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biology

Tetanus

Tetanus is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Tetanus rather than just read about it. In short: Tetanus (from Ancient Greek τέτανος 'tension', 'stretched', 'rigid'), also known as lockjaw, is a bacterial infection caused by Clostridium tetani and characterized by muscle spasms. In the most common type, the spasms begin in the jaw and then progress to the rest of the body.

Tetanus — main illustration
Tetanus — illustration

Key takeaways

  • Tetanus belongs to biology; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Tetanus to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Tetanus from memory before moving on to harder problems.

Reference excerpt

Tetanus (from Ancient Greek τέτανος 'tension', 'stretched', 'rigid'), also known as lockjaw, is a bacterial infection caused by Clostridium tetani and characterized by muscle spasms. In the most common type, the spasms begin in the jaw and then progress to the rest of the body. Each spasm usually lasts for a few minutes. Spasms occur frequently for three to four weeks. Some spasms may be severe enough to fracture bones. Other symptoms of tetanus may include fever, sweating, headache, trouble swallowing, high blood pressure, and a fast heart rate. The onset of symptoms is typically 3 to 21 days following infection. Recovery may take months; about 10% of cases prove to be fatal. C. tetani is commonly found in soil, saliva, dust, and manure. The bacteria generally enter through a break in the skin, such as a cut or puncture wound caused by a contaminated object. They produce toxins that interfere with normal muscle contractions. Diagnosis is based on the presenting signs and symptoms. The disease does not spread between people. Tetanus can be prevented by immunization with the tetanus vaccine. In those with a significant wound and who have had fewer than three doses of the vaccine, both vaccination and tetanus immune globulin are recommended. The wound should be cleaned, and any dead tissue removed. In those who are infected, tetanus immune globulin, or, if unavailable, intravenous immunoglobulin (IVIG) is used. Muscle relaxants may be used to control spasms. Mechanical ventilation may be required if a person's breathing is affected. Tetanus occurs in all parts of the world but is most frequent in hot and wet climates where the soil has a high organic content. In 2015, there were about 209,000 infections and about 59,000 deaths globally. This is down from 356,000 deaths in 1990. In the US, since 2010, there have been less than 40 reported cases each year, almost all of which were in people who had not been vaccinated. An early description of the disease was made by Hippocrates in the 5th century BC. The cause of the disease was determined in 1884 by Antonio Carle and Giorgio Rattone at the University of Turin, and a vaccine was developed in 1924.

Signs and symptoms Tetanus often begins with mild spasms in the jaw muscles—also known as lockjaw. Similar spasms can also be a feature of trismus. The spasms can also affect the facial muscles, resulting in an appearance called risus sardonicus. Chest, neck, back, abdominal muscles, and buttocks may be affected. Back muscle spasms often cause arching, called opisthotonus. Sometimes, the spasms affect muscles utilized during inhalation and exhalation, which can lead to breathing problems. Prolonged muscular action causes sudden, powerful, and painful contractions of muscle groups, called tetany. These episodes can cause fractures and muscle tears. Other symptoms include fever, headache, restlessness, irritability, feeding difficulties, breathing problems, burning sensation during urination, urinary retention, and loss of stool control. Even with treatment, about 10% of people who contract tetanus die. The mortality rate is higher in unvaccinated individuals, and in people over 60 years of age.

Incubation period The incubation period of tetanus may be up to several months, but is usually about ten days. In general, the farther the injury site is from the central nervous system, the longer the incubation period. Shorter incubation periods will have more severe symptoms. In trismus nascentium (i.e., neonatal tetanus), symptoms usually appear from 4 to 14 days after birth, averaging about 7 days. Based on clinical findings, four different forms of tetanus have been described.

Generalized tetanus Generalized tetanus is the most common type, representing about 80% of cases. The generalized form usually presents with a descending pattern. The first sign is trismus or lockjaw, then facial spasms (called risus sardonicus), followed by stiffness of the neck, difficulty in swallowing, and rigidity of pectoral and calf muscles. Other symptoms include elevated temperature, sweating, elevated blood pressure, and episodic rapid heart rate. Spasms may occur frequently and last for several minutes, with the body shaped into a characteristic form called opisthotonos. Spasms continue for up to four weeks, and complete recovery may take months.

