Corynebacterium diphtheriae - Diphtheria

Classic diphtheria is characterized by the formation of a pseudomembrane on respiratory mucous membranes. Initial testing includes CBC and a rapid strep test. A diphtheria culture is usually diagnostic if disease symptoms are present.

Tabs Content

Clinical Overview

Diagnosis

Indications for Testing

Presence of pseudomembrane
Pharyngitis with other organ involvement

Laboratory Testing

CDC diphtheria overview and laboratory testing recommendations
Initial testing – CBC, rapid strep test
Diphtheria culture – usually diagnostic if disease symptoms are present

Differential Diagnosis

Pharyngitis
- Group A Streptococcus
- Epstein-Barr virus
- Viral pharyngitis
- Vincent angina
- Epiglottitis
Skin lesions
- Psoriasis
- Eczema
- Autoimmune immunobullous disease
- Contact dermatitis
- Bacterial infection
  - Streptococcus pyogenes
  - Staphylococcus aureus
  - Group B Streptococcus
Cough
- Pneumonia
  - Viral
  - Bacterial
- Asthma
- Bronchiolitis

Background

Epidemiology

Incidence – very rare in U.S. due to vaccination
Age – usually in children <15 years who are unvaccinated or incompletely vaccinated
Transmission – airborne or direct contact (respiratory secretions or skin lesion)

Organism

Gram-positive bacillus
- Not spore forming
- Unencapsulated
- Pleomorphic
Produces exotoxin that causes many of the symptoms
Results in asymptomatic carriage in some patients

Pathophysiology

Virulence is mediated by prophage-encoded exotoxin
Toxin induces dense necrotic coagulum on mucous membranes
- Causes underlying soft-tissue edema

Clinical Presentation

Incubation period – 2-4 days
Respiratory tract involvement
- Anterior nasal disease
- Faucial disease – classic membranes on pharynx and tonsils, cervical adenopathy, and fever
- Laryngeal and tracheobronchial disease – hoarseness, dyspnea, stridor, and brassy cough
Cardiac disease – myocarditis
- Mortality 3-4 times that of patients without cardiac involvement
- Related to toxin release
Neurologic disease – demyelinating neuropathy
- Usually motor neuropathy
- Related to severity of disease – rare in mild disease
Renal disease – proteinuria, renal failure
Cutaneous disease – chronic nonhealing ulcers with dirty gray membrane, often in mixed infections with Staphylococcus aureus and group A streptococci
Invasive disease
- Endocarditis
- Mycotic aneurysms
- Osteomyelitis
- Septic arthritis

Prevention

Vaccination

ARUP Lab Tests

Tests generally appear in the order most useful for common clinical situations. Click on number for test-specific information in the ARUP Laboratory Test Directory.

Corynebacterium diphtheriae Culture 0060360
Method: Culture/Identification

Recommended Use

Identify Corynebacterium diphtheriae in clinical specimens

Medical Experts

Fisher, Mark A., PhD, D(ABMM), Medical Director, Bacteriology, and Special Microbiology, Antimicrobial Susceptibility Testing, at ARUP Laboratories; Associate Professor of Clinical Pathology, University of Utah

References

Guidelines

U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. Recommended Immunization Schedule for Children and Adolescents Aged 18 Years or Younger. United States, 2018. Centers for Disease Control and Prevention. Atlanta, GA [Last updated: Jan 2018; Accessed: Apr 2018]
Centers for Disease Control and Prevention. Manual for the Surveillance of Vaccine-Preventable Diseases. Centers for Disease Control and Prevention. Atlanta, GA [Updated: Apr 2018; Accessed: Apr 2018]
World Health Organization. Diphtheria vaccine: WHO position paper – August 2017. Wkly Epidemiol Rec. 2017; 92(31): 417-35. PubMed

General References

Khodaei I, Sinha A, Dingle A. Diphtheria: a case report. J Laryngol Otol. 2008; 122(12): 1397-400. PubMed

Mokrousov I. Corynebacterium diphtheriae: genome diversity, population structure and genotyping perspectives. Infect Genet Evol. 2009; 9(1): 1-15. PubMed

References from the ARUP Institute for Clinical and Experimental Pathology^®

Pickering JW, Martins TB, Schroder C, Hill HR. Comparison of a multiplex flow cytometric assay with enzyme-linked immunosorbent assay for auantitation of antibodies to tetanus, diphtheria, and Haemophilus influenzae Type b. Clin Diagn Lab Immunol. 2002; 9(4): 872-6. PubMed

Last Update: July 2018

Corynebacterium diphtheriae - Diphtheria

Diagnosis

Indications for Testing

Laboratory Testing

Differential Diagnosis

Background

Epidemiology

Organism

Pathophysiology

Clinical Presentation

Prevention

ARUP Lab Tests

Medical Experts

References

Guidelines

General References

References from the ARUP Institute for Clinical and Experimental Pathology^®

ARUP Laboratories

ARUP Websites

ARUP Consult


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	Corynebacterium diphtheriae - Diphtheria. ARUP Consult^©. Retrieved February 20, 2019, from: https://arupconsult.com/content/corynebacterium-diphtheriae

Corynebacterium diphtheriae - Diphtheria

Diagnosis

Indications for Testing

Laboratory Testing

Differential Diagnosis

Background

Epidemiology

Organism

Pathophysiology

Clinical Presentation

Prevention

ARUP Lab Tests

Medical Experts

References

Guidelines

General References

References from the ARUP Institute for Clinical and Experimental Pathology®

ARUP Laboratories

ARUP Websites

ARUP Consult

References from the ARUP Institute for Clinical and Experimental Pathology^®