Neonatal tetanus refers to an acute infectious disease characterized by trismus (lockjaw) and generalized tonic muscular spasms. It is caused by the invasion and proliferation of Clostridium tetani at the umbilical stump, which releases tetanospasmin.
Etiology and Pathogenesis
Clostridium tetani is a Gram-positive anaerobic bacterium. Its spores are highly resistant and can survive in the external environment for long periods, remaining unaffected by common disinfectants. The bacterium is widely found in soil, dust, and feces. It can enter the umbilical stump when contaminated instruments are used for cutting the umbilical cord or during bandaging. The resulting hypoxic environment in the stump further promotes bacterial growth.
Tetanospasmin, the toxin produced by Clostridium tetani, spreads to the central nervous system through nerves or lymphatic fluid, where it binds to gangliosides. This prevents the release of inhibitory neurotransmitters (glycine and gamma-aminobutyric acid) from inhibitory neurons, resulting in sustained muscle contractions. Additionally, tetanospasmin inhibits synaptic transmission at the neuromuscular junction, causing acetylcholine to accumulate at the synaptic cleft and continuously stimulate peripheral muscles. This leads to increased muscle tone and spasms, manifested clinically as trismus and opisthotonus. The toxin also excites the sympathetic nervous system, causing symptoms such as tachycardia, hypertension, and excessive sweating.
Clinical Manifestations
The incubation period is usually 4–7 days. A shorter incubation period is associated with more severe disease and higher mortality. Early symptoms include irritability, difficulty opening the mouth, and feeding difficulties. The "tongue depressor test" may aid in early diagnosis. Applying pressure to the tongue with a tongue depressor makes opening the mouth progressively harder, indicating a positive test result.
As the condition progresses, symptoms include trismus, facial muscle tension, a "sardonic smile" appearance, clenched fists, hyperflexion of the upper limbs, extension of the lower limbs, and opisthotonus. Respiratory and laryngeal muscle spasms may lead to cyanosis or asphyxia. A distinctive feature of neonatal tetanus is the preservation of consciousness during spasms, which can be triggered by any mild stimulus. Spasms typically subside gradually after 1–4 weeks with proper treatment, with increased time intervals between episodes and improved feeding ability. Complete recovery may take 2–3 months. Pneumonia and sepsis are common complications during the disease course.
Treatment
Nursing Care
A quiet and darkened environment is provided to minimize stimulation and reduce spasm frequency. Feeding is withheld during the spasm phase, and nutrition is administered intravenously. Feeding via a gastric tube may be attempted after symptoms decrease. The umbilical stump is cleaned with 3% hydrogen peroxide and iodine solution.
Antitoxins
Antitoxins can neutralize free tetanospasmin but are ineffective against toxin already bound to gangliosides, so early administration is critical. Tetanus antitoxin (TAT) can be administered at a dose of 10,000–20,000 U intravenously along with 3,000 U injected around the umbilical stump. Skin sensitivity testing is required before use. Tetanus immunoglobulin (TIG) can alternatively be administered intramuscularly at a dose of 500 U. TIG has a high serum concentration, a long half-life (up to 30 days), and a lower likelihood of causing allergic reactions.
Antispasmodics
Controlling spasms is the key to successful treatment.
Diazepam
This is the first-choice drug. A dose of 0.3–0.5 mg/kg is administered via slow intravenous injection, reaching effective levels within 5 minutes. However, its short half-life makes it unsuitable as a maintenance treatment. It is administered every 4–8 hours.
Phenobarbital
An initial loading dose of 15–20 mg/kg is given by slow intravenous injection, followed by a maintenance dose of 5 mg/kg daily, administered every 12–24 hours. It may be alternated with diazepam.
Chloral Hydrate (10%)
A dose of 0.5 mL/kg is administered via a gastric tube or enema and is often used as a temporary remedy during spasms.
Antibiotics
Penicillin is used at a dose of 100,000–200,000 U/kg per day, administered twice daily. Alternatively, metronidazole can be used, with an initial dose of 15 mg/kg followed by 7.5 mg/kg every 12 hours via intravenous infusion for 7–10 days. These antibiotics eliminate Clostridium tetani.
Prevention
Strict adherence to modern obstetric practices during delivery can prevent neonatal tetanus. If proper sterilization was not followed during delivery, the distal end of the umbilical cord should be excised within 24 hours, and the umbilical cord should be re-ligated and disinfected. Intramuscular injection of TAT (1,500–3,000 U) or TIG (75–250 U) is recommended in such cases.