Predictors of Mortality in Mechanically Ventilated Critical Pertussis in a low Income Country

Pertussis infection in critically ill infants: meta-analysis and validation of a mortality score

BACKGROUND

Despite widespread vaccination programs, pertussis continues circulating within populations and remains a life-threatening infection in infants. While several mortality risk factors have been described, a comprehensive synthesis is lacking. We conducted a meta-analysis of studies investigating mortality risk factors in Pertussis infections and validated those factors in a large cohort.

METHODS

Observational studies published in English were systematically searched in PubMed, EMBASE, and LiSSa databases from 01/2000 to 06/2024. The search yielded 816 unique citations. The primary outcome was mortality before discharge from the Pediatric Intensive Care Unit (PICU). Two independent reviewers assessed the risk of bias and extracted data. A REML-random effect model was used to calculate pooled prevalence and conduct the analysis. The identified risk factors were subsequently evaluated in a monocentric cohort of patients admitted to a tertiary hospital's PICU for severe pertussis between January 1996 and December 2020. Data analysis was conducted between June and August 2024.

RESULTS

Seventeen studies, including 2,725 patients, met the inclusion criteria. The pooled prevalence of mechanical ventilation, continuous renal replacement therapy, and Extracorporeal Membrane Oxygenation support were 55% (95% CI: 40-70; I2 = 98), 15% (95% CI: 3-27; I2 = 95), and 8% (95% CI: 3-12; I2 = 93), respectively. The pooled mortality incidence was 19% (95% CI:12-26; I2 = 96). Identified mortality risk factors included elevated heart rate, presence of pulmonary hypertension, presence of seizures, and elevated white blood cell (WBC) count. Validation in an 83-patient cohort (median age: 45 days, IQR: 30-55) revealed a mortality rate of 12%. Risk factors identified in the meta-analysis were significantly associated with non-survival in the cohort. A mortality prediction score was developed incorporating age < 30 days, heart rate > 200/min, and WBC > 30 G/l, achieving an area under the curve of 0.92 (95% CI: 0.86-0.99).

CONCLUSION

This meta-analysis identified a simple yet effective score to assess the severity of pertussis infection in infants admitted to PICU. Accurate risk stratification may enable timely treatment of critically ill patients, potentially improving outcomes.

TRIAL REGISTRATION

The study protocol was registered on PROSPERO: CRD42024582057.

Burden of pertussis in infants in the Eastern Mediterranean Region and the impact of maternal vaccination: a systematic review

BACKGROUND

Despite vaccine availability, Pertussis remains a global public health challenge, especially among infants. The Eastern Mediterranean Region (EMR) presents a diverse epidemiological landscape with varying vaccination coverages and healthcare infrastructures. This systematic review aimed to assess the burden of pertussis in infants < 1 year of age in the EMR and evaluate the use and impact of pertussis vaccination during pregnancy.

METHODS

Following PRISMA guidelines, we conducted a systematic search of Scopus, Embase, CINAHL Ultimate, and PubMed from inception until April 30, 2024. Studies included reported on pertussis burden in infants or maternal vaccination. Data extraction and quality assessment were performed in duplicate, focusing on incidence, age distribution, disease severity, and vaccination uptake and impact when data were available.

RESULTS

Thirty-six studies were included, the majority from Iran (N = 11), Morocco (N = 5), Tunisia (N = 5), and Oman (N = 3), with underrepresentation of other EMR countries. The incidence of PCR-confirmed pertussis among children with suspected pertussis varied significantly, from 6.7% to 8.9% (Morocco 2018-2019) to 50.4% and 51.6% (Palestine 2004-2008) among children < 12 and < 6 months, respectively, and between 16.3% (Tunisia 2007-2016) to 73.0% (Morocco 2013-2015) in children < 2 months. Age distribution data indicated the highest burden was in infants < 2 months regardless of the population studied. High hospitalization rates and severe complications, including seizures and the need for ventilatory support, were frequently reported in infants < 6 months of age. Only one study from Saudi Arabia addressed maternal pertussis vaccination, reflecting low vaccine uptake and awareness among pregnant women.

