TETANUS

Question 1

The definition of probable tetanus according to CDC

Answer 1

CDC defines probable tetanus as “an acute illness with muscle spasms or hypertonia in the absence of a more likely diagnosis”

Question 2

TRUE OR FALSE: C. tetani is an anaerobic, gram-positive, spore-forming rod whose spores are highly resilient

Answer 2

TRUE

Question 3

The most common infection sites of tetanus in adults

Answer 3

Superficial abrasions to the LIMBS are the most common infection sites in adults.

• Very low concentrations of this highly potent toxin can result in tetanus (minimal lethal human dose, 2.5 ng/kg)

Question 4

Risk factors for increased tetanus risk

Answer 4

• Persons >60 years of age
• Diabetes
• People who inject drugs—particularly those injecting heroin subcutaneously (“skin-popping”)

Question 5

TRUE OR FALSE: Tetanus toxin undergoes retrograde transport into the central nervous system (CNS)

Answer 5

TRUE

• Tetanus toxin is intra-axonally transported to motor nuclei of the cranial nerves or ventral horns of the spinal cord
• Once inside the neuron, the toxin enters a retrograde transport pathway, whereby it is carried proximally to the motor neuron body.
  *Following retrograde transport in the motor neuron, the tetanus toxin undergoes translocation across the synapse to the GABA-ergic presynaptic inhibitory interneuron terminals

Question 6

Muscles of the ______ are affected first, presumably because of the shorter distances toxin must travel up motor nerves to reach presynaptic terminals

Answer 6

Muscles of the face and jaw

• In the typical progression of generalized tetanus, muscles of the face and jaw often are affected first, presumably because of the shorter distances toxin must travel up motor nerves to reach presynaptic terminals.

Question 7

The most common cause of death in tetanus?

Answer 7

Respiratory Failure

• Without ventilatory support, respiratory failure is the most common cause of death in tetanus.

Question 8

Autonomic disturbance is maximal during what week of severe tetanus?

Answer 8

Autonomic disturbance is maximal during the SECOND WEEK of severe tetanus

*Autonomic involvement is evidenced by gastrointestinal stasis, sweating, increased tracheal secretions, and acute (often high-output) renal failure

Question 9

TRUE OR FALSE: The diagnosis of tetanus is based on clinical findings

Answer 9

TRUE

• The diagnosis of tetanus is based on clinical findings
• Treatment should not be delayed while laboratory tests are conducted.
• Culture of C. tetani from a wound provides supportive evidence.

Question 10

What level of serum anti-tetanus IgG is deemed protective and do not support the diagnosis of tetanus?

Answer 10

Levels >0.1 IU/mL (measured by standard ELISA) are deemed protective and do not support the diagnosis of tetanus.

Question 11

What is the preferred antibiotic therapy for severe tetanus?

Answer 11

Metronidazole (400 mg rectally or 500 mg IV every 6 h for 7 days)

Question 12

What is the alternative antibiotic for severe tetanus?

Answer 12

Penicillin (100,000–200,000 IU/ kg per day)

Question 13

The usual method of securing the airway in severe tetanus

Answer 13

Tracheostomy

Question 14

Recovery from tetanus may take how many weeks?

Answer 14

4-6 weeks

Question 15

TRUE OR FALSE: Patients must be given a full primary course of immunization as tetanus toxin is poorly immunogenic and the immune response following natural infection is inadequate

Answer 15

TRUE

Question 16

WHO recommendation for tetanus vaccination

Answer 16

Primary course of three doses in infancy, boosters at 4–7 and 12–15 years of age, and one booster in adulthood

Question 17

WHO recommendations for prevention of maternal and neonatal tetanus

Answer 17

Two doses of tetanus toxoid at least 4 weeks apart to previously unimmunized pregnant women.
The third dose should be given at least 6 months later, followed by one dose in subsequent pregnancies (or intervals of at least 1 year), to a total of five doses to provide long-term immunity

Question 18

Factors associated with poor prognosis in tetanus

Answer 18

Age >70 years
Incubation period <7 days
Short time from first symptom to
admission
Puerperal, IV, postsurgery, burn
entry site
Period of onset <48 h
Heart rate >140 beats/minb
Systolic blood pressure >140 mmHg
Severe disease or spasms
Temperature >38.5°Cb

Question 19

What is the primary cause of tetanus?
A) A viral infection affecting muscle function
B) A neurotoxin produced by Clostridium tetani
C) Direct bacterial invasion into the central nervous system
D) An autoimmune reaction against motor neurons

Answer 19

Correct Answer: B) A neurotoxin produced by Clostridium tetani
Rationale: Tetanus is caused by tetanospasmin, a powerful exotoxin produced by C. tetani, which blocks inhibitory neurotransmission, leading to muscle spasms.

