Pertussis Flashcards
Define pertussis
Whooping cough a highly infections disease caused by gram negative bacteria - bordetella pertussis
Typically presents in children
What is the common pathogen causing pertussis?
Gram stain
Bordetella pertussis
Gram negative coccobacillus
What is the immunisation programme against whooping cough?
Infants - 2,3,4months and 3-5yrs
Also vaccination campaign for pregnant women.
Does not provide lifelong protection - may develop in adolescents/adults.
Vaccine = DTaP vaccine
What are the three different phases of whooping cough?
Catarrhal phase
Paroxysmal phase
Convalescent phase
What are the features of the catarrhal phase of whooping cough?
Symptoms are similar to a viral upper respiratory tract infection
Lasts around 1-2 weeks.
What are the features of the paroxysmal phase of whooping cough?
Cough increases in severity
Bouts are worse at night and after feeding -> may vomit and central cyanosis
Inspiratory whoop
Apnoea
Persistent cough - subjuncitval haemorrhages or anoxia
Between 2-8 weeks
What are the features of the convalescent phase of whooping cough?
Cough subsides over weeks to months
What are the diagnostic criteria for whooping cough?
Suspected if has an acute cough for 14 days or more, without apparent cause and one or more:
Paroxysmal cough
Inspiratory whoop
Post-tussive vomiting
Undiagnosed apnoeic attacks in young infants
How is whooping cough diagnosed?
Per nasal swab culture for Bordetella pertissis. (days or weeks)
PCR and serology
What is the management of whooping cough?
Infants under 6 months admitted
Notifiable disease
Oral macrolide (clarithromycin) if cough within 21 days
Household -> prophylaxis
School exclusion for 48hrs after starting Abs.
What are the common complications of whooping cough?
Subconjuncitval haemorrhage
Pneumonia
Seizures/encephalopathy
Bronchiectasis
Rib fractures, weight loss and atelectasis - from severe cough.
When are pregnant women offered the vaccination against whooping cough?
16-32 weeks gestations
What are the key pathology of pertussis?
Pertussis toxin - disrupts epithelial cell function, increases histamine sensitivity.
Tracheal cytotoxin - paralysed and kills cilia
Adenylate cyclase toxin - interferes with phagocytosis
Dermonecrotic toxin - causes local necrosis.
What are the different periods of infection with pertussis?
Incubation period - 1 to 3 weeks, asymptomatic and not infectious
Catarrhal stage - 1 to 2 w, highly contagious, flu-like
Paroxysmal stage - 1 to 6 weeks - whooping cough
Convalescent stage - 1 to 2 weeks; improvement but coughing attacks may persist.
What are the risk factors for pertussis?
Unvaccinated
Immunosuppressed
Infants <1yr
Teenagers and Elderly
What complications may adults get from pertussis?
Incontinence
Rib fractures - chest wall strain
Weight loss
Syncope
