What is the correct antidote for a patient who is poisoned with the pictured substance?
(photo used with permission courtesy of Maureen Dallhoff, MD)
Which of the substances below causes crystalluria with hexagonal crystals that shimmer on macroscopic urine examination?
Urine drug tests are commonly sent for patients in the emergency department, however care should be taken when interpreting the results of these tests given their limitations. The American College of Medical Toxicology published a position statement on the interpretation of urine opiate and opioid tests [1]. In this publication, they outline many of the limitations of opioid urine drug tests and explain why they exist.
| Cross-reactivity of Various Opioids with Morphine Urine Drug Test [2] | ||
|---|---|---|
| Compound | Equivalent to 300 ng/mL Morphine (ng/mL) | Cross-reactivity (%) |
| Codeine | 224 | 134 |
| Heroin | 366 | 82 |
| Hydrocodone | 1,086 | 28 |
| Hydromorphone | 1,425 | 21 |
| Oxycodone | >75,000 | <0.4 |
| Meperidine | >100,000 | <0.3 |
Previous ALiEM posts discuss further limitations of urine drug tests, specifically for benzodiazepines and opiates.
Read other articles in the EM Pharm Pearls Series and find previous pearls on the PharmERToxguy site.
Acute agitation in the emergency department is a common issue that frequently requires the use of chemical sedation to preserve safety for patients and healthcare workers. A commonly employed treatment regimen is the combination of haloperidol 5 mg + lorazepam 2 mg + diphenhydramine 50 mg (B-52). Diphenhydramine is included in this treatment regimen primarily to prevent extrapyramidal symptoms [1,2]. However, the incidence of extrapyramidal symptoms (EPS) with haloperidol is quite low when treating agitation in the emergency department (ED) [3,4]. Therefore, the excessive and prolonged sedation from adding prophylactic diphenhydramine may outweigh the intended benefit and should be reserved for treatment of EPS if symptoms occur.
Jeffers et al. conducted a multicenter, retrospective, cohort study which compared the efficacy and safety of haloperidol, lorazepam, and diphenhydramine (B-52) (n=200) vs. haloperidol and lorazepam (52) (n=200) in treating patients >18 years old with acute agitation in the ED [5]. Their primary outcome was the administration of additional agitation medication(s) within 2 hours.
| Outcomes | 52 (n=200) | B52 (n=200) | p-Value |
|---|---|---|---|
| Administration of additional sedative within 2 h, n (%) | 40 (20) | 28 (14) | 0.11 |
| Median ED LOS (hours) | 13.8 | 17 | 0.03 |
| Use of restraints, n (%) | 53 (26.5) | 86 (43) | 0.001 |
| Hypotension, n (%) | 7 (3.5) | 32 (16) | <0.001 |
| Administration of anticholinergic within 2 days, n (%) | 15 (7.5%) | 6 (3%) | 0.04 |
| Itching/allergies, n (%) | 1 (0.5) | 1 (0.5) | 1.00 |
| Home benztropine, n (%) | 2 (1) | 4 (2) | 0.41 |
| Insomnia, n (%) | 4 (2) | 0 (0) | 0.06 |
| Unknown, n (%) | 8 (4) | 1 (0.5) | 0.02 |
Overall, the B-52 combination resulted in more oxygen desaturation, hypotension, physical restraint use, and longer length of stay. However, the conclusions from this study may be limited as it was a relatively small study and it used surrogate markers to assess clinical endpoints.
Further discussion regarding the onset and duration of IM medications for acute agitation may be found in this blog post.
Read other articles in the EM Pharm Pearls Series and find previous pearls on the PharmERToxguy site.
Which toxic exposure can present with the pictured rash along with hypertension and tachycardia mimicking pheochromocytoma?
Direct-acting oral anticoagulants (DOACs), including apixaban, rivaroxaban, edoxaban, and dabigatran, are widely used for various indications and considered first-line therapy for prevention of acute ischemic stroke in patients with nonvalvular atrial fibrillation [1]. The management of acute ischemic stroke in patients on DOACs presents a difficult clinical scenario in the emergency department due to concern for increased risk of hemorrhage. IV thrombolytics (e.g., alteplase, tenecteplase), a mainstay in acute ischemic stroke management, are not recommended in current guidelines for patients whose last DOAC dose was within the last 48 hours [2, 3]. Therefore, patients with an acute ischemic stroke who are compliant with their DOACs are often excluded from guideline recommended therapy. Additionally, as covered in a previous ALiEM post, it is not recommended to reverse anticoagulation status in order to administer a thrombolytic.
The use of IV thrombolytics in patients on DOACs was evaluated by Kam et al in a 2022 study published in JAMA [4]. This retrospective analysis included 163,038 patients from the AHA/ASA Get With The Guidelines-Stroke registry with acute ischemic stroke who received IV alteplase within 4.5 hours of symptom onset. Of the total number of patients, only 2207 had documented use of a DOAC within the last 7 days, with 25 of these patients reporting DOAC use within 48 hours. Patients on warfarin or other anticoagulants were excluded. The primary outcome was symptomatic intracranial hemorrhage (ICH) within 36 hours of IV alteplase administration. After adjusting for clinical factors, the rate of symptomatic ICH was not significantly different between patients taking DOACs and those not on anticoagulation (3.7% vs. 3.2%, adjusted OR 0.88, 95% CI 0.70 to 1.10). However, when stratified based on time from last DOAC dose, patients who took their DOAC 0-48 hours prior had an 8% rate of symptomatic ICH compared to 3.2% among those not on DOACs. Furthermore, the rate of any alteplase complication was 12% vs. 6% in those taking DOACs within 48 hours vs. no DOAC.
Read other articles in the EM Pharm Pearls Series and find previous pearls on the PharmERToxguy site.
Jessica Mason, PharmD
PGY-2 Emergency Medicine Pharmacy Resident
Massachusetts General Hospital
An acute aortic dissection (AAD) can be a life-threatening emergency which frequently requires rapid and precise control of the patient’s heart rate and blood pressure. The 2010 guidelines for management of patients with thoracic aortic disease suggest a heart rate goal of <60 bpm and a systolic blood pressure between 100-120 mmHg. In order to achieve this, a rapid-acting beta-blocker (i.e., esmolol) may be used in combination with an IV calcium channel blocker (i.e., nicardipine or clevidipine). These medications need to be monitored closely to avoid overshooting these goals and causing hemodynamic compromise. Ideally, an arterial line would be used to monitor the patient’s blood pressure, however this may not always be feasible so a traditional, noninvasive blood pressure cuff can be used. This may be complicated if the patient has the classic, but not universal, finding of unequal systolic blood pressure values between their left and right extremities. This raises the question, in a patient with an AAD and disparate blood pressures in each arm, which arm reading should be used for monitoring?
A 2018 study from Um et al. evaluated 111 patients with an AAD and compared them with 111 control patients. This study found that while a systolic blood pressure difference of >20 mmHg between sides was a positive predictor for an AAD, the presence of a pulse deficit had a higher diagnostic accuracy. For the purpose of this study, a pulse deficit was defined as “any recorded difference in volume/force or difference in obvious signs of malperfusion”. The cause of an unequal blood pressure or pulse deficit in the upper extremities in this population is typically due to dissection of the brachiocephalic or subclavian arteries. In order to properly achieve the desired blood pressure reduction in patients with divergent blood pressure values, the higher value should be used for titration of antihypertensives. This is due to the occurrence of pseudohypotension occurring in the limb with the dissected artery.
Read other articles in the EM Pharm Pearls Series and find previous pearls on the PharmERToxguy site.