Appropriate indications for venous duplex ultrasonographic examinations

Cellulitis

Cellulitis is a common infection of the skin and subcutaneous tissue caused predominantly by gram-positive organisms. Risk factors include prior episodes of cellulitis, cutaneous lesions, tinea pedis, and chronic edema. Cellulitis is a clinical diagnosis and presents with localized skin erythema, edema, warmth, and tenderness. Uncomplicated cellulitis can be managed in the outpatient setting with oral antibiotics. Imaging often is not required but can be helpful. Recurrent cellulitis is common and predisposing conditions should be assessed for and treated at the time of initial diagnosis. For patients with frequent recurrences despite management of underlying conditions, antimicrobial prophylaxis can be effective.

Top 10 Myths Regarding the Diagnosis and Treatment of Cellulitis

BACKGROUND

Cellulitis is commonly treated in the emergency department (ED). Patients who present with cellulitis incur significant health care costs and may be overtreated with antibiotics. The accurate diagnosis and treatment of cellulitis plays an important role in cost-effective, high-quality medical care, as well as appropriate antibiotic utilization.

OBJECTIVE

We aim to describe common fallacies regarding cellulitis. We present 10 myths that result in misdiagnosis, overtreatment, or inappropriate empiric management of cellulitis. Clinical presentation, including swelling and redness, is explored in depth, along with incidence of community-acquired methicillin-resistance Staphylococcus aureus, management of tick bites, and effective antibiotic therapy for cellulitis.

DISCUSSION

Patients are often treated for cellulitis unnecessarily or inappropriately. Awareness of these myths will help guide providers in clinical decision making in order to effectively tailor treatment for these infections.

CONCLUSIONS

Cellulitis is not as simple as it might seem, and is commonly misdiagnosed in the ED. Noninfectious causes of local symptoms, including lymphedema, venous stasis, and deep vein thrombosis need to be considered. Cellulitis should be treated with empiric antimicrobial therapy based on patient risk factors and regional susceptibility patterns. This review will assist providers in managing cellulitis and avoiding treatment errors that lead to high costs, unwanted side effects for patients, and overuse of antibiotics.

Incidental Findings in Stress Echocardiography

Sonographic follow-up of surgical or other invasive procedures may lead to incidental findings, and knowledge of a patient’s treatment history is an important factor in properly interpreting these results. The treatment regimen for a patient with deep vein thrombosis and its sequelae can include a combination of anticoagulation, thrombolytic therapy, compression stocking, venous bypass, and stenting of the veins. This case presents an incidental finding during a stress echo examination of embolization into the right ventricle of a previously placed iliofemoral venous stent that required surgical removal. It provides an example of the reasons that sonographers need to understand patient history as well as examination protocols to properly evaluate the sonographic images and to anticipate that there may be unexpected findings with every case.

Risk of deep vein thrombosis in patients with cellulitis and erysipelas: a systematic review and meta-analysis

INTRODUCTION

The occurrence of deep vein thrombosis (DVT) is often considered in patients with cellulitis and erysipelas because of the common presentation of unilateral limb swelling, erythema and pain. Different authors however have reached different conclusions about the prevalence of DVT in these patients and for the need for compression ultrasound (CUS). The purpose of this study is to determine the prevalence of DVT in patients with cellulitis and erysipelas, and inform the utility of CUS.

METHODS

A systematic literature search was conducted of Medline and Cochrane for studies that reported groups of patients with cellulitis or erysipelas who had CUS to evaluate for DVT. Study quality assessment was based on the Newcastle-Ottawa Quality Assessment Scale for Cohort Studies. The incidence rates from the included studies were pooled using a random-effects model to calculate an overall DVT rate. Individual and pooled DVT rates with corresponding upper and lower limits were graphed as a forest plot. Between-study heterogeneity was estimated using the I(2) statistic.

RESULTS

Nine studies were included totaling 1054 patients with cellulitis or erysipelas with 18 DVTs. The overall pooled incidence rate was 2.1% (95% confidence interval, 0.5%-9.1%) for proximal DVT and 3.1% (95% confidence interval, 1.9%-4.9%) for any DVT. When analyzed separately, the pooled incidence rate for the three retrospective studies was 1.1% (95% CI, 0.6%-2.2%), while the rate for the six prospective studies was 7.8% (95% CI, 4.2%-14.2%).

CONCLUSION

The risk of DVT in cellulitis and erysipelas is low compared to the average risk of patients referred for CUS and comparable to low risk patients as determined by the commonly employed Wells criteria.

Cellulitis: definition, etiology, and clinical features

Cellulitis is a common condition seen by physicians. Over the past decade, skin and soft tissue infections from community-associated methicillin-resistant Staphylococcus aureus have become increasingly common. In this article, the definition, etiology, and clinical features of cellulitis are reviewed, and the importance of differentiating cellulitis from necrotizing soft tissue infections is emphasized. Empiric antimicrobial recommendations are suggested, including the most recent recommendations from the Infectious Disease Society of America.

