The newest iteration of 'Guidelines for the Early Management of Patients with Acute Ischemic Stroke' was recently published. Here are the key revisions specific to blood pressure management:
If administering rtPA, blood pressure needs to be <185/110 mm Hg. That recommendation didn't change.
Most antidotes have not been adequately studied in pregancy and hold a Pregnancy Risk Category 'C' by the FDA. However, there are a few antidotes that hold a category 'D' or 'X' rating (contraindicated).
In most cases, the benefits of short-term use probably outweigh the risk, especially when accounting for the health and prognosis of the mother.
Intraosseus (IO) access has become quite popular in critically ill patients requiring immediate resuscitation. In a patient responsive to pain, however, pain and discomfort is associated with the force of high-volume infusion through the established line.
Before flushing the line, consider administering preservative-free 2% lidocaine (without epinephrine) for patients responsive to pain prior to flush.
The suggested dose is 20-40 mg (1-2 mL) of the 2% lidocaine, followed by the 10 mL saline flush.
If preservative-free 2% lidocaine is not stocked in your ED, now is the time to consider adding it.
Several medications can produce a false-positive result for methadone on the urine drug screen: diphenhydramine, doxylamine, clomipramine, chlorpromazine, quetiapine, thioridazine, and verapamil.
Add a new one to the list. Tapentadol, a relatively new opioid analgesic similar to tramadol, can also produce a false-positive result for methadone on certain immunoassays.
A separate study concluded that tapentadol does not affect the amphetamine screen.
The two available Tetanus/reduced diphtheria toxoid/acellular pertussis (Tdap) vaccine products in the U.S. are Boostrix and Adacel. Neither were originally approved in older adults age 65 and older. Boostrix received FDA-approval for use in this age group in July 2011, but Adacel never has.
However, in June 2012 ACIP issued new guidance recommending Tdap for all adults age 65 years and older.
"When feasible, Boostrix should be used for adults aged 65 years and older; however, ACIP concluded that either vaccine administered to a person 65 years or older is immunogenic and would provide protection. A dose of either vaccine may be considered valid."
Bottom line: Regardless of which Tdap product is stocked at your institution, both are considered safe to use in adults 65 years and older.
The more well known causes of toxin-induced hyperthermia include sympathomimetics and anticholinergics. In addition, neuroleptic malignant syndrome, serotonin syndrome, and malignant hyperthermia are high on the differential.
Several other xenobiotics can cause hyperthermia in overdose as well:
In general, benzodiazepines should be considered first-line therapy, followed by barbiturates, propofol, or other sedative hypnotics. Phenytoin rarely has a role in the management of toxin-induced seizures. Extrenal cooling measures are also warranted. Specifically for isoniazid, pyridoxine should be administered immediately with a benzodiazepine.
In the rare circumstance you need to treat a patient with suspected PID and an allergy to doxycycline, what is the alternative?
For oral regimens, azithromycin is an option in place of doxycycline.
Suggested regimen for PID with doxycycline allergy:
Background
Patients who are intoxicated with, or emerging from, phencyclidine (PCP) highs present with acute agitation that can be challenging to treat
Risks of physical restraints for combative patients include injury, hyperthermia, rhabdomyolysis, and increased agitation or excited delirium
Haloperidol is an option for chemical restraint that is typically safe and rapid acting
Some concerns related to haloperidol use in PCP-intoxicated patients include worsened PCP-induced hyperthermia, dystonic or anticholinergic reactions, lower seizure threshold, and hypotension
Data
A recent retrospective case series assessed the frequency of adverse effects from the combination of PCP and haloperidol
Of 59 cases, only two patients experienced an adverse reaction, and neither could be conclusively linked to haloperidol administration
This analysis had several major limitations including retrospective design for identifying adverse reactions, potential for false positive PCP screens, and possible haloperidol administration more than 24 hours after PCP intoxication
Bottom Line
While haloperidol may be safe for agitated PCP-intoxicated patients, this paper adds nothing to refute or support its use. Benzodiazepines and calm environment are still first-line therapy.
It should be noted that no data exist showing poor outcomes in PCP-intoxicated patients administered haloperidol, which begs the question "Is there even an issue?" Dr. Leon Gussow, author of The Poison Review, provides a nice answer and summary of the article here.
It seems we've finally put to bed the myth that 10% of penicillin-allergic patients will also react to cephalosporins. Dr. Campagna, et al. recently published a review article concluding that the true cross-reactivity is negligible except when side-chains are similar [PMID 21742459].
This topic was also the subject of a recent post on the Academic Life in EM blog (http://academiclifeinem.blogspot.com/2012/08/busting-myth-10-cephalosporin.html).
But what about the reverse question? Can I give a penicillin to a cephalosporin-allergic patient?
Dr. Romano's group tested 98 patients with skin-test postitive cepahlosprin allergy (mostly IgE -mediated anaphylaxis). Patients were then skin tested for penicillin allergy. Those testing negative were challenged with a penicillin.
25% of patients reacted to the penicillin
Similar side-chain was a strong predictor of cross-reactivity
A Letter to the Editor response to this study pointed out that the authors used a smaller-than-standard size threshold for a positive response to the penicllin AND used a higher-than-standard dose of amoxicillin for testing. In light of this, the rate of subjects with cephalosporin allergy who do not have a history of penicillin allergy but with true IgE-mediated allergy to penicillin might be much closer to 5%.