Neonatal tetanus

Neonatal tetanus (trismus nascentium) is a form of generalized tetanus that occurs in newborns, usually those born to mothers who themselves have not been vaccinated. If the mother has been vaccinated against tetanus, the infants acquire protection through passive immunity. It usually occurs through infection of the unhealed umbilical stump, particularly when the stump is cut with a non-sterile instrument. As of 1998, neonatal tetanus was common in many developing countries, and was responsible for about 14% (215,000) of all neonatal deaths. In 2010, the worldwide death toll was approximately 58,000 newborns. As a result of a public health campaign, the death toll from neonatal tetanus was reduced by 90% between 1990 and 2010. By 2013, the disease had been largely eliminated from all but 25 countries. Neonatal tetanus is rare in developed countries.

Local tetanus Local tetanus is an uncommon form of the disease, in which people have persistent muscle contractions in the same anatomic area as the injury. The contractions may persist for many weeks before gradually subsiding. Local tetanus is generally milder; only about 1% of cases are fatal, but it may precede the onset of generalized tetanus.

… excerpt ends here. Continue reading the full article.

Illustrations

Tetanus illustration
Tetanus: Clostridium tetani is durable due to its endospores. Pictured is the bacterium alone, with a spore being produced, and the spore alone.
Clostridium tetani is durable due to its endospores. Pictured is the bacterium alone, with a spore being produced, and the spore alone.
Tetanus: A neurotransmitter-filled vesicle before and after exposure to the tetanus toxin. The cleavage of the VAMP protein by the toxin inhibits vesicle fusion and neurotransmitter release into the synapse.
A neurotransmitter-filled vesicle before and after exposure to the tetanus toxin. The cleavage of the VAMP protein by the toxin inhibits vesicle fusion and neurotransmitter release into the synapse.
Tetanus: Tetanus deaths per million persons in 2012.mw-parser-output .div-col{margin-top:0.3em;column-width:30em}.mw-parser-output .div-col-small{font-size:90%}.mw-parser-output .div-col-rules{column-rule:1px solid #aaa}.mw-parser-output .div-col dl,.mw-parser-output .div-col ol,.mw-parser-output .div-col ul{margin-top:0}.mw-parser-output .div-col li,.mw-parser-output .div-col dd{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .legend{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .legend-color{display:inline-block;min-width:1.25em;height:1.25em;line-height:1.25;margin:1px 0;text-align:center;border:1px solid black;background-color:transparent;color:black}.mw-parser-output .legend-text{}  0–1  1–2  2–3  4–8  9–13  14–28  29–151
Tetanus deaths per million persons in 2012.mw-parser-output .div-col{margin-top:0.3em;column-width:30em}.mw-parser-output .div-col-small{font-size:90%}.mw-parser-output .div-col-rules{column-rule:1px solid #aaa}.mw-parser-output .div-col dl,.mw-parser-output .div-col ol,.mw-parser-output .div-col ul{margin-top:0}.mw-parser-output .div-col li,.mw-parser-output .div-col dd{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .legend{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .legend-color{display:inline-block;min-width:1.25em;height:1.25em;line-height:1.25;margin:1px 0;text-align:center;border:1px solid black;background-color:transparent;color:black}.mw-parser-output .legend-text{}  0–1  1–2  2–3  4–8  9–13  14–28  29–151
Tetanus: Tetanus deaths between 1990 and 2017 by age group.[53]
Tetanus deaths between 1990 and 2017 by age group.[53]

Worked examples

Example 1 — a first encounter with Tetanus

Start with the simplest possible case. Write down what Tetanus claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Tetanus before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Tetanus ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Tetanus

In research
Tetanus appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Tetanus in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Tetanus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Bacterial diseases, Tetanus, Vaccine-preventable diseases, so understanding it makes those chapters shorter.
In everyday life
Look for Tetanus outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Tetanus in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Tetanus means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Tetanus out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Tetanus in simple terms?

Tetanus (from Ancient Greek τέτανος 'tension', 'stretched', 'rigid'), also known as lockjaw, is a bacterial infection caused by Clostridium tetani and characterized by muscle spasms. In the most common type, the spasms begin in the jaw and then progress to the rest of the body.

Why does Tetanus matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Tetanus?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Tetanus.

Tags

  • Bacterial diseases
  • Tetanus
  • Vaccine-preventable diseases

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