1.
Clostridium tetani
• Gram positive spore forming anaerobic rod
• Reservoir – soil
• Transmission – puncture wounds, trauma, human bites
• The incubation period of tetanus is approximately 8 days but ranges from 3 to 21 days
• Pathogenesis
Spores germinate in tissues with low oxygen and produce tetanus toxins
C. tetani produces two exotoxins
Tetanospasmin – neurotoxic and causes the clinical manifestations of tetanus
Tetanolysin – haemolytic , tissue lysis
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2.
• Although tetanus is now rare in the developed world, the disease remains a threat
to all unvaccinated people, particularly in developing countries.
• Persons >60 years of age are at greater risk of tetanus because antibody levels
decrease over time.
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3.
Predisposing factors
• Absence of antibodies (ie, from inadequate vaccination) + plus ≥2 of the following
A penetrating injury resulting in the inoculation of C. tetani spores
Coinfection with other bacteria
Devitalized tissue
A foreign body
Localized ischemia
• Cryptogenic(unknown cause)-10% = may be due to unnoticed skin abrasions
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4.
pathogenesis
•  Release of tetanospasmin from vegetative C. Tetani  the toxin binds to
peripheral motor neuron terminals
• Retrograde intra-axonal transport of toxin to the spinal cord and brain stem
• Blockade of inhibitory neurotransmitters (glycine and GABA) release in
presynaptic terminalsresting firing rate of motor neurons  rigidity 
Simultaneous recruitment of agonist and antagonistic muscles 20 to limited
glycinegic activity Spasm
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5.
• Preganglionic sympathetic activity Sympathetic hyperactivity and 
circulating catecholamine level
• Blockade of neurotransmitter release at the NMJ paralysis
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6.
• Toxins are produced and disseminated via blood and lymphatics.
• Toxins act at several sites within the central nervous system, including peripheral
motor end plates, spinal cord, and brain, and in the sympathetic nervous system
• Seizures may occur
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7.
Tetanus
• Forms: generalized, localized, cephalic, neonatal
• Defn of terms:
IP – time gap b/n injury and first symptom (trismus)
Onset time – time b/n trismus and first spasm
Risus sardonicus – recession of the lips backward and a grinning like grimace
Opisthotonus – backward arched posture
Trismus (lockjaw) 20 to masseter muscle hypertonicity
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8.
Generalized tetanus(80%)
• Most common presentation of tetanus
• Trismus (lockjaw) 20 to masseter muscle hypertonicity
• Neck shoulder and back muscle stiffness and pain
• Rigid abdomen and stiff proximal limb muscles
• Risus sardonicus, Arched back (Opisthotonus)
• paroxysmal generalized muscle spasm apnea /Cyanosis /laryngospasm
(spontaneous or provoked)
• Hyperpyrexia with clear mentation
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9.
• The disease usually presents with a descending pattern.
• The first sign is trismus or lockjaw, followed by stiffness of the neck, difficulty in
swallowing, and rigidity of abdominal muscles.
• Other symptoms include elevated temperature, sweating, elevated blood pressure,
and episodic rapid heart rate.
• Spasms may occur frequently and last for several minutes. Spasms continue for
3–4 weeks.
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10.
Severity of generalized tetanus
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11.
Complications
• Aspiration pneumonia
• Vertebral fracture
• Muscle rupture
• DVT+PE (VTE)
• Decubitus ulcer
• Rhabdomyolysis (pigment-induced nephropathy)
• Autonomic dysfunction - Labile or sustained HTN, Tachycardia, Hyperpyrexia,
Profuse sweating, Bradycardia and hypotension episodes, Sudden cardiac arrest
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12.
Neonatal tetanus
• Generalized form of tetanus
• Develops in neonates born in unimmunized mothers after unsterile treatment of
the umbilical cord stump
• Occurs within 2 weeks of neonatal life(typically occurs 5 to 7 days following
birth)
• Manifests with poor feeding, rigidity and spasm
• High rate of mortality
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13.
Local tetanus
• Uncommon form of tetanus
• Manifests with localized muscle contraction near the wound
• good prognosis
Cephalic tetanus : Rare form of local tetanus
• Follows head injury or ear infection
• Manifests with trismus and CN palsy (often CN VII), but involvement of cranial nerves
VI, III, IV, and XII may also occur
• High mortality
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14.
Clinical and pathologic progression of tetanus
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15.
