Persistent Cough and Paracoccal
Cough can generally be classified into acute and chronic, based on the duration of manifestation. Persistent, chronic cough can be attributed to both increased reactivity of the respiratory tract and uncontrolled infection. Additional investigations to identify the causative agent allow for timely diagnosis.
In recent years, there has been a global increase in pertussis cases. Severe and fatal cases are observed primarily in newborns and infants, especially those under 3 months of age. The disease manifests as an acute infection characterized by gradually intensifying dry cough, accompanied by fatigue and elevated temperature.
Paracoccal pertussis (caused by Bordetella parapertussis) presents similar symptoms to pertussis but with a milder clinical expression. Often overlooked in clinical thinking, it is essential to consider paracoccal pertussis in the diagnostic plan when dealing with persistent cough.
Vaccination against pertussis does not provide protection against paracoccal pertussis.
Pertussis and paracoccal pertussis are highly contagious respiratory infections affecting all age groups. Even the pertussis vaccine does not confer lasting immunity. Immunity after natural infection is more prolonged and intense than after vaccination.
Paracoccal pertussis can affect all age groups, and it should be considered when the isolated agent is not identified after microbiological testing, and multiple courses of antibiotics have not been effective.
If cough primarily occurs at night, it is crucial to rule out cardiovascular disease, which may also affect the lungs, especially in older patients.
In infants (under 6 months of age), a more severe course of paracoccal pertussis infection may be observed. In both infants and patients in other age groups, coinfection with pertussis and paracoccal pertussis can be demonstrated, leading to a particularly challenging situation.
The incubation period between exposure and onset of the disease is unknown but is presumed to range from seven to ten days, possibly extending up to 21 days. Patients are contagious during the first three weeks of cough symptoms, even before completing a 5-day course of antibiotics to which the causative agent is sensitive.
The infection can also be entirely asymptomatic. Studies show that the most common symptoms with an isolated agent are persistent cough, paroxysmal (in bouts), and the presence of wheezing. In some cases, vomiting may also occur.
However, these symptoms manifest in the majority of cases for a short period.
Appropriate materials for investigation using PCR include nasopharyngeal and throat secretions, or the so-called swab. A sample is taken from the mucous membranes, and the examination is conducted.
For persistent cough without an isolated causative agent, it is essential to search for atypical causes of pneumonia. These include Chlamydia pneumoniae and Mycoplasma pneumoniae, which are also transmitted through airborne droplets.
Paracoccal pertussis typically begins with catarrhal symptoms, including clear nasal secretions (rhinorrhea), fever, and mainly dry cough. Cough may persist for up to 3 months and may be followed by other respiratory infections – secondary bacterial infections. The cough may be described as convulsive.
Appropriate materials for investigation using PCR include throat secretions, sputum, or bronchoalveolar lavage (BAL). Additionally, another suitable method is microbiology, where it is crucial to note in the examination form that paracoccal pertussis is sought, as the microorganism grows on special media that should be used for cultivation. Since routine microbiological testing does not include such media, microbiology results may come back negative.
In recent years, an increase in pertussis cases has been registered in communities and daycare centers. The refusal of some parents to vaccinate their children puts them at risk of the disease, even children with regular immunizations. Although, in most cases, based on vaccine-induced immunity, they experience a significantly milder course of the disease.