UMEM Educational Pearls

When a child is reported to be exposed to a rat poison it is commonly a long acting coumarin like brodifacoum. The rat usually eats the poison then during its traumatic little life will cause its own death by jumping and squeezing through a crack. When a human is exposed, this is the typical sequence of events:

1. Exposure (and when you usually see them in the ED)
2. 24-72 hrs later you will actually see an INR rise if actually ingested

Treatment is the same as for coumadin, vitamin K. However, do not start empirically since the patient will be committed to high doses of vitamin K for several months. Let the patient prove they have been poisoned which means they will require recheck of their INR 2-3 days later though they can be sent home with specific warning signs of anticoagulation.

• For many years the recommendations for managing new-onset seizure (NOS) in the emergency department did not include any specific instruction for such patients with HIV/AIDS.
• A study done by Pesola and colleagues found that, infact, AIDS patients with NOS require additional vigilence in terms of their management.
• This study found that over 15% of AIDS patients with NOS would have erroneously been sent home without appropriate treatment had the standard recommendation for NOS management been followed; these patients were found to have intracranial lesions related to toxoplosmosis and lymphoma, and did not necessarily have focal neurologic deficits.
• It is therefore recommended that all AIDS patients with NOS undergo neuroimaging with lumbar puncture, as indicated.

Show References

Bleeding Dialysis Fistula?

Ever see a patient in the ED c/o "my fistula won't stop bleeding"? If you haven't, you probably will in the future.

Here are some helpful tips on getting these bad boys to stop oozing:

• Local pressure for 10 minutes will stop many of these bleeders
• Can also try locally applied gel foam/thrombin
• Pharmacologic adjuncts may be required, especially if the patient has missed dialysis-DDAVP can be given (makes platelets stickier by causing endothelial cells to release von Willibrand Factor). You can also give platelets, since platelets don't work well in a uremic state. Many dialysis patients are on coumadin because of chronic line clots, so don't forget to reverse this if present
• Probably as a last resort you can tie a superficial circular suture at the puncture site. This works quite well.

Impingement Syndrome and the Diagnostic Accuracy of 5 Common Tests

It is also reported that subacromial impingement syndrome (SAIS) is the more frequent cause of shoulder pain.

The authors of this study attempted to determine the diagnostic accuracy of the following 5 tests for SAIS:

• Hawkins-Kennedy
• Neer
• Empty Can
• Painful Arc
• External Resistance

The study demonstrated that any 3 positive tests out of the 5 has a sensitivity of 0.75 (0.54-0.96) , specificity of 0.74 (0.61-0.88), positive likelihood ratio of 2.93 (1.60-5.36) and negative likelihood ratio of 0.34 (0.14-0.80).  See the table below for the individual test characteristics.  No single test was deemed accurate enough to make the diagnosis by itself.

So in the end you should be familiar with most of these tests in order to use a combination of them to make the diagnosis of impingement syndrome.  Future pearls will review how to perform these tests.

Show References

• Given the recent extremely cold winter weather experienced in some parts of the country, we will likely be expected to recognize and treat true frostbite and its sequelae at an increasing rate.
• Frostbite is the result of focal injury that follows the crystallization of water within subcutaneous tissue when exposed to low temperatures. 
• Sequelae such as chronic neuropathic pain syndromes can results in up to 25% of patients with frostbite due to microvascular damage.
• Hyperbaric oxygen has been shown to effectively treat this sequelae, even if administered in a delayed fashion, and should be considered as a viable therapeutic option.

Show References

With all of the post-transplant patients we see in the ED, a refresher on the toxicities associated with the most common immunosuppressant medications is warranted.

Cyclosporine (Sandimmune^® and Neoral^®/Gengraf^®) and tacrolimus (Prograf^®) are both calcineurin inhibitors that inhibit activation and proliferation of T-lymphocytes and IL-2.

-          Major concerns: Nephrotoxicity, drug interactions (CYP3A4)

-          Adverse Effects:

o       Electrolyte abnormalities: ­K+, ¯Mg+, ­glucose

o       CNS: HA, tremor (statistically higher with tacrolimus)

o       CV: HTN, ­ lipids (increased with cyclosporine)

o       End organ: hepatotoxicity, nephrotoxicity

o       Cosmetic (cyclosporine specific): hirsutism, gingival hyperplasia, acne

Sirolimus/Rapamycin (Rapamune^®) is an M-tor inhibitor that inhibits T-lymphocyte activation and proliferation.

-          Major concerns: Drug interactions (CYP3A4)

-          Adverse Effects:

o       Delayed wound healing

o       Leucopenia, thrombocytopenia

o       Hypercholesterolemia

• Total body calcium consists of about half biologically active (ionized) and half inactive (80% bound to albumin and 20% to other ions)
• hypocalcemia caused by hypoalbuminemia is physiologically insignificant, and correction factors are not accurate or reliable
• The best way to measure true active calcium is to order an ionized calcium level

There are several conditions that alter ionized calcium levels, including:

• alkalosis (increases binding to albumin)
• gas bubbles in the sample (false lowering of calcium)
• anticoagulants (must be collected in a red top tube)
• blood transfusions (binding to citrate)
• cardiopulmonary bypass
• drugs (aminoglycosides, cimetidine, heparin, theophylline)
• fat embolism
• hypomagnesemia (correcting mg levels may preclude need for Ca repletion)
• pancreatitis (several mechanisms, poor prognosis)
• renal insufficiency (impaired phosphate retention)
• sepsis

The bottom line is to measure ionized calcium, and consider all other factors that can be contributing to hypocalcemia in addition to repleting it. 