Question 20

Which of the following is true regarding Clostridium tetani spores?
A) They are easily killed by boiling
B) They survive only in anaerobic environments
C) They can resist many disinfectants and survive in the environment
D) They do not persist in animal intestines

Answer 20

Correct Answer: C) They can resist many disinfectants and survive in the environment
Rationale: C. tetani spores are highly resilient, surviving in soil, dust, and animal intestines, and they resist boiling and many disinfectants.

Question 21

What is the most common site of tetanus infection in adults?
A) Deep puncture wounds
B) Superficial abrasions to the limbs
C) Infected surgical wounds
D) Gastrointestinal mucosa

Answer 21

Correct Answer: B) Superficial abrasions to the limbs
Rationale: In adults, superficial limb abrasions are the most common site of infection due to environmental exposure.

Question 22

Which of the following best describes the mechanism of tetanus toxin?
A) It directly damages motor neurons
B) It enhances neurotransmitter release at synapses
C) It prevents the release of inhibitory neurotransmitters
D) It blocks sensory nerve transmission

Answer 22

Correct Answer: C) It prevents the release of inhibitory neurotransmitters
Rationale: Tetanospasmin blocks inhibitory interneuron discharge by cleaving synaptobrevin (VAMP2), leading to muscle spasms and autonomic disturbances.

Question 23

What is the most common initial symptom of generalized tetanus?
A) High fever
B) Trismus (lockjaw)
C) Seizures
D) Diarrhea

Answer 23

Correct Answer: B) Trismus (lockjaw)
Rationale: The facial and jaw muscles are often affected first due to their proximity to the central nervous system, leading to trismus.

Question 24

Which of the following is a life-threatening early manifestation of tetanus?
A) Sepsis
B) Laryngeal muscle spasm
C) Gastrointestinal stasis
D) Fever above 40°C

Answer 24

Correct Answer: B) Laryngeal muscle spasm
Rationale: Laryngeal spasm can cause airway obstruction, leading to respiratory failure, which is a leading cause of tetanus-related death.

Question 25

What is the gold standard for diagnosing tetanus? A) Serum anti-tetanus IgG measurement B) Wound culture for C. tetani C) Clinical diagnosis D) PCR for tetanus toxin genes

Answer 25

Correct Answer: C) Clinical diagnosis Rationale: Tetanus is diagnosed clinically based on characteristic symptoms; laboratory tests are only supportive and should not delay treatment.

Question 26

Which of the following antibiotics is preferred for tetanus treatment? A) Amoxicillin B) Metronidazole C) Doxycycline D) Ceftriaxone

Answer 26

Correct Answer: B) Metronidazole Rationale: Metronidazole is preferred as it effectively targets anaerobic C. tetani and minimizes further toxin production.

Question 27

How should tetanus spasms be managed? A) With benzodiazepines and IV magnesium sulfate B) With broad-spectrum antibiotics alone C) By using corticosteroids to reduce inflammation D) By administering tetanus vaccine

Answer 27

Correct Answer: A) With benzodiazepines and IV magnesium sulfate Rationale: Benzodiazepines (e.g., diazepam) and magnesium sulfate help control muscle spasms and autonomic dysfunction.

Question 28

When should a tetanus-prone wound be treated with both vaccination and passive immunization (TIG)? A) Only if the wound is deep B) If the last tetanus booster was >10 years ago and the wound is not clean C) Only if C. tetani is cultured from the wound D) If the wound is superficial and minor

Answer 28

Correct Answer: B) If the last tetanus booster was >10 years ago and the wound is not clean Rationale: Patients with uncertain or incomplete vaccination status and a high-risk wound should receive both tetanus toxoid and TIG.

