Recent Developments in Infectious Disease Chemotherapy: Review for Emergency Department Practitioners 2020

Purpose of Review

We discuss and review new antimicrobials for treatment of bacterial, viral, fungal, and parasitic infections with indications, contraindications, and side effects for each. We will also review new information and indications on older agents that are relevant to clinical practice. Many of them may be unfamiliar to Emergency Physicians given their newness and at times hospital restrictions on their use. We also review some new promising agents that are not yet in the clinical pipeline.

Recent Findings

As new antibiotics become available for clinicians to use, new information becomes available with respect to the drugs' indications, efficacy, pathogen resistance, drug-drug interactions, and side effects.

Summary

This article provides Emergency Department clinicians with a useful summary with new information on antibiotic use and recent research into agents which may become available.

EMS Disease Exposure, Transmission, and Prevention: a Review Article

Purpose of Review

This article aims to review recent literature regarding the risks of disease exposure to pre-hospital providers and the patients they serve, as well as the challenges they face in minimizing transmission and exposure.

Recent Findings

Many studies continue to show poor compliance with consistent universal precautions, as well as proper hand hygiene. Vaccination rates are suboptimal despite attempts to encourage compliance. With the spread of multi-drug resistant organisms, new techniques of decontamination need to be investigated.

Summary

There remains a general lack of information and studies regarding the risks of disease exposure and transmission to EMS providers despite the significance hazards their profession can pose. However, there remains a continued theme throughout the majority of EMS and pre-hospital studies, demonstrating that hand washing and consistent use of personal protective equipment remains a persistent, preventable means of disease exposure and transmission.

A case of renal artery thrombosis with renal infarction

Renal artery thrombosis is a rare, but serious and often misdiagnosed, condition. Emergency physicians and other physicians need to consider this diagnosis in unexplained flank pain, especially in patients with risk factors for this disease. In this case report, the authors review a case of renal infarction caused by renal artery thrombosis in a patient with risk factors for thrombosis but no previous history of thromboembolism. A review of scholarly articles was performed and the case is discussed in the context of the current knowledge of this condition. Common presenting symptoms, features of the history and risk factors will all be discussed herein. Diagnostic evaluation of flank pain in the setting of the suspicion of renal infarction will be discussed, including the modalities of high-resolution computed tomography, renal angiography, scintography and ultrasound. Acute management and prognosis will also be discussed.

Platelet aspirin resistance in ED patients with suspected acute coronary syndrome

BACKGROUND

Platelet aspirin resistance is reported to be as high as 45%. The prevalence of emergency department (ED) platelet aspirin resistance in suspected acute coronary syndrome (ACS) is not described. Our purpose was to determine the prevalence of platelet aspirin resistance.

METHODS

We determined platelet aspirin resistance in a convenience sample of ED suspected ACS patients. Eligible patients had longer than 10 minutes of chest pain or an ischemic equivalent. Two hours after receiving 325 mg of aspirin, blood was assessed for platelet function (Accumetrics, San Diego, CA). Definitions are as follows: aspirin resistance, at least 550 aspirin reaction units; positive troponin T, greater than 0.1 ng/mL; significant coronary lesion, at least 70% stenosis. The composite end point was prospectively defined as a 30-day revisit, positive cardiac catheterization, or hospital length of stay (LOS) longer than 3 days.

RESULTS

Of 200 patients, 50.5% were male, 50.0% were black, troponin T was positive in 7.5%, cardiac catheterization was done in 10.5%, and 33.3% had a significant stenosis. Final diagnoses were noncardiac in 83.4%, stable angina in 8.0%, and unstable angina in 8.5%. Overall, 6.5% were resistant to aspirin; and high-risk patients trended to more aspirin resistance than non-high-risk patients (23.1% [3] vs 9.1% [17]; P value 95% confidence interval [CI], -0.0929 to 0.373). One-month follow-up found ED revisits in 12.5% of aspirin-resistant vs 4.9% of non-aspirin-resistant patients (95% CI, -0.114 to 0.182) and rehospitalization in 12.5% of resistant patients vs 4.3% of nonresistant patients (P value 95% CI, -0.108 to 0.187). Although LOS was similar at index admission, if rehospitalized, LOS was 6.5 for aspirin-resistant patients vs 3.2 days in nonresistant patients (P < .0001).

CONCLUSION

This first report of platelet aspirin resistance in patients presenting to the ED with suggested ACS finds that it is present in 6.5% of patients.

