Diphtheria

Diphtheria

Definition

Diphtheria is an acute infections, caused by the exotoxin of diphtheria bacilli. The disease attacks mainly the throat, tonsils, larynx or nose. Where the baccilli produces a grayish-white membrane which spread in to the air passages.

Causative organism

Corynebacterium diphtheria caused by exotoxin of diphtheria bacilli.

Mode of transmission

·  Droplet infection.

·  Infected cutaneous lesions.

·  Infective object or dust, contaminated with nasopharyngeal secretions.

Incubation period - 2-6 days occasionally longer

Clinical manifestations

The onset of symptoms is typically gradual. Most common presenting symptoms are

·  Sore throat

·  Malaise

·  Cervical lymphadenopathy

·  Low grade fever.

·  Pharyngo tonsillar diphtheria - sore throat and difficult in swallowing

·  Mild erythema is the earliest pharyngeal finding

·  Isolated spots of gray and white exudate.

·  Membranous pharyngitis

·  Massive swelling of the tonsils, Uvula, cervical lymph nodes, submandibular region, and anterior neck (the so-called "bull neck" of toxic diphtheria).

·  Aspiration of the membrane can lead to suffocation.

·  Laryngeal diphtheria causes obstructive croup stridor and eventually asphyxia.

·  Respiratory stridor may ensue, leading to respiratory insufficiency and death.

Complications

Diphtheria toxin can lead to

·  Damage of the heart (myocarditis)

·  Nervous system

·  Kidneys.

·  Neurological (Encephalitis encephalopathy)

·  Prolonged convulsions

·  Infantile spasm

Control measures

1.  Cases and carriers

·  Earlydetection: Carriers can be detected only by culture method. Swabs can be taken from both the nose and throat and examined by culture methods for diphtheria bacilli.

·  Isolation: Suspected cases and carriers should be promptly isolated, preferably in a hospital for at least 14 days.

·  Treatment: For Cases when diphtheria is suspected diphtheria antitoxin should be given without delay. IM or IV in doses ranging from 20,000 to 1,00,000 units or more depending upon the severity of the case.

2.  For Carriers : The carriers should be treated with 10 days course of oral erythromycin which is the most effective drug for the treatment carriers.

a. Contacts : Contacts need special attention. They should be throat swabbed and their immunity status determined. The bacteriological surveillance of close contact should be continued for several weeks.

b. Community : The only effective control is by active immunization with diphtheria toxoid. All children who are not previously immunized should be given a dose of 500 to 1000 IV diphtheria antitoxin.

Treatment

·  The specific treatment is diphtheria antitoxin which must be given immediately

in doses ranging from 10,000 to 80,000 units according to the severity of the case.

·  Antibiotics (penicillin) help to eliminate the infection and prevent production of further toxin.

·  Bed rest is essential to prevent heart failure.

·  Tracheostomy may be needed if there is respiratory obstruction.

Preventive measures

·  Diphtheria can be prevented by active immunization either by DPT or diphtheria vaccine.

·  The current practice is to immunize all infants with DPT starting from the age of 6weeks.

·  DPT vaccine protects not only against diphtheria but also against pertussis and tetanus.

·  A booster dose (0.5 ml) of DPT is recommended at the age of 1½ to 2 years followed by another dose (DT only) at the age of 5 and 6 years.