Tetanus

Tetanus is a life-threatening, vaccine-preventable neurological disease caused by the neurotoxin of Clostridium tetani, characterized by muscle spasms, rigidity, and autonomic dysfunction. It is a medical emergency requiring ICU-level care.[1-2]

1. History

• Port of entry: Ask about recent wounds (puncture, crush, burns, abrasions), dental procedures, otitis media, surgical wounds, injection drug use, or umbilical stump care (neonates)[1][3]
• Incubation period: Time from injury to first symptom — typically 3–21 days; shorter incubation (<7 days) = worse prognosis[3-4]
• Period of onset: Time from first symptom to first spasm — ≤48 hours indicates poor prognosis[4]
• Symptom progression: Jaw stiffness → neck stiffness → dysphagia → truncal rigidity → generalized spasms (cephalocaudal progression)[2-3]
• Triggers: Spasms worsened by loud noises, bright lights, and physical touch[1-2]
• Vaccination history: Number of primary doses, date of last booster — critical for risk stratification. Tetanus can occur even in partially vaccinated individuals[3]
• Important negatives: Preserved consciousness (lucidity is maintained in tetanus; altered mental status suggests alternative diagnosis)[2]
• In 20–50% of cases, no obvious wound is identified[4]

2. Alarm Features

• Respiratory compromise: Dyspnoea, apnoeic spells, laryngospasm — risk of airway obstruction and respiratory arrest[2-3]
• Rapid symptom evolution: Short incubation period (<7 days) and period of onset (≤48 hours)[4]
• Generalized spasms with opisthotonus[2]
• Autonomic dysfunction: Labile blood pressure, tachycardia alternating with bradycardia, profuse sweating, fever — most feared complication and leading cause of death[2]
• Cardiovascular events: Takotsubo cardiomyopathy (most common cardiac complication), arrhythmia, sudden cardiac arrest — occur days 5–20 of illness[3][5]
• Rhabdomyolysis from prolonged spasms → myoglobinuria → acute kidney injury[2-3]
• Rigid abdomen mimicking acute surgical abdomen — reported cases of unnecessary laparotomy[2-3]

3. Medications

Treatment medications

• Human tetanus immunoglobulin (hTIG): 500 IU IM (single dose); equine antitoxin if hTIG unavailable (test dose first)[2-3]
• Metronidazole: 500 mg IV q6–8h for 10 days — first-line antibiotic[3]
• Benzodiazepines (diazepam, midazolam): IV for spasm control and sedation — titrate to effect[3]
• Magnesium sulfate: For autonomic dysfunction and adjunctive spasm control[3-4]
• Neuromuscular blocking agents: For refractory spasms in intubated patients[1]
• Labetalol: For sympathetic hyperactivity[3]
• Tetanus toxoid vaccine (Td or Tdap 0.5 mL IM): Administer at different site from hTIG[3]

Medication cautions

• Penicillin: Non-competitive GABA-A inhibitor — can theoretically potentiate tetanus neurotoxin effects and cause seizures; metronidazole preferred[3]
• Avoid short-acting antihypertensives that may cause rebound hypotension in dysautonomia
• Prophylactic heparin for VTE prevention during prolonged immobility[3]

4. Diet

• NPO initially if significant trismus or dysphagia (aspiration risk)[2]
• Enteral feeding via soft, small-bore nasogastric tube or central venous catheter for nutrition[3]
• High caloric needs due to sustained muscle contractions and hypermetabolic state
• Adequate hydration critical — rhabdomyolysis risk requires aggressive IV fluid resuscitation

5. Review of Systems

• HEENT: Trismus (lockjaw), dysphagia, voice changes, risus sardonicus[2]
• Respiratory: Dyspnoea, apnoeic spells, stridor (laryngospasm)[2-3]
• GI: Abdominal rigidity/pain (can mimic acute abdomen), reduced oral intake[2-3]
• GU: Acute urinary retention (autonomic dysfunction)[2]
• Neuro: Back pain, muscle stiffness, spasms, preserved consciousness[2]
• Autonomic: Sweating, labile blood pressure, tachycardia, fever[2]

