What is pertussis? 

Pertussis is a highly contagious respiratory infection that can spread through the air when people cough or sneeze. This disease is also known as whooping cough due to its "whooping" sound, which is a gasp for breath that happens after a series of intense coughs. This violent coughing can cause you to suffer from the cough and breathing difficulty that lasts weeks or even months after infection.¹

Pertussis can affect people of all ages, but babies and children are the age groups that are more vulnerable. When it occurs in infants, it can be life-threatening, especially in babies under 2 months old because they have not yet received the pertussis vaccination. This is the reason why pertussis vaccination is recommended during pregnancy as it allows the mother to pass antibodies to protect the baby when birthed. The pertussis vaccination is recommended between 16 and 32 weeks of pregnancy for optimal effectiveness.

The onset of pertussis symptoms typically occurs 7 to 10 days after getting infected. At first, you may experience flu-like symptoms such as fever, runny nose, and cough. As the illness progresses, the cough becomes more persistent, often causing bouts of coughing followed by a characteristic “whooping” sound. It's important to remember that pertussis is highly contagious, especially during the first 2-3 weeks of infection. Antibiotics are typically prescribed to manage the infection and reduce its severity. However, early diagnosis and treatment are essential not only to relieve symptoms but also to prevent complications and prevent the spread of the disease to others, particularly vulnerable populations such as infants and young children.^1,2

Complications of pertussis

Complications can be serious and deadly especially in babies under 1 year old. Below are possible complications that can arise from pertussis.

Pneumonia

Pneumonia is a common complication of pertussis, especially in infants under 1 year old. About 1 in 5 (22%) babies who are hospitalised for pertussis develop pneumonia. While adults can also suffer from pertussis-related pneumonia, the incidence is lower. A study shows that pneumonia is not only the most common complication that arises among pertussis patients, but it is also the leading cause of severe disease and death due to pertussis.^3,4

Pneumonia is a lung infection caused by bacteria, viruses, or fungi. When you suffer from pneumonia, you may experience fever, cough with yellow or green mucus production, and difficulty breathing due to the accumulation of fluid in your lungs.^1,5

Apnea

Apnea is another common complication of pertussis. It is a temporary pause in breathing. Up to 68% (2 in 3) of infants hospitalised due to pertussis may experience episodes of apnea which are linked to severe hypoxia (low blood oxygen levels) resulting from a mismatch between ventilation (the amount of air reaching your lungs) and perfusion (the blood flow to your lung air sacs). Research suggests that apnea episodes in pertussis patients can occur either following consecutive bouts of coughing or suddenly without warning. Neonates and young children who are not fully vaccinated are particularly vulnerable to this complication.^6,7,8

Central nervous system (CNS) complications

In rare instances, less than 2% of pertussis cases can lead to complications involving the central nervous system (CNS). These complications may manifest as convulsions, sudden and uncontrolled movements caused by abnormal electrical activity in the brain, and encephalopathy (a general term for brain dysfunction).

These CNS complications can arise due to various factors such as:

• Hypoxia: Low levels of oxygen in the blood, which can occur during severe coughing spells
• Hypoglycemia: Low levels of glucose (sugar) in the blood, which can affect brain function
• Toxins: Harmful substances produced by the pertussis bacteria or released during the immune response
• Secondary infection: Additional infections that may occur alongside pertussis
• Cerebral bleeding: Bleeding within the brain, potentially caused by increased pressure during coughing episodes^1,9

Fractures

In adults or the elderly, pertussis can sometimes lead to fractures, particularly when coughing gets intense. Imagine the force of those coughing fits putting pressure on your rib cage—sometimes it's enough to cause rib fractures. And in even rarer cases, all that strain can lead to fractures in your spine, like in your lower back or sacrum. These complications result from the repetitive stress and strain on the spine during prolonged bouts of whooping cough.¹⁰

Hernia

Hernia is a condition where an internal part of your body pushes through a weak spot in your abdomen's wall. It could be fat or even your intestines making their escape. Hernias can pop up in various places like the inguinal area (between your lower abdomen and upper thigh), the femoral canal (similar to inguinal but closer to your thigh), around your belly button (umbilical), at a previous surgical site (incisional), or elsewhere. In pertussis patients, this happens because of the increased pressure inside your belly during severe coughing.^1,11

Other possible complications

• Urinary Incontinence: an involuntary leakage of urine that can occur due to pressure on the bladder and pelvic floor muscles caused by coughing
• Pulmonary Hypertension: increased pressure in the blood vessels of the lungs, making it more challenging for the heart to pump blood effectively
• Subcutaneous Emphysema: occurs when air leaks into the tissue beneath the skin, creating a distinctive crackling sensation as the gas moves through the tissue
• Pneumothorax (collapsed lung): occurs when air escapes into the space between the lung and the chest wall, causing the lung to collapse^1,12

How to prevent these complications? 

Complications mainly occur in people who are not fully immunised against pertussis, especially babies under 1 year old. To prevent these potentially life-threatening complications, the best approach is to avoid contracting pertussis in the first place. For parents, following the recommended vaccination schedule during pregnancy is crucial as it allows antibodies to be passed on to the baby before they receive their first pertussis shot at 2 months old. It's also important to adhere to vaccination schedules for both children and adults.

Taking preventive measures such as avoiding contact with sick individuals and practising regular handwashing can help prevent the spread of the disease. Since pertussis is contagious, it's crucial to stay home and minimise contact with others to prevent further transmission.

When getting infected, know when to seek medical help to ensure timely treatment with antibiotics. Additionally, avoiding smoking is important, as it can worsen respiratory symptoms and increase the risk of complications from pertussis. By incorporating these preventive strategies into your routine, you can reduce the risk of pertussis complications and protect both yourself and others from the disease.

Summary

• Pertussis, caused by the bacterium Bordetella pertussis, is a highly contagious respiratory infection. One distinctive feature of this illness is a characteristic "whooping" sound—a high-pitched inhalation between severe coughing fits
• While pertussis can affect individuals of all ages, it poses greater risks in infants and can lead to life-threatening complications especially in infants under 2 months old
• Complications associated with pertussis include pneumonia, hernia, seizures, encephalopathy, fractures, apnea, urinary incontinence, pneumothorax, subcutaneous emphysema, and pulmonary hypertension
• The most effective way to prevent complications is to avoid contracting the disease in the first place. Vaccination plays a crucial role in protecting both you and your babies from pertussis

FAQs

What are the risk factors of pertussis?

• Being pregnant
• Epidemic exposure
• Lack of immunisation (not vaccinated)
• Having close contact with an infected individual 

What are the neurological complications of pertussis?

Neurological complications can include seizures (convulsions) and encephalopathy (brain damage), which may occur due to factors such as hypoxia, hypoglycemia, or toxins.¹³

What organs are affected by pertussis?

Pertussis affects the lungs and respiratory tract. However, it can also cause complications to various organs such as the brain, the bones, the abdomen, and the pelvic floor, mainly due to increased pressure during coughing.

What are the stages of pertussis?

• Catarrhal Stage: This initial stage typically lasts 1-2 weeks and may present flu-like symptoms such as fever, cough, runny nose, headache, and a general feeling of unwellness
• Paroxysmal Stage: Lasting several weeks, this stage is characterised by severe and prolonged bouts of coughing, often accompanied by a distinctive "whooping" sound. These episodes can cause difficulty breathing, exhaustion, and even fainting
• Convalescent Stage: During this stage, the intensity and frequency of coughing gradually decrease. However, coughing may persist for several months before resolving completely