Diphtheria: Symptoms, Treatments, Medications and Prevention

Diphtheria is a highly contagious bacterial infection caused by Corynebacterium diphtheriae. Although diphtheria was once a leading cause of childhood illness and death, widespread vaccination has significantly reduced its occurrence in many parts of the world. However, the disease remains a serious public health concern in regions with low immunization coverage. Diphtheria primarily affects the throat and nose but can also impact the skin and other organs. It is characterized by the formation of a thick, gray membrane in the throat that can lead to breathing difficulties, and it produces toxins that can cause severe complications like heart failure and nerve damage.

What is Diphtheria?

Overview of Diphtheria

Diphtheria is an acute bacterial infection primarily affecting the respiratory system. It is caused by the bacterium Corynebacterium diphtheriae, which releases a toxin that inhibits cellular function. The bacteria usually enter the body through the nose or mouth and primarily infect the mucous membranes of the throat and nose. Once infected, the bacteria multiply and produce a toxin that spreads through the bloodstream, leading to potentially fatal complications.

The hallmark sign of diphtheria is a thick, grayish-white coating (pseudomembrane) that forms in the throat and can obstruct the airway, making it difficult to breathe. If left untreated, diphtheria can spread to other parts of the body, causing damage to the heart, nerves, and kidneys.

Types of Diphtheria

There are two main forms of diphtheria:

1. Respiratory Diphtheria

This is the most common and dangerous form of diphtheria, affecting the throat, tonsils, and nasal passages. It is characterized by the formation of the pseudomembrane, difficulty breathing, and toxin-related complications.

2. Cutaneous Diphtheria

Cutaneous diphtheria affects the skin and is more common in tropical regions and among people living in poor hygiene conditions. It is less severe than respiratory diphtheria and causes skin ulcers that may become infected.

Transmission of Diphtheria

Diphtheria is highly contagious and spreads through direct contact with an infected person or by inhaling droplets from coughs or sneezes. The bacteria can also survive on surfaces like utensils or personal items, and the infection can be contracted by touching contaminated objects. It is especially dangerous in crowded or unsanitary conditions.

Who is at Risk of Diphtheria?

Diphtheria can affect people of all ages, but certain populations are at higher risk due to various factors such as geographic location, age, vaccination status, and living conditions.

High-Risk Populations

1. Unvaccinated Individuals

People who have not been vaccinated or who have incomplete immunization schedules are at the highest risk of contracting diphtheria. This includes children who have missed routine vaccinations and adults who may not have received booster doses.

2. Children

Children under the age of 5 are especially vulnerable to diphtheria, as their immune systems are still developing. Without timely vaccination, they are at greater risk of severe complications or death from the disease.

3. Elderly Adults

Older adults are also at increased risk, especially if they have not received booster vaccines or if their immunity has waned over time. Age-related weakening of the immune system makes elderly individuals more susceptible to infections, including diphtheria.

4. People in Crowded Living Conditions

Diphtheria thrives in crowded or unsanitary conditions, where close contact facilitates the spread of the bacteria. Refugee camps, slums, and overcrowded urban areas are especially vulnerable to outbreaks.

5. Healthcare Workers

Healthcare workers who care for patients with diphtheria or who work in areas where the disease is prevalent are at higher risk of exposure to the bacteria. Proper protective measures, including vaccination, are essential for this group.

6. Travelers to Endemic Areas

Travelers to regions where diphtheria is still common are at increased risk, particularly if they are unvaccinated or have not received booster shots. These regions include parts of Asia, the Middle East, Eastern Europe, and Africa.

Symptoms of Diphtheria and How It Is Diagnosed

The symptoms of diphtheria can vary depending on the form of the disease and the individual’s overall health. Respiratory diphtheria, which affects the throat and nose, presents with more severe symptoms than cutaneous diphtheria. Early recognition of the symptoms is crucial, as timely treatment can prevent serious complications.

Symptoms of Diphtheria

1. Respiratory Diphtheria

Respiratory diphtheria affects the throat and upper respiratory tract. The most distinctive feature is the development of a thick, gray membrane in the throat.

• Sore throat: One of the earliest symptoms, often accompanied by hoarseness or difficulty swallowing.
• Thick, gray pseudomembrane: This membrane forms over the tonsils, throat, or nasal passages, making it difficult to breathe or swallow. The pseudomembrane can extend into the airway, causing suffocation if not treated.
• Swollen neck (bull neck): Swelling in the neck due to enlarged lymph nodes is a characteristic sign of diphtheria.
• Difficulty breathing: As the pseudomembrane grows, it can obstruct the airway, leading to labored breathing or respiratory distress.
• Fever and chills: A low-grade fever is common, along with other flu-like symptoms.
• Cough: A mild cough may occur as the infection affects the respiratory tract.