Diagnosis
• Entirely on clinical findings
• Spatula test – gag stimulation causes masseter muscle spasm
• The WHO definition of adult tetanus requires at least one of the following signs:
Trismus (inability to open the mouth) or
Risus sardonicus (sustained spasm of the facial muscles); or
Painful muscular contractions.
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16.
DDx: -
Strychnine poisoning, Dystonic drug reaction (phenothiazines, metoclopramide),
Hypocalcemic tetany, Malignant neuroleptic syndrome
Rabies, Stiff-person syndrome (SPS)
Meningitis /encephalitis,
Acute intraabdominal process ,Alveolar abscess, Dental infection
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17.
Duration of illness
• Tetanus toxin-induced effects are long lasting because recovery requires the
growth of new axonal nerve terminals.
• The usual duration of clinical tetanus is 4-6 weeks
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18.
Treatment
• Principle
Cardiorespiratory support
Eliminate the source of toxin
Neutralize unbound toxin
Prevent muscle spasms
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19.
goals of treatment
• The goals of treatment include:
Halting the toxin production
Neutralization of the unbound toxin
Airway management
Control of muscle spasms
Management of dysautonomia
General supportive management
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20.
1. General measures
• Admit in a quiet ICU with a possibility for continuous monitoring but minimal
disturbance
• Hydration
• Nutritional support (IV/PO)
spasms result in high metabolic demands and a catabolic state.
• Physiotherapy to prevent contracture
• psychological support, analgesia
• Treatment of superimposed infection eg aspiration pneumonia
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21.
2. Treatment of source infection
• Wound debridement
• Antibiotic therapy to eradicate vegetative C.Tetani; choice are:
Metronidazole 500mg IV TID or QID , Penicillin 2 -4 million units IV Q4-6hrs
lower dose of penicillin should be used as high dose has a GABA inhibitory effect
Others Clindamycin, vancomycin ,chloramphenicol, Tetracyclines, macrolides,
cephalosporins can be used .
We suggest a treatment duration of 7 to 10 days.
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22.
3. Neutralization of unbound toxin
Antitoxin
• Since tetanus toxin is irreversibly bound to tissues, only unbound toxin is available
for neutralization
• Human tetanus immune globulin (HTIG)
A dose of 3000 to 6000 units IM should be given as soon as the diagnosis of
tetanus is considered, with part of the dose infiltrated around the wound .
HTIG should be administered at different sites than tetanus toxoid
• Pooled IV Ig and equine antitoxin are used as alternative to HTIG
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23.
4. Active immunization
• Since tetanus is one of the few bacterial diseases that does not confer immunity
following recovery from acute illness, all patients with tetanus should receive active
immunization with a total of three doses of tetanus and diphtheria toxoid (Td) spaced at
least two weeks apart, commencing immediately upon diagnosis.
• Subsequent tetanus doses, in the form of Td, are recommended at 10-year intervals
throughout adulthood
Tetanus toxoid should be administered at a different site than tetanus immune
globulin.
It should be assumed that anyone who is not adequately vaccinated or protected
against tetanus is also inadequately protected against diphtheria (not Tdap)
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24.
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25.
2. Control of muscle spasm
• Generalized muscle spasms are life threatening since they can cause respiratory failure,
lead to aspiration, and induce generalized exhaustion
• Benzodiazepines (Diazepam, midazolam), Barbiturates, chlorpromazine, propofol,
dantrolene, baclofen
Diazepam 10 to 30 mg IV and repeated as needed every 1 to 4 hours; total daily
doses as high as 500 mg may be required for an adult
Chlorpromazine 50–150 mg IM injection every 4–8 hours
• Neuromuscular blocking agents- Vecuronium is less likely to cause autonomic problems
than Pancuronium
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26.
Respiratory care
• Intubation / Tracheostomy + mechanical ventilation for adequate oxygenation
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27.
Management of autonomic dysfunction
• Magnesium sulfate -acts as a presynaptic neuromuscular blocker, blocks catecholamine release
from nerves,
5 gm (75mg/kg) IV loading dose, then 2–3 grams/hour until spasm control is achieved
Can control the autonomic dysfunction and spasm
• Labetalol – both α and β blockers are preferred.
Beta blockade alone with propranolol, for example, should be avoided because of reports of
hypotension and sudden death.
• Esmolol (short acting B blocker), verapamil, clonidine, morphine can be used.
• Continuous spinal anesthesia can also be used- epidural bupivacaine-20 to 50 mL of 0.25%
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28.
prognosis
 Case-fatality rates for non-neonatal tetanus in developing countries range from 8
to 50 percent
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29.
Reference
• Harrison 20th edition
• Uptodate 2018
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