🦠 Tetanus: Lockjaw, Spasms, and the Power of Prevention

Tetanus is a classic board question because it combines microbiology, neurophysiology, immunization schedules, and emergency management—all highly testable.

USMLE Buzzwords: “Lockjaw” + puncture wound + risus sardonicus = Tetanus

🦠 Etiology & Pathogenesis

• Caused by Clostridium tetani, an anaerobic, spore-forming gram-positive rod

• Found in soil, enters via puncture wounds or contaminated injuries

• Produces tetanospasmin, a neurotoxin that blocks inhibitory neurotransmitters (GABA, glycine)

• Leads to sustained muscle contraction (spastic paralysis)

😬 Clinical Features

Sign/Symptom	Description
Trismus	Lockjaw—difficulty opening the mouth
Risus sardonicus	Facial muscle spasm causing a grimace
Opisthotonos	Rigid arching of the back
Muscle spasms	Severe spasms triggered by stimuli
Dysphagia	Difficulty swallowing due to muscle rigidity
Autonomic instability	BP lability, tachycardia, arrhythmias

🧪 Diagnosis

• Clinical diagnosis—no reliable toxin assays

• History of trauma, inadequate immunization, no booster in >10 years

• No sensory loss (unlike botulism), and patient is fully alert

💉 Management & Prevention

Scenario	Action
Active tetanus	Supportive ICU care, metronidazole, TIG, benzodiazepines
Wound prophylaxis	Clean wound, update Tdap based on immunization history
Vaccine schedule	DTaP series in childhood, Tdap at age 11, Td every 10 years
Pregnancy	Tdap between 27–36 weeks every pregnancy

🩹 Tetanus Wound Prophylaxis Chart

Immunization History	Clean Minor Wound	Dirty Wound
≥3 doses, <5 years	No vaccine needed	No vaccine or TIG needed
≥3 doses, >5 years	Give Tdap if >10 years	Give Tdap if >5 years
<3 doses or unknown	Tdap + TIG	Tdap + TIG

📚 Sample USMLE Vignette

A 34-year-old male presents with jaw stiffness and back spasms after stepping on a nail. He is alert but has not received a tetanus booster in 15 years. Diagnosis?

✅ Answer: Tetanus → treat with metronidazole + TIG + supportive care

📲 Call to Action

🧪 Boost your immune system—and your score.

📲 Download the King of the Curve App for:

• Infection-based case reviews

• Vaccine guidelines flashcards

• Step 1 microbiology tables

• Curve Coins and timed quizzes

---

---

Frequently Asked Questions (FAQs)

• How many hours should I study for the MCAT each day?

  Aim for 4-6 focused hours, ensuring you incorporate breaks to avoid burnout.

• What is the best way to handle test anxiety?

  Practice mindfulness techniques, take practice exams under realistic conditions, and maintain a balanced lifestyle.

• How can I stay motivated during the long application process?

  Set short-term goals, seek support from mentors, and reward yourself for small achievements.

• What role does exercise play in MCAT preparation?

  Regular exercise improves focus, reduces stress, and enhances overall mental clarity.

• How does King of the Curve help with MCAT preparation?

  KOTC offers personalized learning tools, gamification features, and adaptive question banks to help students stay on track without burnout.