We know vancomycin should be dosed based on weight rather than the default 1 gm dose so many patients receive. A past Academic Life in EM post explores the nuances of proper vancomycin dosing. But do higher loading doses in the ED actually lead to more therapeutic trough levels?
New Data
A new randomized trial compared ED patients receiving 30 mg/kg initial doses vs. 15 mg/kg. [1] There was a significantly greater proportion of patients reaching target trough levels of 15 mg/L at 12 hours among the patients who received a 30 mg/kg loading dose as compared with a traditional 15 mg/kg dose (34% vs 3%, P < 0.01). This study did not use a max dose of 2 gm. They included patients up to 120 kg who received 3.6 gm loading doses! Patients with creatinine clearance < 50 mL/min were excluded. There was no difference in incidence of nephrotoxicity between the groups.
Application to Clinical Practice
| Performance Characteristics of Common Drug Abuse Screening Immunoassays | ||
| Drug/Class | Detection Interval (***) | Comments |
| Amphetamines | 1-2 days (2-4 days) | Decongestants, ephedrine,l-methamphetamine, selegilene & bupropion metabolites may give False (+) results; MDA & MDMA are variably detected |
| Barbiturates | 2-4 days | Phenobarbital may be detected for up to 4 weeks |
| Benzodiazepines | 1-30 days | Benzos vary in reactivityand potency; False (+) results may be seen with oxaprozin |
| Cannabinoids | 1-3 days (>1 month) | Screening assays detect inactive and active cannabinoids; Confirmatory assays detects inactive metabolite THCA (tetrahydrocannabinoic acid) |
| Cocaine | 2 days (1 week) | Screening & confirmatory assays detect inactive metabolite BE (benzoylecgonine); False (+) results are unlikely |
| Opiates | 1-2 days; 2-4 days (<1 week) | Semisynthetic opiates derived from morphine show variable cross-reactivity; Fully synthetic opioids (e.g., fentanyl, meperidine, methadone, propoxyphene, tramadol) have minimal cross reactivity; Quinolone may cross-react |
| Methadone | 1-4 days | Doxylamine may cross-react |
| Phencyclidine | 4-7 days (>1 month) | Dextromethorphan, diphenhydramine, ketamine, & venlafaxine may cross react |
| Propoxyphene | 3-10 days | Duration of positivity depends on cross reactivity of metabolite norpropoxyphene |
(***)Values are after typical use; values in parentheses are after heavy or prolonged use.
From January 1st to January 30th, 2015, 102 people from 14 states were reported to have measles. This one month total is greater than the annual number of U.S. cases from 2002 to 2012. Most of these cases are related to a large outbreak from a Californian amusement park. Measles can spread in communities without adequate vaccination (low herd immunity). The majority of the people in the US who get measles are unvaccinated. However, measles remains common in many parts of the world.
Bottom Line:
As noted in the recent ACEP Fact Sheet, “A very high index of suspicion for Rubeola is necessary especially among patients with an exposure history, travel to foreign or domestic areas where disease is present, and those without adequate immunization. Immediate isolation of these patients should be considered in the ED or other outpatient healthcare setting.”
Hypertensive Emergency Pearls
Patient presents with right shoulder pain following minor trauma. What's the diagnosis....and what's the Cunningham technique?
Tetrodotoxin is lethal poison that blocks sodium channels. A famous sushi called "Fugu" is cut from a puffer fish that contains this poison. The idea is to get just enough of the toxin to cause peri-oral paresthesia but not too much to get seizures, paralysis and cardiac dysrrhythmias. A recent outbreak in Minneapolis, Minnesota was just reported in the MMWR so it can really happen anywhere, its a great read - dried puffer was bought from a market in NYC.
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6351a2.htm
2-3 mg of the toxin is lethal to an adult human. No antidote exists though I would try hypertonic sodium bicarbonate for the cardiac dysrrhythmias and appropraite supportive. If the patient survives 24 hrs, the patient will do well without sequelae if appropriately supported.
Patients with myasthenia gravis (MG) may be seen in the emergency department for symptoms that are not related to their MG, such as an upper respiratory tract infection or chest pain, for example.