2. Cutaneous Diphtheria

Cutaneous diphtheria is less severe than respiratory diphtheria and primarily affects the skin.

• Chronic skin lesions: Red, painful sores or ulcers that are slow to heal may develop, typically on the hands, legs, or feet.
• Secondary infections: The ulcers may become infected with other bacteria, leading to further complications if not treated.

Complications of Diphtheria

If left untreated, diphtheria can lead to life-threatening complications due to the spread of the toxin produced by Corynebacterium diphtheriae.

• Myocarditis: The diphtheria toxin can damage the heart muscle, leading to inflammation (myocarditis) and potentially causing heart failure.
• Neuropathy: The toxin can also affect the nervous system, leading to paralysis, particularly in the throat muscles, making it difficult to breathe or swallow.
• Kidney damage: In some cases, the toxin can cause kidney damage, resulting in renal failure.
• Respiratory failure: Severe respiratory diphtheria can obstruct the airway, leading to suffocation if the pseudomembrane is not removed.

Diagnosis of Diphtheria

Timely diagnosis of diphtheria is critical, as early treatment can significantly reduce the risk of complications. Healthcare providers use a combination of clinical assessment and laboratory tests to confirm the diagnosis.

1. Physical Examination

The first step in diagnosing diphtheria is a thorough physical examination. Doctors will look for classic signs such as a sore throat, fever, swollen neck, and the presence of the grayish-white pseudomembrane in the throat or nose.

2. Throat Swab

A sample of the pseudomembrane or throat secretions is collected using a swab and sent to the laboratory for analysis. The sample is cultured to detect the presence of Corynebacterium diphtheriae. A positive culture confirms the diagnosis.

3. Toxin Detection

To confirm whether the strain of Corynebacterium diphtheriae is producing the diphtheria toxin, a special laboratory test called the Elek test may be performed. This test detects the presence of diphtheria toxin in bacterial cultures.

4. Blood Tests

In severe cases of diphtheria, blood tests may be conducted to evaluate the extent of organ damage, such as myocarditis or kidney failure. These tests help assess the patient’s overall health and guide treatment decisions.

Treatments of Diphtheria

Diphtheria is a medical emergency that requires prompt treatment to prevent severe complications or death. The main goals of treatment are to neutralize the toxin produced by the bacteria, eliminate the infection, and manage complications.

1. Antitoxin Therapy

The primary treatment for diphtheria is the administration of diphtheria antitoxin. This antitoxin neutralizes the toxin produced by Corynebacterium diphtheriae before it can cause further damage to the body’s organs.

• Administration: The antitoxin is typically given intravenously or intramuscularly, depending on the severity of the infection. A skin test is often performed first to check for allergic reactions to the antitoxin.
• Timing: Antitoxin therapy is most effective when given early in the course of the disease. Delayed treatment may reduce its effectiveness, especially if the toxin has already caused significant damage to the heart, nerves, or kidneys.

2. Antibiotic Therapy

In addition to antitoxin therapy, antibiotics are used to kill the Corynebacterium diphtheriae bacteria and prevent further spread of the infection. Common antibiotics used to treat diphtheria include:

• Penicillin
• Erythromycin

Antibiotics help clear the infection from the respiratory tract or skin lesions, reducing the risk of transmission to others. Antibiotic treatment typically lasts for 14 days, and follow-up testing is necessary to ensure the bacteria have been completely eradicated.

3. Respiratory Support

In severe cases of respiratory diphtheria, where the pseudomembrane obstructs the airway, mechanical intervention may be necessary to ensure proper breathing.

• Endotracheal intubation: A tube may be inserted into the airway to keep it open and prevent suffocation.
• Tracheostomy: In extreme cases, where the airway is completely blocked, an emergency procedure called a tracheostomy may be performed. This involves creating an opening in the neck to bypass the blockage and allow the patient to breathe.

4. Treatment of Complications

Diphtheria can cause serious complications that require additional treatment. For example:

• Heart damage (myocarditis): Patients with diphtheria-related myocarditis may require medication to support heart function or treat arrhythmias.
• Neuropathy: Nerve damage caused by diphtheria may result in temporary or permanent paralysis. In such cases, physical therapy may be needed to help patients regain muscle function.

Most Common Medications for Diphtheria

The treatment of diphtheria relies on a combination of antitoxin therapy and antibiotics to neutralize the toxin and eliminate the bacterial infection. The choice of medication depends on the severity of the infection and the patient’s overall health.

