How does tetnus disease affect the nervous system?
Tetanus, caused by the bacterium *Clostridium tetani*, primarily affects the nervous system, leading to severe and potentially life-threatening complications. Here's how tetanus affects the nervous system:
1. Toxin Production:
* _C. tetani_ bacteria produce a potent neurotoxin called tetanospasmin, which is responsible for the neurological symptoms of tetanus.
* The bacteria usually enters the body through deep puncture wounds or injuries. From the wound site, it releases the tetanospasmin into the bloodstream.
2. Binding to Nerve Terminals:
* Tetanospasmin travels through the bloodstream until it reaches the central nervous system, particularly the spinal cord and brain.
* It binds to specific receptors on the motor neurons, which are responsible for controlling muscle movement.
3. Inhibition of Neurotransmission:
* Once bound to the motor neurons, tetanospasmin blocks the release of certain neurotransmitters, including glycine and gamma-aminobutyric acid (GABA).
* These neurotransmitters normally inhibit muscle contractions. By blocking their release, tetanospasmin leads to uncontrolled muscle spasms and rigidity.
4. Muscle Spasticity and Rigidity:
* The continuous muscle contractions caused by the lack of inhibitory neurotransmitters result in severe spasticity and rigidity.
* The muscles remain in a contracted state, leading to stiffness and difficulty with movement.
5. Trismus (Lockjaw):
* One of the characteristic symptoms of tetanus is trismus, also known as lockjaw.
* It occurs when the muscles of the jaw and face go into sustained spasms, making it difficult or impossible for the person to open their mouth.
6. Risus Sardonicus (Sardonic Smile):
* Another distinctive feature of tetanus is risus sardonicus, often referred to as the sardonic smile.
* This refers to the involuntary contraction of the facial muscles, resulting in a fixed grin-like expression.
7. Spreading Rigidity:
* The rigidity and spasms can progress from the initial wound site to other parts of the body, affecting the neck, trunk, and limbs.
* In severe cases, it can lead to generalized tetanus, where the entire body becomes rigid and immobile.
8. Autonomic Nervous System Involvement:
* In some cases, tetanus can also affect the autonomic nervous system, which controls involuntary functions such as heart rate, breathing, and blood pressure.
* This can result in complications such as irregular heartbeat, fluctuations in blood pressure, excessive sweating, and difficulty breathing.
9. Respiratory Compromise:
* Severe muscle spasms can interfere with breathing, especially the muscles involved in respiration.
* In extreme cases, respiratory failure may occur, requiring mechanical ventilation.
Tetanus is a medical emergency, and early diagnosis and treatment are crucial to prevent severe neurological complications and potentially fatal outcomes. Vaccination against tetanus is the most effective way to prevent this disease.