6. Collateral History and Family History

• Vaccination records: Verify with primary care or immunization registry — critical for management decisions[3][6]
• Injection drug use history: Subcutaneous ("skin popping") or IM injection of street drugs, particularly heroin, is a major risk factor; outbreaks linked to contaminated heroin[2][4]
• Occupational/environmental exposure: Farming, gardening, soil contact[2]
• Immigration/refugee status: Patients from regions with poor vaccination infrastructure[3]
• Family history is not directly relevant (tetanus is not hereditary and not contagious)[3]

7. Risk Factors

• Undervaccination or unvaccinated status — most important risk factor[1]
• Older age (>65 years): Waning vaccine-induced immunity; born before universal vaccination programs[1-2]
• Injection drug use: Especially subcutaneous injection; contaminated heroin[2][4]
• Diabetes mellitus: Infected extremity ulcers; lower antitetanus antibody levels[2-4]
• Immunosuppression (HIV, immunosuppressive therapy)[3][6]
• Wound type: Puncture wounds, crush injuries, burns, chronic wounds, devitalized tissue[1][3]
• Male sex[2]
• Domestic/gardening injuries[2]
• Post-surgical patients with necrotic infections, septic abortions[3]
• Conflict/disaster zones disrupting vaccination programs[4]

8. Differential Diagnosis

• Export Diagnosis Distinguishing Features Refs Strychnine poisoning Virtually indistinguishable; rapid onset (30 min of ingestion); absence of tonic contraction between spasms; positive serum/urine assay[1]
• Neuroleptic malignant syndrome (NMS) Altered mental status; very high CK; gradual onset; medication history (antipsychotics)[1]
• Drug-induced dystonia Reversible with anticholinergics (procyclidine); absence of trismus; medication history (phenothiazines, metoclopramide)[1-2]
• Hypocalcemic tetany Low serum calcium; absence of trismus or facial spasms; rapid response to diazepam[1]
• Stiff-person syndrome / PERM Positive GAD and anti-glycine antibodies; altered mental status and seizures common[1]
• Meningitis/encephalitis Altered mental status; CSF abnormalities; seizures[1]
• Peritonitis/acute abdomen Abdominal rigidity from tetanus can mimic surgical abdomen — key pitfall[1, 3]
• Cephalic tetanus mimics Brainstem stroke, Bell's palsy, myasthenia gravis, botulism[1]
• Key distinguishing feature of tetanus: Preserved consciousness with trismus, rigidity, and stimulus-provoked spasms.[2]

9. Past Medical History

• Vaccination history (most critical element) — including childhood series and booster dates[1][3]
• Prior tetanus infection (does not confer immunity — full re-vaccination required)[2]
• Diabetes mellitus, HIV/AIDS, immunosuppressive conditions[3][6]
• Chronic wounds or ulcers
• History of injection drug use[2][4]
• Recent surgery, dental procedures, or trauma[3]

10. Physical Exam

Vital signs

• Tachycardia (HR >120 bpm in severe disease)[4]
• Labile blood pressure (hypertension alternating with hypotension)[2][4]
• Tachypnoea (RR >30–40)[4]
• Fever (often absent at presentation; if present early, consider alternative diagnosis or superinfection)[2]

Focused exam

• Trismus (lockjaw): Inability to open mouth — present in 93–98% at admission[2][4]
• Risus sardonicus: Sustained facial muscle spasm producing a grimacing smile[2]
• Opisthotonus: Extreme back hyperextension (late sign, now less common)[2]
• Abdominal rigidity: Board-like abdomen persisting between spasms[2]
• Bilateral hypertonia with superimposed spasms, hyperreflexia, reduced power[2]
• Sensory and cerebellar exam: Normal[2]
• Mental status: Alert and lucid (obtundation = consider NMS or other diagnosis)[2]
• Wound inspection: Identify port of entry; assess for devitalized tissue, foreign bodies[3]
• Dysphagia assessment: Pharyngeal spasm → aspiration risk[2]

11. Lab Studies

Recommended initial labs

• CBC (mild leukocytosis common; neutrophilia = poor prognostic indicator)
• BMP (electrolytes, BUN, creatinine — assess for AKI)
• Creatine kinase (elevated from sustained muscle contraction; monitor for rhabdomyolysis)
• CRP and procalcitonin (moderate CRP elevation expected; marked rise suggests concurrent bacterial infection)
• Urinalysis (haematuria as proxy for myoglobinuria → rhabdomyolysis screening)
• Calcium, magnesium, phosphorus (rule out hypocalcemic tetany; monitor Mg during replacement)
• Liver function tests
• Blood gas analysis
• Serum/urine strychnine assay if poisoning suspected[2]
• No confirmatory lab test exists for tetanus — diagnosis is clinical.[1][3] Wound cultures have limited utility (C. tetani is difficult to culture and can be present in normal flora).[3] RT-PCR for C. tetani neurotoxin gene can provide supportive information.[2]

