What is the management for a diphtheria case?

Management of Diphtheria

Diphtheria requires immediate administration of diphtheria antitoxin (DAT) upon clinical suspicion, without waiting for laboratory confirmation, along with concurrent antimicrobial therapy such as erythromycin or penicillin to prevent mortality. 1

Immediate Management Steps

1. Antitoxin Administration

• Administer diphtheria antitoxin (DAT) immediately upon clinical suspicion
• Test for sensitivity to equine serum before administration due to risk of allergic reactions:
  • 7% risk of immediate hypersensitivity
  • 5% risk of serum sickness
• Do not delay DAT administration while waiting for laboratory confirmation
• Note: DAT is most effective when given within the first 48 hours of symptom onset; administration after day 2 of symptoms shows limited effectiveness 2

2. Antimicrobial Therapy

• Initiate antimicrobial therapy concurrently with DAT administration
• First-line options:
  • Erythromycin:
    • Children: 40 mg/kg/day orally for 7-10 days
    • Adults: 1 g/day orally for 7-10 days 1, 3
  • Benzathine penicillin:
    • Children <6 years: 600,000 units IM (single dose)
    • Persons ≥6 years: 1,200,000 units IM (single dose) 1
• Obtain throat cultures before starting antimicrobial therapy 1
• Note: While both antibiotics are effective, a study in Vietnam found penicillin resulted in faster fever clearance (median 27 hours vs 46 hours with erythromycin) 4

Monitoring and Supportive Care

1. Respiratory Management

• Monitor closely for airway compromise due to pseudomembrane formation
• Be prepared for respiratory support if needed (20% of patients may require ventilation) 2
• Assess for bull neck development (sign of severe disease) 1

2. Cardiac Monitoring

• Perform ECG monitoring for myocarditis and conduction abnormalities
• Heart block is a potentially fatal complication 5
• Myocarditis can develop even after appropriate treatment initiation 4

3. Neurological Assessment

• Monitor for signs of diphtheritic polyneuropathy, which:
  • Can occur 2-50 days after infection onset
  • Often presents with bulbar dysfunction (98% of cases)
  • May follow a biphasic course with secondary worsening after 40 days
  • Can cause prolonged disability 2

Contact Management

1. Contact Identification

• Identify all close contacts including:
  • Household members
  • Persons with habitual, close contact with the patient
  • Individuals directly exposed to oral secretions 6, 1

2. Contact Management Protocol

• Obtain throat cultures from all close contacts before starting prophylaxis
• Monitor contacts daily for 7 days for signs of disease
• Provide antimicrobial prophylaxis immediately:
  • Benzathine penicillin (single IM injection) or
  • Erythromycin (oral for 7-10 days)
• Perform follow-up cultures after completion of antimicrobial therapy
• Treat persistent carriers with an additional 10-day course of oral erythromycin 1

3. Vaccination of Contacts

• For contacts with unknown/incomplete vaccination status: provide immediate dose of age-appropriate diphtheria toxoid-containing vaccine and complete primary series
• For fully vaccinated contacts (≥3 doses) who haven't received a booster in the past 5 years: provide age-appropriate booster dose 1

Special Considerations

1. Cutaneous Diphtheria

• Manage contacts as for respiratory diphtheria if the strain is toxigenic
• Routine investigation or prophylaxis of contacts is not necessary if the strain is non-toxigenic 1

2. Pregnancy

• While no evidence exists that tetanus and diphtheria toxoids are teratogenic, waiting until the second trimester to administer Td is a reasonable precaution 6

3. Hypersensitivity Concerns

• Persons with previous Arthus-type hypersensitivity reactions or temperature >103°F (39.4°C) following prior tetanus toxoid should not receive Td more frequently than every 10 years 6

Common Pitfalls to Avoid

1. Delaying antitoxin administration - DAT must be given immediately upon clinical suspicion
2. Inadequate contact tracing - Failure to identify and manage all close contacts
3. Overlooking cardiac complications - Myocarditis can develop even after appropriate treatment
4. Insufficient monitoring for neurological complications - Polyneuropathy can develop weeks after initial infection
5. Incomplete antimicrobial course - Ensure full completion of prescribed antibiotics
6. Failure to update vaccination status - Both patients and contacts require appropriate vaccination 1

The basic reproductive number of diphtheria is 1.7-4.3, and vaccination alone can only interrupt transmission in 28% of outbreak settings, making isolation and antibiotics essential components of management 7.