Tetanus (Local)

Localised tetanus is a rare form of tetanus in which muscle spasms and rigidity are confined to the area near the site of injury, usually a single limb.[1-2] It is more common in individuals with partial immunity (e.g., primary childhood immunisation without subsequent boosters) and carries a favourable prognosis compared to generalised tetanus — but can progress to generalised disease if untreated, which carries significant mortality.[1-2]

1. History

• Port of entry: Identify the wound — puncture, laceration, abrasion, burn, crush injury, surgical wound, or injection site[2]
• Timing: Incubation period 3–21 days (median ~7 days); shorter incubation = worse prognosis[2-3]
• Symptom characterization: Muscle stiffness, spasms, or weakness localised to the injured limb or region; mild cases may present with weakness only[2]
• Progression: Ask about spread of stiffness/spasms beyond the injured area (suggests generalisation)[2]
• Triggers: Spasms exacerbated by auditory, tactile, or visual stimuli[1]
• Vaccination history: Number of doses, timing of last booster — critical for risk stratification[2][4]
• Important negatives: No trismus, no dysphagia, no generalised rigidity, no respiratory difficulty (these suggest generalisation)[2]

2. Alarm Features

• Trismus (lockjaw) — suggests cephalic or generalised progression[1-2]
• Dysphagia or voice changes — early sign of pharyngeal involvement[1]
• Respiratory compromise: dyspnoea, tachypnoea, apnoeic spells[1]
• Opisthotonus or generalised rigidity[1]
• Autonomic instability: labile BP, tachycardia/bradycardia, profuse sweating[1]
• Incubation period <7 days or period of onset <48 hours — poor prognostic indicators[2-3]
• Rapid spread of spasms beyond the injury site[2]

3. Medications

• Antibiotics: Metronidazole 500 mg IV q6–8h × 10 days (first-line); prevents local C. tetani proliferation[2]
• Alternative: benzathine benzylpenicillin or IV benzylpenicillin (note: penicillin is a non-competitive GABA-A inhibitor and theoretically may potentiate tetanus neurotoxin effects, though no clinical cases reported)[2]
• Antitoxin: Human tetanus immunoglobulin (HTIG) 500 IU IM — neutralises unbound circulating toxin[2]
• If HTIG unavailable: equine tetanus antitoxin (with intradermal test dose)[2]
• Spasm control: IV benzodiazepines (diazepam) — titrate to control spasms and produce sedation[2]
• Vaccination: Administer Td or Tdap 0.5 mL IM at a different site from HTIG; tetanus does not confer immunity, so a full vaccination course is required after recovery[1-2]
• Contraindicated: Avoid phenothiazines and metoclopramide (can cause dystonic reactions mimicking tetanus and confound diagnosis)[3]

4. Diet

• Localised tetanus without dysphagia: oral diet as tolerated
• If any dysphagia develops (suggesting progression): NPO, consider soft small-bore NG tube or parenteral nutrition[2]
• Adequate hydration is essential, especially if rhabdomyolysis is a concern[1]

5. Review of Systems

• Neurological: Jaw stiffness, difficulty opening mouth, neck stiffness, back pain, abdominal rigidity[1]
• Respiratory: Dyspnoea, sensation of chest tightness, difficulty breathing[1]
• GI: Dysphagia, reduced oral intake, abdominal pain/rigidity (can mimic acute abdomen)[1-2]
• GU: Urinary retention (autonomic dysfunction)[1]
• Constitutional: Fever (rare at presentation; if present, consider superinfection or alternative diagnosis)[1]
• Musculoskeletal: Pain, stiffness, or spasms in the affected limb[2]

6. Collateral History and Family History

• Vaccination records: Confirm childhood series completion and booster history; military service since 1941 suggests at least one dose[5]
• Wound circumstances: Soil/faecal contamination, gardening, farming, animal exposure[1-2]
• Injection drug use: High-risk portal of entry, associated with severe disease[1]
• HIV/immunosuppression status: Immunocompromised patients require HTIG regardless of vaccination history[2][4]
• Family history is generally not contributory for tetanus

7. Risk Factors

• Incomplete or absent vaccination — most critical risk factor[1-2]
• Older age (waning immunity)[1]
• Male sex[1]
• Domestic or gardening injuries, farming[1][6]
• Puncture wounds, crush injuries, burns, frostbite[2]
• Injection drug use[1]
• Immunosuppression (HIV, diabetes, chronic disease)[1-2]
• Rural residence in endemic areas[6]
• In 20–50% of cases, no obvious wound is identified[3]