CONCLUSIONS

This review underscores the substantial burden of pertussis among infants in the EMR and the lack of data on maternal immunization. The findings emphasize the need for enhanced surveillance and targeted public health interventions to reduce disease incidence. Future research should prioritize underrepresented countries to ensure comprehensive data for informed public health strategies.

TRIAL REGISTRATION

PROSPERO (CRD42024573471).

Critical pertussis: A multi-centric analysis of risk factors and outcomes in Oman

OBJECTIVES

To identify risk factors and outcomes of patients with critical pertussis.

DESIGN

Retrospective observational cohort study.

SETTING

Sultan Qaboos University Hospital and The Royal Hospital, Muscat, Oman.

SUBJECTS

Children aged <13 years presenting to the emergency departments and diagnosed with laboratory-confirmed pertussis by polymerase chain reaction between January 2013 and December 2018.

MEASUREMENTS AND MAIN RESULTS

In total, 157 patients were diagnosed with pertussis, of which 12% (n = 19) had critical pertussis. Patients with critical pertussis had a higher white blood cell count (WBCC) [adjusted odds ratio (aOR) 1.05; 95% confidence interval (CI) 1.02-1.08; P = 0.003], absolute lymphocyte count (ALC) (aOR 1.08; 95% CI 1.03-1.15; P = 0.004) and absolute neutrophil count (ANC) (aOR 1.05; 95% CI 1.01-1.10; P = 0.032) than patients with non-critical pertussis, even after multi-variate adjustment. The area under the curve for discriminatory accuracy of laboratory variables was 0.75 (95% CI 0.65-0.85), 0.74 (95% CI 0.64-0.84) and 0.72 (95% CI 0.60-0.83) for maximum WBCC, ALC and ANC, respectively, with Youden's cut-off values of 31.5 × 10⁹/L, 19.9 × 10⁹/L and 5.0 × 10⁹/L, respectively.

CONCLUSIONS

In children, higher WBCC, ALC and ANC were significant predictors of critical pertussis. A cut-off level of 31.5 × 10⁹/L for WBCC was associated with critical pertussis.

Clinical Profile of Critical Pertussis in Children at a Pediatric Intensive Care Unit in Northern India

Objective

To delineate the clinical profile, complications, intensive care needs, and predictors of mortality in children with critical pertussis.

Methods

Retrospective analysis of case records of children in the pediatric intensive care unit of a tertiary-care hospital, with a diagnosis of critical pertussis over 3 years. Diagnostic criteria included CDC case definition and confirmation by polymerase chain reaction (PCR), when available. Survivors and nonsurvivors were compared to identify predictors of mortality.

Results

36 records were analysed, most cases were infants (31, 86.1%). 10 (27.7%) were (below 6 weeks of age). In the rest, 16 (61.5%) were partially immunized or unimmunized against pertussis. Rapid breathing (88.9%), paroxysmal cough (86.1%) and apnea (41.7%) were common presenting complaints. Hypoxemia (97.2%), hyperleukocytosis (61.1%) and encephalopathy (52.8%) were common complications. Intensive care needs were mechanical ventilation in 11 (30.6%), vasoactive support in 7 (19.4%) and exchange transfusion in 3 (8.3%). Female gender, apnea, hyperleukocytosis, encephalopathy, need for vasoactive support, and mechanical ventilation predicted mortality.

Conclusion

Pertussis demands attention due to its varied presentation, increased complications and higher mortality.

Leukemoid Reaction in Infant Pertussis: Is There a Place for Hydroxyurea? A Case Report

A 73-days old infant of 34 weeks' gestation was hospitalized with a co-infection of respiratory syncytial virus (RSV) and Bordetella pertussis (BP). She required invasive ventilation for 9 days in the context of malignant pertussis with persistent hypoxemia and hypercapnia secondary to a leukemoid reaction. Despite an increase of white blood cell (WBC) count up to 70 G/L and ensuing pulmonary hypertension, no hemodynamic compromise occurred. Without clear indication for leukapheresis nor exchange transfusion, an off-label treatment with hydroxyurea was given for 5 days with gradual decrease of WBC count, without any complication and hospital discharge on day 29. To our knowledge, no effective therapy for malignant pertussis has been described in the literature and complications are frequent with leukoreduction procedures. We discuss an alternative to invasive procedures in young infants to fulfill the need to decrease rapidly leukocyte counts in a leukemoid reaction associated with Bordetella pertussis infection. To our knowledge, hydroxyurea has never been used in malignant pertussis but is a well-known medication for oncologic and hematologic diseases such as acute myeloid leukemia or sickle cell anemia. Its effects in this setting are not well understood but the positive outcome in our patient supports the need for further studies.

