Tetanus, also sometimes known as ‘lockjaw’, is a condition that results in the contraction of skeletal muscle causing the individual to experience pain, tightness and to generally seize up. The name lockjaw comes of cause from the fact that tetanus can likewise cause the jaw specifically to lock making it hard to speak. Infection normally comes through the contamination of a wound, and is this way caused by animal bites or cuts caused by dirty objects such as nails (there is a misconception that rust causes tetanus but in fact it is only dangerous for housing the Clostridium tetani bacteria). The condition is actually caused by a neurotoxin produced by a gram positive, obligate anaerobic bacterium called ‘Clostridium tetani’. Infections can now be prevented using immunization which is highly effective, or by the administering of ‘post-exposure prophylaxis’ after the individual has received the wound.
As tetanus affects skeletal muscle, the main symptoms are muscular. Fortunately the non-skeletal muscles such as the heart are not affected. While the condition can be treated mostly successfully it can be lethal in some cases and roughly 10% of recent cases of tetanus have ended in death, with this 10% mostly being elderly unvaccinated patients. These fatalities are often caused by respiratory problems that come as a result of the muscle spasms and contractions.
The incubation period of tetanus is normally round eight days, though it can drag on for up to several months making it sometimes hard to identify the cause of the problem (the incubation period refers to the amount of time it takes for the symptoms to become apparent). This generally corresponds to the location of the bite – the further the bite from the central nervous system, the longer it will take for the symptoms to take effect.
Interestingly there are actually multiple types of tetanus with slightly varying symptoms which are classified as follows:
Generalised tetanus: This is the most common form of tetanus and makes up roughly 80% of all tetanus. This normally presents with a descending pattern (starting at the top of the body and moving downward) where the first sign is trismus, or lock jaw, and a facial spasm known as risus sardonicus. This is then followed by a stiffness of the neck with difficulty swallowing, then of the pec muscles (across the chest). Other symptoms can also include hotter temperature with sweating, high blood pressure and irregular heart beat. As the condition progresses the individual may start to spasm into awkward shapes known as opisthotonos.
Neonatal tetanus: A neonate means new born child (from neo and natal), and so neonatal tetanus is that found in newly born children – often as a result of an infection of the umbilical stump. This has a faster acting progression and the incubation period is normally only four days. This is a rare condition in developed countries, but elsewhere is responsible for around 15% of neonatal deaths. If the mother has been immunised against tetanus then this can help to give the child ‘passive immunity’.
Local tetanus: This is tetanus where the contractions and spasms are localised to the site of the injury. This normally lasts for a few weeks before subsiding and is a milder, less threatening form of tetanus with only about 1% of cases being fatal. It is important for the patient to be treated however in order to prevent the condition developing into generalised tetanus.
Cephalic tetanus: This is a rare version of tetanus that sometimes occurs alongside ear infections. Here the tetani bacteria is present in the flora of the ear or around the head and affects mostly the cranial nerves and facial nerves.
There are currently no blood tests that will diagnose tetanus, and instead doctors will likely use the ‘spatula’ test in which they touch the posterior pharyngeal wall with a soft instrument before observing the effect. Should this result in a biting of the jaw, rather than the usual gag reflect, this can be a sign of tetanus and is around 94% effective. Often though if an individual has received a bite from an animal, or is concerned about a wound and they have not had recent vaccination, then they will be administered one as a precaution.
In fact the CDC recommends that adults receive a booster vaccination every ten years. This vaccination is of tetanus toxoid. At the same time the booster will be given to anyone with a puncture wound who throughout their lifetime have had fewer than three of these vaccinations. Still though the vaccine is not 100% effective at preventing all cases of tetanus. Unlike a vast number of infectious diseases the body cannot produce an immune response to tetanus after infection, and even a lethal dose of the neurotoxin will not due to the severe potency of the toxin.
If you receive a bite then you should immediately wash the wound, and should then visit a doctor where you will be administered the booster vaccination if necessary. Should the tetanus set in however then you may be treated with tetanus immunoglobulin IV or IM, metronidazole IV and diazepam. Infected tissue around the wound may have to be removed also. If the condition progresses then these quantities will increase and you would be given magnesium as an intravenous infusion to combat the muscle spasm and may have to have a tracheotomy and mechanical ventilation to prevent suffocation (lasting three to four weeks). The individual should also consume large numbers of calories (around 3,500-4,000) in order to make up for the increased muscle activity, and should consume at least 150g of protein (often given in liquid form through a drip). Full recovery will take around four to six weeks.