Question 29

Why is natural tetanus infection not protective against future infections? A) Tetanus toxin does not induce an immune response B) The bacteria mutate frequently C) Immunity is lost after 6 months D) Tetanus toxin weakens the immune system

Answer 29

Correct Answer: A) Tetanus toxin does not induce an immune response Rationale: Tetanus toxin is poorly immunogenic, meaning natural infection does not provide immunity, so vaccination is still required.

Question 30

How long does it typically take for full recovery from tetanus? A) 1–2 weeks B) 2–3 weeks C) 4–6 weeks D) More than 6 months

Answer 30

Correct Answer: C) 4–6 weeks Rationale: Recovery is slow (4–6 weeks) because new neuronal connections must form to compensate for toxin-induced dysfunction.

Question 31

What is the typical incubation period of Clostridium tetani after wound infection? A) 24–48 hours B) 3–5 days C) 7–10 days D) 4–6 weeks

Answer 31

Correct Answer: C) 7–10 days Rationale: The incubation period for tetanus typically ranges from 7 to 10 days, although it can vary based on the site of infection and bacterial load.

Question 32

What is the first step in the pathogenesis of tetanus after wound infection? A) Direct bacterial invasion of the central nervous system B) Toxin uptake into the nervous system and cleavage of VAMP in inhibitory neurons C) Immediate onset of muscle spasms D) Toxin degradation by the immune system

Answer 32

Correct Answer: B) Toxin uptake into the nervous system and cleavage of VAMP in inhibitory neurons Rationale: Clostridium tetani releases tetanospasmin, which is transported retrogradely into neurons, where it cleaves VAMP (synaptobrevin), preventing GABA-mediated inhibition.

Question 33

What are the initial symptoms of tetanus that typically appear within 24–72 hours after toxin uptake? A) Severe muscle spasms and seizures B) Muscle aches, trismus (lockjaw), and myalgia C) Cardiovascular instability and respiratory failure D) Paralysis and loss of deep tendon reflexes

Answer 33

Correct Answer: B) Muscle aches, trismus (lockjaw), and myalgia Rationale: Early tetanus symptoms include muscle pain, stiffness, and trismus (lockjaw) due to toxin-mediated inhibition of inhibitory neurotransmitters.

Question 34

What is the primary cause of muscle spasms in tetanus? A) Direct bacterial invasion of muscles B) Activation of excitatory neurons by tetanus toxin C) Disinhibition of motor neurons due to loss of GABAergic control D) Increased acetylcholine release at neuromuscular junctions

Answer 34

Correct Answer: C) Disinhibition of motor neurons due to loss of GABAergic control Rationale: Tetanus toxin blocks GABAergic inhibition, leading to uncontrolled motor neuron activity and severe muscle spasms.

Question 35

Which of the following is a major autonomic disturbance seen in severe tetanus? A) Severe bradycardia only B) Labile blood pressure, tachycardia, or bradycardia C) Hypotension with shock D) Persistent fever with leukopenia

Answer 35

Correct Answer: B) Labile blood pressure, tachycardia, or bradycardia Rationale: Tetanus affects the autonomic nervous system, causing fluctuating blood pressure and abnormal heart rate (tachycardia or bradycardia).

Question 36

What happens in the final phase of tetanus recovery (after 4–6 weeks)? A) Toxin is degraded, leading to cessation of spasms and restoration of normal muscle tone B) Spasms persist indefinitely due to irreversible damage C) Cardiovascular instability worsens, requiring long-term support D) The immune system eliminates C. tetani, preventing future infections

Answer 36

Correct Answer: A) Toxin is degraded, leading to cessation of spasms and restoration of normal muscle tone Rationale: After 4–6 weeks, the toxin is metabolized, leading to the gradual resolution of muscle spasms and restoration of autonomic control.

Question 37

What is the primary cause of death in severe tetanus? A) Uncontrolled muscle contractions B) Bacterial sepsis C) Respiratory failure due to laryngeal spasms D) Stroke from excessive muscle strain

Answer 37

Correct Answer: C) Respiratory failure due to laryngeal spasms Rationale: Tetanus can cause laryngeal muscle spasms, leading to airway obstruction and respiratory failure, which is the most common cause of death.