8. Differential Diagnosis

• Strychnine poisoning: Virtually indistinguishable from tetanus; rapid onset (<30 min of ingestion); absence of tonic contraction between spasms; positive serum/urine assay[1]
• Drug-induced dystonia (phenothiazines, metoclopramide): Rapid onset, reversible with anticholinergics (procyclidine), absence of trismus[1][3]
• Hypocalcaemic tetany: Low serum calcium, absence of trismus or facial spasms[1]
• Neuroleptic malignant syndrome (NMS): Altered mental status (unlike tetanus where lucidity is preserved), very high CK, gradual onset[1]
• Stiff-person syndrome / PERM: Positive GAD and anti-glycine antibodies, rapid response to diazepam[1]
• Local wound infection / abscess: Localised pain and swelling without rigidity or spasms
• Compartment syndrome: Pain with passive stretch, swelling, neurovascular compromise
• For cephalic tetanus: stroke, Bell's palsy, myasthenia gravis, botulism[1]

9. Past Medical History

• Prior tetanus episodes (does not confer immunity — full revaccination required)[1]
• Vaccination history (most important element)[2]
• Diabetes, cardiovascular disease, immunosuppression — poor prognostic factors[2]
• Prior Arthus reaction to tetanus toxoid (delay revaccination >10 years)[4]
• Surgical history (recent colorectal surgery has been reported as a portal of entry)[2]

10. Physical Exam

• Vital signs: Tachycardia, hypertension, or labile BP suggest autonomic involvement and possible generalisation[1]
• Wound inspection: Identify and characterise the portal of entry; look for necrotic tissue, foreign bodies, signs of infection[2]
• Localised findings: Increased tone, rigidity, and/or spasms confined to the affected limb or region[2]

Assess for generalisation

• Trismus (inability to open mouth >2 finger-breadths)
• Risus sardonicus (sustained facial muscle spasm)
• Abdominal rigidity (board-like abdomen persisting between spasms)[1]
• Opisthotonus (late sign)[1]
• Neurological exam: Hypertonia, hyperreflexia, reduced power; sensory and cerebellar exam normal; consciousness preserved (obtundation suggests alternative diagnosis)[1]
• Respiratory assessment: Respiratory rate, accessory muscle use, ability to handle secretions[1]

11. Lab Studies

• CBC: Mild leukocytosis common; neutrophilia is a poor prognostic indicator[1]
• BMP/electrolytes: Rule out hypocalcaemia (tetany mimic); assess renal function[1-2]
• CK (creatine kinase): Elevated with rhabdomyolysis from spasms[1]
• CRP / procalcitonin: Moderate CRP elevation expected; marked rise suggests concurrent bacterial infection[1-2]
• Urinalysis: Assess for haematuria/myoglobinuria (proxy for rhabdomyolysis)[1]
• Magnesium: Baseline and monitoring if IV MgSO₄ used for autonomic dysfunction[1]
• Blood gas: Assess ventilation and acid-base status
• Tetanus antibody titre (ELISA): Titres >0.1 IU/mL make tetanus unlikely but do not exclude it; cases have been reported above protective thresholds[2-3]
• Wound culture / RT-PCR for C. tetani: Supportive but not confirmatory; C. tetani is difficult to culture and can be present in healthy individuals[1-2]
• Urine toxicology: If strychnine poisoning suspected[1]

12. Imaging

• Wound CT: May identify foreign bodies or gas locules supporting diagnosis[1]
• Neuroimaging (CT/MRI brain): Usually unnecessary; will not show acute parenchymal abnormalities in tetanus; useful to exclude stroke in cephalic tetanus[1]
• Chest X-ray: If respiratory compromise or aspiration suspected
• Imaging is generally unnecessary in straightforward localised tetanus[1]

13. Special Tests

• Modified Ablett Classification — most widely used severity grading system:[3] Export Grade Severity Features References 1 Mild Mild-moderate trismus, generalised spasticity, no spasms, no respiratory compromise[1]
• 2 Moderate Moderate trismus, marked rigidity, short spasms, RR >30, mild dysphagia[1]
• 3 Severe Severe trismus, prolonged reflex spasms, RR >40, apnoeic spells, HR >120[1]
• 4 Very Severe Grade 3 features + violent autonomic disturbances (labile BP, tachy/bradycardia)[1]
• Tetanus Severity Score (TSS): Includes age, dyspnoea, time from symptom to admission, comorbidities, entry site, BP, HR, temperature; sensitivity 77%, specificity 82% — outperforms Phillips and Dakar scores[2-3]
• Spatula test: Historically sensitive and specific but no longer recommended due to risk of precipitating laryngospasm[1]
• RT-PCR for C. tetani neurotoxin gene: Supportive adjunct[1]

