Saturday, September 22, 2018

Diphtheria Update

Diphtheria kills 12 children in 13 days in two Delhi govt hospitals

At least 12 children have died of diphtheria in 13 days, between September 6 and 19, in two government hospitals in Delhi, as reported in HT, Sept. 21, 2018. Eleven children have died in the North Delhi Municipal Corporation-run Maharishi Valmiki Infectious Diseases Hospital and one child died in the Delhi government-run Lok Nayak Hospital. Of the 300 cases reported so far this year, 85 people were admitted with the bacterial infection at the Valmiki Hospital from September 1 to September 19, hospital authorities said.

Here is a recap of diphtheria, the disease.

· Diphtheria is an infectious disease caused by the gram-positive bacteria Corynebacterium diphtheriae.
·         The infection is transmitted via close contact with infectious material from respiratory secretions (direct or via airborne droplet from coughing or sneezing) or from skin lesions or clothes of the infected person or by touching contaminated objects such as toys.
·         Humans are the only known reservoir for C. diphtheriae. Immunity, either via natural infection or vaccine-induced does not prevent carriage. Hence, asymptomatic carriers play an important role in disease transmission.
·         Diphtheria is fatal in 5-10% of cases. Mortality rate is higher in young children.
·         Clinically, diphtheria presents as respiratory diphtheria or cutaneous diphtheria or an asymptomatic carrier state.
·         Respiratory diphtheria is caused by toxigenic strains of C. diphtheria. It mainly involves the pharynx (throat) and upper airways. Symptoms include sore throat, malaise, cervical lymphadenopathy and low grade fever. In some patients, toxin induces the formation of a thick grey coating “pseudomembrane” over the throat and tonsils making it difficult for the patient to breathe and swallow. The membrane is composed of necrotic fibrin, leukocytes, erythrocytes, epithelial cells and organisms. This membrane adheres tightly to the underlying tissue and bleeds with scraping.
·         Complications include blocking of airway, myocarditis, peripheral neuropathy, paralysis, pneumonia or respiratory failure.
·         A form of malignant diphtheria is associated with extensive "membranous pharyngitis" along with massive swelling of the tonsils, uvula, cervical lymph nodes, submandibular region and anterior neck ("bull neck" of toxic diphtheria). Respiratory stridor may ensue, leading to respiratory insufficiency and death. Aspiration of the membrane can also cause suffocation in these patients.
·         Cutaneous diphtheria is usually a mild disease and presents as cutaneous sores or shallow ulcers. Complications are uncommon in cutaneous diphtheria.
·         Diagnosis is usually clinical. Definitive diagnosis requires culture of a throat swab or swab from the skin lesion to isolate the bacteria. However, if clinical suspicion for diphtheria is high, then treatment must be started immediately without waiting for lab confirmation.
·         Treatment: Administration of diphtheria antitoxin and antibiotics. Antitoxin is usually not required in cutaneous disease due to the lack of pseudomembranes or cardiac involvement
·         Antibiotic of choice: Erythromycin (500 mg four times daily x 14 days) or procaine penicillin G (300,000 units every 12 hours for patients ≤10 kg and 600,000 units every 12 hours for patients >10 kg IM). When the patient is able to take orally, give oral penicillin V (250 mg four times daily) x 14 days.
·         Diphtheria antitoxin, to neutralize the effects of the toxin, is administered intravenously over 60 minutes for rapid inactivation of the toxin. But, it must be administered early because once the toxin enters the cell, it is ineffective. A hypersensitivity test must be done prior to administration.
o    The American Academy of Pediatrics (AAP) recommends 20,000 to 40,000 units for pharyngeal/laryngeal disease of <48 hours duration, 40,000 to 60,000 units for nasopharyngeal disease, and 80,000 to 120,000 units for >3 days of illness or diffuse neck swelling (bull neck).
·         Patients should be kept in isolation until two consecutive cultures taken at least 24 hours apart are negative.
·         All close contacts of the patients including the health care workers should be administered diphtheria toxoid (DT) vaccine, if vaccination status is not updated. After cultures have been obtained, contacts should receive antimicrobial prophylaxis with a single dose of penicillin G benzathine (600,000 units IM for persons <6 years of age and 1.2 million units IM for persons ≥6 years of age) or oral erythromycin (500 mg four times daily x 7-10 days).
·         Prevention is via a 3-dose primary vaccination series with diphtheria containing vaccine (DTwP/DTaP vaccine or pentavalent vaccine) followed by 3 booster doses. Vaccination should begin as early as 6-week of age with subsequent doses given at an interval of 4 weeks between doses. The 3 booster doses should preferably be given during 12-23 months, at 4-7 years and at 9-15 years of age. Ideally, there should be at least 4 years between booster doses.

(Source: Uptodate, CDC, WHO)

Dr KK Aggarwal
Padma Shri Awardee
President Elect Confederation of Medical Associations in Asia and Oceania   (CMAAO)
Group Editor-in-Chief IJCP Publications
President Heart Care Foundation of India
Immediate Past National President IMA

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