From the Guidelines
The most specific combination of signs and symptoms for diphtheria includes a characteristic gray-white pseudomembrane covering the tonsils, pharynx, and/or nasal cavity, accompanied by sore throat, low-grade fever, malaise, and cervical lymphadenopathy (swollen neck lymph nodes) creating a "bull neck" appearance, as described in the most recent and highest quality study 1. This pseudomembrane is firmly adherent to the underlying tissue and bleeds when attempts are made to remove it, which distinguishes it from other throat infections. Patients may also experience hoarseness, stridor, and respiratory distress if the membrane extends into the larynx or trachea. Some key points to consider when diagnosing diphtheria include:
- The presence of a pseudomembrane in the pharynx, which is the hallmark of respiratory diphtheria 1
- The pseudomembrane can be firmly adherent to the underlying tissue and may bleed when attempts are made to remove it
- Systemic complications can occur due to the diphtheria toxin, including myocarditis (heart inflammation) with cardiac arrhythmias, and peripheral neuropathy causing paralysis, particularly of the soft palate and eye muscles
- Early recognition is crucial as treatment with diphtheria antitoxin must be administered promptly, along with appropriate antibiotics such as penicillin or erythromycin, to prevent potentially fatal complications, as recommended by the Advisory Committee on Immunization Practices (ACIP) 1. The diagnosis is confirmed by isolating Corynebacterium diphtheriae from throat cultures. Some other relevant information includes:
- Respiratory diphtheria-like illness caused by toxigenic Corynebacterium ulcerans infections can be clinically indistinguishable from toxigenic Corynebacterium diphtheriae infections 1
- Clinicians should consider respiratory diphtheria among patients who have low-grade fever and pseudomembranous pharyngitis, and treat promptly with diphtheria antitoxin and antibiotics without waiting for laboratory confirmation 1.
From the Research
Combination of Signs and Symptoms for Diphtheria
The most specific combination of signs and symptoms for diphtheria includes:
- Formation of a pseudomembrane in the throat 2, 3
- Systemic effects such as myocarditis and neuropathy, which are associated with increased fatality risk 2
- Local growth of the bacterium in the pharynx with pseudomembrane formation or, less commonly, in the stomach or lungs 3
- Acute disease of the upper respiratory tract usually involves one or more of the following: tonsillar zones, larynx, soft palate, uvula, and nasal cavities 3
Predictors of Diphtheritic Cardiomyopathy
The combination of signs and symptoms that predict the development of diphtheritic cardiomyopathy includes:
- Pseudomembrane score of >2 4
- Bull neck 4
- Myocarditis on admission 4
- Elevated aspartate aminotransferase level 4
- Presence of troponin T, which identifies additional children with subclinical cardiac damage 4
Clinical Diagnosis
Clinical diagnosis is confirmed by the isolation and identification of the causative Corynebacterium spp., usually by bacterial culture followed by enzymatic and toxin detection tests 2