Pertussis (Whooping Cough)

An acute bacterial respiratory infection characterised by an inspiratory whoop following paroxysmal cough. It is highly contagious with an incubation period of 7-10 days. It is a notifiable disease.

Cause

Bordetella pertussis, spread by droplet infection

Clinical features

Stage 1: Coryzal (catarrhal: 1-2 weeks)
- Most infectious stage
- Running nose, mild cough, slight fever
Stage 2: Paroxysmal (1-6 weeks)
- More severe and frequent repetitive cough ending in a whoop, vomiting, conjuctival haemorrhage
- Fever may be present; patient becomes increasingly tired
- In infants <6 months: paroxyms lead to apnoea, cyanosis (coughing bouts and whoops may be absent)
Stage 3: Convalescent
- Paroxysmal symptoms reduce over weeks or months
- Cough may persist

Complications may include

Respiratory: pneumonia (new onset fever a symptom), atelectasis, emphysema, bronchiectasis, otitis media
Nervous system: convulsions, coma, intracranial haemorrhage
Others: malnutrition, dehydration, inguinal hernia, rectal prolapse

Differential diagnosis

Chlamydial and bacterial respiratory tract infection
Foreign body in the trachea

Investigations

Clinical diagnosis
Blood: complete blood count
Chest X-ray

Management

Treatment

Maintain nutrition and fluids
Give oxygen and perform suction if the child is cyanotic
For the unimmunised or partly immunised, give DPT (three doses) as per routine immunisation schedule
Isolate the patient (avoid contact with other infants) until after 5 days of antibiotic treatment
Treatment should be initiated within 3 weeks from onset of cough: Erythromycin 500 mg every 6 hours for 7 days
- Child: 10-15 mg/kg every 6 hours

Note: Cough mixtures, sedatives, mucolytics, and antihistamines are USELESS in pertussis and should NOT be given

Prevention

Educate parents on the importance of following the routine childhood immunisation schedule
Ensure good nutrition
Avoid overcrowding
Booster doses of vaccine in exposed infants