Altered Mental Status-Does Your Patient Have Non-Convulsive Status Epilepticus?

Ever intubated a patient in status epilepticus and wondered if they were still seizing after sedation and paralysis? Ever taken care of an altered patient and wondered if you should consult neurology and attempt to get an EEG?

NCSE is defined as continuous seizure activity without obvious outward manifestations of a seizure. This is important for emergency physicians to consider because it has to be detected early to prevent morbidity and mortality.

When to consider NCSE:

• Prolonged postictal period
• Unexplained altered mental status in a patient with a history of seizures
• Altered mental status associated with "eye twitching" or blinking
• Stroke patient who clinically looks worse than expected

Scaphoid Fractures:

For suspected scaphoid fractures with negative radiographs it is common practice to put a person in a short arm thumb spica splint until followup up radiographs can be obtained in 10-14 days.

However, there is evidence that a short arm thumb spica splint is not enough for people that have a true scaphoid fracture.  Gellman et al demonstrated that long arm thumb-spica cast immobilization for six weeks followed by short arm thumb-spica cast immobilization decreased time to union by 25% when compared to short arm thumb-spica casting alone.

The theory is that the short arm splint still allows for forearm rotation that can cause shearing motion of the volar radiocarpal ligaments.  A long arm splint prevents this shearing action.  The disadvantage of a long arm splint though is potential elbow joint stiffness and muscle atrophy that can occur during the prolonged period of immobilization.

So for your next patient with a scaphoid fracture seen on radiographs place them in a long arm thumb spica splint.

Show References

CARBAPENENEMS

• Broadest spectrum of activity of all classes
• Imipenem has slightly better gm + activity; lowers seizure threshold
• Meropenem has slightly better gm - activity
• Ertapenem does not cover Pseudomonas
• Doripenem has the most activity against Pseudomonas
• May use in PCN allergic patients (cross reactivity lower than previously thought)

TIGECYCLINE

• Has broad coverage, but does not cover Pseudomonas
• Bacteriostatic; derivative of tetracycline
• Does NOT require renal dosing
• Higher mortality in VAP than other agents; do not use for intra-abdominal infections (poss higher risk of perforation)

AMIKACIN

• Has antipseudomonal activity
• Used in combination with other agents for MDR (multi-drug resistant) bacteria
• Causes nephrotoxicity and ototoxicity

COLISTIN

• Bacteriocidal against many MDR gram - bacteria
• Not active against Proteus, Provincia, Burkholderia, Neisseria, or Serratia
• Nephrotoxicity and ototoxicity reported

Show References

• In states without mandatory physician reporting of patients with seizures, the decision of whether to breach confidentiality and report a poorly controlled epileptic patient who continues to drive an automobile becomes an ethical dilemma.
• In making this decision, one must consider the probability and magnitude of the potential harm.
• If the probability and magnitude are both low, or the probability of harm is high but the associated magnitude is low, there is generally no moral obligation to breach confidentiality and report.
• If the probability of harm is low but the potential magnitude of the harm is high, one should strongly consider reporting the case.
• Each case should be handled on an individual basis, take into consideration the risks and benefits to the patient and society if reporting is ensued, and perhaps elicit the advice of risk management.

Show References

The Rapid Ultrasound in Shock (RUSH) Exam

• Evaluating the ED patient with undifferentiated shock can be challenging.
• Ultrasound can be an invaluable tool in helping to differentiate between hypvolemic, cardiogenic and obstructive shock.
• The RUSH exam essentially focuses on the evaluation of the "pump", the "tank" and the "pipes".
• The pump: exclude pericardial effusion, global estimate of LV EF, and determine if RV strain is present.
• The tank: evaluate the IVC/jugular veins for volume status, look for fluid in the thorax/peritoneum, and exclude pulmonary edema or pneumothorax.
• The pipes: look for a ruptured AAA or aortic dissection and DVT.

Show References

Pulmonary Embolism-Myths and Misconceptions

Just wanted to mention a few myths/misconceptions about acute PE that I have recently heard discussed in the ED.

1. Emergency physicians have to "get help" to give thrombolytic therapy. Sure it makes sense that we consult critical care and perhaps interventional radiology in some cases. But we do not need permission to use this drug by ourselves if indicated. Consider using lytics ESPECIALLY if the patient is unstable or if there is evidence of RV dysfunction (elevated troponin, echo criteria for dysfunction, or CT with large RV and bowing of the septum). What about the patient with RV dysfunction and a normal BP? Evidence is mounting that lytics are indicated to reduce the severity of pulmonary hypertension. 