Diabetic muscle infarction: a rare complication of advanced diabetes mellitus

Diabetic muscle infarction is a rare complication of diabetes mellitus first described in 1965. It typically arises in patients with long-standing diabetes mellitus who have complications of the disease, including nephropathy, retinopathy, and neuropathy. It typically presents with acute onset of thigh pain with an associated palpable tender mass. Recurrent episodes in the same or opposite limb are common. Laboratory evaluation does not generally show any consistent abnormality except for poor glucose control. Histologic features of diabetic muscle infarction consist of large areas of muscle necrosis and edema. Magnetic resonance imaging (MRI) findings in patients without clinical evidence of infection may be typical enough to make tissue biopsy unnecessary. In the appropriate clinical setting, MRI may obviate invasive testing and is the preferred imaging modality. Treatment is supportive with analgesics, rest, and immobilization.

Elevated Serum Cardiac Markers Predict Coronary Artery Disease in Patients With a History of Heart Failure Who Present With Chest Pain: Insights From the i*trACS Registry

The significance of a history of heart failure (HF) in patients presenting with acute coronary syndromes and elevated cardiac markers is unclear. The authors performed an analysis of patients enrolled in the Internet Tracking Registry of Acute Coronary Syndromes (i*trACS). Cardiac marker measurement and cardiac catheterization were performed in 1174 patients. Of these, 116 (9.9%) had heart failure (HF). Coronary artery disease (CAD) was found in 61 (52.6%) patients in the HF group and 581 (54.9%) in the group without HF. In the non-HF cohort, positive markers occurred in 306 patients, in whom 217 (70.9%) had CAD at catheterization. In the HF subset, 24 patients had positive biomarkers and 15 (62.5%) had CAD. A history of HF did not lessen the likelihood of CAD as evidenced by angiography and does not diminish the utility of cardiac markers in diagnosing acute coronary syndromes.

An overview of non-cardiac cocaine toxicity

Cocaine use in the United States continues to be a significant problem. Cocaine use is responsible for approximately 143,000 Emergency Department visits annually. The cardiac effects of cocaine are well known and much is written on this topic; this is beyond the scope of this article. Cocaine use is also responsible for a variety of non-cardiac, systemic complications, which it is our purpose to review. Multiple systemic effects of cocaine are seen with both acute and chronic use. These systems include: psychological and psychiatric, neurological, renal, pulmonary, gastrointestinal, obstetrical, and otolaryngological.

Head injury: which patients need imaging? Which test is best?

Some patients with head injuries definitely need to undergo an imaging study--usually computed tomography (CT). Most, however, are in a category of "apparently mild" injury, and controversy continues about which of them need to undergo imaging studies to rule out intracranial injuries.

Urine protein as a rapid screen for renal function in the ED: can it replace serum creatinine in selected patients?

Many radiology departments are unwilling to perform studies that require contrast administration to adult emergency department patients over the age of 35 without having a documented serum creatinine concentration of less than 2.0 mg/dl within a week of the study. Significant diagnostic delays may ensue waiting for this serum test. The present study was performed to determine whether a negative urine protein test, obtained by dip testing, will serve as a marker for a serum creatinine concentration below 2.0 mg/dl in emergency department patients who give no history of a disease which potentially could cause renal insufficiency. Emergency patients aged 35 years or more presenting to a university hospital who did not volunteer a history of hypertension, diabetes mellitus, multiple myeloma, or systemic lupus erythematosus in triage were enrolled. Only patients with a negative urine protein test whose serum creatinine was tested for other reasons were included. Of the 310 patients who had no protein in their urine and no history of disease which potentially could cause renal insufficiency, none had a serum creatinine concentration greater than 2.0 mg/dl (mean=0.82 mg/dl, SD 0.28). Ages ranged from 35 to 96 years (mean=59.7 years, SD=17.5). All patients would have qualified for a contrast load for contrast computed tomography studies or for intravenous pyelogram. In patients who do not have a known history of hypertension, multiple myeloma, systemic lupus erythematosus, diabetes mellitus, or specific renal disease, urine dip testing for protein in the emergency department may be a rapid and safe screen for imaging studies requiring contrast without having to await serum creatinine testing.

Variable diagnostic approach to suspected pulmonary embolism in the ED of a major academic tertiary care center

The purpose of this study is to retrospectively examine the patterns of diagnostic modality utilization in the setting of suspected acute pulmonary embolism (PE) by physicians in the emergency department (ED) of a major academic tertiary care center. All patients (n=180) with a hospital discharge diagnosis of PE that were admitted through the ED during 1997 to 1999 were included. Overall test frequency and distribution, ancillary testing used when the initial ventilation-perfusion (V/Q) scan or spiral computed tomography (sCT) angiogram was nondiagnostic, concordance of V/Q and sCT, and sensitivities of D-dimer assays, arterial blood gas analysis, and deep venous imaging were assessed. There was a wide discrepancy in practice, most pronounced when first-line radiological studies were nondiagnostic. There was a poor correlation of PE detection between sCT and V/Q. D-dimer assay, arterial blood gas analysis, and deep venous imaging are insensitive tests for PE, and "gold standard" pulmonary angiography is rarely used.

