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Tetanus

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Tetanus, Tetanic opisthotonus, Clostridium tetani, Risus Sardonicus, Sardonic Grinning, Rictus Grin

  • See Also
  • Pathophysiology
  1. Clostridium tetani
    1. Motile spore forming Gram Positive obligate Anaerobe
    2. Organism lives in soil as well as the stool of domestic animals and people
  2. Tetanus spores enter patient via wounds (even minor, superficial wounds, umbilical stump of newborn)
    1. Spores germinate
  3. Germinated spores produce Tetanus toxin (exotoxin)
    1. Tetanus toxin spreads to nerves either hematogenous or retrograde transmission via nerves
  4. Toxin irreversibly binds nerves
    1. Blocks presynaptic release of inhibitory neurotransmitters (Glycine, GABA)
  • Epidemiology
  1. Incidence (2008 U.S.): 0.06 per million persons
  • Risk Factors
  1. Contaminated wounds or Puncture Wounds (e.g. open Fractures, ocular injuries)
    1. However up to 30% of Tetanus cases occur in clean wounds (e.g. surgical wounds)
  2. Inadequate tetanus Vaccination (or large pathogen burden)
  3. Advanced age (waning immunity)
  4. HIV Infection
  5. Diabetes Mellitus
  6. Corticosteroids or other immunosuppressants
  • Signs
  1. General
    1. Muscle spasms are initially intermittent, each lasting seconds to minutes
    2. With progression, spasms increase in frequency and duration
    3. Spasms may be triggered by even minor stimuli (light touch)
  2. Opisthotonos (arching of back)
    1. Diffuse muscle firing of both the stronger extensor and weaker flexor back muscles
  3. Lockjaw (Trismus)
    1. Painful, contractions of the masseter and neck muscles
  4. Facial muscle spasms
    1. Risus Sardonicus (Sardonic Grinning)
  5. Abdominal rigidity (older children and adults)
  6. Other regions of muscle spasm
    1. Oropharyngeal muscle spasm (Dysphagia)
    2. Neck muscle spasm (Torticollis)
    3. Laryngeal muscle spasm (airway compromise)
    4. Respiratory muscle spasm (apnea)
  7. Autonomic instability associated with Catecholamine release (onset 1 week after motor symptoms)
    1. Fever
    2. Irritability and motor restlessness
    3. Sweating
    4. Tachycardia
    5. Labile Blood Pressure including Hypertension
    6. Dysrhythmias
  • Types
  1. Neonatal Tetanus (accounts for 50% of worldwide deaths)
    1. Associated with contamination of the neonatal umbilical stump
    2. Presents in the first week of life with poor feeding, decreased movement, irritability, muscle rigidity and spasms
  2. Localized Tetanus to one body region (rare)
    1. Typically progresses to Generalized Tetanus
    2. Lower mortality if Tetanus remains localized
  3. Cephalic Tetanus
    1. Localized Tetanus from a head, ears, nose or neck wound
    2. Involves muscles of eyes, face, Tongue and pharynx
    3. Affects Cranial Nerves and may result in a secondary Bell's Palsy
    4. Often progresses to generalized Tetanus
  4. Generalized Tetanus (80% of cases)
    1. Associated with rigidity, spasm and Autonomic Dysfunction
  • Diagnosis
  1. Tetanus is a clinical diagnosis
  2. Specific testing identifies Clostridium tetani in only 30% of Tetanus cases
  • Differential Diagnosis
  1. Local Trismus
    1. See Trismus
    2. Alveolar abscess or other local soft tissue infection
    3. Mandibular Trauma
  2. Tetany (generalized increased tone)
    1. Hypocalcemia
    2. Hypoparathyroidism
    3. Hypomagnesemia
    4. Strychnine Poisoning
    5. Dystonic Reaction
  3. Opisthotonos (arched back)
