Tetanus

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Medicine

Last updated on:
February 4^th, 2021

Medicine

Last updated on:
February 4^th, 2021

Hi there!

You’re looking at a short reference article from Explain Medicine (one of four distinct learning formats available in Clinical Odyssey). Try it out, and have fun improving your clinical skills.

Clinicals - History

Fact	Explanation
Introduction	Tetanus is a disease that affects the nervous system. It is characterized by muscle spasms due to the tetanospasmin toxin released by Clostridium tetani. C. tetani is an anaerobic bacterium that is commonly found in the soil.
Tetanus-prone wounds	The presence of puncture type wounds, contamination with dirt or manure, sepsis, burns, high-velocity missile injuries, or frostbite increases the risk of tetanus. Also, any wound over six hours old should be considered tetanus-prone.
Trismus	Spasms involving the masseter and temporal muscles may result in trismus, also known as lockjaw, which is an inability to open the mouth. This occurs when C. tetani reaches the spinal cord and brainstem via retrograde axonal transport. Then, the release of tetanospasmin causes defects in the anterior horn inhibition of muscular contraction. The result is involuntary, sustained muscle contraction.
Muscle rigidity	Patients present with prolonged, tonic contraction of involved muscle groups. This occurs due to the inhibition of inhibitory neuromuscular signaling from the anterior horn.
Muscle spasms	Muscle "spasms" are short-lasting muscle contractions. They may be elicited from movements or sensory stimuli. These reflex spasms occur due to hyperactivity of the lower motor neurons due to denervation.
Dysphagia	The involvement of the muscles of the tongue, pharynx, and esophagus can lead to difficulty swallowing. This occurs due to the inhibition of inhibitory neuromuscular signaling from the anterior horn.
Opisthotonus	Patients with generalized tetanus may present with arching of the back due to involvement of the dorsal extensor muscles.
Apnea/upper airway obstruction	Patients may present with shortness of breath due to involvement of the respiratory and laryngeal muscles.
Pain	Pain in tetanus occurs due to severe spasms. Atypically, pain and allodynia can occur due to the involvement of sensory nerves.
Duration	The initial symptoms of tetanus usually occur around ten days after an inoculating trauma. However, the incubation period may range from three days to three weeks.
Localized tetanus	Localized tetanus is a less common form of the disease characterized by spasm of muscles directly adjacent to the wound site. This presentation may precede generalized disease.
Cephalic tetanus	Cephalic tetanus is characterized by trismus, eyelid retraction, dysphagia, deviated gaze, and risus sardonicus. This presentation is caused by involvement of the bulbar musculature.

Introduction

Tetanus is a disease that affects the nervous system. It is characterized by muscle spasms due to the tetanospasmin toxin released by Clostridium tetani. C. tetani is an anaerobic bacterium that is commonly found in the soil.

Tetanus-prone wounds

The presence of puncture type wounds, contamination with dirt or manure, sepsis, burns, high-velocity missile injuries, or frostbite increases the risk of tetanus. Also, any wound over six hours old should be considered tetanus-prone.

Trismus

Spasms involving the masseter and temporal muscles may result in trismus, also known as lockjaw, which is an inability to open the mouth. This occurs when C. tetani reaches the spinal cord and brainstem via retrograde axonal transport. Then, the release of tetanospasmin causes defects in the anterior horn inhibition of muscular contraction. The result is involuntary, sustained muscle contraction.

Muscle rigidity

Patients present with prolonged, tonic contraction of involved muscle groups. This occurs due to the inhibition of inhibitory neuromuscular signaling from the anterior horn.

Muscle spasms

Muscle "spasms" are short-lasting muscle contractions. They may be elicited from movements or sensory stimuli. These reflex spasms occur due to hyperactivity of the lower motor neurons due to denervation.

Dysphagia

The involvement of the muscles of the tongue, pharynx, and esophagus can lead to difficulty swallowing. This occurs due to the inhibition of inhibitory neuromuscular signaling from the anterior horn.

Opisthotonus

Patients with generalized tetanus may present with arching of the back due to involvement of the dorsal extensor muscles.

Apnea/upper airway obstruction

Patients may present with shortness of breath due to involvement of the respiratory and laryngeal muscles.

Pain

Pain in tetanus occurs due to severe spasms. Atypically, pain and allodynia can occur due to the involvement of sensory nerves.

Duration

The initial symptoms of tetanus usually occur around ten days after an inoculating trauma. However, the incubation period may range from three days to three weeks.

Localized tetanus

Localized tetanus is a less common form of the disease characterized by spasm of muscles directly adjacent to the wound site. This presentation may precede generalized disease.

Cephalic tetanus

Cephalic tetanus is characterized by trismus, eyelid retraction, dysphagia, deviated gaze, and risus sardonicus. This presentation is caused by involvement of the bulbar musculature.

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