can present with:

• Cough
• Pleuritic chest pain
• Leukocytosis (WBC as high as 20-30)
• Elevated temperature (as high as 105F!)
• CXR that "looks" like pneumonia
• Both can present acutely

Be afraid, be very, very afraid....

• Acute chest syndrome (ACS) is the leading cause of death in sickle cell patients
• ACS is defined by the presence of a new infiltrate and one of the following: chest pain, wheezing, fever, tachypnea, or cough
• Early and aggressive therapy is needed to minimize mortality
• Up to 50% of patients develop respiratory failure
• Treatment
  • Broad spectrum antibiotics - including a macrolide
  • Pain control to reduce hypoventilation
  • Early use of blood transfusion to improve O2 carrying capacity
  • Incentive spirometry
  • Bronchodilators if wheezing present
  • Hematology consult

Atypical presentations of ACS in the elderly are common.
Only 40% of patients > 85yo present with chest pain. Dyspnea is the most common presenting complaint in these patients. Other atypical presentations include isolated nausea, vomiting, diaphoresis, or syncope.

The presence of an atypical presentation is not reassuring in terms of prognosis. Patients presenting atypically have a 3-fold higher in-hospital mortality (13% vs. 4%). This doesn't even include the patients that are inadvertently discharged home because of failure to diagnose ACS.

Malpractice insurance may not cover the following activities:

• Practicing outside the scope of your specialty (eg: writing admission orders, running upstairs to run resuscitations).
• Undocumented treatment (ie: no ED chart generated)
• Prehospital orders
• EMTALA violations
• Hospital committee work
• Contract violations
• Fraud (including billing mistakes)
• Defamation
• Violation of privacy
• Harassment
• Sexual misconduct
• Assault and battery
• Other crimes

Disclaimer: This information does not constitute legal advice, is general in nature, and because individual circumstances differ it should not be interpreted as legal advice. The speaker provides this information only for Continuing Medical Education purposes.

Thanks to Larry Weiss, MD, JD

Rheumatic Fever

• Significant cause of cardiovascular morbidity in developing countries and still present in the USA, although declining in incidence.
• American Heart Association update of the Jones Criteria (1992):
  • Major Criteria
    (1)    Carditis (of any of the layers of the heart)
    (2)    Polyarthritis
    (3)    Subcutaneous Nodules
    (4)    Erythema Marginatum
    (5)    Chorea
  • Minor Criteria
    (1)    Arthralgia (not a criterion if polyarthritis is present)
    (2)    Fever
    (3)    Elevated acute-phase reactants (ESR, CRP)
    (4)    Prolonged P-R interval
• Diagnosis made by presence of TWO MAJOR or ONE MAJOR PLUS TWO MINOR.
• Diagnosis can also be made with presence of chorea and documented strep pharyngitis.

• Acute Management
  • Treat the Infection
    (1)    Penicillin (Pen V for 10 days or Pen G IM)
  • Alleviate Symptoms
    (1)    Salicylates are particularly effective for migratory arthritis
    (2)    High Dose ASA (80-100mg/kg/Day for several weeks, and then taper)
    (3)    NSAIDs for those who cannot tolerate ASA
    (4)    Steroids reserved for moderate to severe carditis.
     

• Apraxia = Inability to carry out physical acts despite intact motor function.

• Agnosia = Inability to recognize and identify objects and/or sounds despite intact sensory function.

Sulfonylureas

• Sulfonylureas cause insuline release via cAMP/protein kinase C
• All sulfonylurea overdoses should be admitted for 24 hrs regardless of symptoms
• Antidote for recurrent hypoglycemia due to sulfonylureas (overdose or therapeutic misadventure) is octreotide, after your glucose
• Octreotide, a somatostatin analogue, turns of insulin secretion completely
• Octreotide 50 mcg SQ q 6 hrs for 24 hrs then observe for hypoglycemia 12-24 hrs

Fasono et al. Comparison of Octreotide and Standard Therapy Versus Standard Therapy Alone for the Treatment of Sulfonylurea-Induced Hypoglycemia. Ann Emerg Med 2007 Aug 29.