Rationing and the role of the emergency department as society's safety net

Emergency medicine has an integral role in the establishment of universal access to health care for all persons living in the United States. Currently, emergency departments provide the only unfunded mandate available to millions of American residents who otherwise have no access to health care coverage. Any effort to establish universal care must accept health care rationing as a basic principle, and establish a minimum standard of benefits to which all human beings are entitled in this country. People and employers should be allowed to purchase additional care based on their willingness and ability to pay, but under no circumstances should anyone be denied a basic package of health care benefits. Emergency care must be part of those basic benefits. Emergency medicine charges should be structured so that they are not unduly onerous to society, and should reflect true expenses, including marginal costs for nonurgent care. Emergency physicians (EPs) and hospital administrations should recognize their critical role in serving society in roles that are not strictly medical, and allocate resources to benefit the general population in the greatest way. This role will be expanded to include preventive care, to provide for basic pharmacologic coverage as needed, and to provide necessary immunizations when traditional primary care has failed. We have a moral obligation to recognize that resources are limited and to allocate them so as to benefit the greatest number of patients in the greatest way. As members of the medical profession best equipped to assume such a task, it is incumbent upon EPs to act as advocates to the public to enable us to fulfill this mission.

Tricyclic antidepressant poisoning

Tricyclic antidepressant poisoning causes predictable electrocardiographic abnormalities and can be lethal. Cardiac arrhythmias, hypotension, seizures, and coma are common. Sodium bicarbonate is still considered the treatment of choice for severe toxicity, although a variety of supportive measures may be taken. Hypertonic saline appears to be a promising alternative. A QRS interval longer than 100 ms appears to be a better predictor of serious complications than is an elevated serum tricyclic antidepressant level. Cardiovascular toxicity is classically manifested as ventricular dysrhythmias, hypotension, heart block, bradyarrhythmias, or asystole. Activated charcoal binds tricyclic antidepressants. Give 30 to 50 g orally or by nasogastric tube with or without a cathartic (sorbitol 0.5 g/kg or 30 g of magnesium sulfate). Sodium bicarbonate is indicated if the QRS duration is more than 100 ms or the terminal right-axis deviation is more than 120 degrees. The suggested dosage is 1 to 2 mEq/kg, repeated as needed. Tricyclic antidepressants are used not only for depression but also for chronic pain syndromes, obsessive-compulsive disorder, panic and phobic disorders, eating disorders, migraine prophylaxis, and peripheral neuropathies.

Dissection of the vertebral arteries: case report and discussion

Vertebral artery dissection is an unusual condition with potentially protean neurologic presentations. It may occur spontaneously or follow apparently minor neck trauma. Ischemic symptoms related to the posterior circulation ensue and may be due to obstruction or embolization. The ensuing stroke is ischemic, although subarachnoid hemorrhage may be a complication as well. A case of vertebral artery dissection in a young woman who developed symptoms approximately one week after mild neck injury is reported, and the topic is reviewed.

Serum magnesium levels in asthmatic patients during acute exacerbations of asthma

The purpose of this study was to determine whether serum magnesium levels in asthmatic patients during acute exacerbations differ from those of a control population. Twenty-three known asthmatics presenting to the emergency department in acute exacerbation (cases) and 15 nonasthmatic patients (controls) matched for age, sex, race, and socioeconomic status had serum magnesium assays drawn. Admission criteria were: age 18 to 50 years with no history of alcoholism, heart disease, renal disease, or diuretic use. Patients giving a history of pregnancy were excluded. Serum magnesium levels were not significantly different in the two study populations, nor did they correlate with the severity of asthma (mean values: cases, 2.04 +/- 0.159 versus controls, 2.03 +/- 0.134 mg/dL; SD of the difference of the means = .048). An analysis for beta-error demonstrated the true difference of the means to be less than .1 (95% confidence) or less than .13 (99% confidence). In conclusion, serum magnesium levels in asthmatics are not significantly different from those of a control nonasthmatic population. They are not clinically useful for predicting the severity of disease.

Intravenous glucagon in the management of esophageal food obstruction

The use of intravenous glucagon in patients with obstructing esophageal food impaction of at least 24-hours duration has recently been described. Two cases of acute esophageal obstruction were relieved within ten minutes by intravenous infusion of 1 mg of glucagon. Esophagram performed both before and after glucagon administration confirmed the original obstruction and the passage of the food bolus. Therapy for bolus obstruction of the esophagus has classically included proteolytic enzyme digestion, as well as esophagoscopy with manual extraction. Each entails risk of esophageal perforation and mediastinitis. Also, the dose of proteolytic enzymes, such as papain, may take several hours to administer while endoscopic examination is generally not feasible as an outpatient emergency procedure. Intravenous glucagon can dissolve food other than meat and has the further advantage of safety in the patient in which anticholinergics, another occasionally employed therapy, are contraindicated. A protocol for management of these patients is included.