OVERVIEW

What is whooping cough?

Whooping cough (pertussis) is an acute respiratory infectious disease caused by Bordetella pertussis.

The illness typically lasts 2–3 months, hence the name "whooping cough."

It is mainly characterized by intermittent spasmodic coughing followed by an inspiratory whoop. It commonly affects infants and young children and may lead to complications such as suffocation, pneumonia, or pertussis encephalopathy, with a relatively high mortality rate.

In recent years, the incidence among infants, young children, and adults has shown an increasing trend.

There is no highly effective treatment, but symptoms can be managed through antibiotics and supportive therapy. Respiratory isolation is required during the illness, though the patient's quality of life is not severely affected.

SYMPTOMS

What are the symptoms of whooping cough?

The disease typically has an incubation period of 7–10 days on average. Whooping cough develops subtly and progresses slowly but persistently, worsening over time like a long downhill slope. The illness often lasts 2–3 months, hence the name "whooping cough." The clinical course is divided into three stages:

(1) Catarrhal stage symptoms

This stage lasts about 7–14 days from onset until the appearance of paroxysmal spasms. Initial symptoms resemble a cold, including fever, cough, sneezing, and tearing. After 2–3 days, the fever subsides, but the cough worsens, particularly at night, progressing from a dry cough to spasmodic coughing.

(2) Paroxysmal stage symptoms

This stage typically lasts 2–4 weeks or longer. Fever is usually absent by this point, and the patient experiences bouts of spasmodic coughing—rapid, consecutive coughs (10 to dozens in a row) followed by a deep inhale. This cycle repeats until thick mucus or stomach contents are expelled, often occurring at night.

Activities like running, eating, exposure to cold, or emotional changes can trigger coughing fits. During episodes, the patient appears distressed with a flushed face. Repeated coughing may cause neck vein distension or even incontinence.

Severe cases may lead to facial swelling, subconjunctival or nosebleeds, or intracranial hemorrhage. Newborns and infants often lack typical spasmodic coughing and may instead exhibit breath-holding spells, facial cyanosis, suffocation, or convulsions.

Brain hypoxia can cause seizures (asphyxial attacks), usually at night. Without prompt treatment, these may lead to fatal suffocation.

(3) Convalescent stage symptoms

This stage lasts 2–3 weeks. Coughing fits diminish, and the patient’s appetite and energy return to normal. Complications may prolong recovery.

(4) Complications

1. Bronchopneumonia: A common complication from secondary infection, marked by high fever, rapid shallow breathing, and cessation of spasmodic coughing. Severe cases in children may include emphysema or subcutaneous emphysema.

2. Whooping cough encephalopathy: The most severe complication, caused by brain hypoxia or hemorrhage, leading to altered consciousness, seizures, or high fever, potentially life-threatening. Survivors may retain neurological deficits like limb weakness.

3. Others: Subconjunctival hemorrhage, inguinal hernia, or rectal prolapse.

CAUSES

What causes whooping cough?

Whooping cough is an acute respiratory infectious disease caused by Bordetella pertussis. It spreads through respiratory transmission, primarily affecting infants and young children, though it can occasionally occur in adults.

DIAGNOSIS

How is whooping cough diagnosed?

When diagnosing whooping cough, doctors primarily consider the patient's exposure history, symptoms, and auxiliary tests.

• Epidemiological history
  The disease is highly contagious, with over 90% of susceptible individuals in close contact developing the illness. It is more common in winter and spring and predominantly affects infants and young children.
• Typical clinical manifestations
  Symptoms include catarrhal symptoms, worsening cough as fever subsides, paroxysmal spasmodic coughing, and a characteristic "whooping" sound at the end of coughing episodes, which is more pronounced at night. No obvious lung abnormalities are detected.
• Laboratory tests
  • Complete blood count: In the early stages and during the initial spasmodic phase, white blood cell counts are often elevated, with lymphocyte proportions increasing to 60%–80%. About one-third of patients with secondary infections show a relative decrease in lymphocytes.
  • Serological tests: Using Bordetella pertussis as the antigen, ELISA can detect specific IgM for early diagnosis. A positive diagnosis is also confirmed if the antibody titer against B. pertussis is ≥1:320.
  • Bacteriological tests: Nasopharyngeal swabs collected early in the illness for bacterial culture yield higher positive rates. Direct detection of B. pertussis colonies is a reliable method. Post-cough nasopharyngeal swab cultures from the posterior pharyngeal wall also have high positivity rates.
  • Molecular tests: Hybridization or PCR testing of nasopharyngeal secretions using cloned B. pertussis gene fragments offers high specificity and sensitivity, enabling rapid diagnosis. However, results must be interpreted alongside clinical findings.

Due to symptoms like fever and cough, whooping cough may be confused with upper respiratory infections or tuberculosis. Doctors differentiate it through serological and bacteriological tests. Among the above laboratory tests, items 1 and 2 require venous blood sampling—simple, quick, and minimally uncomfortable. Items 3 and 4 involve secretion collection, which is non-invasive and highly accurate but slightly more expensive.

TREATMENT

How to Treat Whooping Cough?

Whooping cough generally requires hospitalization in pediatrics or infectious disease departments. The main treatments include respiratory contact isolation and medication. Drug therapy is suitable for severe symptoms, and attention should be paid to potential complications, such as lung or brain symptoms. Most cases have poor outcomes, with sequelae like severe pneumonia or impaired limb mobility.

• General Treatment
  Hospitalization is usually required. Respiratory isolation should be enforced, with fresh indoor air and a quiet environment to avoid factors that may trigger coughing. Proper nutrition and careful nursing are essential to prevent complications. Infants under six months may experience sudden suffocation or convulsions and require dedicated monitoring.
• Antibiotic Treatment
  Effective in the catarrhal or early paroxysmal stages, antibiotics can alleviate symptoms and shorten the course. Erythromycin is the first choice, while roxithromycin or azithromycin are alternatives. Other options include intramuscular ampicillin or a combination of trimethoprim (TMP) and SMZ for 7–14 days.
• Symptomatic Treatment
  Expectorants and cough suppressants like salbutamol can reduce coughing. Severe cases may require sedatives such as phenobarbital or diazepam.
• Adrenocortical Hormones
  For critically ill children, such as those with encephalopathy, oral prednisone or intravenous hydrocortisone may be used, but the side effects of hormones should be monitored.

DIET & LIFESTYLE

What should be paid attention to in daily life with whooping cough?

• During the course of the disease, rest and avoid activities in crowded places;
• In terms of diet, drink plenty of water and eat more fruits and vegetables; maintain a balanced diet with reasonable portions of meat and vegetables, use less salt and high-salt seasonings when cooking; eat fewer pickled vegetables and meats; avoid spicy and irritating foods;
• Engage in about 30 minutes of moderate-intensity exercise daily, avoiding excessive strain;
• Ensure sufficient sleep every day.

PREVENTION

How to prevent whooping cough?

• During peak seasons of the disease, ventilate rooms frequently by opening windows and avoid crowded places;
• Drink plenty of water daily, maintain a light diet, and engage in moderate exercise such as jogging, yoga, or walking to boost immunity;
• Vaccination with the DPT (diphtheria, pertussis, tetanus) triple vaccine can prevent this disease.