UMEM Educational Pearls

D-Dimer in the Critically Ill

• Diagnosis of VTE in the critically ill can be challenging and these patients are at high risk for the disease
• Only 3.6% - 16% of critically ill patients have a negative d-dimer, regardless of the presence or absence of VTE
• Even in patients with low pretest probability, d-dimer in the critically ill is of limited utility

Crowther MA, et al. Neither baseline tests of molecular hypercoagulability nor D-dimer levels predict deep venous thrombosis in critically ill medical-surgical patients. Intensive Care Med 2005;31(1):48-55.

Direct Renin Inhibitor-Aliskiren (Tekturna)

This drug is the 1st in a new class of antihypertensives called direct renin inhibitors-1st approved in 2007. This drug, along with three others being developed, inhibits the entire Renin-Angiotensin-Aldosterone System (RAAS) which has been shown to lead to definitive 24 hour blood pressure control.

Why should emergency physicians care, you ask?

• It is only matter of time before we start seeing patients on this drug. I saw my first just a few weeks ago, and according to some of our nephrologists we can expect to see a whole lot more.  Emergency Physicians should at the very least know about this new class of drug.
• Side effects of the drug are similar to ACE inhibitors (ACE-I), like hyperkalemia.
• The drug can cause angioedema, so development of angioedema on this drug pretty much takes all three angiotensin drugs (ACE inhibitors, angiotensin receptor blockers, and direct renin inhibitors) off the list of potential BP meds for the patient. All three can cause angioedema.

J Hypertension March 2007

Just a reminder, after a recent case of a patient that had a large AMI the day after a negative dobutamine stress test...

Neither stress testing nor coronary angiography are definitive for ruling out unstable/vulnerable plaques. If the HPI for your patient is very concerning, don't obviate your concern just because of a recent negative stress test or angiography. These tests are good at identifying large occlusions, but they tell us nothing about recent rupture or about composition of the plaques, and we now know that it is the composition that determines plaque instability. Size doesn't always matter...

Ultrasound in Pregnancy

1.  A full bladder is needed for Transabdominal Ultrasound and an empty bladder for transvaginal ultrasound.
2. A gestational sac should be visible on transabdominal ultrasound with a quantative HcG of 5000-6000 mIU/ml, and a quant of 1500-2000 mIU/ml on transvaginal.
3. When taking photos, ensure that you show all of the applicable landmarks.  [i.e.: bladder, and uterus]  If you just zoom in on the pregnancy anybody else (i.e.: your expert witness) reading the scan will not be able to confirm that the pregnancy is in the uterus.
4. To confirm an IUP, you must see the yolk sac within the gestational sac.  A double decidual sign is an early sign of pregnancy but it is not always seen and should not be relied upon.
5. If you have a confirmed IUP an additional ectopic pregnancy is extremely unlikely unless the patient was taking medication to stimulate their ovaries (i.e. Infertility treatment).  If on stimulation therapy a very thorough exam needs to be done to look for additional pregnancies.
6. If Quant >2000 mIU/ml and there is no evidence of an IUP, patient needs to be treated as an ectopic pregnancy.

Cerebral Edema in Patients with DKA

• Cerebral Edema is a rare, yet catastrophic complication of Pediatric DKA.
  • Occurs in ~1% of episodes of pediatric DKA
  • Mortality rate of 40-90%; 20-40% of survivors have lasting Neuro Sequelae.
• Risk Factors
  • High initial BUN
  • Low paCO2
  • No increase of the sodium during therapy
  • Treatment with bicarbonate
• Diagnosis is made clinically
  • Warning Signs = Headache, Vomitting, Lethargy, Bradycardia, and Hypertension
  • Keep Mannitol (0.25-1.0 grams/kg) at the bedside.  Administer it and stop IVF once you suspect Cerebral Edema.
    
    Glaser N, et al: Risk factors for cerebral edema in children with DKA. NEJM.2001:344:264-9
     

Tamiflu (oseltamivir)

• Must be administered within 48 hours of onset of symptoms
• Patient must be 1 year or older
• Rare cases of anaphylaxis, Stevens-Johnson, TEN and erythema multiforme have been reported.
• Not proven safe in pregnancy nor harmful.

• Romberg testing is an important component of the neurological examination which assesses proprioception (i.e. sense of joint position/balance) which is a function of the dorsal columns of the spinal cord.

• A Romberg test is performed by asking the patient to stand erect with their feet together and arms/hands at their side.  You first ask the patient to stand this way with their eyes open for 1 minute and then with their eyes closed for 1 minute.

• A positive Romberg test results if the patient exhibits clear swaying or even falling ONLY when their eyes are closed.  This suggests that the patient's ataxia is sensory in nature (i.e. dorsal columns), rather than cerebellar.

• Patients with cerebellar ataxia will typically loose their balance and sway even with their eyes open.

• Classic neurological abnormalities associated with a positive Romberg test include tabes dorsalis (neurosyphilis) and sensory peripheral neurpathy, among others.

• Be sure to cautiously standby while performing this test in order to protect the pateint should they fall.

