A pilot study to develop a prediction instrument for endocarditis in injection drug users admitted with fever

Prediction Models of Infective Endocarditis Usable Ahead of Performing Blood Cultures: A Narrative Review

Infective endocarditis (IE) often presents as a fever of unknown origin due to its extremely diverse clinical presentations, requiring diverse advanced medical equipment and tests to make a correct diagnosis. Whether a physician can suspect IE in a clinical setting is dependent on the physician's knowledge and experience. If IE is not suspected, antibiotics are administered without obtaining blood cultures, complicating the clinical course and prognosis. To avoid delayed diagnosis or entering the maze of diagnostic difficulties of IE cases, a prediction model to deduce IE likelihood can be used at an early stage after a patient's arrival at the hospital before blood culture examinations would be invaluable. In this study, we aimed to review the literature on such prediction models for IE diagnosis in existence, discussing their strengths and limitations. A narrative review was conducted by two researchers using PubMed. Comprehensive searches included the index terms "infective endocarditis" or "infectious endocarditis", coupled with "prediction model" or "prediction rule" or "predictive model". Five articles reporting one of the three prediction models were identified. The first model, developed for intravenous drug users (IDUs) admitted to the emergency departments of two to three hospitals showed a good area under the curve (AUC) of 0.8; however, the small sample size and overfitting of the model were a limit. The second model for inpatients in all departments of four hospitals showed an AUC of 0.783 with a shrinkage coefficient of 0.963, indicating high generalizability. Moreover, it featured the highest ease of use because it consisted of only five factors readily available in any hospital. The third model, developed for inpatients admitted to an emergency department at a single center, consisted of 12 factors and achieved the highest AUC (0.881). All models demonstrated fair to good AUC. The second model excelled in generalizability and ease of use, while the third model was superior in performance. To further improve the accuracy of each IE prediction, further high-level evidence studies, such as randomized controlled trials in multiple facilities, are mandatory.

Correlation of Physical Exam Findings with Fever in Patients with Skin and Soft Tissue Infections

Introduction

The objectives of this study were to determine the prevalence of fever in adult ED patients with skin and soft tissue infections (SSTI) and to determine which, if any, physical exam, radiograph and laboratory test findings were associated with fever.

Methods

We conducted a prospective, observational study at an urban county trauma center of adults who presented to the ED for evaluation of suspected SSTI. ED providers measured area of erythema and induration using a tape measure, and completed data sheets indicating comorbid conditions and the presence or absence of physical exam findings. Fever was defined as any recorded temperature ≥ 38°C during the first six hours of ED evaluation.

Results

Of the 734 patients enrolled, 96 (13.1%) had fever. Physical and laboratory exam findings associated with the presence of a fever in multivariable logistic regression were the area of erythema, particularly the largest quartile of area of erythema, 144 – 5,000 cm², (odd ratio [OR] = 2.9; 95% confidence interval [CI] [1.6 – 5.2]) and leukocytosis (OR = 4.4, 95% CI [2.7 – 7.0]). Bullae, necrosis, streaks, adenopathy, and bone involvement on imaging were not associated with fever.

Conclusion

Fever is uncommon in patients presenting to the ED for evaluation of suspected SSTI. Area of erythema and leukocytosis were associated with fever and should be considered in future decision rules for the evaluation and treatment of SSTI.

Cotton Fever: Does the Patient Know Best?

Fever and leukocytosis have many possible etiologies in injection drug users. We present a case of a 22-year-old woman with fever and leukocytosis that were presumed secondary to cotton fever, a rarely recognized complication of injection drug use, after an extensive workup. Cotton fever is a benign, self-limited febrile syndrome characterized by fevers, leukocytosis, myalgias, nausea and vomiting, occurring in injection drug users who filter their drug suspensions through cotton balls. While this syndrome is commonly recognized amongst the injection drug user population, there is a paucity of data in the medical literature. We review the case presentation and available literature related to cotton fever.