12. Imaging

• Wound CT: May identify foreign bodies or gas locules at wound site[2]
• Neuroimaging (CT/MRI brain): Usually unnecessary; consider only if differential includes stroke, encephalitis, or PRES[2]
• Lumbar puncture: CSF is normal in tetanus; perform only if meningitis is suspected[3]
• Chest X-ray: Baseline and for aspiration pneumonia surveillance
• Echocardiography: If cardiovascular instability — screen for Takotsubo cardiomyopathy (most common cardiac complication, occurring in ~40% of cardiovascular events)[3][5]

13. Special Tests

Severity scoring systems

Modified Ablett Classification (most widely used)

• Grade 1 (Mild): Mild trismus, generalized spasticity, no spasms, no respiratory compromise
• Grade 2 (Moderate): Moderate trismus, marked rigidity, short spasms, RR >30
• Grade 3 (Severe): Severe trismus, prolonged reflex spasms, RR >40, apnoeic spells, HR >120
• Grade 4 (Very severe): Grade 3 features + violent autonomic disturbances (labile BP, tachycardia/bradycardia)
• Tetanus Severity Score (TSS): Includes age, dyspnoea, time to admission, comorbidities, entry site, BP, HR, temperature — sensitivity 77%, specificity 82%; outperforms Phillips and Dakar scores[3-4]
• Spatula test: Previously used (touching posterior pharynx → jaw spasm instead of gag reflex) — no longer recommended due to risk of precipitating laryngospasm.[2]
• Heart rate variability (HRV): Emerging tool via wearable ECG devices; inversely related to disease severity and associated with autonomic dysfunction.[7-8]

14. ECG

• Sinus tachycardia: Most common finding, especially in severe disease[2][4]
• Labile heart rate: Alternating tachycardia and bradycardia reflecting autonomic instability[2][4]
• Arrhythmias: Reported in ~19% of cardiovascular events[5]
• ST-segment changes / T-wave inversions: May indicate Takotsubo cardiomyopathy or catecholamine-mediated myocardial injury[3][5]
• Reduced heart rate variability: Correlates with disease severity and autonomic dysfunction[7-8]
• Continuous telemetry is essential — sudden cardiac arrest accounts for ~16% of cardiovascular events[5]

15. Assessment

• Tetanus is a clinical diagnosis based on the triad of trismus, muscle rigidity, and stimulus-provoked spasms in a patient with a compatible exposure history and inadequate vaccination.[1-3] There is no confirmatory laboratory test.
• Severity stratification using the modified Ablett classification guides ICU management, though early ICU admission should be considered even for mild disease given the risk of rapid deterioration.[2][4]
• Typical presentation: Trismus → neck stiffness → dysphagia → truncal rigidity → generalized spasms (cephalocaudal progression) over hours to days.[2-3] Atypical presentations include isolated rigid abdomen (mimicking surgical abdomen), cephalic tetanus (mimicking stroke or Bell's palsy), and localized tetanus confined to an injured limb.[2-3]
• Complications to anticipate: Laryngospasm/respiratory failure, autonomic dysfunction (days 5–20), Takotsubo cardiomyopathy, rhabdomyolysis/AKI, nosocomial infections (pneumonia, line infections), VTE from prolonged immobility, and PRES.[2-3][5]

16. Treatment Plan

Initial stabilization (ED)

• Airway: Ensure ventilation; prepare for early intubation if laryngospasm, severe trismus, or respiratory compromise[2-3]
• IV benzodiazepines (diazepam or midazolam) for immediate spasm control[3]
• Quiet, dark environment — minimize stimuli[1][3]

Definitive treatment (ICU)

