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

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.