The emergency physician should be careful in prescribing new medications to patients with MG, as that can precipitate a myasthenic crisis (and therefore cause significant morbidity and mortality). Below is a list of medications that are commonly implicated; an extensive list can be found on www.myasthenia.org/docs/MGFA_medicationsandmg.pdf)
Extracorporeal Treatment Strategies for Acute Methanol Poisoning (When to Dialyze)
Methanol toxicity is classically included in the differential for the intoxicated patient presenting to the ED. Add a negative EtOH level, anion/osmolar gap, blindness and you have yourself a slam dunk diagnosis. The goal is to stop the liver from metabolizing methanol to formic acid. Outside of fomepizole (or old school ethanol therapy), dialysis is often discussed, but when should you actually get the nephrologist on the phone?
This month the Extracorporeal Treatments in Poisoning Workgroup released a systematic review and consensus statement to help clinicians decide when to pull the HD trigger. Their suggestions are below.
When to start HD:
Which Modality: Intermittent HD (IHD) should be used over continuous renal replacement therapies (CRRT), as you can clear the toxin faster with higher HD flows.
When to stop HD: Extracorporeal treatment can be terminated when the methanol concentration is less than 200 mg/L or 6.2 mmol/L and a clinical improvement is observed.
Bottom Line: Consider early hemodialysis in most patients presenting with methanol toxicity. Clinical exam and routine lab testing will likely provide enough information to determine the need for IHD, but specific methanol levels can be helpful to guide adjunctive treatment options.
Reference
Roberts DM, Yates C, Megarbane B, et al. Recommendations for the Role of Extracorporeal Treatments in the Management of Acute Methanol Poisoning: A Systematic Review and Consensus Statement. Crit Care Med. 2015;43(2):461-472.
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Elderly male presents with the skin findings below. He is also on a medication for atrial fibrillation. What's the diagnosis?
Posterior Myocardial Infarctions (PMI)
- Posterior myocardial infarctions (PMI) are different than typical ST-elevation MI; the ECG findings include: septal & anterior ST-segment depression, dominant tall/broad R waves, and upright T waves.
- In a study among 117,739 subjects with STEMI, 824 with PMI were more likely to present with cardiac arrest, cardiogenic shock, and congestive heart failure.
- The median time from arrival ECG to revascularization with PCI was longer among subjects with PMI.
- The median time from arrival ECG to systemic thrombolysis was also longer among subjects with a PMI.
- Increased awareness and recognition of PMI is needed to improve reperfusion times among this subpopulation with STEMI.
Overuse injury
Seen in runners, military recruits (marching), ballet dancers and in jumping sports (heavy landing).
Insidious onset of heel pain, that is worse with jumping then running then later with simple weight bearing.
Tenderness to palpation posteriorly (medially or laterally), and squeezing bilateral posterior calcaneus.
Testing:
XR: May not be positive for 2 to 4 weeks. Sclerotic appearance (vertically oriented) posterior calcaneus.
MRI: high signal T2 at fracture site.
DDx: plantar fasciitis.
Treatment: Reduction of activity if Sxs mild, for severe pain start a trial of non weight-bearing (boot or splint with crutches).
Stretching of calf, achilles, plantar fascia.
As noted previously (UMEM Pearl of 1/7/2015), tuberculosis (TB) is a major infectious disease that occurs worldwide. Strains of tuberculosis can be resistant to one or more anti-tuberculosis medications. TB strains resistant to at least one medication have been found in all surveyed countries.
What is multidrug-resistant tuberculosis (MDR TB)?
Treatment of MDR TB
Bottom line:
As noted previously, in your emergency department have a high index of suspicion for TB and MDR TB in patients with an appropriate risk profile.
60 year-old male presents with 6 months of weight loss,epistaxis, and increased headache when bending over. What's the diagnosis?
Of pediatric patients who have anteroposterior (AP) pelvic xrays (XR), there is a 4.6% rate of pelvic fracture or dislocation, compared to 10% in adults.
