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]
- Antitoxin: Human tetanus immunoglobulin (HTIG) 500 IU IM — neutralises unbound circulating toxin [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 ClassificationLancet[3]
- 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
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16. 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.
17. 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.
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