Predictors of a positive duplex scan in patients with a clinical presentation compatible with deep vein thrombosis or cellulitis

BACKGROUND

Deep vein thrombosis (DVT) and cellulitis are common conditions whose symptoms lead patients to seek medical attention in the emergency department (ED). Distinguishing between these two conditions quickly and accurately is important.

OBJECTIVES

To determine the yield of duplex scanning among ED patients whose clinical presentation is compatible with DVT or cellulitis. In addition, to determine whether baseline clinical variables are predictive of the final diagnosis among ED patients with an initial clinical impression of 'DVT versus cellulitis' who underwent duplex scanning.

METHODS

In this historical cohort study, patients with a final diagnosis of DVT (positive duplex) were compared on several baseline variables with patients with a final diagnosis of cellulitis (negative duplex and antibiotics prescribed) .

RESULTS

One hundred-nine of 542 ED patients referred for a duplex scan were initially diagnosed as 'DVT versus cellulitis', 17% of whom had DVT confirmed by a positive duplex scan. Comparing patients with DVT versus those with cellulitis, 0% versus 15.3% had rigors (P=0.06); 0% versus 8.3% had distinct margins of erythema (P<0.01); 5.3% versus 22.2% were currently on antibiotics (P=0.09); and 50% versus 21.3% had an elevated white blood cell count (P=0.04).

CONCLUSION

There are differences in a number of baseline characteristics of 'DVT versus cellulitis' patients who went on to have either positive or negative duplex scans, some of which were statistically significant despite the limited sample size. These findings should be confirmed prospectively in a larger study sample since they may have the potential to aid in the clinical differentiation between DVT and cellulitis.

Appropriate indications for venous duplex scanning based on D-dimer assay

Because of the rapid growth in requests for lower extremity duplex scanning, we tested a new rapid D-dimer assay method, the Miniquant test, for its ability to rule out deep vein thrombosis (DVT) in patient subgroups with the following risk factors: malignancy, postoperative state, and cellulitis. One hundred twenty-six consecutive patients with suspected DVT underwent clinical assessment, D-dimer testing with quantitative Miniquant D-dimer assay, and duplex scanning according to standard criteria for the diagnosis of DVT. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were calculated versus duplex scanning for the various risk factor subgroups. Our results showed that the Miniquant D-dimer assay is useful preselection procedure (high NPV) in selected patient subgroups with suspected proximal DVT, including patients with cellulitis and those without malignancy or postoperative state. This preselection procedure has the potential for avoiding a large proportion of unnecessary duplex scanning, thus saving time and reducing costs.

Enoxaparin treatment in high-risk trauma patients limits the utility of surveillance venous duplex scanning

OBJECTIVE

The value of surveillance venous duplex scanning for detecting unsuspected deep venous thrombosis (DVT) in trauma patients who are receiving enoxaparin prophylaxis is open to question. This study was undertaken to determine whether enoxaparin reduced the clinical utility of surveillance scanning and whether management of these patients was altered by findings of the scans.

METHODS

The medical records of trauma patients who met defined criteria for high DVT risk, admitted during 30 consecutive months, were reviewed. These patients received enoxaparin 30 mg every 12 hours for the duration of their admissions. Per protocol, surveillance lower extremity venous duplex scans were performed within 72 hours of enoxaparin administration and then weekly until patients were discharged from the hospital. The records were reviewed for thromboembolic events (DVT or pulmonary embolism [PE]), patient location and ambulatory status, therapeutic interventions (systemic anticoagulation, vena cava filter), and complications of enoxaparin therapy.

RESULTS

A total 241 patients underwent 513 venous duplex examinations (1-13 per patient). Eight patients had DVT on the initial scan; seven of these patients were asymptomatic. Five were treated with anticoagulation and/or vena cava filter placement. Of the 233 patients with initially negative duplex scan results, five patients (2%) developed clinically unsuspected lower extremity DVT while hospitalized. All of these five patients were in an intensive care unit. Three of the five patients had no change in treatment. Two of the five underwent anticoagulation, and one vena cava filter was placed. PE occurred in two hospitalized patients, one of whom was ambulatory, with negative duplex scan results. After hospital discharge, six other patients had symptomatic DVT or PE despite in-hospital scans with negative results. Complications associated with enoxaparin included hemorrhage (2) and thrombocytopenia (8).

CONCLUSIONS

After initial negative scan results, repeat surveillance duplex scanning during hospitalization detected a low incidence (2%) of DVT in high-risk patients. Furthermore, the detection of unsuspected DVT altered the clinical management of less than 1% of the patients tested. Thus, after a venous duplex scan with negative results and initiation of enoxaparin prophylaxis, subsequent surveillance duplex examinations are not warranted in asymptomatic trauma patients.