This study is a sub analysis of a prospective observational cohort of children with blunt torso trauma conducted by PECARN. 7808 patients had pelvic imaging, with 65% of them having an AP XR. The XR sensitivity ranged from 64-82% (based on age groups) for detecting fractures. All but one patient with a pelvic fracture not detected on XR had a CT scan. The CT scan detected all but 2 fractures both of which were picked up later as healing fractures on repeat pelvic XR. Some of the patients who had a missed fracture on XR were hemodynamically unstable or wound up requiring operative intervention.
The authors support the following algorithm:
-With hemodynamically unstability children, obtain a pelvic XR
-For hemodynamically stable children when the physician is planning to get a CT, there is no indication for XR
Bottom line: Consider using AP pelvic radiographs in the hemodynamically stable patient with a high suspicion for fracture or dislocation who are not undergoing CT.
Left Ventricular Hypertrophy & Arrhythmias: Any Association?
Associations between left ventricular hypertrophy (LVH) and both supraventricular (SVT)/ventricular arrhythmias (VT/VF) have previously been reported.
A recent review & meta-analysis of 10 studies (27,141 patients) revealed the following:
- Incidence of SVT was 11% with LVH compared to 1% without (p <0.001)
- LVH patients had 3.4-fold greater odds of developing SVT
- Incidence of VT/VF was 5.5% with LVH compared to 1.2% without (p <0.001)
- LVH patients has 2.8 greater odds of developing VT/VF
The reason for increased arrhythmogenicity in LVH is not clearly understood.
A consistently observed abnormality in LVH is non-uniform propagation of the action potential throughout the myocardium, which sets the stage for arrhythmias based on early or delayed afterdepolarizations.
Given the heterogeneity in this meta-analysis further research between LVH & sustained arrhythmias is needed to infer true causality.
We often think of Plantar Fascitis as the cause of heel pain but there are a lot of other causes. Some of those include:
Hydroxocobalamin is an effective cyanide antidote when administered intravenously. Although intraosseous (IO) access is often used in critically ill patients with difficult or delayed IV access, the efficacy of IO administration has not been investigated until recently.
In a recent randomized animal study, acute cyanide toxicity was induced in two groups of swine where 150 mg/kg Hydroxocobalamin was administered via IV vs. IO. The survival rate, reversal of hypotension, and laboratory results were similar between the IV and IO group.
The finding of this study suggest that IO administration of Hydroxocobalamin is as efficacious as IV administration and its administration in acute cyanide toxicity should not be delayed due to lack of IV access when IO access is available.
Is progesterone yet another disappointing neuroprotectant?
Traumatic brain injury (TBI) affects more than 1.7 million persons in the U.S. annually. The incidence of TBI is increasing globally, especially in developing countries. Despite improvement in trauma systems and critical care, the morbidity and mortality associated with severe TBI remain high.
Progesterone has been shown in preclinical and phase 2 randomized clinical trials to have pluripotent neuroprotective properties and improve mortality in TBI.
Two multicenter phase 3 trials were recently completed and published in the December 25th issue of the New England Journal of Medicine. However, their results were disappointing.
Both studies used the Glasgow Outcome Scale (GOS) or Extended Glasgow Outcome Scale (GOS-E) at 6 months as their primary outcome. The GOS and GOS-E capture the degree of recovery from brain injury in terms of disability, stratified into levels by death, vegetative state, severe disability, moderate disability, and good recovery.
Progesterone was not found to have any benefit in functional outcome at 6 months.
Both of these studies were well designed and conducted. However, they were based on small effect sizes of the phase 2 trials. In addition, they had very favorable outcome rates in the placebo group, thereby making it hard to demonstrate a benefit by their sample sizes.
There has been a long history of failed neuroprotectant trials likely due to the complex and variable injury mechanisms involved in TBI. The currently available outcome measures are also insensitive to the targeted mechanistic endpoints. More research is needed to understand not only potential therapies but also how to select appropriate patients for these therapies.
Take Home Point: Progesterone does not have any clear benefit in TBI at this time.
Diaphragm weakness and its significance
There are several ways to monitor diaphragm strength and function
Clinical Relevance