• The use of central venous pressure as a monitor of volume status remains very controversial in the critical care literature
• Remember that CVP can be affected by many conditions
• Important conditions that affect the accuracy of CVP include: 
  • right ventricular disease
  • tricuspid valve disease
  • pericardial disease
  • changes in intrathoracic pressure (PEEP, positive pressure ventilation) 
  • arrhythmias
  • reference level of the transducer

Care of the Crashing Asthma Patient

Several things should be considered in the crashing asthmatic:

• First and foremost, there is very little date on how to manage the crashing asthmatic!
• Any sick asthma patient should have IV fluid replacement-these patients have tons of insensible losses. IV fluids may also help with post-intubation hypotension cause by compression of the vena cava.
• Many EM folks have left Ketamine in the dust for intubating an asthmatic....anecdotally, it works, but creates very sticky and tenacious lung boogers that are hard to suction. Why make your job even harder?
• Sounds like common sense, but RSI the patient in the position of comfort (usually tripod) and then quickly lay them back supine.
• Consider instituting the "kitchen sink approach" to asthma care. This includes beta agonists, anticholinergics, Mg, steroids, IVF, epi, nebulized Lidocaine, perhaps non-invasive ventilation, inhaled (yes, inhaled) steriods. Our job really begins once they have been tubed.
• Sounds corny, but consider a "bedside coach." Believe it or not, some really sick asthmatics can be talked through a severe, life-threatening exacerbation. This can be a nurse, tech, physician. Someone to talk to them during this crisis. It works sometimes.
• Any intubated asthmatic who goes into PEA arrest should not be declared dead unless bilateral needle decompressions and bilateral chest tubes have been performed.
• If an intubated asthmatic codes once intubated, consider the following: (1) disconnect from the ventilator and bag VERY slowly...4-6 breaths/minute or even slower! (2) Although controversial, some consider manual chest wall compression helpful in "getting rid" of trapped air. (3) Vigorous IVF-positive pressure ventilation worsens the patients hyperinflation which compresses the vena cava, and (4) consider needle decompression and then chest tube insertion

Adenosine should never be used in the setting of a wide complex regular tachycardia as a diagnostic maneuver. Adenosine will convert some types of VT, and this may mislead the health care provider into thinking that the WCT is an SVT. The electrophysiology literature is rife with reports of "adenosine-sensitive VT," and these patients are often young and without prior history of CAD...the very patients that we'd most be inclinded to assume have SVT.

The bottom line is that one should always assume that a regular WCT (without obvious evidence of sinus tachycardia) is VT, and treat the tachydysrhythmia as such.

Most of use remember that Fifth disease is a viral infection presenting with a distinctive rash (slapped check) caused by Parvovirus B19.  But do you know the numbering of the other six Contagious Illnesses that are associated with rashes:

1. First Disease – Measles caused by the rubeola virus
2. Second Disease – Scarlet Fever caused by Streptococcus pyogenes Group A
3. Third Disease – German Measles caused by rubella virus
4. Fourth Disease – Dukes Disease – In the late 1880-1900’s it was widely published about but in the 1960’s it was not proven to exist by either epidemiologic criteria or isolation of an etiologic agent.  Now felt to be a mild form of scarlet fever.  Some reports of it being caused by a Coxsackvirus or Echovirus
5. Fifth Disease - Erythema infectiosum caused by Parvovirus B19. Slapped Check
6. Sixth Disease - Exanthem subitum (meaning sudden rash), also referred to as roseola infantum (or rose rash of infants), sixth disease. Presents as rapid onset high fever, followed by a fine red rash when the fever subsides. Caused by Herpes Virus 6.

Febrile Seizures

• Diagnosis: Simple vs Complex
  • Simple Febrile Seizure
    • Age = 6mos to 5yrs
    • Single Seizure
    • Generalized
    • Lasting less than 15 minutes
    • Child returns to baseline and has normal neurological exam.
  • Complex Febrile Seizure
    • Same as above, except can be focal seizure or prolonged or with multiple seizures within 24 hours.
    • May indicate a more serious disease process.

• Etiologies:
  • Viral illnesses are the predominant cause of febrile seizures.
    • Human herpes simplex virus 6 (HHSV-6) has been associated with about 20% of pts with first febrile seizures.
  • Shigella gastroenteritis also has been associated.
  • The rate of serious bacterial infections is similar to those found in pt’s with fever without a source

• Key Point:
  • Do NOT forget to work-up the fever as you would for the patient’s age!
  • A lower threshold for performing full-sepsis work-up with LP is advocated in those pt’s less than 12 months of age.
     

Here are a couple of herbals touted as aphrodesiac's and the toxcity associated with them (the price of love):

Chan Su or "Love Stone" - A chinese herbal that is suppose to be topically applied, unfortunately all of the instructions are in chinese and those who ingest it will die a digoxin-like death. It has a compound that is essentially a potent digoxin-like substance.

Yohimbine - herbals that contain this can cause priapism -  shocker

• The brainstem is the lower extension of the brain that connects the brain to the spinal cord.

