Pertussis: Symptoms, Diagnosis, and Treatment PDF

Pertussis Introduction to pertussis Pertussis is an acute respiratory tract infection caused by Bordetella pertussis and Bordetella parapertussis. Sydenham first used the term pertussis, meaning intense cough, in 1670. It is preferable to whooping cough because most infected individuals...

Pertussis Introduction to pertussis Pertussis is an acute respiratory tract infection caused by Bordetella pertussis and Bordetella parapertussis. Sydenham first used the term pertussis, meaning intense cough, in 1670. It is preferable to whooping cough because most infected individuals do not “whoop.” Etiology of pertussis Bordetella pertussis is the cause of epidemic pertussis and the usual cause of sporadic pertussis. Bordetella parapertussis is an occasional cause of sporadic pertussis Pathogenesis of pertussis  Bordetella organisms are small, fastidious, Gram-negative coccobacilli that colonize only ciliated epithelium.  Pertussis is extremely contagious, with attack rates as high as 100% in susceptible individuals exposed to aerosol droplets at close range.  High airborne transmission is known to occur.  The incubation period ranges from 3-12 days Clinical manifestations of pertussis Classically, pertussis is a prolonged disease, divided into 1. Catarrhal stage 2. Paroxysmal stage and 3. Convalescent stage Clinical manifestations of pertussis The catarrhal stage The catarrhal stage (1-2 weeks) begins insidiously after an incubation period ranging from 3- 12 days with nondistinctive symptoms of congestion and rhinorrhea variably accompanied by low-grade fever, sneezing, lacrimation, and conjunctival suffusion. Clinical manifestations of pertussis The paroxysmal stage As initial symptoms wane, coughing marks the onset of the paroxysmal stage (2-6 weeks). The cough begins as a dry, intermittent, irritative hack and evolves into the inexorable paroxysms that are the hallmark of pertussis. Clinical manifestations of pertussis The paroxysmal stage (continued)  A well-appearing, playful toddler with insignificant provocation suddenly expresses an anxious aura and may clutch a parent or comforting adult before beginning a machine-gun burst of uninterrupted cough on a single exhalation, chin and chest held forward, tongue protruding maximally, eyes bulging and watering, face purple, until coughing ceases and a loud whoop follows as inspired air traverses the still partially closed airway. Clinical manifestations of pertussis The paroxysmal stage (continued) Posttussive emesis is common, and exhaustion is universal. The number and severity of paroxysms escalate over days to a week and remain at that plateau for days to weeks. At the peak of the paroxysmal stage, patients may have more than 1 episode hourly. Clinical manifestations of pertussis The convalescent stage As the paroxysmal stage fades into the convalescent stage (≥2 weeks), the number, severity, and duration of episodes diminish. Clinical manifestations of pertussis  Infants younger than 3 months of age do not display the classic stages.  The catarrhal phase lasts only a few days or is unnoticed, and then, after the most insignificant startle from a draft, light, sound, sucking, or stretching, a well-appearing young infant begins to choke, gasp, gag, and flail the extremities, with face reddened.  Cough may not be prominent, especially in the early phase.  Whoop infrequently occurs in infants younger than 3 months of age who at the end of a paroxysm lack stature or muscular strength to create sudden negative intrathoracic pressure. Clinical manifestations of pertussis Apnea and cyanosis can follow a coughing paroxysm, or apnea can occur without a cough. Apnea may be the only symptom. Apnea and cyanosis both are more common with pertussis than with neonatal infections from viruses, including respiratory syncytial virus. The paroxysmal and convalescent stages in young infants are lengthy. Clinical manifestations of pertussis  Pertussis should be suspected in any individual who has a pure or predominant complaint of cough, especially if the following features are absent: fever, malaise or myalgia, exanthem or enanthem, sore throat, hoarseness, tachypnea, wheezes, and rales.  For sporadic cases, a clinical case definition of cough of 14 days or longer duration with at least 1 associated symptom of paroxysms, whoop, or posttussive vomiting.  Pertussis should be suspected in older children whose cough illness is escalating at 7-10 days and whose coughing episodes are not continuous.  Pertussis should be suspected in infants younger than 3 months of age with gagging, gasping, apnea, cyanosis, or an apparent life-threatening event. Differential diagnosis of pertussis  Adenoviral infection usually are associated with features, such as fever, sore throat, and conjunctivitis.  Mycoplasma pneumoniae infection causes protracted episodic coughing, but patients usually have a history of fever, headache, and systemic symptoms at the onset of disease as well as more continuous cough and frequent finding of rales on auscultation of the chest. Differential diagnosis of pertussis Chlamydia trachomatis infection is associated with purulent conjunctivitis, tachypnea, rales or wheezes Respiratory syncytial virus infection is associated with predominant lower respiratory tract signs. Investigations in pertussis  Fullblood count: Leukocytosis caused by absolute lymphocytosis is characteristic.  Chest X ray: Chest radiographic findings shows perihilar infiltrate or edema (sometimes with a butterfly appearance) and variable atelectasis. Pneumothorax, pneumomediastinum, can be seen occasionally.  Confirmation of infection by B. pertussis is by culture, polymerase chain reaction (PCR) and serology Treatment of pertussis Antibiotics: an antimicrobial agent always is given when pertussis is suspected or confirmed. Macrolides are preferred agents such as azithromycin or erythromycin. Isolation of patients with pertussis  Patients with suspected pertussis are placed in isolation with droplet precautions to reduce close respiratory or mucous membrane contact with respiratory secretions.  All healthcare personnel should wear a mask upon entering the room.  Screening for cough should be performed upon entrance of patients to emergency departments, offices, and clinics to begin isolation immediately and until 5 days after initiation of macrolide therapy.  Children and staff with pertussis in childcare facilities or schools should be excluded until macrolide has been taken for 5 days. Care of household and other close contacts A macrolide agent should be given promptly to all household contacts and other close contacts as postexposure prophylaxis. Complications of pertussis  Secondary bacterial pneumonia  Seizures  Encephalopathy  The principal complications of pertussis are apnea and secondary infections (such as otitis media and pneumonia)  Fever, tachypnea or respiratory distress between paroxysms, and absolute neutrophilia are clues to pneumonia.  Expected pathogens for the secondary bacterial pneumonia include Staphylococcus aureus, Streptococcus pneumoniae, and bacteria of the oropharyngeal flora. Complications of pertussis Increased intrathoracic and intraabdominal pressure during coughing can result in:  Conjunctival and scleral hemorrhages, petechiae on the upper body  Epistaxis  Hemorrhage in the central nervous system and retina  Pneumothorax  Subcutaneous emphysema  Umbilical and inguinal hernias  Laceration of the lingual frenulum occurs occasionally Complications of pertussis  Pulmonary hypertension and cardiogenic shock.  Seizures usually are a result of hypoxemia, but hyponatremia from excessive secretion of antidiuretic hormone during pneumonia can occur.  The neuropathology documented in pertussis is cerebral parenchymal hemorrhage and ischemic necrosis.  Bronchiectasis has been reported rarely after pertussis. Prevention of pertussis Universal vaccination of infants Vaccines used are 1. DTaP vaccines( diphtheria and tetanus toxoids combined with acellular pertussis vaccines) 2. Tdap vaccines (tetanus toxoid, reduced-diphtheria toxoid, and acellular pertussis antigen vaccine)