A36.0 Pharyngeal diphtheria

Name of the Condition

• Pharyngeal diphtheria

Summary

Pharyngeal diphtheria is a localized form of diphtheria affecting the pharynx and tonsils. It is caused by Corynebacterium diphtheriae and is characterized by the formation of a thick, adherent pseudomembrane in the throat. The infection may also produce a potent exotoxin that can lead to systemic complications, even if the primary site is limited to the pharynx.

Causes

Pharyngeal diphtheria is caused by infection with Corynebacterium diphtheriae, a gram-positive bacterium. The disease spreads through respiratory droplets or direct contact with an infected person’s respiratory secretions. The exotoxin produced by the bacteria is responsible for tissue damage and potential systemic effects.

Risk Factors

• Lack of vaccination or incomplete immunization against diphtheria.
• Close contact with an infected individual.
• Poor hygiene or crowded living conditions.
• Travel to regions with low vaccination coverage.

Symptoms

• Sore throat and difficulty swallowing.
• Fever and chills.
• Swollen cervical lymph nodes (bull neck appearance).
• Thick, grayish-white pseudomembrane covering the tonsils or pharynx.
• Hoarseness or muffled voice.
• Nasal discharge or nasal membrane involvement (in some cases).

Diagnosis

Diagnosis involves clinical assessment of symptoms, particularly the presence of the characteristic pseudomembrane. Laboratory confirmation includes throat cultures or PCR to detect Corynebacterium diphtheriae. Toxin detection assays may also be performed to assess the risk of systemic complications.

Treatment Options

• Diphtheria antitoxin: Administered to neutralize circulating toxin.
• Antibiotics: Penicillin or erythromycin to eradicate the bacterial infection.
• Supportive care: Airway management if membrane obstructs breathing, and monitoring for cardiac or neurological complications.

Prognosis and Follow-Up

With prompt treatment, the prognosis is generally good, but complications can occur. Follow-up includes monitoring for signs of myocarditis or neuropathy, which may develop days to weeks after the initial infection. Recovery depends on the extent of toxin-related damage and timely intervention.

Complications

• Airway obstruction from the pseudomembrane.
• Myocarditis (inflammation of the heart muscle).
• Peripheral neuropathy or paralysis.
• Kidney failure in severe cases.

Lifestyle & Prevention

• Ensure up-to-date vaccination with the diphtheria toxoid-containing vaccine.
• Practice good hygiene, including handwashing.
• Avoid close contact with infected individuals during outbreaks.
• Seek medical care promptly if symptoms suggestive of diphtheria appear.

When to Seek Professional Help

Seek immediate medical attention if you experience a severe sore throat, difficulty breathing, or a thick membrane in the throat, especially if you are unvaccinated or have been exposed to someone with diphtheria.

Tips for Medical Coders

When coding for pharyngeal diphtheria (A36.0), ensure documentation supports the anatomical site (pharynx/tonsils) and confirms the presence of the characteristic pseudomembrane or laboratory confirmation of Corynebacterium diphtheriae. Note any associated complications or treatment interventions, as these may impact coding specificity.