1. Diphtheria Antitoxin

The diphtheria antitoxin is the cornerstone of diphtheria treatment. It works by neutralizing the toxin produced by the bacteria, preventing further damage to the body’s organs.

• Administration: Given intravenously or intramuscularly.
• Timing: Must be administered as soon as possible after diagnosis to prevent serious complications.

2. Penicillin

Penicillin is one of the most commonly prescribed antibiotics for diphtheria. It is effective at killing the Corynebacterium diphtheriae bacteria and is often used in combination with the antitoxin.

• Administration: Typically given orally or intravenously for 14 days.
• Efficacy: Penicillin is highly effective at clearing the bacterial infection from the respiratory tract or skin.

3. Erythromycin

For patients who are allergic to penicillin, erythromycin is an alternative antibiotic used to treat diphtheria. Erythromycin is also effective in eliminating the bacteria and is often used for respiratory and cutaneous diphtheria.

• Administration: Given orally or intravenously, depending on the severity of the infection.
• Duration: Treatment usually lasts for 14 days.

4. Supportive Medications

In addition to antibiotics and antitoxin, patients with diphtheria may require other medications to manage symptoms and complications, such as:

• Analgesics: Pain relievers like acetaminophen or ibuprofen to reduce throat pain and fever.
• Cardiac medications: For patients with myocarditis, medications to regulate heart rhythm and support cardiac function may be necessary.

Where is Diphtheria Most Prevalent?

Diphtheria has become rare in countries with strong immunization programs, but it remains a serious public health concern in regions with low vaccination coverage. Outbreaks can occur in areas where vaccination rates have declined, as well as in regions affected by conflict, poor healthcare infrastructure, or limited access to vaccines.

1. Asia

Several countries in South Asia and Southeast Asia continue to report diphtheria cases, particularly in areas with low immunization coverage. Countries like India, Bangladesh, and Indonesia have experienced periodic outbreaks, often due to gaps in vaccination programs and crowded living conditions.

2. Africa

Parts of Sub-Saharan Africa remain at high risk for diphtheria, particularly in rural areas where healthcare access is limited. Countries such as Nigeria, Ethiopia, and Sudan have reported outbreaks, often exacerbated by conflict, displacement, and insufficient vaccination coverage.

3. Eastern Europe

Some countries in Eastern Europe and the former Soviet Union have seen a resurgence of diphtheria in recent decades. Economic instability, political unrest, and disruptions to healthcare systems have contributed to declining vaccination rates, leading to outbreaks in countries such as Ukraine, Russia, and Kazakhstan.

4. Middle East

Regions in the Middle East affected by conflict and displacement, such as Syria and Yemen, have reported diphtheria outbreaks. Refugee camps and overcrowded living conditions create an environment where diphtheria can spread rapidly.

5. South America

Although diphtheria is rare in most of South America, outbreaks have been reported in countries like Venezuela, where the healthcare system has been strained due to political and economic crises. Declining vaccination rates have led to a resurgence of the disease in some areas.

Prevention of Diphtheria

The most effective way to prevent diphtheria is through vaccination. Widespread immunization programs have drastically reduced the incidence of diphtheria in many parts of the world. In addition to vaccination, good hygiene practices and public health measures can help prevent the spread of the disease.

1. Vaccination

The diphtheria vaccine is part of routine childhood immunization programs in many countries. The vaccine is usually given in combination with vaccines for tetanus and pertussis (whooping cough) as part of the DTaP vaccine for children or the Tdap vaccine for adolescents and adults.

• DTaP vaccine: Given in a series of five doses during childhood, typically at 2, 4, 6, and 15-18 months, with a booster dose at 4-6 years.
• Tdap booster: Adolescents and adults should receive a Tdap booster shot every 10 years to maintain immunity.

2. Hygiene Practices

Good hygiene practices can help reduce the spread of diphtheria, particularly in areas where the disease is endemic. These include:

• Handwashing: Regular handwashing with soap and water can help prevent the transmission of bacteria.
• Avoiding close contact: Avoiding close contact with infected individuals or those showing symptoms of diphtheria can reduce the risk of transmission.

3. Public Health Measures

Public health authorities play a critical role in preventing and controlling diphtheria outbreaks. Key measures include:

• Surveillance and monitoring: Monitoring vaccination coverage and promptly responding to outbreaks can prevent the spread of diphtheria.
• Quarantine of infected individuals: Infected individuals should be isolated to prevent the spread of the bacteria to others.
• Education and awareness campaigns: Educating the public about the importance of vaccination and early diagnosis can help prevent diphtheria.