Abstract & Commentary
Synopsis: A case of fatal respiratory diphtheria in an unvaccinated Pennsylvania resident who had visited Haiti brings to light the need for all international travelers to be current with all recommended vaccinations, including a primary series of diphtheria toxoid.
Source: Fatal Respiratory Diphtheria in a US Traveler to Haiti: Pennsylvania, 2003. MMWR Morb Mortal Wkly Rep. 2004;52(53):1285-1286.
A 63-year-old Pennsylvania missionary who had never been vaccinated against diphtheria contracted the illness while he was in Haiti for 1 week helping to build a church. The day before leaving Haiti he noted a sore throat, and 2 days later he presented to an emergency department for evaluation of persistent pharyngitis with difficulty swallowing. Rapid tests for group A streptococci and heterophile agglutinins were negative, and he was treated with oral amoxacillin and clavulanate potassium. After 2 more days the patient returned to the ED with chills, sweating, nausea, vomiting, restlessness, and difficulty both swallowing and breathing. On examination, he was afebrile with stridor and expiratory wheezing, and his neck was swollen. Radiographs of the neck and chest showed prevertebral soft-tissue swelling, enlargement of the epiglottis, and opacity at the left lung base. He was admitted to the ICU with a diagnosis of epiglottitis and airway obstruction. During intubation for impending respiratory failure, laryngoscopy revealed a yellow exudate on the tonsils, posterior pharynx, and soft palate, with sloughing of the anterior pharyngeal folds. Despite treatment with azithromycin, ceftriaxone, nafcillin, and steroids, he became hypotensive and febrile. Culture of the throat swab specimen was negative for Corynebacterium diphtheriae. Sputum culture grew methicillin-susceptible Staphylococcus aureus. However, diphtheria was later confirmed as the diagnosis during a tracheostomy at another facility when a white exudate consistent with C diphtheriae infection was observed. A pseudomembrane covered all of the supraglottic structures. Gram stain of the laryngeal exudate showed Gram-positive cocci and yeast. Diphtheria antitoxin (DAT) was administered on the ninth day of illness. Two days later, cultures of the pseudomembrane were still negative, but PCR performed at the CDC for C diphtheria tox genes was positive. Despite treatment, the patient died on day 17 of illness due to cardiac complications. Analysis of close contacts of the patient showed no additional cases of diphtheria, but antibiotic prophylaxis and immunization with a diphtheria toxin-containing vaccine were offered to all close contacts.
Comment by Maria D. Mileno, MD
In the context of the entire travel medicine consultation, immunization with a diphtheria toxoid-containing vaccine carries little "talk show interest" for persons traveling abroad. Diphtheria has fortunately been quite uncommon in the United States since universal vaccination began in the 1940s. While young children have 95% coverage rates, testing of adults indicates that the percentage of US residents with protective diphtheria antibody levels ( > 0.1 IU/mL ) decreases progressively with age, from 91% at 6-11 years to approximately 30% at ages 60-69 years. As our traveling population ages, we will likely see more cases in returned travelers who choose to explore endemic regions unless broader vaccination coverage of travelers can be attained.
Disease associated with respiratory diphtheria should be suspected in all persons with membranous nasopharyngitis or obstructive laryngotracheitis who returned recently from areas where the disease is endemic. See the Table or check www.cdc.gov/travel/diseases/dtp.htm.
Also, diphtheria may occur especially among persons who live with local people within endemic areas. Infected travelers returning to the United States with incubating or untreated disease can transmit C diphtheria to their close contacts. The diphtheria case fatality rate is 1 in 20. Although the tetanus-diphtheria (Td) booster vaccine is administered as an IM injection, with adjuvant containing potentially irritating antigens, the usual reaction is that of local pain, swelling, and induration at the site of injection. Occasionally, there may be painful swelling from elbow to shoulder 2-8 hours following vaccination if frequent boosters have been given. Rarely, there are reports of anaphylaxis, generalized rash and itching, fever, systemic symptoms, brachial neuritis, and Guillain-Barré syndrome. Compared to the children’s formulation, there is less diptheria toxoid in the Td adult booster. Contraindications include severe illness with or without fever, history of neurological or severe hypersensitivity following Td, and allergy to thimerosal or gelatin adjuvants. While the recommended protection time for this vaccine is 10 years, our clinic staff requests that individuals document diphtheria-tetanus immunization within the past 5 years and follows with a discussion of the risks involved.
In summary, all international travelers should be up to date with all apparently routine recommended vaccinations in addition to taking destination-specific disease prevention precautions.
Dr. Mileno, Director, Travel Medicine, The Miriam Hospital, Assistant Professor of Medicine, Brown University, Providence, RI, is Associate Editor of Travel Medicine Advisor.