whooping cough



OVERVIEW

Definition

Pertussis is an acute respiratory infection caused by Mycobacterium pertussis.

It is characterized by a paroxysmal, spasmodic cough, which is terminated by an inspiratory roar like that of a chicken.

The course of the disease is long, and the cough can last for 2 to 3 months without treatment, hence the name “pertussis”.

Pertussis is highly contagious, but can be effectively prevented by vaccination.

Incidence

Pertussis is distributed throughout the world and is common in temperate and cold zones.

It can occur in all seasons, but is most common in winter and spring.

It can occur at any age, but is most common in children under 5 years of age.

Causes

Causes

Infectious agents

Patients with pertussis, people with latent infections, and carriers are the source of the disease.

The disease is contagious from the incubation period until 6 weeks after the onset of illness.

Route of transmission

The disease is mainly spread by respiratory droplets, coughing, talking, sneezing secretions scattered in the air to form aerosols, through the respiratory tract inhalation infection.

Transmission within the family is more common, and the possibility of indirect transmission is small.

Susceptible Population

The population is generally susceptible to pertussis, with the highest susceptibility in children under 5 years of age.

Because the mother lacks sufficient protective antibodies to be passed on to the fetus, the incidence is higher in infants under 6 months of age and can also occur in newborns.

If children have been vaccinated for more than 12 years and the level of antibodies in their bodies decreases, the incidence of the disease can still reach more than 50%.

Pathogenesis

After invading the respiratory tract, B. pertussis adheres to the mucous membranes of the respiratory tract, where it proliferates and produces toxins.

The toxin can lead to the degeneration of mucosal epithelial cells, paralysis of cilia on the epithelial surface, reduction of protein synthesis, and destruction of organelles.

As a result of ciliary dyskinesia, the mucous secretions produced by inflammation cannot be discharged, irritating the respiratory tract and causing a continuous spasmodic cough until the secretions are discharged.

The child is in an expiratory state during the spasmodic cough, and at the end of the spasmodic cough there is a high pitched, chicken-like inspiratory sound due to the inhalation of a large amount of air through the spasmed vocal folds.

Prolonged cough stimulation can make the cough center of the cerebral cortex to form a persistent excitation foci, in the recovery period or the first healing of the disease, once by the smoke, steam, cold air stimulation or crying, can also cause spasmodic coughing episodes.

Pertussis mainly causes damage to the bronchial and fine bronchial mucosa, but lesions may also be seen in the nasopharynx, larynx and trachea.

Inflammation of the bronchial and peri-alveolar interstitium occurs, tracheal and bronchial lymph nodes are often enlarged, and secretions can cause atelectasis or bronchiectasis when they block the bronchi.

Predisposing factors

Not having been immunized against pertussis.

Infants and young children who have not been immunized against pertussis.

Close contact with a person with pertussis.

Symptoms

The disease is characterized by a paroxysmal, spasmodic cough and a chicken-like inspiratory roar at the end of the cough. The incubation period ranges from 2 to 21 days, with an average of 7 to 10 days. The onset of the disease may be followed by a kata phase, a spasmodic cough phase, and a recovery phase.

Catarrhal phase

The period of time from onset to the onset of paroxysmal spasmodic cough is called the kata phase.

Symptoms include low-grade fever, cough, sneezing, tearfulness, and malaise, and symptoms last 7 to 10 days.

The cough begins as a single dry cough, and the fever subsides after 3 to 4 days, but the cough intensifies, especially at night, when it is most contagious, and can be effectively controlled with prompt treatment during this period.

Spasmodic cough

The main symptom is a characteristic paroxysmal, spasmodic cough that lasts 2 to 6 weeks or longer.

Coughing episodes may be preceded by chest tightness, throat tickling and other discomforts.

Facial edema, subconjunctival hemorrhage, and rhinorrhea may occur with frequent spasmodic coughs.

Extension of the tongue during spasmodic cough may cause ulceration of the tethered ligament.

In children, seizures can be characterized by a painful expression, redness of the face and ears, and in some patients, jugular vein rupture, which can lead to incontinence.

In infants and newborns, asphyxia, profound cyanosis, and convulsions may occur due to the small vocal folds. Attacks often occur at night, and if rescue is not timely, death can often be caused by asphyxia.

Recovery period

The number of paroxysmal spasmodic coughs decreases until they disappear.

The cough improves and resolves after 2 to 3 weeks.