Association of hyponatremia with in-hospital outcomes in infective endocarditis: A 5-year review from an Indian Intensive Care Unit

Hyponatremia is commonly noted with cardiovascular disorders, but its role in infective endocarditis (IE) is limited to being a marker of increased morbidity in IE patients with intravenous drug use. This was a 5-year retrospective review from an Indian Intensive Care Unit (ICU). Patients >18 years with IE and available serum sodium levels were included in the study. Pediatric and pregnant patients were excluded from the study. Hyponatremia was defined as admission sodium <135 mmol/L. Detailed data were abstracted from the medical records. Primary outcomes were need for invasive mechanical ventilation, ICU length of stay, and in-hospital mortality. Secondary outcomes included development of acute kidney injury, acute decompensated heart failure (ADHF), acute respiratory distress syndrome, stroke, and severe sepsis in the ICU. Two-tailed P < 0.05 was considered statistically significant. Between January 2010 and December 2014, 96 patients with IE were admitted to the ICU with 85 (88.5%) (median age 46 [34.5-55] years, 51 [60.0%] males) meeting our inclusion criteria. The comorbidities, echocardiographic, and microbiological characteristics were comparable between patients with hyponatremia (56; 65.9%) and eunatremia (29; 34.1%). Median sodium in the hyponatremic cohort was 131 mmol/L (127.25-133) compared to the eunatremic cohort 137 mmol/L (135-139) (P < 0.001). The primary outcomes were not different between the two groups. Hyponatremia was associated more commonly with ADHF (12 [21.4%] vs. 0; P = 0.007) during the ICU stay. Hyponatremia is commonly seen in IE patients and is not associated with worse hospital outcomes. ADHF was seen more commonly in the hyponatremic patients in comparison to those with eunatremia.

Validation of a prediction rule for endocarditis in febrile injection drug users

BACKGROUND

Infectious endocarditis (IE) in febrile injection drug users (IDUs) is a critical diagnosis to identify in the emergency department (ED). A decision tool that identifies patients at very low risk for endocarditis using readily available clinical data could reduce admissions and cost.

OBJECTIVE

To evaluate the diagnostic performance of a previously derived decision instrument to rule out endocarditis in febrile IDUs (Prediction Rule for Endocarditis in Injection Drug Users [PRE-IDU]) and to develop a prediction model for likelihood of endocarditis for those who are not ruled out by PRE-IDU.

METHODS

Febrile IDUs admitted to rule out endocarditis were prospectively enrolled from 2 urban EDs in June 2007 to March 2011. Clinical data from ED presentation (first 6 hours) and outcome data from inpatient records were recorded and reviewed by 2 independent investigators. Diagnosis of IE was based on modified Duke criteria and discharge summaries. The diagnostic performance of PRE-IDU, which combines tachycardia, cardiac murmur, and absence of skin infection, was determined using recursive partitioning and logistic regression modeling.

RESULTS

Of the 249 subjects, 18 (7%) had IE. Recursive partitioning yielded an instrument with 100% sensitivity (95% confidence interval [CI], 84%-100%) and 100% negative predictive value (95% CI, 91%-100%), but low specificity (13%; 95% CI, 12%-13%). Multiple logistic regression modeling with the 3 clinical predictors allowed risk stratification with posttest probabilities ranging from 3% to 20%.

CONCLUSION

The PRE-IDU instrument predicted IE with high sensitivity and ruled out IE with high negative predictive value. Our logistic regression model provided posttest probabilities ranging from 3% to 20%. The PRE-IDU instrument and the associated model may help guide hospital admission and diagnostic testing in evaluation of febrile IDUs in the ED.

Intravenous drug abuse and tricuspid valve endocarditis: Growing trends in the Middle East Gulf region

Traditionally, tricuspid valve endocarditis is uncommon in the Middle East region. However, recent global data indicate growing trends in the use of illicit drug abuse, specifically injectable heroin, in the Middle East Gulf region. The presence of many transit port services in the Middle East Gulf States has led to smuggling of substance abuse drugs in the region. The Middle East Gulf States, currently a transit market, are also becoming a growing consumer market in view of the increased substance abuse in the youth. However, there is a paucity of data with respect to the prevalence or incidence of tricuspid valve endocarditis in the region, probably due to underdiagnosis or underreporting. A high index of suspicion of tricuspid valve endocarditis is essential in patients with a history of intravenous drug abuse. This article reviews the epidemiology of illicit drug abuse in the Middle East Gulf region, as well as the diagnosis and treatment of tricuspid valve endocarditis, and calls for all physicians in the region to be vigilant while dealing with intravenous drug abuse.