2. "Just get a d-dimer." Be very careful. Lots of false positives. D-dimer often clouds the picture more often than not. 

3. "The mortality rate of missed PE is high." Often quoted as a 30%+ mortality rate if missed. Recent data suggests that it is < 5%. 

Missed cases of ACS account for 10% of all malpractice cases in emergency medicine, yet account for 30% of all the money emergency physicians pay out in malpractice cases. This misdiagnosis is the biggest cause of monetary payout in the specialty.

Three main themes account for the majority of missed cases of ACS:
1. Failure to recognize atypical presentations (e.g. dyspnea)
2. Failure to recognize high-risk groups (e.g. women, diabetics)
3. Over-reliance on negative tests (e.g. negative troponin or recent stress test)

Temporal Arteritis (TA) is commonly associated with the sudden onset of a unilateral headache centered around the temporal region.  The most devastating consequence of TA is blindness though this is only reported in up to 50% of cases though can be bilateral in up to 33% of patients.

According to the American College of Rheumatology criteria for classification of temporal arteritis this diagnosis can be made in the ED without a biopsy.  You just need at least 3 of the following 5 items to be present (sensitivity 93.5%, specificity 91.2%) to make the diagnosis :

1. Age of onset older than 50 years
2. New-onset headache or localized head pain
3. Temporal artery tenderness to palpation or reduced pulsation
4. Erythrocyte sedimentation rate (ESR) greater than 50 mm/h
5. Abnormal arterial biopsy (necrotizing vasculitis with granulomatous proliferation and infiltration)

Show References

The umbilical site normally heals by 1 month of age. 

Any fluid draining after this period suggests an abnormal connection between the surface of the abdomen and the underlying structures, and requires further investigation.  Clear yellow fluid could represent a persistent connection of the bladder with the umbilicus called a patent urachus. The fluid that leaks is actually urine. The treatment is surgical closure of the connection.

Pus oozing from the umbilical stump would imply infection, especially if there is concomitant redness of the skin around the umbilicus.  An omphalitis can be life-threatening, and requires admission for invtravenous antibiotics.

Umbilical hernias are common in infants, and are usually noted with diastasis of the rectus muscles.  Most umbilical hernias resovle by school age, and do not require surgical intervention.

An umbilical granuloma is a small piece of bright red, moist flesh that remains in the umbilicus after cord separation. It is scar tissue, usually on a stalk, that did not become normally covered with skin cells. It contains no nerves and has no feeling. Most can be simply cauterised with silver nitrate.

Apologies - last few bullets were cutoff - Continuing - Prophylaxis against RCIN has been attempted with the following:

• IV saline infusion
• Sodium Bicarbonate bolus
• IV acetylcysteine infusion

No one therapy has been show to have superior efficacy.

Radiocontrast Induced Nephropathy (RCIN)

• Occurs within 24 hrs of administration followed by oliguric phase
• Usually improves within a week and rarely needs dialysis
• Initial injection is an osmotic load, leads to volume expansion and diuresis. Follwed by intense vasoconstriction suggesting possible ischemic role in pathophysiology.
• There is also a direct toxic effect to the kidneys however
• High Risk patients: HTN, DM,  Chronic Renal Insuff, Bence Jones proteinuria and large injections of IV dye
• Possible prophylaxis: There is almost no data studying this effect in the Emerg Dept patient. One trial look at IV acetylcysteine in the Emergent CT (RAPPID trial) did show benefit but has flaws within the study. IV hydration and sodium bicarbonate

Show References

• Apart from time and rehabilitation, there is currently no effective treatment for reversing brain damage caused by stroke.

• Clinical recovery after a stroke results from neuro-restorative processes such as neurogenesis, angiogenesis, synaptic plasticity, and/or re-modeled and strengthened connections between neurons. 

• Stem cell therapy for stroke is a novel, but progressive area of research which would potentially facilitate the neuro-restorative processes required for recovery. 

• Despite the extremely complex nature of brain function and central nervous system networks, successful stem cell therapy for brain infarct could become the wave of the future for optimal stroke management.

Show References

Patients in the Critical Care setting may develop HIT as a result of chronic pre-existing risk factors (malignancy, obesity, hypertension, diabetes or medications) or acquired factors secondary to their ICU stay (post-operative state, trauma, central lines or medications such as heparin).

Diagnosis of HIT:

• platelet count<150,000 or relative decrease of 50% or more from baseline
• documentation of antibodies binding platelet factor 4 and heparin, as well as a confirmation test
• typically occurs 5-14 days after initiation of heparin therapy
• can have a rapid (usually a result of previous exposure) or delayed onset
• thrombotic complications develop in 20-50 percent of patients

Treatment of HIT:

• Remove all sources of heparin (including heparin-bonded catheters)
• initiate a non-heparin anticoagulant
• Direct thrombin inhibitors:
  • Lepirudin (cleared by kidney)
  • Argatroban (cleared by liver)
  • Bivalirudin (cleared by proteolysis 80% and kidney 20%)
• Other agents used include:
  • Danaparoid (antifactor Xa activity - not available in North America)
  • Fondaparinux (synthetic selective inhibitor of Xa)

Show References