A 62-year-old man comes to the emergency department due to 3 days of severe sore throat, difficulty swallowing, and hoarseness. He has no chronic medical conditions but has not seen a physician for many years. The patient received recommended childhood vaccinations but has had none since then. He is a farmer and has not traveled recently but has been in contact with migrant farmworkers. Temperature is 38.3 C (101 F), blood pressure is 110/60 mm Hg, and pulse is 116/min. Physical examination reveals pharyngeal erythema and edema with coalescing, gray exudate. Bilateral cervical lymph nodes are enlarged and tender. A rapid streptococcal test result is negative. Throat swab culture grows non-spore-forming, gram-positive rods. Which of the following is most helpful in preventing the systemic complications of this infection in this patient?

Question

A 62-year-old man comes to the emergency department due to 3 days of severe sore throat, difficulty swallowing, and hoarseness.  He has no chronic medical conditions but has not seen a physician for many years.  The patient received recommended childhood vaccinations but has had none since then.  He is a farmer and has not traveled recently but has been in contact with migrant farmworkers.  Temperature is 38.3 C (101 F), blood pressure is 110/60 mm Hg, and pulse is 116/min.  Physical examination reveals pharyngeal erythema and edema with coalescing, gray exudate.  Bilateral cervical lymph nodes are enlarged and tender.  A rapid streptococcal test result is negative.  Throat swab culture grows non-spore-forming, gram-positive rods.  Which of the following is most helpful in preventing the systemic complications of this infection in this patient?

Quizplus · Accepted Answer

11ec160b_3821_e731_9249_7149fca84324_MD0001_00 Diphtheria is caused by infection with toxigenic strains of Corynebacterium diphtheriae, a non-spore-forming, gram-positive rod that is transmitted by aerosolized droplets. Cases are rare in the United States due to widespread vaccination efforts. However, infections can occur in those who received inadequate childhood vaccines or those who did not receive booster vaccination every 10 years. The manifestations of diphtheria are due to the elaboration of diphtheria toxin (DT), an exotoxin that irreversibly inhibits host protein synthesis by ADP-ribosylation of elongation factor-2. Local effects include pharyngitis and tonsillitis, often with thick, grey-white pseudomembranes. Systemic effects are caused by the absorption of DT into the bloodstream and include potentially life-threatening cardiac (eg, myocarditis) and neurologic complications. The primary treatment for diphtheria is the urgent administration of diphtheria antitoxin, which contains preformed, neutralizing antibodies that binds and inactivates circulating toxin. Because it cannot inhibit the toxin that has already entered cells, it should be administered as soon as possible. Antibiotic therapy (eg, penicillin, erythromycin) is also given to reduce continued elaboration of DT from the nasopharyngeal infection. (Choice A) Inhaled, racemic epinephrine can be used in the treatment of croup, which usually presents with cough, inspiratory stridor, and/or hoarseness. Epinephrine could reduce airway swelling in patients with diphtheria, but it would not inhibit the local and systemic effects of the toxin. (Choice B) C diphtheriae is noninvasive and does not typically enter the bloodstream. Although antibiotics are administered in acute infection, this component of therapy is less important than providing antitoxin to neutralize DT. (Choice C) Corticosteroids are sometimes used in the treatment of epiglottitis to reduce airway inflammation and limit the risk of airway compromise. Epiglottitis manifestations typically include stridor, drooling, respiratory distress, and the assumption of the "tripod" position. Most cases are caused by infection with Haemophilus influenzae type B in unvaccinated individuals. (Choice E) Active immunization with the diphtheria toxoid (given as part of the childhood DTaP vaccine) prevents diphtheria. Diphtheria toxoid can also be given as part of tetanus boosters in adults. However, the immune response to vaccination is slow; in undervaccinated patients who are acutely ill, administration of preformed antitoxin antibodies is preferred. Educational objective: The primary treatment for diphtheria is diphtheria antitoxin (passive immunization), which inactivates circulating toxin. Antibiotics should also be administered to reduce continued production of toxin. __________ References: Diphtheria remains a threat to health in the developing world-an overview. (http://www.ncbi.nlm.nih.gov/pubmed/15049077) Clinical characteristics and management of 676 hospitalized diphtheria cases, Kyrgyz Republic, 1995. (http://www.ncbi.nlm.nih.gov/pubmed/10657201)

A 62-Year-Old Man Comes to the Emergency Department Due to 3