Tetanus is an illness characterized by an acute onset of hypertonia, painful muscular contractions (usually of the muscles of the jaw and neck), and generalized muscle spasms without other apparent medical causes. Q
Clostridium tetani, an obligate anaerobic gram-positive bacillus, causes tetanus.
This bacterium is nonencapsulated and forms spores, which are resistant to heat, desiccation, and disinfectants. The spores are ubiquitous and are found in soil, house dust, animal intestines, and human feces.
Spores that gain entry can persist in normal tissue for months to years. Under anaerobic conditions, these spores geminate and elaborate tetanospasmin and tetanolysin. Tetanospasmin that is released by the maturing bacilli is distributed via the lymphatic and vascular circulations to the end plates of all nerves. Q
Tetanospasmin then enters the nervous system peripherally at the myoneural junction and is transported centripetally into neurons of the CNS.
These neurons become incapable of neurotransmitter release.
The neurons, which release gamma-aminobutyric acid (GABA) and glycine, the major inhibitory neurotransmitters, are particularly sensitive to tetanospasmin, leading to failure of inhibition of motor reflex responses to sensory stimulation.
This results in generalized contractions of the agonist and antagonist musculature characteristic of a tetanic spasm.
The shortest peripheral nerves are the first to deliver the toxin to the CNS, which leads to the early symptoms of facial distortion and back and neck stiffness.
Once the toxin becomes fixed to neurons, it cannot be neutralized with antitoxin. Recovery requires sprouting of new nerve terminals and new synapses.
The median incubation period is 7 days, and, for most cases incubation ranges from 4-14 days. Patients with clinical manifestations occurring within 1 week of an injury have more severe clinical courses.
Patients with generalized tetanus present with trismus in 75% of cases.
Autonomic dysfunction manifests as extremes in blood pressure, dysrhythmias, and cardiac arrest.
Neonatal tetanus presents with an inability to suck 3-10 days after birth. Presenting symptoms include irritability, excessive crying, grimaces, intense rigidity, and opisthotonus.
No laboratory tests specific for the diagnosis of tetanus exist.
Laboratory studies may demonstrate a moderate peripheral leukocytosis.
An assay for antitoxin levels is not readily available. However, a level of 0.01 IU/mL or greater in serum generally is considered protective, making the diagnosis of tetanus less likely.
Cerebral spinal fluid (CSF) studies usually are within normal limits.
Emergency Department Care: Treatment of tetanus is directed toward the treatment of muscle spasm, prevention of respiratory and metabolic complications, neutralization of circulating toxin to prevent the continued spread, and elimination of the source.
Admit patients to the ICU. Due to risk of reflex spasms, maintain a dark and quiet environment for the patient. Avoid unnecessary procedures and manipulations.
Consider prophylactic intubation in all patients with moderate-to-severe clinical manifestations.
Perform tracheostomy in patients requiring intubation for > 10 days.
Surgical therapy includes debridement of wounds to remove organisms and to create an aerobic environment.
The current recommendation is to excise at least 2 cm of normal viable-appearing tissue around the wound margins. Incise and drain abscesses.
The maintenance of nutrition is extremely important and should be carried out in seriously ill patients via nasoduodenal tubes, gastrostomy tube feedings, or parenteral hyperalimentation.
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