Diphtheria is a respiratory tract infection caused by the bacteria Corynebacterium diphtheriae. The disease mainly affects the mucous membranes of the respiratory tract but can also affect other body parts such as the skin, the tissue lining of the eyes, ears and genitals. The disease is often characterized by low fever, sore throat, and a pseudomembrane adhering over the lining of tonsils and nasopharynx.
The most common form of diphtheria is the respiratory diphtheria that affects the respiratory tract. This infection has a fatality rate of 10 to 15% and is higher for children under the age of five and adults over 40. The major causes of death for respiratory diphtheria are airway obstruction, cardiac problems, and neuropathy.
The other form of diphtheria is called the cutaneous form that mainly affects the skin and tissue linings. This type of infection is considered a milder form of diphtheria and is not common compared to the respiratory form.
Diphtheria is transmitted through droplets or by direct contact with infected secretions. Droplets can be spread by speaking, sneezing, spitting and coughing. When the bacteria enter the respiratory tract, it can reside there and multiply. Most commonly, the bacteria infects the nose and the throat. If throat infection occurs, a gray to black, tough, fiber-like covering known as the pseudomembrane forms around the tonsils or nasopharynx. This psedomembrane can block the airways that can really be fatal if left untreated.
The bacteria produces toxins that can travel to the blood stream and can damage the organs such as the heart, leading to cardiac problems. Bone and blood infections can also happen as well as neurological complications such as vision problems, muscle weakness, and paralysis of the soft palate.
Symptoms begin to appear 2 to 5 days after the infection has been acquired. The symptoms include sore throat, fever, body weakness, difficulty of swallowing, hoarseness, and difficulty breathing. The adherent gray membrane develops when the infection becomes severe. When this membrane extends to the larynx and trachea, suffocation and eventually death will occur. Enlargement of neck lymph nodes and neck swelling also occurs if the infections aggravate leading to the appearance of a "bull-neck".
Diagnosis of Diphtheria is based upon the laboratory works and clinical symptoms. Even when laboratory results are not yet confirmed, early treatment should be undertaken to avoid further complications.
Administration of diphtheria antitoxin is the main treatment of choice. The antitoxin works faster and more effectively when given at the early phase of the disease.
Antibiotics are also administered to stop toxin production. Penicillin and Erythromycin are the recommended drugs.
For severe cases, supportive measures are also given such as intubation and close monitoring of potential cardiac and neurological complications.
Prevention can be achieved through immunization. Immunization for infants and children comprise of 5 DTaP vaccinations administered at ages 2, 4 and 6 months. The fourth dose is given between 15 to 18 months of age and the fifth at 4 to 6 years old. After completing the childhood immunizations, children age 11 to 12 need to have a single dose of DTaP. Booster shots are given every 10 years to maintain antibody levels.