14. ECG

• Indications: Obtain ECG in all suspected tetanus cases, especially if autonomic dysfunction is present[7-8]
• Findings: ECG abnormalities present in >93% of hospitalised tetanus patients in one series, despite normal echocardiography[7]

Patterns to recognise

• Sinus tachycardia (most common)
• Bradycardia (can alternate with tachycardia)
• Arrhythmias[8]
• ST-segment changes (Takotsubo cardiomyopathy — most common cardiovascular event, occurring in ~40% of cardiac events)[2][8]
• Heart rate variability (HRV): Reduced in tetanus patients compared to healthy individuals; further reduced in those with autonomic dysfunction (Ablett Grade 4 vs Grade 3)[9]
• Cardiovascular events occur from day 5 to 20 of illness and carry 21% mortality[8]

15. Assessment

• Localised tetanus is a clinical diagnosis characterised by muscle spasms and rigidity confined to the region of injury, typically in a patient with partial immunity.[1-2] Key clinical pearls:
• Rarely fatal in isolation, but the critical danger is progression to generalised tetanus if untreated[2]
• Localised tetanus may represent a low toxin load or an early feature of generalised disease[3]
• Diagnosis is challenging because it is rare and may present with only muscle weakness[1-2]
• No confirmatory laboratory test exists — diagnosis is clinical[2][10]
• Consciousness is preserved; altered mental status should prompt consideration of NMS, strychnine poisoning, or other diagnoses[1]
• Recovery takes 4–6 weeks as inhibitory neurotransmission must be restored through regeneration of axonal terminals[1]

16. Treatment Plan

Initial stabilisation

• Ensure airway patency; have intubation equipment at bedside[2]
• Place patient in a quiet, darkened environment to minimise stimulus-triggered spasms[1-2]

Pharmacotherapy

• HTIG 500 IU IM (at a different site from vaccine)[2]
• Tdap or Td 0.5 mL IM — initiate active immunisation series[2]
• Metronidazole 500 mg IV q6h × 10 days[2]
• Diazepam IV — titrate to control spasms[2]
• Wound debridement if necrotic tissue present[2]

If progression to generalised disease

• ICU admission with mechanical ventilation capability[2]
• Magnesium sulfate or labetalol for autonomic dysfunction[2]
• Neuromuscular blocking agents for refractory spasms[10]
• DVT prophylaxis with heparin[2]
• Nutritional support via NG tube or central line[2]
• Bedside physical therapy[2]

Discharge planning

• Administer additional dose of Td/Tdap before discharge[2]
• Complete full vaccination series (tetanus does not confer natural immunity)[1-2]
• Supportive psychotherapy may be needed[2]

17. Disposition

• Admit all suspected tetanus cases, even localised forms — early ICU admission should be considered given the risk of generalisation[1]
• ICU admission criteria: Any respiratory compromise, dysphagia, generalised spasms, autonomic instability, Ablett Grade ≥2[1][3]
• Observation: Localised tetanus without alarm features may be monitored on a step-down unit with ICU capability, but close monitoring is essential
• Specialist consultation: Infectious disease, critical care/intensivist, surgery (for wound debridement)[2]
• Discharge criteria: Resolution of spasms, stable vitals, ability to tolerate oral intake, completion of initial treatment course, vaccination plan in place[2]

18. Follow Up / Return Precautions

• Follow-up timing: Close outpatient follow-up within 1 week of discharge; physical therapy referral[2]
• Complete vaccination series: Return for additional Td/Tdap doses at 1 month and 1 year after initial dose[5]

Return immediately for

• Spread of stiffness or spasms beyond the original area
• Jaw stiffness or difficulty opening mouth
• Difficulty swallowing or breathing
• Fever, sweating, or palpitations
• Expected recovery: Protracted; 4–6 weeks for neurotransmission restoration; convalescence may be prolonged with potential long-term neurological sequelae[1][4]
• Key counselling point: Tetanus infection does not confer immunity — full vaccination is mandatory to prevent recurrence[1-2]

References

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

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

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

4. Prevention of Pertussis, Tetanus, and Diphtheria With Vaccines in the United States: Recommendations of the Advisory Committee on Immunization Practices (ACIP). — Liang JL, Tiwari T, Moro P, et al. MMWR. Recommendations and Reports : Morbidity and Mortality Weekly Report. Recommendations and Reports. 2018.

5. FDA Drug Label. — Updated date: 2010-10-28. Food and Drug Administration.

6. 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.

7. Maternal and Neonatal Tetanus. — Thwaites CL, Beeching NJ, Newton CR. Lancet. 2015.

8. 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.

9. 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.

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