A recent review of the topic appeared in Lancet Infectious Disease, linked here:
Tetanus: recognition and management
General
Tetanus is rare in the developed world but worth discussing because it is a must not miss diagnosis.
Tetanus is caused by infection with Clostridium tetani. It produces a neurotoxin that is transported to the CNS retrogradely (by reverse axonal transport) where it blocks inhibitory neurotransmitter release thereby allowing unopposed motor activity. Four forms of tetanus are described: neonatal (not discussed here), localized (near the site of injury), cephalic (localized to the head and neck ), and generalized. Either of the localized forms can progress to generalized tetanus.
Epidemiology
Although considered rare in the developed world, 17 to 33 cases are diagnosed yearly in the United States. Inoculation sources can include any violation of skin integrity. Injection drug use, any type of wound, piercings, acupuncture, subQ or IM injections (either therapeutic or recreational), are possible sources. Up to 30% of cases are associated with no discernible history of a wound or injury. This epidemiology argues strongly for universal vaccination.
Clinical features
Clinical features include rigidity, spasm, trismus, opisthotonus, and dysphagia. Fever is often present but not invariably at presentation.
Diagnosis
Diagnosis is based on clinical features and confirmatory testing. A high index of suspicion is important due to non-textbook presentations (acute abdomen, dysphagia, stroke concerns, dystonia). The diagnostic test of choice is C tetani PCR from wound material. Anti tetanus toxin antibodies are also recommended, and while a low tighter is supportive of the diagnosis and high antibody levels rule against the diagnosis, this test is not definitive. Occasional cases have been reported in patients who had “protective” antibody titers.
Aspects of immunity
Natural infection does not confer immunity. Near elimination of the disease in the developed world is attributable to universal vaccination practices. Since there is no person to person transmission, herd immunity does not exist.
Treatment
Surgical debridement even for innocuous appearing wounds is indicated. Antibiotics should include metronidazole which according to low level evidence is associated with better overall outcomes. Antioxin in the form of tetanus immunoglobulin is indicated. Invasive mechanical ventilation is necessary in around 50% of patients and should this be required, primary tracheostomy is preferred.
Benzodiazepines are an important part of the treatment with diazepam as the benzo of choice. High doses and continuous drips are often necessary. Adjunctive neuromuscular blockade may be needed.
Dysautonomia
Dysautonomia is common and is a significant cause of mortality.
IV magnesium sulfate as a treatment for dysautonomia is associated with improved outcomes and a bolus/drip regimen is recommended, targeting serum levels of 2 to 4 mmole/L. Opiates have a significant role in the management of dysautonomia. Otherwise, vasoactive drugs as appropriate for the patient’s hemodynamic state may be indicated.
Finally, general symptomatic and supportive care to include fluids, nutritional support, stress ulcer prophylaxis, VTE prophylaxis along with skin and wound care are indicated.