Bordetella pertussis: new concepts in pathogenesis and treatment

PURPOSE OF REVIEW

The purpose of this review is to summarize and discuss recent findings and selected topics of interest in Bordetella pertussis virulence and pathogenesis and treatment of pertussis. It is not intended to cover issues on immune responses to B. pertussis infection or problems with currently used pertussis vaccines.

RECENT FINDINGS

Studies on the activities of various B. pertussis virulence factors include the immunomodulatory activities of filamentous hemagglutinin, fimbriae, and adenylate cyclase toxin. Recently emerging B. pertussis strains show evidence of genetic selection for vaccine escape mutants, with changes in vaccine antigen-expressing genes, some of which may have increased the virulence of this pathogen. Severe and fatal pertussis in young infants continues to be a problem, with several studies highlighting predictors of fatality, including the extreme leukocytosis associated with this infection. Treatments for pertussis are extremely limited, though early antibiotic intervention may be beneficial. Neutralizing pertussis toxin activity may be an effective strategy, as well as targeting two host proteins, pendrin and sphingosine-1-phosphate receptors, as novel potential therapeutic interventions.

SUMMARY

Pertussis is reemerging as a major public health problem and continued basic research is revealing information on bacterial virulence and disease pathogenesis, as well as potential novel strategies for vaccination and targets for therapeutic intervention.

Characteristics of Bordetella pertussis infection among infantsand children admitted to paediatric intensive care units in Greece: A multicentre, 11-year study

AIM

To describe children with pertussis who required intensive care.

METHODS

This is a retrospective analysis of pertussis admissions to all (six) national intensive care units in Greece from 2003 to 2013.

RESULTS

A total of 31 children were included, 28 of whom were younger than 12 months old. Cough was the most prominent symptom, being present in 27 of 31 (87%) patients, and on admission, only 7 (22.6%) satisfied the case definition. Mechanical ventilation was initiated in 13 (42%) patients. Six patients died because of respiratory failure (two) or multi-organ system failure (four). The patients who died had significantly higher white blood cell counts (WBC) (77 800-31 600, P = 0.031) and neutrophils (29 016-12 795, P = 0021) than those who survived and lower minimum values of serum sodium (125-133, P = 0002). They also had a longer duration of hospitalisation prior to their paediatric intensive care unit admission (6-1 days, P = 0022). Three patients were diagnosed with pulmonary hypertension, and only one of them survived. Age, gender and immunisation status did not differ between survivors and non-survivors. Two patients received exchange blood transfusion, and survival benefit was not apparent.

CONCLUSION

Young infants are at risk of severe pertussis, resulting in serious complications or death. Elevated WBC and low serum sodium are associated with higher mortality. Despite advances in life support and treatment of organ failure in childhood critical illness, pertussis still has substantial mortality.

Pertussis leukocytosis: mechanisms, clinical relevance and treatment

The significant and sometimes dramatic rise in the number of circulating white blood cells (leukocytosis) in infants suffering from pertussis (whooping cough) has been recognized for over a century. Although pertussis is a disease that afflicts people of all ages, it can be particularly severe in young infants, and these are the individuals in whom leukocytosis is most pronounced. Very high levels of leukocytosis are associated with poor outcome in infants hospitalized with pertussis and modern treatments are often aimed at reducing the number of leukocytes. Pertussis leukocytosis is caused by pertussis toxin, a soluble protein toxin released by Bordetella pertussis during infection, but the exact mechanisms by which this occurs are still unclear. In this minireview, I discuss the history of clinical and experimental findings on pertussis leukocytosis, possible contributing mechanisms causing this condition and treatments aimed at reducing leukocytosis in hospitalized infants. Since recent studies have detailed significant associations between specific levels of pertussis leukocytosis and fatal outcome, this is a timely review that may stimulate new thinking on how to understand and combat this problem.