    1. Strychnine Poisoning
  4. Risus Sardonicus (Sardonic Grin)
    1. Strychnine Poisoning
    2. Wilson's Disease
    3. Water dropwort (Oenanthe crocata) Poisoning
      1. Appendino (2009) J Nat Prod 72(5):962-5 +PMID:19245244 [PubMed]
  5. Other conditions
    1. Meningitis
    2. Encephalitis
    3. Rabies
    4. Neuroleptic Malignant Syndrome
  • Management
  1. Background: Goals of management
    1. Eliminate Tetanus infection
      1. Wound Debridement and removal of necrotic tissue
      2. Antibiotics (see below)
    2. Neutralize unbound peripheral Tetanus toxin
      1. Treat with human tetanus Immunoglobulin
    3. Decrease effects of CNS bound Tetanus toxin
  2. Anti-Tetanus agents
    1. Human Tetanus immune globulin (TIG)
      1. Administer 3000-6000 units in a site away from the Tetanus ToxoidVaccine
      2. Equine Tetanus immune globulin (TIG) may be used if human formulation is not available
      3. Equine Tetanus antitoxin may be used if immune globulin is not available (test hypersensitivity first)
    2. Antibiotics
      1. Metronidazole (first-line)
      2. Penicillin
      3. Treat co-infection if suspected (with third generation Cephalosporin)
      4. Other antibiotics with activity (Doxycycline, Macrolides, Clindamycin, Vancomycin, chloramphenicol)
    3. Tetanus Toxoid booster
      1. Given on patient recovery
      2. Primary Tetanus infection does not confer immunity
  3. Other measures
    1. Ensure adequate airway (Advanced Airway)
      1. Rapid Sequence Intubation with non-depolarizing paralytic (e.g. Rocuronium)
    2. Control muscle spasm (sedation, Analgesics and muscle relaxants)
      1. Propofol
      2. Intravenous Benzodiazepines
      3. Morphine or Hydromorphone
      4. Other agents may be considered (e.g. Baclofen, Dantrolene, pecedex, phenobarbital, Magnesium)
      5. May also consider neuromuscular blocking agents (e.g. Vecuronium)
    3. Wound care
      1. See Wound Debridement as above
    4. Autonomic instability
      1. Avoid Propranolol (association with Sudden Cardiac Death)
        1. Other Beta Blockers may be used (e.g. Metoprolol)
      2. Clonidine
        1. May decrease sympathetic drive
  • Complications
  • Acute
  1. Airway
    1. Trismus
    2. Laryngospasm or respiratory arrest
  2. Cardiopulmonary
    1. Decreased diaphragm excursion
    2. Aspiration
    3. Aspiration Pneumonia
    4. ARDS
    5. Pulmonary Embolism
  3. Miscellaneous
    1. Fractures
    2. Death
  • Complications
  • Chronic
  1. Abnormal Gait
  2. Muscle rigidity
  3. Memory loss
  4. Persistent vegetative state
  • Course
  1. Incubation period: 3 to 21 days (10 days on average)
  2. Earlier onset after exposure is associated with more aggressive infection and worse prognosis
  3. Tetanus duration is 6-8 weeks (to allow nerve regrowth)
  4. Expect a long, slow recovery if survived
  • Prognosis
  1. Mortality is reduced to as low as 15% in developed countries with intensive care
  2. Adult Mortality: 52%
  3. Neonatal mortality: 88%
  • Prevention
  1. Tetanus Vaccine
  2. Tetanus Immunoglobulin
    1. Dirty wound with <3 doses of tetanus Vaccine in Primary Series
  3. Clean wounds well
    1. Irrigate extensively with adequate pressure
    2. Debride necrotic tissue
  • Resources
  1. CDC Tetanus information
    1. http://www.cdc.gov/tetanus/
  2. CDC Tetanus surveillance
    1. http://www.cdc.gov/tetanus/surveillance.html
  • References
  1. Harrison and Ruttan (2019) Crit Dec Emerg Med 33(7): 3-12
  2. Nordt, Swadron, Orman and Ran in Herbert (2015) EM:Rap 15(7):15-16