What are the other Names for this Condition? (Also known as/Synonyms)

• Infection by Corynebacterium Diphtheriae

What is Diphtheria? (Definition/Background Information)

• Diphtheria is an acute, deadly infection of the nose, tonsil, throat or voice box. It is caused by Corynebacterium diphtheriae bacteria (gram positive bacilli)
• The bacterium infects the mucous membranes of the respiratory tract (nose and throat), skin, ear, and eyes. After they infect the mucous membranes, they produce a toxin (poisonous substance produced by living cells), which travels in the blood to affect distant organs such as the heart, nerves, and kidneys
• The most striking feature of diphtheria is the formation of pseudo-membrane (false layer of tissue) in the nasal (nose) cavity, tonsil, and throat, which can obstruct the air passages and lead to death if left untreated
• The main treatment options include supportive care and the use of Diphtheria antitoxin and antibiotics. However, 1 in 2 individuals die of the infection if left untreated, and 1 in 10 die, despite treatment

Who gets Diphtheria? (Age and Sex Distribution)

• In the past, Diphtheria was more common in children. Presently, it more commonly affects individuals older than 40 years, mainly due to the fact of incomplete vaccination (such as a lack of booster dose) in them
• There is no gender, racial, or ethnic preference observed
• Although, currently, Diphtheria is seen primarily in developing countries such as India, Indonesia, Nepal, Pakistan, Sudan, and Thailand (per the WHO)

What are the Risk Factors for Diphtheria? (Predisposing Factors)

The risk factors of Diphtheria include:

• The most important risk factor is coming into contact with respiratory droplets (through coughing and sneezing) of infected individuals with Diphtheria, or infected individuals without the disease (called carriers)
• Other factors that increase the chances of infection include living in overcrowded places, poor hygiene, absent or incomplete immunization, failing to get booster shots at specified intervals, and travel to countries where Diphtheria is not yet eradicated

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Diphtheria? (Etiology)

The causes of Diphtheria include:

• Corynebacterium diphtheriae bacteria cause Diphtheria. Humans are the main reservoir (source) of C. diphtheria. It is a highly contagious infection that spreads easily and quickly from one individual to another
• The main route of transmission is via respiratory droplets (cough, sneeze, or through spit). The droplets present on objects can also cause infection. Also, Diphtheria skin lesions can be a source of infection
• C. diphtheria primarily infects the nose and throat. Individuals with infection of the throat may exhibit a gray leather-like covering (pseudo-membrane) that can occlude the airway passages. The bacterium can occasionally affect the skin and cause lesions too
• Toxins produced by Corynebacterium diphtheriae may enter the body via the blood stream and cause further complications such as inflammation of the heart (myocarditis), paralysis, and nerve inflammation

There are 4 subspecies of Corynebacterium diphtheriae. These include:

• Corynebacterium belfanti
• C. gravis
• C. intermedius
• C. mitis

What are the Signs and Symptoms of Diphtheria?

Some individuals infected with C. diphtheria may not exhibit any symptoms of the disease. Such individuals are called carriers and they can infect others, causing disease in them.

In others who are infected by Diphtheria, the signs and symptoms may include:

• Difficulty or painful swallowing, sore throat, hoarseness
• Difficulty in breathing, rapid breathing, abnormal loud breathing sound (stridor)
• Gray to black, leathery, thick layer (pseudo-membrane) can be seen covering the nose, oral, or throat cavity. These pseudo-membranes represent dead tissue and bacteria
• Drooling of saliva or secretions due to obstruction by the pseudo-membrane
• Fever and chills, weakness
• “Barking” type of cough
• Watery or bloody nasal secretions
• Bluish skin
• Swollen neck glands
• Skin lesions
• Toxic (very sick) appearance

How is Diphtheria Diagnosed?

The following tests and procedures may be used to diagnose Diphtheria:

• Thorough evaluation of the individual’s medical history and a complete physical examination that includes the skin, throat, nose, heart, lymph nodes, etc.
• During history-taking the physicians may want to know the following:
  • When the symptoms began and whether they are becoming worse
  • Personal and family history related to travel, contact with sick persons (if any), etc.

Diphtheria may be initially diagnosed based on history and physical examination. The presence of pseudo-membrane is big clue to suspect Diphtheria in individuals with other related symptoms.

Other diagnostic tests may include:

• Albert or gram stain to help detect the bacteria in secretions
• Throat or nose culture to detect the bacteria to confirms a diagnosis
• Diphtheria toxin levels (assay)
• Electrocardiogram
• Other tests such as complete blood count or renal function tests may be performed to determine the severity of the infection

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Diphtheria?

The complications of Diphtheria include:

• Inflammation of the heart (myocarditis) can progress to cause heart failure or sudden death
• Neurological complications include temporary muscle paralysis, visual defects, respiratory muscle paralysis (causing respiratory failure), and swallowing difficulties
• C. diphtheria toxin can cause kidney damage

Statistically, 50% of the infected individuals who remain untreated die of the disease.

How is Diphtheria Treated?

The treatment should begin immediately after taking tests for culture of organisms, without waiting for its results. All individuals suspected of having Diphtheria should be immediately placed under isolation.

• C. diphtheria antitoxin shot given intramuscularly (IM) or through an intravenous line (IV) to stop progression of the disease
• Antibiotic treatment with penicillin or erythromycin

The supportive care for Diphtheria may include:

• Hospitalization
• Monitoring of vital signs
• Administration of intravenous fluids
• Clearing away airway secretions or blockages
• Breathing tube and ventilator support, if required
• Oxygen therapy
• Complete bed rest

Counselling and treatment may be provided to all other individuals who came in contact with the Diphtheria-infected individual.

How can Diphtheria be Prevented?

The preventative measures of Diphtheria include:

• Vaccination:
  • Childhood immunizations via five DTaP vaccinations given at ages 2, 4, and 6 months, and then at 15-18 months, and finally when the child is 4-6 years of age
  • Children aged 11 to 12 years should receive Tdap booster
  • Adults should receive Tdap booster every 10 years
  • With certain health conditions, these vaccines may not be recommended. Hence, do consult your healthcare provider before administering any vaccine
• Travelers should update their vaccination status while traveling to countries where Diphtheria is prevalent
• Individuals who have come in contact with Diphtheria-infected individuals should receive preventative (prophylactic) antibiotics and booster dose vaccination

What is the Prognosis of Diphtheria? (Outcomes/Resolutions)

• The prognosis of Diphtheria is generally good with prompt diagnosis and treatment
• Diphtheria severity may vary from individual to individual (being mild or severe); it may progress and cause death in up to 10% of the individuals, even after treatment
• 50% of the affected individuals die of the disease if there is a lack of treatment

Additional and Relevant Useful Information for Diphtheria:

• Diphtheria is rare these days, especially in the developed countries, largely due to the immunization and health programs in place in these nations
• Unfortunately, Diphtheria does continue to pose problems in certain developing countries; although, not to the extent as seen before the discovery of vaccines
• In the United States, there have been only 5 cases of Diphtheria in the past decade. Whereas, in 1921, around 200,000 cases were reported