• hTIG 500 IU IM (single dose) — neutralizes circulating unbound toxin; administer at different site from vaccine[2-3]
• Tetanus toxoid vaccine (Td or Tdap 0.5 mL IM) — regardless of prior vaccination status[3]
• Metronidazole 500 mg IV q6h × 10 days — first-line antibiotic to stop toxin production[3]
• Wound debridement — remove necrotic tissue to eliminate anaerobic environment[3]
• Titrate benzodiazepines for ongoing spasm control and sedation[3]
• Neuromuscular blocking agents (e.g., vecuronium) for refractory spasms in intubated patients[1]

Autonomic dysfunction management

• Magnesium sulfate IV or labetalol for sympathetic hyperactivity[3]
• Arterial line and invasive hemodynamic monitoring[3]
• Vasopressors (dopamine, norepinephrine) for hypotensive episodes[3]

Supportive care

• Enteral feeding via NG tube[3]
• DVT prophylaxis with heparin[3]
• Bedside physical therapy[3]
• Taper benzodiazepines over 14–21 days as spasms diminish[3]

Pre-discharge

• Administer additional dose of Td/Tdap vaccine[3]
• Complete full vaccination series post-recovery[2]
• Physical therapy and psychotherapy referral[3]

17. Disposition

• All suspected tetanus cases require ICU admission — even mild (Ablett Grade 1) disease can rapidly deteriorate[2-3]
• Median hospital stay: 22–30 days; severe cases may require weeks of mechanical ventilation[9-10]
• Mechanical ventilation required in 65–90% of severe cases (Ablett Grade 3–4)[9-10]
• Specialist consultation: Critical care/intensivist, infectious disease, surgery (wound debridement), neurology if diagnostic uncertainty
• Tetanus is not contagious — no isolation precautions required beyond standard precautions
• Mortality: ~13% in tertiary centers with ICU access; significantly higher without mechanical ventilation[4][10]

18. Follow Up / Return Precautions

• Complete the full tetanus vaccination series after recovery (natural infection does not confer immunity)[2]
• Physical rehabilitation: Begin as early as possible once spasms resolve; recovery of inhibitory neurotransmission takes 4–6 weeks[2-3]
• Psychotherapy: Many patients require supportive psychotherapy after prolonged ICU stay[3]
• Expected recovery: Protracted but most patients achieve full functional recovery with sustained ventilatory support[2]
• Return precautions: Seek immediate care for recurrence of muscle stiffness, jaw tightness, difficulty swallowing, or breathing difficulty
• Wound care education: Proper wound cleaning and timely tetanus prophylaxis for future injuries[3]
• Booster schedule: Td/Tdap every 10 years lifelong[3]

References

1. What Is Tetanus?. — Zhou S, Malani P. The Journal of the American Medical Association. 2026.

2. Tetanus: Recognition and Management. — Sudarshan R, Sayo AR, Renner DR, et al. The Lancet. Infectious Diseases. 2025.

3. Tetanus. — Ergönül Ö, Kolsuz S, Figueroa JP. Lancet. 2026.

4. Tetanus. — Yen LM, Thwaites CL. Lancet. 2019.

5. Magnitude, Patterns, and Associated Predictors of Cardiovascular Events in Tetanus: A 2-Year, Single-Center, Ambidirectional Cohort Study Involving 572 Patients. — Pham OKN, Tran BN, Duong MC, et al. Open Forum Infectious Diseases. 2023.

6. The Survivor: A Clinical Case of Tetanus in a Non-Immunized, Parenteral Drug User, Former Female Convict With HIV and HCV. — Vicente-Alcalde N, Martín-Casquero T, Ruescas-Escolano E, Tuells J. Vaccines. 2020.

7. Heart Rate Variability as an Indicator of Autonomic Nervous System Disturbance in Tetanus. — Duong HTH, Tadesse GA, Nhat PTH, et al. The American Journal of Tropical Medicine and Hygiene. 2020.

8. Heart Rate Variability Measured From Wearable Devices as a Marker of Disease Severity in Tetanus. — Hai HB, Cattrall JWS, Hao NV, et al. The American Journal of Tropical Medicine and Hygiene. 2024.

9. Management and Outcome of Adult Generalized Tetanus in a Chinese Tertiary Hospital. — An Y, Guo Y, Li L, et al. Frontiers in Public Health. 2023.

10. Management and Outcome of Adult Generalized Tetanus Patients in a Tertiary Hospital in Anhui, China: A Retrospective Study. — Huang J, Cai E, Ding W, et al. Frontiers in Public Health. 2025.