If there are complications, the duration of the disease can be up to several weeks.

Complications

Bronchopneumonia

Most common, often occurs during the spasmodic cough phase, secondary to other bacterial or viral infections.

It is characterized by high fever, shortness of breath, and fine wet rales in both lungs on auscultation.

When the cough is severe, the alveoli may rupture, causing pneumothorax, mediastinum and subcutaneous emphysema.

Pertussis encephalopathy

This is the most serious complication and occurs mainly in the spasmodic cough phase. It is easily seen in newborns and infants under 3 months of age.

It presents with impaired consciousness, convulsions, and respiratory failure, which can be life-threatening.

Some survivors have sequelae such as hemiplegia, mental retardation and epilepsy.

Worsening of tuberculosis

Pertussis may worsen the existing tuberculosis, and may even cause tuberculosis of corniform type or tuberculous meningitis.

Others

Due to the increase in abdominal pressure when coughing, it may lead to umbilical hernia, inguinal hernia, rectal prolapse, etc.

Consultation

Department of Medicine

Infectious diseases

If you have a history of close contact with a person with pertussis, or if you have a spasmodic cough, severe cough at night, coughing up sputum, or a “rooster-like” aspiration, we recommend that you consult a doctor promptly.

Respiratory medicine

If you have the above symptoms, you can also go to the respiratory medicine department. After confirming the diagnosis, refer to the Department of Infectious Diseases for treatment.

Pediatrics

Children with the above symptoms are advised to consult a pediatrician promptly.

Preparation

How to get to the doctor: registration, preparation of documents, common problems

Tips for medical consultation

Chest auscultation and chest imaging may be required during the visit, so dress in clothes that are easy to put on and take off, avoid wearing clothes made of metal, and inform the doctor if you are pregnant or planning to become pregnant.

Avoid contact with people in the vicinity, wear masks and gloves, and take non-public transportation before going to the doctor.

For patients with high fever, physical cooling can be done first, such as applying cold compresses to the forehead and wiping hands, feet and armpits with warm water.

Checklist for medical preparation

Pay particular attention to the time of onset of symptoms, special manifestations, etc.

Is there fever? What is the highest degree? Is there a pattern?

Is there a spasmodic cough? Is the cough severe during the day or at night?

Is there coughing up sputum? What does the phlegm look like?

Is there a chicken-like sound in your throat when you inhale?

How long have these symptoms been present?

Have you been in contact with anyone who has had pertussis?

Have you been immunized against whooping cough? When was it given?

Test results from the last 6 months to bring to your doctor’s appointment

Laboratory tests: blood tests

Imaging tests: chest X-ray, chest CT scan

Medication in the last 3 months, bring box or package if available

Antibiotics: erythromycin, azithromycin, clarithromycin

Diagnosis

Diagnosis is based on

medical history

Not vaccinated against pertussis.

Close contact with a pertussis patient.

Local pertussis epidemic.

Clinical manifestations

Initially, there is mostly low-grade fever, cough, sneezing, tearing, and malaise, characterized by a paroxysmal, spasmodic cough that ends with a chicken-like inspiratory growl and may persist untreated for 2 to 6 weeks or longer.

Initially, there may be no obvious physical signs.

During the spasmodic cough phase there is marked rales on lung auscultation, facial distress, and jugular venous rage. There may be ulceration of the tongue tie.

Severe cough may result in facial and eyelid edema, conjunctival hemorrhage, and rhinorrhea.

In neonates and infants under 3 months of age, breath-holding and cyanosis are most often seen after several coughs.

Laboratory Tests

Routine blood tests: peripheral blood leukocyte and lymphocyte counts are markedly elevated. If neutrophils are also increased, secondary infection is indicated.

Serologic tests: pertussis-specific IgM antibodies for early diagnosis.

Pathogenetic testing: Nasopharyngeal swab for nucleic acid testing or bacterial culture is used to confirm the diagnosis of pertussis.

Fasting is not required before the test.

Imaging

Chest X-ray: In the absence of complications, the chest x-ray may be unremarkable or mildly abnormal.

Remove necklaces, earrings, cell phones, watches, removable dentures, artificial limbs, prosthetic eyes, etc. before the examination.

Differential diagnosis

Bronchitis, Pneumonia

Similarity: Bronchitis and pneumonia caused by Bordetella pertussis, adenovirus, respiratory syncytial virus, parainfluenza virus, etc. can manifest as pertussis-like spasmodic cough, clinically referred to as “pertussis syndrome”.