• Neurological functions located in the brainstem include those necessary for survival (breathing, digestion, heart rate, blood pressure) and for arousal (being awake and alert).

• Most of the cranial nerves come from the brainstem.  The brainstem is the pathway for all fiber tracts passing up and down from peripheral nerves and spinal cord to the highest parts of the brain.

Spontaneous Pneumomediastinum

• Spontaneous pneumomediastinum is largely a benign disease typically seen in young males ages 18-21 years
• It is typically caused by activities that increase alveolar pressure such as coughing, sneezing, vomiting, inhalational drug use, and Valsalva maneuver
• The most common symptoms include chest pain and dyspnea; chest pain is usually centrally located, may radiate to the neck, and may be worse with inspiration
• CT scan is the "gold standard"; CXR is a good place to start but it is normal in up to 30% of cases
• The vast majority of patients do not require admission or supplemental O₂
• Advise patients to avoid strenuous activity until after symptom resolution (typically takes about 2 weeks)
• Any patient with a fever, elevated WBC count, hemodynamic instability, severe dysphagia or odynophagia should first be evaluated for infectious mediastinitis or esophageal perforation (spont. pneumomediastinum is a diagnosis of exclusion in these patients)

AAA...be afraid, be very afraid

Abdominal Aortic Aneurysm (AAA)  is known as the great masquerader in the elderly for good reason....

• May look EXACTLY like a kidney stone
• May cause vague abdominal and/or back pain....probably one of the reasons we scan older folks with abdominal pain. Presentations of AAA in the older patient may not be impressive!
• May be associated with the "blue toe syndrome" (where mural thrombus flips distally and occludes small vessels in the feet and toes)
• A pulsatile mass is frequently absent
• 10% of urology referrals for older (>65) patients with suspected kidney stones result in a diagnosis of AAA

The 5 most important factors at predicting the presence of ACS in a patient presenting with chest pain (in order of importance):
1. nature of anginal symptoms (i.e. the HPI)
2. prior history of CAD
3. male gender
4. older age
5. increasing number of traditional risk factors

Notice this means that the MOST important factor is the HPI...the OLDCAAAR. If the patient has a concerning HPI, NEVER drop your concerns just because the patient is young or has minimal other risk factors.

Rhogam 

• Remember to administer Rhogam to any Rh negative mother that has the following conditions:
• Pregnancy/delivery of an Rh-positive baby
• Abortion/threatened abortion at any stage of gestation
• Ectopic pregnancy
• Antepartum fetal-maternal hemorrhage (suspected or proven) resulting from antepartum hemorrhage (e.g., placenta previa), amniocentesis, chorionic villus sampling, percutaneous umbilical blood sampling, other obstetrical manipulative procedure (e.g., version) or abdominal trauma
• Transfusion of Rh incompatible blood or blood products (i.e.: platelets)

Dosing:

• 300 mcg IM
• Can give 50 mcg IM within 72 h of exposure of a therapeutic or spontaneous abortion if gestation age is 12 weeks or less. (Order as MICRhogam)
• Additional doses of Rhogam may be necessary when the patient has been exposed to > 15 mL of Rh-positive red blood cells. This may be determined by use of qualitative or quantitative tests for fetal maternal hemnorrhage but generally will only occur during a full term delivery or if incompatible blood products are given.

Trivial Fact: Rhogam is Pregnancy Class C

Neonate with Red Eye

• Crusty Eye – Not Red
  • Dacryostenosis - nasolacrimal duct obstruction
  • It is the most common cause of tearing in childhood.  
  • No photophobia, corneal is normal
  • Tx  = Warm compresses and gentle massage

• Purulent Conjunctivitis - Ophthalmia neonatorum
  • Chemical (due to prophylactic eye drops) - day 1
  • Gonorrhea –
    • Presents early on (day 2-5)
    • OCULAR EMERGENCY – may cause globe perforation
    • Associated Systemic Infection - meningitis
    • Ceftriaxone (25-50mg/kg) – Treat until Cx’s return.
  • Chlamydia –
    • Longer incubation period (day 5-14)
    • Causes Eyelid Scarring leading to blindness
    • Associated Systemic Infection – Pulmonary
    • Ceftriaxone (25-50mg/kg) + Topical Erythromycin
    • If Culture +, then PO erythromycin to prevent late onset pneumonitis.

• Remember that it is important to check a patient's peripheral vision when concerned about stroke, and when performing a neurological exam in general.
• Recognizing grossly abnormal peripheral vision often suggests the presence of various types of visual field cuts and helps localize a stroke lesion.
• When performing a general, very gross examination for peripheral vision abnormalities:

1. It is sometimes helpful to ask the patient to cover the eye that you are NOT checking for abnormality at the time.
2. Ask the patient to look straight ahead.
3. Ask the patient to tell you when they are able to see the long, narrow object (i.e. your finger, a pencil, etc.) that you slowly move forward into their view, starting from the point where the finger tips of the patient's laterally abducted arm would be (i.e. the object begins at a distance approximately equal to the patient's arm length).
4. Using this axis of reference, normal peripheral vision should occur at 45 degrees or less.