• It is traditionally taught that in hypotensive patients the presence of a carotid pulse corresponds to a SBP of 60-70 mmHg, a femoral pulse with a SBP of 70-80 mmHg, and a radial pulse with an SBP of at least 80 mmHg
• These physical exam estimates of BP have been shown to poorly correlate with the patient's actual BP
• Similarly, non-invasive measurements of BP (automated cuff) in patients with hypotension may either overestimate or underestimate SBP by as much as 20 mmHg
• Since physical exam estimates and non-invasive measurements are inaccurate in low-flow states, utilize invasive arterial monitoring
• Radial and femoral artery sites have been found to produce results that are clinically interchangeable

Splenic Artery Aneurysm

• According to autopsy studies, splanchnic artery aneurysms (spleen, celiac, etc.) may be more frequent than AAA
• Most asymptomatic and detected incidentally on CT
• Splenic artery aneurysms most common splanchnic aneurysm
• With increased use of abdominal CT, emergency physicians will be seeing this diagnosis more often

Who cares, you ask?

• Splanchnic artery aneurysms are at risk for rupture
• This type of vascular abnormality will be discovered more often because of increased CT use
• Aneurysms > 2cm indication for repair
• Consider consultation and /or expeditious followup if this is encountered
• May be treated with catheter embolization or surgery

Although CHF is usually associated with low cardiac output, "high output failure" can occur as well. In this condition, cardiac output is normal or even high but not high enough to meet markedly elevated metabolic demands of the heart in certain conditions. Those conditions include: severe anemia, thyrotoxicosis, lartge arteriovenous sunts, Beriberi, and Paget disease of the bone.

What should I do about this finding on the MRI I ordered

Now tha ta lot of EDs are getting MRIs on a more urgent basis, we will need to know what to do with the resutls.  However, the natural history of findings on MRI has not been well studied, so what should we do with that small meningioma you find.  Well some researchers in the Netherlands have attempted to address your question. In a population-based study [Rotterdam Study] , 2000 adults aged 45 or older underwent a brain MRI.

Some of the common findngs were:

• Asymptomatic brain infarcts were observed in 7%.
• Aneurysms and benign tumors (mostly meningiomas) were each found in nearly 2%.
• The two most urgent findings were a chronic subdural hematoma and a 12-mm aneurysm. Both required surgey.
• Only two out of the 2000 (0.001%) people had symptoms related to their MRI findings (hearing loss in both).
• The prevalence of asymptomatic brain infarcts and meningiomas increased with age, as did the volume of white-matter lesions, whereas aneurysms showed no age-related increase in prevalence.

Most of the study patients were white and middle class so these results may not be generalized to the general public.  I am sure more studies are in the works, but for now don't be two suprised if you find an asympomatic infarct or meningioma.

Vernooji MW, Ikram MA, Tanghe HL. Incidental Findings on Brain MRI in the General Population. NEJM. 2007;357(18):1821-1828.

Children s/p Heart Transplantation – Rejection

• Children need heart transplantation for complex congenital heart defects (hypoplastic left heart syndrome is most common) or dilated cardiomyopathies.

• Signs of Acute rejection
  • Chest Pain is uncommon
  • Common presentions: fever, myalgias, and vomiting.
    • ECG may show a decreased R wave amplitude and an increased QRS duration.
  • Labs are most often NOT diagnostic in acute rejection.
    • Troponin and CK levels may or may not be elevated.
    • Elevated LFTs are concerning for right heart failure.
  • Echo – Diastolic dysfunction is the earliest change seen in acute rejection
• Signs of Chronic Rejection
  • Clinical symptoms often related to the accelerated atherosclerosis
  • “Silent” ischemia or infarction – decreased exercise tolerance or malaise
  • Syncope

Woods, WA. Care of the Acutely Ill Pediatric Heart Transplant Recipient. Pediatric Emergency Care. 23(10):721-724, October 2007.

Carbamazepine

• Anticonvulsant that can be monitored (you can draw a level)
• Toxicity resembles a TCA with seizures and cardiac conduction delays
• > 40 mcg/mL assoc with coma, seizures, respiratory failure and cardiac toxicity
• Treat widened QRS comples with sodium bicarbonate
• Adsorbs very well to activated charcoal, multi-dose may be required

• Xanthochromia is the result of metabolized hemoglobin in cerebrospinal fluid (CSF), which suggests intracranial bleed.
• It helps differentiate traumatic lumbar puncture results from true intracranial bleeding.
• It causes the CSF to have a yellowish color which can be detected with the naked eye or analyzed with a machine (done visually at UMMS).
• It typically takes at least 6 hours for xanthochromia to manifest itself. 

Degree of D-Dimer elevation and Mortality Rates

Evidence now exists that links the degree of D-Dimer elevation with mortality rate. The higher the D-Dimer, the higher the PE mortality rate.

Consider this when risk stratifying patients with PE. This adds to our use of biomarkers for risk stratification. Elevation of BNP, D-Dimer, and Troponins have been shown to predict mortality.