Difference: this type of bronchitis and pneumonia spasm cough without inspiratory roar, but the main identification is based on serologic and etiologic testing.

Hilar lymphoma

Similarity: spasmodic cough due to compression of the trachea and bronchi by enlarged hilar lymph nodes.

Difference: no chicken-like echoes. Differential diagnosis can be made on the basis of history of tuberculosis exposure, systemic symptoms of tuberculosis toxicity, increased erythrocyte sedimentation rate, positive tuberculin test, and pulmonary imaging.

Tracheal, bronchial foreign body

Similarities: Tracheal and bronchial foreign bodies may present with spasmodic cough.

Differences: tracheal and bronchial foreign bodies have a sudden onset, a history of foreign body inhalation, no leukocytosis in blood, and foreign body shadows or lung atelectasis can be seen on X-ray. Bronchoscopy may reveal the foreign body.

Treatment

Emergency treatment

Infants with severe spasmodic coughs need to be hospitalized and guarded.

If suffocation occurs, keeping the airway open is critical. Artificial respiration, sputum and oxygen should be administered immediately, and mechanical ventilation should be given by endotracheal intubation if necessary.

If serious complications occur, immediate treatment is required.

General treatment

Isolation: isolate according to respiratory infectious disease, keep the room quiet, fresh air and appropriate temperature and humidity.

Specialized guarding: Infants under half a year of age need to be guarded by specialized personnel because asphyxia often occurs suddenly, especially at night.

Medication

Antimicrobial treatment

Antimicrobial therapy removes pathogens from the nasopharynx and reduces transmission; its use in the spasmodic cough phase usually does not shorten the course of the disease. Early antimicrobial therapy reduces the morbidity and mortality in children with severe disease.

Macrolide antibiotics: B. pertussis is still sensitive to macrolide antibiotics, erythromycin, roxithromycin or azithromycin can be applied.

Other antibiotics: such as clarithromycin.

Others

For expectorant and cough suppressant, oral or intravenous aminobromine hydrochloride can be used.

If the sputum is thick and sticky, ultrasonic nebulization inhalation can be used.

Oral salbutamol can be used when the cough is severe.

Traditional Chinese Medicine (TCM)

Traditional Chinese medicine (TCM) refers to whooping cough as “tonic cough” or “heron’s cough”, and TCM treatment can improve the symptoms. TCM treatment is based on evidence-based diagnosis and treatment by a regular TCM physician.

Prognosis

Cure

The prognosis is related to age, pre-existing health conditions and the presence of complications.

It can be cured after antibiotic treatment.

Elderly children have a good prognosis after treatment. The younger the child, the worse the prognosis.

Newborns and infants are prone to complications of pneumonia and encephalopathy and have a poorer prognosis.

Children with rickets or malnutrition have severe pertussis and poor prognosis.

Hazards

Infants and newborns may have asphyxiating episodes due to the small vocal chambers, and can die of asphyxia if not rescued in time because it often develops at night.

Pertussis can have serious complications such as bronchopneumonia, pertussis encephalopathy, etc. The prognosis is poor.

Daily Management

Daily Management

Dietary management

Diet should be light and easy to digest, such as vegetable porridge, rice soup, egg soup, noodle sheet, etc.

Eat more vegetables and fruits to supplement sufficient vitamins and trace elements.

When cough is severe, sweets such as chocolate, sugar and fruits that are too sweet such as apples, bananas and grapes should not be eaten.

Avoid spicy and greasy food, and do not eat barbecue.

Life management

Ensure sufficient rest and maintain a good mental state.

Avoid overwork, heavy exercise, etc.

Prevention

Pertussis can be immunized by vaccination, so all infants and children should be vaccinated on time according to the national vaccination schedule.

The vaccine protects for about 4 to 5 years, after which the protective effect gradually diminishes over time.

If there are suspected symptoms, it is necessary to go to the hospital in time for consultation and isolation. If there are no complications, it can be treated in isolation at home for 30-40 days, and infants within 6 months need to be hospitalized for isolation.

Unvaccinated frail infants and young children who have been in close contact with pertussis patients can be injected with antitoxin-containing immunoglobulin for prophylaxis.

Infants and young children who have not completed vaccination but have been in close contact with a pertussis patient can be prevented with medications such as erythromycin or cotrimoxazole tablets.