Bottom line: The cross-reactivity of penicillins in cephalosporin-allergic patients is somewhere between 5-25%.
Activated charcoal is most effective if given within 1 hour of overdose.
Prehospital administration of charcoal can be challenging, but may save significant time compared to waiting until arrival to the ED. The patient has to be transported by EMS, registered, seen by a provider, order for charocal placed...
Two studies evaluated the time difference between prehospital and hospital administration of GI decontamination.
Bottom line: Don't underestimate the amount of time that goes by before you evaluate non-crashing patients upon arrival to the ED. If the story supports an overdose and the patient doesn't have contraindications for receiving charcoal, recommend it be given in the prehospital setting for greatest potential benefit.
Patients frequently report having a sulfa allergy. In most cases, the allergic reaction was secondary to a sulfonamide antimicrobial agent, such as sulfamethoxazole-trimethoprim.
The question is: Can I use furosemide (or other non-antimicrobial agents containing a sulfa component)?
There is minimal evidence of cross-reactivity between sulfonamide antimicrobials and non-antimicrobials.
Despite this, the U.S. FDA-approved product information for many non-antimicrobial sulfonamide drugs contains warnings concerning possible cross-reactions.
Bottom line: If a patient had a true IgE-mediated anaphylatic reaction to a sulfonamide antimicrobial, it may be best to avoid other sulfa-related medications (use ethacrynic acid if a loop diuretic is needed). Otherwise, the available literature does not support cross-reactivity between sulfonamide antimicrobials and non-antimicrobials.
Carbon monoxide (CO) and hydrogen cyanide (HCN) are two of the main gases causing injury and death from smoke inhalation in fire victims. During the first phase of a fire, and prior to depletion of oxygen reserves and subsequent production of CO, formation of HCN from the thermal breakdown of nitrogen-containing materials may be the primary cause of lethal poisoning in an enclosed-space fire.
A recent, retrospective, observational study from Poland assessed the prevalence of toxic HCN exposure in victims of enclosed-space fires.
Important findings:
Conclusion: The high prevalence of coincident HCN concentrations and COHb levels in victims of enclosed-space fires emphasises the need to suspect HCN as a co-toxin in all persons rescued from fire who show signs and symptoms of respiratory distress.
Carbapenems (meropenem, ertapenem, doripenem, imipenem/cilastatin) are broad-spectrum antibiotics that have good gram-negative and anaerobic coverage and are used to treat resistant bacterial infections.
Early retrospective studies showed ~10% cross-reactivity in penicillin-allergic patients.
More recent prospective studies verified penicillin allergy by the accepted standard (ie, skin test to the major and minor penicillin determinants) and tested for carbapenem allergy by administering a full therapeutic dose to carbapenem skin test-negative patients.
The cross-reactivity between skin tests appears to be around 1%, with all carbapenem skin test-negative patients tolerating the challenge.
There is a growing recognition of patients who have a subtoxic acetaminophen level at the 4-hour mark, but then still go on to have a toxic level later.
This is concerning in that we usually can exclude the chance for toxicity if the 4-hour, post-ingestion level is < 150 mcg/mL following an acute ingestion (plotted on Rumack-Matthew nomogram).
It still is not clear exactly what subset of patients need to have a second level drawn, but a recurring theme seems to be ingestion of acetaminophen in combination with agents that slow GI motility, such as diphenhydramine or opioids. It may be worth ordering a second APAP level (possibly at 8 hours) in patients ingesting these prodcuts.
A recent paper reviewed 53 articles to assess the utility of vasopressors in cardiac arrest. The authors aimed to determine if vasopressors improved ouctomes in this patient population. Here are their conclusions:
Although these conclusions don't support the use of vasopressors in cardiac arrest, we should not abandon these therapies. Most of the trials were completed before wide-spread recognition of the post-cardiac arrest syndrome, implementation of therapeutic hypothermia protocols, and early cardiac catheterization.
Levamisole is a pharmaceutical with anthelminthic and immunomodulatory properties that was previously used in both animals and humans to treat inflammatory conditions and cancer.
It has been identified as a cocaine adulterant in the U.S. since 2003, with the DEA estimating that by 2009 up to 70% of cocaine seized contained levamisole.
Leukopenia, agranulocytosis, and vasculitis are well known complications of levamisole use.
One important complication to keep in mind is the possibility of multifocal inflammatory leukoencephalopathy (MIL). Although no formal case of leukoencephalopathy in the setting of cocaine use has yet been reported, various neurological side effects were described with levamisole therapy, the most concerning complication being MIL.
Issue 1: Mean INR in study patients was only 1.22 (median 1.2). An INR of 1.2 represents very little actual anticoagulation.
Issue 2: In the small subgroup of patients with INR 1.5 to 1.7 (n = 269) there was a higher risk of ICH (7.8%), but did not reach statistical significance (it was significant in the unadjusted risk population).
Bottom line: Patients with INRs < 1.5 may be ok to receive tPA. Patients with INRs 1.5 or greater need further study.
Naltrexone and methylnaltrexone are both mu-receptor antagonists that look similar and have similar names. But, they have very different uses.
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.