1) Disease Description (Causes and Symptoms)
- Definition summary: Diphtheria is an acute infectious disease in which toxins produced by Corynebacterium diphtheriae cause membranes (pseudomembranes) to form in epithelial tissues such as the pharynx, nasal cavity, and larynx, and may cause organ damage, including damage to the myocardium and nerves, through systemic toxin effects. In Korea, it is classified as a Class 1 legally designated infectious disease, and its incidence has declined greatly due to vaccination (DPT).
- Causes and transmission: It is transmitted through respiratory secretions (saliva, nasal discharge, and cough droplets) from infected people or carriers, or through contact with skin lesions. The incubation period is usually 2–6 days.
- Pathophysiology: The bacteria settle on mucous membranes and form local inflammation and grayish-white pseudomembranes. Some strains secrete toxins that travel through the bloodstream and exert toxic effects on the myocardium, nerves, and other tissues.
- Main symptoms: Sore throat, a pharyngeal pseudomembrane (white/gray membrane), fever (mild to high), cough and hoarseness (when the larynx is involved), difficulty breathing, loss of appetite, generalized malaise, swollen lymph nodes, runny nose and nosebleeds (when the nasal cavity is involved), and, rarely, skin lesions.
- Risk factors/epidemiological characteristics: The risk is higher mainly in young children, particularly those aged 4 years or younger, and cases are more common in autumn and winter. Vaccination has greatly reduced the incidence.
2) Treatment Methods
- Immediate principles
- Antitoxin must be administered promptly before toxin-related complications, such as myocarditis and nerve paralysis, develop.
- At the same time, antibiotics, mainly penicillin-class drugs or erythromycin, are used to eliminate the bacteria and reduce transmissibility.
- Drug treatment
- Antitoxin: Equine antitoxin derived from horse serum is standard, and testing for hypersensitivity (anaphylaxis) is required before administration. If symptoms are severe or toxin exposure is suspected, administer it immediately after a skin hypersensitivity test.
- Antibiotics: Penicillin (e.g., benzathine penicillin or procaine penicillin) or erythromycin (or other indicated antibiotics such as amoxicillin). The duration of administration depends on the local condition and culture results.
- Supportive treatment
- Airway management: If there is difficulty breathing due to laryngeal or glottic edema or pseudomembranes, securing the airway (oxygen, airway intubation, or tracheostomy) takes priority.
- Hospitalization and isolation: Isolate the patient until cultures are confirmed negative after antibiotic treatment (generally after two consecutive negative results or after the designated period has elapsed).
- Rest and observation: Strict bed rest is recommended for the first 1–2 weeks. Even during recovery, avoid overexertion for approximately 1 month and monitor for cardiac and neurological symptoms.
- Prevention and public health measures
- Administer preventive antibiotics to contacts (according to national guidelines) and check or update their vaccination status.
- Report to public health authorities (legally designated infectious disease).
- Complication management
- If myocarditis develops, monitor electrocardiograms and cardiac enzymes. If neurological symptoms such as spasms or paralysis occur, consultation with relevant specialties and intensive treatment are required.
3) Checklist Before an Outpatient Visit (Items to Bring, Information to Provide, and Example Preparation Questions)
- Items to bring
- List of medications currently being taken (including prescription drugs, OTC medicines, herbal medicines, and supplements)
- Recent vaccination records (including DPT)
- Notes recording when symptoms began and how they have progressed (fever, difficulty breathing, difficulty swallowing, voice changes, etc.)
- Recent travel history (whether there has been overseas travel) and contacts (possible exposure to an infected person)
- Copies of previous test results, if available (culture or imaging)
- Information to tell the healthcare provider in advance
- Any previous history of allergy to horse serum or serum products
- Underlying respiratory or cardiac conditions, such as asthma or heart disease
- Whether you are pregnant (when considering antibiotics and antitoxin)
- Example preparation questions for the patient (key questions the doctor may ask during the outpatient visit)
- When did the symptoms begin? What was the first symptom?
- Are you experiencing difficulty breathing, difficulty swallowing, or voice changes?
- When did you most recently receive the DPT (diphtheria) vaccine?
- Does anyone in your family or among your acquaintances have the same symptoms?
- Do you have a history of drug or serum allergies?
4) Examples of General Questions to Ask the Doctor
- What are the expected effects and side effects of this medication (antibiotic/antitoxin)?
- What is the prognosis of the disease? How long will isolation/treatment be necessary?
- When will it be possible to return to daily activities (school/work) after recovery?
- How should family members and people living with me be managed (contact testing and preventive measures)?
- What are the signs of myocarditis or neurological complications, and when should I come to the hospital immediately?
5) Examples of Disease-Specific Questions
- Regarding antitoxin
- Do I need to receive antitoxin (horse serum)? How is the hypersensitivity test performed before administration?
- Regarding prevention and vaccination
- My (or my child’s) DPT vaccination history is uncertain. Is an additional vaccination (booster) needed, and when should it be given?
(Reference summary: Incubation period of 2–6 days; transmission mainly through respiratory secretions and direct contact; because antitoxin is derived from horse serum, hypersensitivity testing is required; antibiotics are used concurrently; approximately 2 weeks of rest is recommended initially; complications may include myocarditis, neuritis, and paralysis; DPT vaccination and contact management are key to prevention.)