Clostridium tetani - Tetanus

  • Diagnosis
  • Background
  • Lab Tests
  • References
  • Related Topics

Indications for Testing

  • Muscle spasms, trismus, and dysphagia, especially in setting of obvious wound

Criteria for Diagnosis

Laboratory Testing

  • Initial testing
    • CBC with differential
    • Cerebrospinal fluid analysis – to rule out other causes of encephalitis/meningitis
    • Gram stain of wound
    • Wound culture – need to order anaerobic wand culture
  • Difficult to confirm rapid diagnosis based on testing – must use clinical judgment for therapy decisions
  • Vaccination status and immunodeficiency evaluation
    • Evaluate the ability of a patient to produce antibody to pure protein vaccine after vaccination to rule out antibody deficiency
    • Recommend pairing with diphtheria and Haemophilus influenzae IgG testing

Differential Diagnosis

Tetanus is a central nervous system disease resulting from neurotoxin produced by Clostridium tetani spores.


  • Incidence – 0.03/100,000 in the U.S.
    • Most common in developing countries – as many as 28/100,000
  • Age
    • >50 years, often in rural areas
    • Unvaccinated or incompletely vaccinated infants
  • Transmission
    • Post-injury (50%)
    • Drug abuse or animal-related injuries (25%)
    • Wounds of unknown cause (20%)
    • No known source (5%)


  • Slender, gram-positive, sporulating, anaerobic bacillus
    • Spores can survive in soil for years

Risk Factors

  • Extremes of age
  • Residence in developing country
  • Lack of vaccination
  • Immunocompromised condition


  • Tetanus toxin (tetanospasmin) binds to nerve endings and prevents release of central nervous system neurotransmitters
  • Spores usually enter through penetrating wound
  • Toxin may affect neurons for 4-6 weeks

Clinical Presentation

  • 3-14 days incubation
  • Generalized disease (most common form)
    • Initial complaints – difficulty swallowing, neck stiffness, pain
    • Tonic contractions of skeletal muscles and intermittent intense muscle spasm – opisthotonus, stiff neck, risus sardonicus, trismus, apnea, dysphagia
    • Fractures of vertebrae not uncommon
    • Symptoms of overreactivity – irritability, restlessness, sweating, tachycardia
    • Complications – rhabdomyolysis with renal failure; sudden cardiac arrest
  • Localized disease
    • Partial immunity allows localized effect of toxin at wound site; often precedes generalized tetanus
    • Prolonged, steady, painful contraction in wound region
  • Cephalic disease
    • Involves cranial nerves (CN), if organism has entered wound in head or neck region
      • CN VII most common
    • Focal neuropathies
    • May develop into full-blown, generalized form of disease
  • Neonatal disease
    • Usually associated with inappropriate birth practices in developing countries (eg, poor hygiene involving umbilical stump) and maternal nonvaccination
    • Most cases occur within first 14 days after birth
      • Median incubation is 5-7 days
    • Spasms, trismus, rigidity, seizures, inability to suckle
    • High mortality
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.

Encephalitis Panel with Reflex to Herpes Simplex Virus Types 1 and 2 Glycoprotein G-Specific Antibodies, IgG, CSF 2008916
Method: Semi-Quantitative Enzyme-Linked Immunosorbent Assay/Semi-Quantitative Chemiluminescent Immunoassay

Anaerobic Organism Identification 0060164
Method: Identification. Methods may include biochemical, mass spectrometry, or sequencing.


Negative culture does not rule out disease

Isolates may be non-toxigenic

Anaerobe culture is NOT included with this order

Diphtheria, Tetanus, and H. Influenzae b Antibodies, IgG 0050779
Method: Quantitative Multiplex Bead Assay


U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. Recommended Immunization Schedules for Persons Aged 0 Through 18 Years. United States, 2015. Centers for Disease Control and Prevention. Atlanta, GA [Last Updated Jul 2011; Accessed: Nov 2015]

General References

Brook I. Current concepts in the management of Clostridium tetani infection. Expert Rev Anti Infect Ther. 2008; 6(3): 327-36. PubMed

Gibson K, Uwineza B, Kiviri W, Parlow J. Tetanus in developing countries: a case series and review. Can J Anaesth. 2009; 56(4): 307-15. PubMed

Thwaites L, Beeching NJ, Newton CR. Maternal and neonatal tetanus. Lancet. 2015; 385(9965): 362-70. PubMed

Medical Reviewers

Last Update: September 2016