Lesson of the month 1: Pericardial mass and cardiac tamponade associated with Mycoplasma pneumoniae

Correlation of DNA load, genotyping, and clinical phenotype of Mycoplasma pneumoniae infection in children

Introduction

This study aimed to investigate the correlation between Mycoplasma pneumoniae (MP)-DNA load in the bronchoalveolar lavage fluid (BALF) of children with MP pneumonia (MPP) and its subtypes, relevant laboratory data, imaging, extrapulmonary complications in infected children, and its clinical significance in evaluating the disease.

Methods

Children hospitalized with MPP at Tianjin Children's Hospital between December 2017 and December 2020 were selected for the study, excluding those with mixed viral, bacterial, and fungal infections. Children were divided into low- and high-load groups according to the MP DNA load in BALF using real-time quantitative fluorescence polymerase chain reaction (PCR). After a successful MP culture, positive specimens were subjected to PCR-Restriction fragment length polymorphism and Multiple-locus variable number tandem repeat analysis typing. Basic data, clinical information, laboratory data, and radiological results were collected from all children included in the study.

Results

The PI-I type dominated the different load groups. Children in the low-load group had more wheezing and shortness of breath; however, children in the high-load group had a higher length of hospitalization, maximum fever temperature, higher chills/chilliness, incidence of abdominal pain, and higher C-reactive protein (CRP), procalcitonin (PCT) and aspartate aminotransferase (AST) levels. Children in the high-load group were more likely to have imaging changes such as pleural effusion, and the incidence of respiratory infections and extrapulmonary complications was higher than that of those in the low-load group. We applied Spearman's correlation analysis to clarify the relationship between MP DNA load and the clinical severity of MPP. We found that MP DNA load was positively correlated with length of hospitalization, maximum fever temperature, CRP, PCT, Interleukin-6 (IL-6), and AST levels, and negatively correlated with fever and cough durations, white blood cell count (WBC), and proportion of monocytes (MONO). The degree of correlation was as follows: length of hospitalization > IL-6 > cough duration > AST > fever duration > PCT > WBC > proportion of MONO > maximum fever temperature > CRP levels.

Conclusions

MP DNA load was not correlated with MP typing but was significantly correlated with the children's clinical phenotype. Therefore, the MP DNA load helps in the early diagnosis of infection and can better predict disease regression.

[Clinical implications of the genus Mycoplasma]

Dentro del género Mycoplasma, las especies que tradicionalmente se han relacionado con cuadros infecciosos han sido principalmente M. pneumoniae, M. genitalium, M. hominis o U. urealyticum. Sin embargo, existen otras muchas que están implicadas y, que muchas veces, son desconocidas para los profesionales sanitarios. El objetivo de esta revisión es identificar todas las especies del género Mycoplasma que se han aislado en el hombre y determinar su participación en la patología infecciosa humana.

Mycoplasma pneumoniae Presenting With Pericardial Tamponade

Mycoplasma pneumoniae (MP) is a common cause of community acquired pneumonia in school aged children but rarely causes pericardial and pleural effusions in a previously healthy host. We report an adolescent presenting with pericardial effusion with tamponade and pleural effusions most likely caused by MP infection. Definitive diagnosis of pericardial effusion is a challenge even when pericardial fluid or tissue is available. Serology is the mainstay of diagnosis. IgM is a reliable indicator of recent MP infection, but rising titers are needed which could delay diagnosis. Pericardial effusion with tamponade is a rare presentation of MP infection. As appropriate treatment significantly affects the outcome, investigating for MP should be part of the routine workup for pericarditis of unknown etiology.

A case of cardiac tamponade due to an isolated abscess in the ascending aorta of a pregnant woman with a history of intravenous substance abuse

We describe the case of a 23-year-old white female, 10-12 weeks pregnant, with a history of intravenous drug use and a recently diagnosed pneumonia, who was found deceased in her bed after a night of sleep. Although postmortem serum toxicology tested positive for alprazolam, tetrahydrocannabinol, and morphine, the ultimate cause of death was determined to be cardiac tamponade secondary to an isolated abscess in the ascending aorta. The patient had several risk factors for aortic rupture and cardiac tamponade including intravenous drug use, pneumonia, and pregnancy. However, an autopsy of the patient showed an isolated abscess of the ascending aorta without evidence of infective endocarditis, coronary artery rupture, aortic aneurysm, or aortic dissection making this an unusual case of cardiac tamponade. The aim of this case report is to encourage providers to obtain a tissue culture of any aortic abscesses so that the organisms involved can be identified. The identification of such organisms may help guide antimicrobial treatment in similar presentations in the future.