What is neonatal tetanus?

Tetanus is a neurological disorder (caused by gram-positive rod Clostridium tetani) which is characterized by increased in muscle tone and muscle spasms. If tetanus occurs in neonates (neonate is a baby of age less than 4 weeks or 28 days) it is called “neonatal tetanus”. Neonatal tetanus is commonly seen in the first 2 weeks of life.

How common is neonatal tetanus?

Tetanus is completely preventable by active immunization, but still it occurs throughout the world and in most of the cases in unimmunized individuals. Tetanus also occurs, albeit less frequently in partially immunized individuals and among fully immunized individuals (very rarely) who fail to take the requisite booster doses of tetanus vaccine (toxoid) and maintain adequate protective antibody level.

What is the causative organism of tetanus (neonatal tetanus)?

Tetanus is caused by bacteria Clostridium tetani, which is gram-positive rod. Clostridium tetani is a motile and an anaerobic (grows in absence of air or oxygen) organism. Clostridium tetani is worldwide in distribution and found in soil, animal feces, and inanimate objects (at the tip of thorns, iron nails and in many other objects) and sometimes even in human excreta.

The specialty of Clostridium tetani is its ability to form “spores” which are colorless, oval, and look like drumstick or tennis racket. The spores can survive for years (may be decades) in some environment and become vegetative form when the environment is favorable. The spores of Clostridium tetani are resistant to boiling for 20 minutes and also resistant to several disinfectants, which makes it very difficult to remove from environment. But the vegetative forms are easily deactivated by various antibiotics (penicillin, metronidazole etc.) and normal disinfection procedures.

What is the cause of increased muscle tone and muscle spasm in tetanus?

Clostridium tetani secrete a powerful toxin (which is a protein) called tetanospasmin, which is responsible for increased muscle tone and increased muscle spasm in tetanus. Tetanospasmin is formed by the vegetative forms of the organisms, which occur under control of plasmid. Tetanospasmin than undergo autolysis (auto breakdown) to form a single chain protein (toxin), which is than cleaved to form a structure with a heavy chain (100 kDa) and a light chain (50 kDa). The heavy chain mediates binding to and entry into nerve cells and a light chain blocks neurotransmitter release. The amino acid structure of tetanus toxin (tetanospasmin) and botulinum toxin are partially homologous. Tetanospasmin and botulinum toxin are the 2 most powerful toxins known to affect humans.

What is the incubation period of neonatal tetanus?

The incubation period of neonatal tetanus is approximately 2 weeks.

What are the clinical manifestations of neonatal tetanus?

Neonatal tetanus is generalized form of tetanus and usually have fatal outcome if not treated appropriately. The baby is weak and unable to breastfeed properly. There may be trismus or lockjaw due to spasm of masseter muscles. Abdominal muscles also become rigid.

How neonatal tetanus is diagnosed?

Diagnosis of neonatal tetanus is done on the basis of the clinical findings. If mother is vaccinated for tetanus appropriately, most likely it is not due to tetanus. Neonatal tetanus is generally seen if mother is not immunized or inadequately immunized during pregnancy.

How neonatal tetanus is treated?

Treatment of neonatal tetanus includes general measures, antibiotics, antitoxins, control of muscle spasm and active immunization.

General measures:

General measures in treatment of neonatal tetanus include maintenance of patent airway and respiratory support till recovery; neutralize unbound toxin and elimination of the source of toxin (umbilical cord may be cut further to remove source of toxin). The patient should be admitted to a neonatal intensive care unit, where continuous observation and cardiopulmonary monitoring facility is available.

Additional general measures include adequate hydration, maintenance of proper nutrition with breastfeeding etc.

Antibiotic therapy:

Antibiotics are used to remove the vegetative form of Clostridium tetani, which are the source of the tetanus toxin, although the value of antibiotics is unproven and questionable. The most commonly used antibiotic in neonatal tetanus is penicillin. Other alternatives to penicillin include metronidazole, clindamycin and erythromycin. If there is presence of other infection, it should be treated with appropriate antibiotics.

Antitoxins:

Tetanus antitoxin can effectively neutralize unbound toxin which may be in the circulation or in the wound, but do not have any effect on toxin that is bound to neural tissue. Human tetanus immunoglobulin should be promptly given intramuscularly in divided doses. The volume is large and should be given in divided dose (as it is given intramuscularly, by which route large quantity can not be injected). Prompt administration of tetanus immunoglobulin can lower mortality significantly.

Muscle spasms should be controlled with diazepam or lorazepam. Prevention of muscle spasm is very important as it can cause laryngospasm or sustained contraction of ventilatory muscles.

How to prevent neonatal tetanus?

Neonatal tetanus can be effectively prevented by adapting asceptic techniques during delivery and by conducting delivery in hospitals (institutional delivery). If the delivery is done at home (as is the practice in many developing countries) the umbilical cord should be cut with sterile instrument/blade.

As part of prevention, active immunization of all pregnant women with tetanus toxoid should be done. For the first time pregnancy 2 doses of tetanus toxoid should be administered intramuscularly in the deltoid muscle during 16^th to 28^th week of pregnancy with at least 4 weeks apart, irrespective of immunization status against tetanus. During subsequent pregnancies, single tetanus toxoid should be administered intramuscularly during 16^th to 28^th week of pregnancy to prevent neonatal tetanus.

What is the prognosis of neonatal tetanus?

The mortality rate from neonatal tetanus is still high. But the rate may be higher if proper experience and adequate facilities are not available in hospitals.

Neonatal tetanus is a “notifiable disease” in many countries, but unfortunately the reporting is incomplete and inaccurate, especially in the developing and poor countries. Due to inappropriate and incomplete reporting the World Health Organization undertake periodic estimation of cases and deaths due to tetanus to assess the global burden of tetanus (including neonatal tetanus), as WHO considers the reported cases of tetanus to be underestimation. The last estimated data on tetanus is available for the year 2002.