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
    • Paired IgG titers from samples taken pre-vaccination and 1 month post-vaccination may be used if antibody deficiency suspected
    • 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


Prevaccination and 1 month postvaccination titers necessary


If concentrations of IgG, IgM, and IgA are low, low-normal or even normal, and antibody deficiency still strongly suspected, determine IgG subclass and response to protein antigens such as diphtheria, tetanus toxoid, and H. influenzae as well as to pure polysaccharide antigens such as unconjugated pneumococcal vaccine


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: August 2016